MadModder
Gallery, Projects and General => Project Logs => Topic started by: Darren on November 09, 2008, 08:05:17 PM
-
As promised here is a picture of the valve that I'm designing a base for. In the picture you can see some bases and top caps that I made over a year ago.
I decided that for the final build of my amplifier I need something with a more "engineered" look as well as function.
More pic's coming soon, this is just a teaser....... ;D
-
Nice Darren. :thumbup:
Now I've familar with tubes, but you got me on this one. What does it do or supposed to do? ???
By the way. Welcome to Madmodder.
regards,
Bernd
-
It does this
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_7490600.jpg?t=1226280656)
Part of my music hobby...this is a test build just to get the circuit right. It worked so well it stayed like this for almost a year, then I moved.
That was over a year ago and what with renovations etc I'm only just opening up the boxes again.
-
Wow Darren. I am impressed! That is definitely one of the styles I like. Care to elaborate more on this? I would love to learn some audio stuff.
Eric
-
Hi guys,
Well to go into it deeply would be a whole new subject, simply I build valve amps for stereo hifi reproduction. Been doing it a while and this valve is one of the "Big Boys"
It's an 833 triode, operating voltage in this picture is 1,100 Volts DC, DC is far more dangerous than AC btw. It produces a glorious sound that has to be heard to appreciate fully.
Ok, so what have I been doing in respect to this, and what does it have to do with forum. Well as I said earlier I've been making some new bases for the valve. It needs something to make it stand up and somewhere to connect the cables to.
I found this forum after I'd started so the pics are a little jumbled. I'll put some info up bit by bit as I sort some photo's and all will be revealed slowly.
Everything in this mini-project is machined from a 20mm 303 stainless bar.
The thumbscrews------------In this pic I'm putting a chamfer on, initially I mounted these on a 6mm thread held in the lathe collet. But it didn't go too well as the thread wasn't quite central. I think this is just the way it goes with threading. So here I'm doing it again but holding the part on a shoulder instead. Worked perfectly.
You can see another on the spindle nose to get a better idea.
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_9813.jpg?t=1226281490)
-
The Pillar.........
In the background is a prototype that I'm making more of in the lathe. I'm making them back to back as this makes holding them easier and there is little waste this way.
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_9820.jpg?t=1226283205)
Here you can see I'm marking the bars with the cutoff tool. In the collet is a collet depth stop. This enables me to mark the bar, change the workpiece and mark another bar in exactly the same place. Makes my life easier as I had four to do and two marks on each end making eight marks altogether.
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_9824.jpg?t=1226283502)
Here you can see a length of 20mm SS bar in the milling machine. I'm using a center finder that arived in the post only yesterday, so first time out with this one.
It's so simple yet it works very well.
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_9814.jpg?t=1226283099)
-
Now I need to put some flats on the ends of those two bars. I could do this in the mill, but, my mill is not so clever and I can't hold the cutters that I have left in it !!
No matter we can use the lathe instead.
Here you can see several things going on, the 1" cutter is being centered in the 4 jaw chuck with a dial gauge, the workpiece is being held in a tool holder that just happened to be the right size. To the right of the tool holder you should just be able to make out a square...
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_9827-1.jpg)
Having marked the bars previously with the parting off too gave me a clear indication of where to mill to.
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_9828-1.jpg)
And now for the other side, squaring it up with, well urm a square....
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_9832-1.jpg)
Almost done
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_9835-1.jpg)
There, that's that job done
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_9837-1.jpg)
Darren
-
Hi Darren,
Well I like what your doing even if I haven't a clue about these valve thingys ???
I've heard of valves and even seen old footage of them in various things.... Well pre-birth date! So I'll see if I can't pick up a little knowledge along the way ;D
I'm going to have to e blag some stuff in order to get the together to purchase an E36 collet set for my mill and a 5c collet set and chuck for my lathe.... It's no good I just really think these items will make my machining more interesting and occasionally less frustrating! (Tool variants do my nut in... I have some metric and some imperial and can't hold all with the MT3 collets that I have!)
I do like that centre finder do-dad I've seen them advertised etc but never knew that was their use.... Never really investigated though either!
To finish my little blathering... I'll just say this. I'm glad your posting and look forward to seeing what you make and learning a little on the way :thumbup:
Ralph.
-
Ralph, blather away by all means. It can be a lonely hobby otherwise...
TBH it's nice to be able to share, I've done very little of this sort of stuff but do enjoy it. No idea if I'm doing it right or wrong ??? Like I said before I'm learning as I'm going along.
If you have any tips please fire away.
I used the 4 Jaw cos I didn't have a 1" collet, milled at approx 460RPM and I've been turning the bars at 1800 RPM. That seems to be the sweat spot.
For the life of me I can't get a good finish on steel, Stainless is great. Turn it and it's done, OK maybe a quick run over with a Scotchpad and it looks really nice.
Brass of course is easy, I tend to turn that at 3000RPM with high feed speeds too.
Plastic is cheap and nice to use, esp for prototypes.....
If you can afford it you should seriously consider a collet set-up. They are a dream to use compared to a chuck for smaller items. The runout is almost non existent, even if you take the work out, rotate it and put it back
Darren
-
OK for those interested a little tutorial for you.... ;D
The valve I'm making the bases for is what's known as a triode (as in three elements) Simply it's an amplifying device that amplifies the flow of voltage/current which is the flow of electrons. (electricity, voltage=pressure/current=flow)
(http://www.localhistory.scit.wlv.ac.uk/Museum/Engineering/Electronics/history/triode2.jpg)
We have a heater which we typically connect to a low voltage of around 6.3V, though this can vary from valve to valve. This heats the cathode which is sitting at a negative DC voltage potential. The anode is sitting at the positive DC potential. (voltage potential typically 250-500V DC)
Point to note, electrons move from negative to positive and not the other way around as most people believe. This is important.
Our heater heats up the cathode, this makes the electrons become a little excited and thus easier to leave the cathode. Some will hover around and just off the cathode, this is called the "space charge"
Now, opposites attract, and equals repel, remember that girl from school?
Electrons are no different, they want to flow across the vacuum inside the glass envelope and hurtle towards the positive anode, bit like us young men on our first date ;D
We need to control these electrons into some sort of order, Slow them down a bit if you like.
We do this by applying a negative low voltage on the grid, typically 60-100 volts, but can be as low as 1 or 2 volts. If we increase the negative voltage (more negative) the flow of electrons will slow from the cathode to the anode (equals repel), if we make the grid more positive more electrons will flow.
So there we have it, we have a low voltage controlling a much larger voltage,
Now imagine that the low voltage is coming from your CD player output.......music modulates, so we have a negative voltage modulating the grid of the valve which in turn modulates the higher voltage flow and thus amplifies a low signal into a much larger one.
I hope you can follow that? It sounds complicated, but it's really very simple :thumbup:
Darren
-
And then came the transistor! ;D
I should have know what you were talking about Darren. A long time ago I took a home course on electronics. It started out with the triode tube and advanced to the transistor. I now know what you are doing.
Bernd
-
Transistors, is swearing allowed on here ;D
OK, they are good for general circuitry, better than valves......but, for music they just so harsh, give me a valve any day ;D
Ok not much done today on these bases, but here's a pic all the same.
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_9838-1.jpg)
-
Transistors, is swearing allowed on here ;D
Sorry about that Darren. :-[ Didn'y know I was swearing. :bugeye: ;D
Yes, so I've heard that the tubes make a better amplifier for music for the true audiophile. :thumbup:
Bernd
-
Oh I'll prob be doing some "technical" swearing myself as time goes by....
Be sure to correct me too Bernd ;D
-
Hi Darren,
Seeing as it isn't your first hobby, you are doing great on what you have done already.
If these bits are going on public view when working, I would suggest you have a few lessons from Ralph, he can get plain bits of metal looking like works of art, and would compliment your artwork with glass.
So going by your replies to Bernd, 'a pile of dog transistors' is swearing?
Nice terminology.......... 'Holy transistors!'.
Yep, that could be put to good use in the right context. Well, that gets around the swearing rule on this site, now what's next? Capacitors?, thyristors sounds good, or maybe a little bit of resistance now and again.
All in fun BTW.
John
-
That looks good Dave, a lot of people really favor these Boxfords from what I can tell.
Alas I have an ambitious project in mind for the future in that I wish to turn a new 12" or even 13" platter for my record player.
On those lines I'm thinking a Colchester Student for example, I also wish to turn 30mm S bars up to around 300 or 400mm long and drill and tap the ends.
I can do the last bit on my S&B if the new lathe isn't able.
I know from experience, that I want the next lathe purchase to be my last, famous last words.
Thanks John, I will speak to Ralph hopefully face to face sometime. I have been playing with metal for a long time.
It's the machining/engineering that's new to me...loving it though.
Did you see the link to my now very old web site? http://homepage.ntlworld.com/darren.dean/index.htm
-
"House work" today was clearing ground at the top of a high and very steep ground against a wall for preparation to planting a hedge. 100 Copper beach in this case.
Is that modding?
Ok, so taking a break from that this evening I thought that it was about time I got back to my amplifier build.
Tonight I laid out the various pieces on top of a chassis box.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0386.jpg)
At the back is the output transformer. Upside down in this instance. This connects the circuit to the speakers. One speaker in this case as these chassis are built as a pair in the form of two mono blocks for stereo reproduction.
At the front is the valve secured by the parts I've been working on in previous posts.
The orange wire is just stopping the valve from falling over. These fittings will be secured with a 6mm bolt from underneath. They will need electrically isolating from the chassis so I'm thinking of making "top hats" to facilitate the insulation. They will be subjected to some high temperatures, enough to singe wood so the top hats will be fabricated from Teflon rod as seen in the pictures.
A closer view
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0387.jpg)
And one from the side showing more detail.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0390.jpg)
Transformer the right way up
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0391.jpg)
Now then, I need to cut a hole in the chassis for the transformer connecting wires. I have a hole punch as shown in this picture, but it's a little small. I need to be careful here as the highest voltage is 1,200 volts DC. So a clearance gap from the connection to the chassis needs to be large enough for the voltage not to be able to jump the across. The hole punch is 50mm and I need a min of 55mm. 60mm would be better and tidier.
The chassis is 1.25mm thick steel and is hard work for a hole punch which can cause distortion, otherwise I would make one the correct size.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0392.jpg)
So I'm thinking of purchasing a Bi-metal hole saw of the correct size required.
But maybe someone here can suggest another way? I'd like the result to be tidy, spose that goes without saying.
-
Have you ever heard of a "tree panning" tool? I think that's the American name for it. It's used to cut out holes in wood if the hole is bigger than the biggest drill you can get and also to make wooded wheels.
I know I've got several. I'll go look and update this post when I find them.
Bernd
-
Do you mean something like this Bernd?
http://cgi.ebay.co.uk/1-New-Hole-Saw-Kit-Adjustable-Metal-2-pc-Circle-Cutter_W0QQitemZ190275185971QQcmdZViewItemQQptZUK_Home_Garden_PowerTools_SM?hash=item190275185971&_trksid=p3286.c0.m14&_trkparms=66%3A3|65%3A7|39%3A1|240%3A1318
Cheap enough, but are they ok with steel, those blades look like they would snap at the slightest provocation.
Saved a pic for future ref when the auction has long gone !!
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/6368_1.jpg)
-
Darren,
I have some of those hole punches up to about 3", but as you say, at the thickness you are working with, they are very hard work. RS do a range of all sorts of sizes and shapes, but are rather expensive.
The hole saw method would be favourite, but stick with a good quality one if drilling thru steel, the cheaper ones have a tendancy to go blunt rather quickly. The Starrett range, to me, are the better end of the bunch for general steel drilling work.
But you will need to make sure you have a very rigid setup for the plate holding as they can be rather fierce on start up and break through.
The trepanning tool will work, but you have to take it v-e-r-y steady, and use only a fine feed down handle, a normal drill press handle will be putting you in the 'trouble area', and could easily break the tip off or rip the cut off centre, especially as you are breaking through. That system is very flexible for sizing, but a bad 'not very rigid' design.
You could easily make a more rigid trepanning system yourself, if you were doing a fair amount of the same size. Base it around a flycutter design but rather than an angled base, have it flat on the bottom with a rigidly fixed robust cutter in a fixed position for the job.
John
-
Hi Darren
Another way to open the hole out would be to mount it on a face plate up against a sacrifical plate and just bore it out, the technique has been shown elsware on MODMODDER I think it was Bernd who posted it, but I stand to be corrected on this.
Have Fun
:wave:
Stew
-
Darren,
Yes, that is what I was thinking about. I said for cutting wood because it would give an idea of approximatley what I was suggesting. Bog's has elaborated further on this.
Stew has another idea which I think would work if it is possible to mount the plate on a faceplate. Yes Stew I believe I've mentioned that some were on Madmodder.
The last thing I would resort to is the chain drilling method. Punch out the center part, file the sharp edges and then if you have a mill, use a boring tool to bore to size. Ofcourse if you have many parts to do then this would be a pain in the you know were. :)
Just some different ways to get the job done. I guess it will depend on what tooling you have at your disposal.
Bernd
-
The trepanning tool Bog shows is basically the same as I use to cut inspection holes in aircraft panels. I think mine is a General Tool which is a pretty decent quality tool and if I remember correctly I think it set me back about $15 USD. I turn it either by a cordless drill or with an old fashioned wood brace and as others have stated, it requires a steady hand when free handing a hole. I also have used it to cut instrument holes in a panel blank that could be placed in a drill press. That works much easier! Turn the tool slow and have the material well clamped as the cutter can and will try to dig in. A slow feed is required with enough back force to prevent the digging in.
A Google search turned up a lot of high dollar versions for mills, but for the infrequent use this tool will normally see those are way overkill.
The other alternative, if you have a boring head for your mill, would be to make an offset bit for that and use it to cut the hole.
-
Thanks for the tips guys, after reading all the suggestions I had a dig around of what I had that may do the job. But first a picture to show some scale of the project.
As you can see, mounting on the faceplate may have been a tad difficult in this case.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0394.jpg)
So digging out some candidate tooling from the lathe I gathered these. They are turret tooling for the Smart and Brown lathe.
The two outer ones didn't have enough adjustment to go to 60mm. But the center one though not having fine adjustment looked promising.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0396.jpg)
I am of course holding the tool bit in the wrong direction for lathe work, but should work as a trepanning tool on the mill. My only reservation was the fact that the tool bit was only held with one screw. However, this proved more than adequate when it can down to it.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0397.jpg)
You can see that I have marked the work out by drawing up in CAD and then printing onto an A4 sheet. held to the work with sticky tape. If you have several identical pieces to do this can save a lot of work in marking out time. For me, well it's just more accurate, center punch through the paper as normal.
Just beginning to take a cut, working ok but I decided that the tool tip was a bit too wide, so reground it to a point. You can see that I have a 45 deg chamfer on the tool. My thinking was that if the cut came out a little rough I would always lower the quill to tidy up the finish by increasing the size of the hole. Again this worked quite well.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0404.jpg)
The result, quite tidy I'd say, took minimal cleaning up and didn't burn the painted finish at all.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0409.jpg)
Then to drill the two valve base mounting holes with a 19mm hole saw. This was easy of course.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0405.jpg)
Transformer now the right way up and in position, Lovely jubley !!!
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0410.jpg)
The trapanning was done at the slowest speed of my mill. Cutting proved to be stable if a little on the slow side.
(112rpm digitally tested with my new "cheap" tool from the far east. I had no idea what speeds my mill was giving me and the belt positions were very confusing to say the least)
-
Nice one Darren,
A clear case of making do with what you already have.
Using dedicated machine tooling for use to do other things is a method I use.
I remember a couple of years ago, when ball turners started to become popular. I hacked together a fixture that used the boring head off my mill to do the job about 10 to 15 years ago, with very good results.
Use what you have got and keep the pennies in your pocket.
John
-
TBH honest John the trepanning came out neater than either the hole saw or simple drilling. I guess it was too low a speed for the drill bit and I gave it very little support.
But the hole saw, though quick was a bit messy on the paintwork. Dragged the swaf around a bit I guess.
Not to worry, it will all be hidden in the end and I'm pleased with the result. Great when I was considering buying a new tool and made do with what I had.
As ever, thanks guys you lot are a real bonus.... :dremel:
-
Looks good Darren.
I guess I'm going to have to find those pics of me doing a 1/4" thick aluminum plate. I put a 14.25" dia hole in it with a home made tree panning tool. I'll have to put up a thread in the tool area about it. Don't want to hijack this thread.
Bernd
-
A couple of suggestions on using a hole saw. For a neat clean hole without destroying the painted surface start the hole saw from the painted side but stop just after the teeth of the saw mark a full circle. Withdraw the saw and re-insert the pilot bit from the reverse side and proceed to cut the hole. The result will be a clean hole on both sides without the normal "tear out" and the swarf will not be harming the surface. This tip is especially useful when hole sawing wood.
When cutting a hole in a thick piece of material again pierce the material with the pilot drill and cut just enough to mark the perimeter of the saws kerf. Once the kerf is clearly defined stop the saw and withdraw it from the work. Drill a "chip relief hole" just inside the outer kerf mark. Make the relief hole so that its circumference is tangent to the outer edge of the kerf mark. The idea is to give the swarf an exit when sawing through rather than filling the tooth gullets and plugging the saw.
Also be sure to use plenty of lube/coolant that is appropriate for the type of metal being cut.
I hope the sketch makes sense. Using the drawing function in a word processor is rather limited.
-
Nice tips there Roger, I have another to do yet, and prob more after and will take note of what you said, ta.... :thumbup:
Onward we march....
Now we have the holes cut in the chassis it's time to mount the valve bases/holders. I need to make some fixtures and incorporate a method of electrical isolation from the valve pins and the chassis itself. These two pins carry the voltage for the valve heater. In this case 10V @ 10A. Nothing too scary here even if it is a tad power hungry at 100VA.
1VA = 1V @ 1A = 1W, so these valves (ok, tubes for you guys over there) consume 100W each just for their heaters and there are two of them to make stereo reproduction.
Quite and expensive amp to run this one, but oh the sound... :)
Anyways, I took a 30mm SS 303 bar and drilled a 6mm hole through the center
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0411.jpg)
Parted them off and made four pieces, note outer dia not turned to size as yet. That comes later.
You may also note in the picture a collet stop ready to be fitted to the collet also shown. I wanted to make these four pieces identical in length and a collet stop is perfect for this. It allows each piece to be fitted into the collet at identical depths. But,it also serves another purpose.
Because each piece is so short it would be very difficult to clamp them in the collect squarely. In fact it would be almost impossible. Having the stop to push them up against solves this problem.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0414.jpg)
Here you can see the stop fitted. The depth is set by the thread on the bar and a locknut.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0415.jpg)
First piece faced off. By zeroing the topslide on the lathe and with the use of the collet stop we can make all four the exact same length.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0418.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0422.jpg)
Now they were turned around, again against the stop and chamfered
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0424.jpg)
All four done
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0425.jpg)
Now I needed to make the electrical isolators. For this I chose to use a bar of Teflon. I got part way through and realised that white teflon picked up dirt like a magnet picks up steel swarf :bugeye:
Not good, in the final application appearance is everything and dirty white bits just won't do.....
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0434.jpg)
So, I junked that idea, thinking I've learnt something new tonight at least. Save the Teflon for another use later.
Swapped the Teflon out for a bar of Acetal, or Delrin if you prefer.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0435.jpg)
A bit of jigery pokery and a little while later we have these, some top hat isolators and some washers.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0436.jpg)
Now I needed to true them all up to the same diameter. Slipped them onto a 6mm allthread and clamped with a nut.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0437.jpg)
Well that didn't work did it. I suspected it wouldn't, not enough support and too much vibration=chatter = a rough finish.
Well, I was turning 30mm held in a 6mm threaded bar after all.
So I shortened them down and did half at a time. But I still needed to steady the end with a tailstock center. But alas I don't have one for this lathe. I do for the mini lathe but it's not here.
I came up with this. Centered the allthread and used an old center punch held in the tailstock chuck. Crude, but it worked quite well. Scuse the rust, it got left outside at some time.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0438.jpg)
Well that worked just fine, here is a pic of the washers underneath. The electrical connections will also fix here with a lug.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0439.jpg)
And the top, all neat and tidy
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0444.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0447.jpg)
All in all it's going quite well so far and progressed another stage.
Darren
-
Watching this one.
So Darren... when you are done, can you help those of us who want to build a valve amp do so? I would like to tackle one perhaps next fall. I am sure with smaller valves though. Would need help in selecting the right stuff and the electric schematics.
Eric
:mmr:
-
Nice one Darren
Your making a nice neat Job of it:- love the improviced centre. :headbang:
Shows good use of collets and collet stop, been trying to identify lathe, what bread is it ?. :whip:
Have
:wave:
Fun
Stew
-
Darren,
Nice improvisation yet again, use what you've got to get the job done.
One of my collet stops is the same as yours, and I found a problem when using small collets. The threaded rod won't come far enough forwards to act as a stop.
I drilled and tapped both ends of the main threaded rod 3mm, so a long 3mm bolt with the head cut off and fitted into the end can reach up those small collets. You can make all sorts of little stops just by reshaping the bolt heads and screwing into the end.
John
-
Eric,
No probs, should you want to build a "tube" amp I'm sure I can help. I'm no expert though, but seemed to have managed to have built 20 or so amps to date.
SETs are my flavour, as opposed to PP.
Stew,
Yep, when I was looking for a lathe I just knew I wanted collet facility. Not regretted it for a moment, the chuck gets rarely used on this lathe. It has a "proper" collet lever assembly and is really fast to use when changing parts.
It's a Smart and Brown Model L Capstan Lathe http://www.lathes.co.uk/smartbrown/page2.html
I have a 6 tool possition sliding turret, a double action cut-off slide, a normal compound slide and a normal tailstock. Unusual for this model is a 5c collet nose, most used a smaller Smart & brown collet that is hard to find. Also the spindle is fully hardened and runs on roller bearings as opposed to plain bearings. It's 3ph with a 2 speed motor and I use a rotary converter to get my 3ph supply.
The whole thing sits on a ridiculously heavy cast iron cabinet which behaves as one unit with the lathe.
All in all it's a superb machine, but lacks feeds and screw facilities as it's a "plain" lathe.
Really used for large volume production work before CNC came along.
John,
Yes I can see the limitation there. I was going to make a larger dia end plug for the stop as I thought it was too small to hold small lengths squarely.
This turned out to be not so and it is fine as is. Held those small parts perfectly square with no effort on my part.
I really do like using collets I have to say.
Darren
-
Hi Darren
I recognise your lathe now we use to have some where I work, them and symilar Swiss make:- Saublin, we must have had 30+ all gone now. Very good machines, we use to run them at high speeds making small brass components, depending on what we were doing, they were set up with a capstan head or cross slide etc we had a full kit of attachements. We had women operating them, they were very skilled, and had a great light tuch, they could adjust size just by varying the pressure they aplied, and repeat it time after time. :bow:
Cheers :wave:
Stew
-
Yes the 3,000 rpm is nice for doing brass, esp without auto feed.
Darren
-
Eric,
No probs, should you want to build a "tube" amp I'm sure I can help. I'm no expert though, but seemed to have managed to have built 20 or so amps to date.
SETs are my flavour, as opposed to PP.
....
Darren
Valves... Tubes... I work with 2 Brits who are determined to teach me 'proper' English! :smart:
Eric
-
Eric,
I work with 2 Brits who are determined to teach me 'proper' English
You only think you work with them, they are the initial infiltration, preparing you for when we make our comeback, and turn you into a colony again. :D
Bogs
-
Shhh, we've almost got them under control John.....see, we got them to set up this site for us and it was done willingly to boot.
Like I said, almost there :lol:
-
Eric,
I work with 2 Brits who are determined to teach me 'proper' English
You only think you work with them, they are the initial infiltration, preparing you for when we make our comeback, and turn you into a colony again. :D
Bogs
If you can fix the economy, you are more than welcome to it. :lol: :poke:
Eric
-
Right you lot, back to the topic :D
I need to make some sort of connector for the top to pins of the valve. One pin is at a very low voltage (the Grid) and the other is at a very lethal high voltage.
Lethal as in you'd only get the one chance to touch it cos you won't be around for a second go...!!
So obviously whatever is made for this pin needs good insulation. I was thinking of using some of that Teflon that made an appearance earlier.
At the mo, the following may or may not be the final choice. I'll press on with it and see how it goes.
Suggestions are more than welcome.
Taking a 15mm copper water pipe and sizing it up to the pin in question.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0449.jpg)
Cleaned it up on the lathe and tapered the end internally.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0451.jpg)
Onto the miller held in a hexagon collet fixture in order to make three slits at 120deg.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0459.jpg)
Starting to make the first cut and it's cutting really smoothly.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0462.jpg)
All three cuts now done
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0466.jpg)
Then turned a bar on the lathe to the same dia of the valve pin to open out the end of the slitted tube. This was to prevent too much force on the valve itself.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0467.jpg)
Well that's where I'm at and I'm not quite sure where I'm going with this. It's the fact that it needs insulating that adds complications, otherwise it would be a simple matter to make some sort of clamp.
Design in progress...... :)
-
Just a suggestion: Those look like minature car battery terminals, so why not a battery cable clamp in miniature? Then, make a cover/cap out of the teflon (or other insulator) and hide it all.
-
The valve pin is 14.4mm dia or more prob 9/16
I think I may be trying too hard here, a clamp would be better than something with a push fit ,if only for safety reasons.
I'm having trouble getting my head around the insulating bit.
I will think some more on it, please keep any suggestions coming chaps..... :D
-
Well, it originally connected to something. Do you have any piccs or sketches of that? Is it possible to replicate?
I like the idea you started with, but maybe modified a bit. I'll PM you a quick .jpg of a part I whipped up. Top is threaded, so you can use nuts and washers to sandwich a wire or ring terminal. Feel free to post or use at your discretion.
Edit, nevermind, I'll find a host and post the pic. Give me a minute.
Edit again, my spellink stinks!
-
Something like this? Sorta what you have, but without the taper on the inside, and a sliding fit. Adjust to make good connection by squeezing the prongs together. Maybe use some contact grease or Artic Silver (stuff to give good contact on computer CPU heat sinks)?
(http://dosomefink.com/mkportal/modules/gallery/album/a_1029.jpg)
-
OK that is something similar to what would have been used originally,
I'll see if I can sort a pic, depends if I can find sumut in the den :lol:
-
This is what would have been used, though this one is much smaller it's the same design
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0469.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0470.jpg)
Apart from the fact they are no longer avail, and I've yet to see any pop up on Ebay in the last 3yrs, you could say they are a bit difficult to find.
-
Looks like I just reinvented the wheel, then. I'm assuming the outer profile of the insulator doesn't matter, just whatever appeals to you. You ought to be able to machine that up, and so the looks of the connector part aren't so important, just the function.
-
Darren,
Might be a stupid idea, but could you use terry clips.
C-o-C attached
The heat resistant insulation might be the problem.
John
-
How about a Plug cap (mini spark plug) cut down if need be and the internals of one of the ceramic caps.
peter
-
Thanks Guys I'm working on something this evening, not ready to show just yet though.
John,
I've seen those clips on the market stall and did give them some consideration.
I have to think about safety foremost but almost as important is the finished looks.
Apart from that I'd like to make something myself, after all, it what we have these tools for init :thumbup:
-
I wasn't happy with the way this valve cap was going so decided to approach it with a different idea.
A 20mm SS bar was knurled on it's outer edge, I'll explain why in a mo.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0471.jpg)
Then drilled and bored to a sliding fit on the valve pin
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0474.jpg)
Testing the fit on the valve
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0475.jpg)
Now I need an insulating jacket for this part, this was made from Teflon. I gave myself 5mm insulation thickness all round. This should be ample.
From above
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0477.jpg)
Below
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0478.jpg)
These two parts are a tight fit. I mean the tolerances aren't even close. If these where two metal parts they would have no chance of being pressed together.
However this is Teflon, slippyest substance known to man, so they say. They're not kidding either, it's quite slippy in your hands and a with 50mm bar you can easily loose your grip.
Anyhow, I was planning to use a press to push these together, but it turned out easy enough to do by hand.
Now you can see why the knurling, it's an attempt at giving them some grip to keep them together. It should work.
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/IMG_0479.jpg)
I need to tap the SS top with a 5mm thread, but I need to order one first. Then I can fit these two parts together.
The electrical wire will thread into a cross drilled hole and be secured by a grub screw from inside the unit. From inside to avoid anything showing and any "live" metal bits.
The whole contraption will be secured to the valve with two 3mm grub screws. A bit hard to explain but I first need to order a 5mm tap before I can continue.
Darren
-
Hi Darren...
So I'm trying to get my head around this! :scratch:
Is the new knurled part instead of the split copper bit? Is the thread that you are putting into it to make it something like the rendering by Roger?
Or are you making it a little like the pic of the original style clip? A wire exiting the top side of the teflon and the stainless bit with the threaded hole and a bolt clamping the wire to it inside the teflon drum so that no one can touch it?
Just a few questions to keep you busy :D
I've also thought of a clamp idea so If this dosen't work as well as you envision I could post that? Problem is I'm struggling to Crap o Cad the damn thing!!! It'd probably me easier for me to make it!!
Still my idea might not work, and it wouldn't be your idea, so it's probably a good thing I can't draw!!
I'm more than intrigued about the final product :)
Ralph.
-
Hi Ralph,
I think you got it, replace the copper bit earlier.
This pic should help, now ordered the 5mm tap so should progress soon... :)
(http://i401.photobucket.com/albums/pp92/thebodger/833/Machining%20and%20case%20work/Valvepindrawing.jpg)
-
Ahah! You now want it to be a fixed cap rather than a removable sprung loaded one.
Talk about moving the goalposts. :lol:
Wasted brain cells Bogs.
-
Suddenly it all became clear!!! :thumbup:
Good stuff, Just the snail mail post to delay the job.... I get that quite often too!
Keep us posted.
Ralph.
-
Saftey was the main criteria, looks second.
Actually the method of fixing is not terribly important, just so long as it stays put.
TBH H&H would still have a fit and suggest it all goes behind bars. But then I'm not selling it so they can......."place own words here"....... :lol:
The valve gets a bit hot in use, around 200 degC, but that is unlikely to kill you. Keep you nice and toasty though, esp as there are two of them..... :D
-
I am dying to see this finished!
:borg:
Eric
-
HI Eric,
Thanks for the encouragement.
Though this is only one part of a whole amp and is quite a big project. Not many people build amps of this caliber.
I believe I'm prob the third to do so, one other chap in the states and another in the UK. Though I think we all started before learning of each other.
There may be others now as I've not really been looking since I started this amp three years ago.
I'll have to take some other pictures of what's involved in making these valves work, it all takes up quite some room.... :dremel:
-
This is the only commercial avail 833 valve amplifier....
http://www.stereophile.com/tubepoweramps/704wavac/
Sorta explains why I'm building my own, TBH I would anyway even if I could afford this one...which I can't of course.... :(
-
Tim asked for a pic of my valve amps,
Well this is only one in working progress, up and running in this pic though.... :ddb:
Rather than start a new thread I've bumped this one.
Tim go to the start of this thread to see some pictures and details.... :thumbup:
I'll take some more of other amps for you...
-
Tim asked for a pic of my valve amps,
Well this is only one in working progress, up and running in this pic though.... :ddb:
Rather than start a new thread I've bumped this one.
Tim go to the start of this thread to see some pictures and details.... :thumbup:
I'll take some more of other amps for you...
I've just read all the way through this thread and :bow: :bow: :bow: :bow: :bow: I am impressedm, and a little jealous too. What sort of speakers do you have? Diy as well?
I'd love to see your other valve amps too.
Tim
-
Tim,
I've just popped into the music room to take some pictures, please excuse the mess and dust :(
We are renovating and there is dust everywhere, also this room is packed with stuff as we empty other rooms to work. I do wish the garage would come along more quickly so I can move some things over there. But this rain is really holding things back.
Anyway, some very quick and dirty pics with no posing shots at all....honest.... :lol: Not all my amps, some are still packed since we moved and some have found new homes.
My phono stage "True Realism" As you can see things are packed in tightly as we want minimum lead lengths between components due to the low signals. We don't want stray stuff getting in and being amplified along with the music. It's a SRPP circuit and was quite hard to get right. It's a lot more complicated than it looks. Those two little circuit boards are the RIAA stages. Technically quite difficult to get right. Valves are ECC83's.
Always a working progress as you can see....
The amp
(http://i401.photobucket.com/albums/pp92/thebodger/HiFi/Valve%20Amps/True%20Realism/IMG_2219.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/HiFi/Valve%20Amps/True%20Realism/IMG_2225.jpg)
The power supply
(http://i401.photobucket.com/albums/pp92/thebodger/HiFi/Valve%20Amps/True%20Realism/IMG_2224.jpg)
The Power Amps at a whopping 2W per channel, don't be deceived by two measly watts, these can punch some volume out. All depends on the speakers which are usually built to match. All 1920's valves, my own design using a MH41 triode which I believe I was the first to use for HiFi. Power valve is a PX4.
Each box is mono, so two used to make a stereo.
The 833 amps are tagged onto the end of these as a further stage.
(http://i401.photobucket.com/albums/pp92/thebodger/HiFi/Valve%20Amps/IMG_2216.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/HiFi/Valve%20Amps/IMG_2220.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/HiFi/Valve%20Amps/IMG_2222.jpg)
(http://i401.photobucket.com/albums/pp92/thebodger/HiFi/Valve%20Amps/IMG_2223.jpg)
The speakers,
My own design using London Ribbons for the high end, Wharfdales with a wizzer for the mids, and Fane pop 50's 12" for the base, and there is a lot of punchy base, too much in fact.
(http://i401.photobucket.com/albums/pp92/thebodger/HiFi/Speakers/IMG_2226.jpg)
The turntable, one of many, my own design and build of plinth, tonearm mount, stand etc
(http://i401.photobucket.com/albums/pp92/thebodger/HiFi/Turntables/IMG_2214.jpg)
The 833 amplifier stage has no caps and no resistors, just a power supply, output transformer and wire. Nothing to get in the way and taint the purity of the music.
As you can see, I'm into HiFi and deff a valve man, hate silicon, sounds dreadful IMHO. A quick and dirt post for you, I could write till the cows come home about this stuff but better not eh :lol:
There you go that's a taster for you :thumbup:
-
I am very impressed.
Not so much now, but a few years ago I was pretty keen into HiFi too, I did seriously consider building my own valve amp, although I probably have gone for a kit as I wasnt to sure of my abilities with high voltages.
One thing that is nigh-on impossible to beat with valve amps (apart from the obvious audio benefits) is the absolutely stunning beauty of them. Imagine the scene. Listening to some great music in a dark room, the only illumination coming from the gentle glow from the valves, Ahh, heaven!! :med:
I did mod a few commercial amps (sillicon though), mostly upgrading the caps to Elna's and improving the psu's in them. I also modded a cheapish cd player with the same sort of thing, and also removing the muting transistors and replacing with a relay. I never had any vinyl so all my music is on cd.
Great mono-bloc's, and kudos on the tight wiring on the RIAA pre-amp. :thumbup:
One seriously impressed Tim.
-
Hey Darren,
How about writing a post on setting us audio newbs on the right path of build say a small valve amp?
Eric
-
Very impressive Darren.
I remember hearing (no pun intended) about these types of amps putting out better music than the silicone jobs of today.
Bernd
-
Darren, I believe you went to the same wiring school I did!
One day in class the flight sergeant handed each of us a box of bits and a circuit diagram to build a triode audio amp. It was not long before he was bawling me out for wasting time and soon after that he was holding up my efforts as an example to the class how not to do things! I damn near had to sit in the corner for a hour while the others finished up.
Then we had the tests, of the 24 in the class mine was the only one that worked! :lol:
-
Hey Darren,
How about writing a post on setting us audio newbs on the right path of build say a small valve amp?
Eric
I've got an amp that uses two American TV valves, very plentiful and cheap.
Even better is that it is one of the best sounding amps I have ever built and has been copied all over the world.
My mate designed it for my first valve amp build and I was the first to ever build it (my mate knew it would work so didn't bother to build it himself till much later)
Neither of us got any credit, not even a mention. Together we have built some weird and exotic amps over the years and that where often copied.
Eric, let me dig it out sometime and go through the motions. It's a very simple circuit, can be built in a day or so.
Look up 6EM7 valve amplifier and you will find :thumbup:
-
Darren, I believe you went to the same wiring school I did!
One day in class the flight sergeant handed each of us a box of bits and a circuit diagram to build a triode audio amp. It was not long before he was bawling me out for wasting time and soon after that he was holding up my efforts as an example to the class how not to do things! I damn near had to sit in the corner for a hour while the others finished up.
Then we had the tests, of the 24 in the class mine was the only one that worked! :lol:
John, valve amp wiring should be like a birds nest, my PX4 amp is way too neat..... :doh:
-
Very impressive Darren.
I remember hearing (no pun intended) about these types of amps putting out better music than the silicone jobs of today.
Bernd
There is no comparison between valves and silicon amplifiers.....silicon is harsh and lifeless. There is no way around it no matter how much money or design you throw at it.
When you hear your first ever female vocals on a valve amp you get a very strange feeling and are compelled to look around to see who is there. It's hard to describe, but most people even if they are not into music get quite confused for a while.
That 6EM7 amp I mentioned is famous for it.
-
One seriously impressed Tim.
Aww shucks, thanks Tim...
Oh I'm gonna have to build one as a project arn't I
I'd really given up, I've built so many and have found one that made me stop.
Most were just built on a piece of wood, only about three or four were ever cased.
Build it, listen for a while, strip half of it down and try another valve.....
Over and over and over and over and over and over and over and over and over and over and over and over and over
I seriously couldn't tell you how many...
Have a look for we4212 valve or tube as they like to call them, might be a picture out there somewhere?
-
Ner ner na ner ner.... I've heard Darrens system play..... :headbang: (not really head banging tune but it'll do!)
Loud? Your not kiddin!! :bugeye: And I don't think it was much turned up!
A bit of Jazz type stuff I think (Darren will tell you) True, very clear. I'd like to hear something I know on it so I could compare the two though :)
I've seen those circuits up close too :jaw: they really are quite unbelievably tightly fitted together! Also seen some of the funkiest valves and diodes ever..... Some of them are just huge!! :jaw:
Very cool..... I still like the idea of one as a light :thumbup:
Ralph.
-
John, valve amp wiring should be like a birds nest, my PX4 amp is way too neat..... :doh:
Not according to the flight sergeant! And you have to use wires of the right colours too! :lol:
-
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_7490600.jpg?t=1226280656)
Darren,
Do the filaments need to run that hot? :bugeye: Granted, my experience with tubes is about 35 years in the past, but I only remember the cathodes glowing a warm red, even the radar magnetrons, not bright enough to read the newspaper by. I suspect that there is a reason, but it exacpes me.
Weston
-
Ner ner na ner ner.... I've heard Darrens system play..... :headbang: (not really head banging tune but it'll do!)
Loud? Your not kiddin!! :bugeye: And I don't think it was much turned up!
A bit of Jazz type stuff I think (Darren will tell you) True, very clear. I'd like to hear something I know on it so I could compare the two though :)
I've seen those circuits up close too :jaw: they really are quite unbelievably tightly fitted together! Also seen some of the funkiest valves and diodes ever..... Some of them are just huge!! :jaw:
Very cool..... I still like the idea of one as a light :thumbup:
Ralph.
I'll put some Slade on for you next time Ralph, that works well :thumbup:
-
John, valve amp wiring should be like a birds nest, my PX4 amp is way too neat..... :doh:
Not according to the flight sergeant! And you have to use wires of the right colours too! :lol:
I always thought people in authority were the least experienced or knowledgeabe....that confirms it..... :ddb:
It's to do with picking up stray inductance/capacitance from nearby wires. Better if they cross sharply. :thumbup:
-
(http://i401.photobucket.com/albums/pp92/thebodger/IMG_7490600.jpg?t=1226280656)
Darren,
Do the filaments need to run that hot? :bugeye: Granted, my experience with tubes is about 35 years in the past, but I only remember the cathodes glowing a warm red, even the radar magnetrons, not bright enough to read the newspaper by. I suspect that there is a reason, but it exacpes me.
Weston
Thorated fillaments, designed for such abuse, it excites the electrons better.
Talking of heat, the valve sits there at around 200 deg C, you could do toast with them. Certainly don't need the heating on.
Brill for the winter :)
-
A bit of Jazz type stuff I think (Darren will tell you) True, very clear.
Diana Krall
BTW, if you thinks that was loud, the 833 amp is 50W....
-
"...it excites the electrons better".
Indeed, any more and they will be launching Photon Torpedoes.
-
I'll put some Slade on for you next time Ralph, that works well :thumbup:
Oh yer! :headbang: Slade is good!
Diana Krall
Another name to investigate!
BTW, if you thinks that was loud, the 833 amp is 50W....
Your going to hurt the neighbours ears!! :lol:
Ralph.