Re: Transformer Varnishing methods
« Reply #20 on: October 29, 2018, 03:58:34 PM »
Just bought them now so ,I'll have to wait and see condition , they look good though .

6SJ7?    all I could see from the pics is a pair of EL86's and a pair 6au6's

I'll have a look for the schematic now as well , if anyone can post it please do .

looks like theres not much to go wrong with them in any case .

Found the manual for it ,I see the tube lineup changed over the years ,the two I found look like the later models with silicon diodes in the power supply and 6au6/EL86 .
« Last Edit: October 29, 2018, 04:35:06 PM by Tubetec »


CJ

Re: Transformer Varnishing methods
« Reply #21 on: October 29, 2018, 09:56:18 PM »
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

PRR

Re: Transformer Varnishing methods
« Reply #22 on: October 30, 2018, 02:53:05 PM »
Sorry, I was thinking of the 200AB. The CD is a significantly different topology. And a later design leading to different tube types.

Re: Transformer Varnishing methods
« Reply #23 on: October 30, 2018, 03:27:30 PM »
Even the 200cd underwent a few different tube lineups over its very long production . Ive been reading up on these and wow there is quite a bit can go wrong , the resistors tend to fall apart ,as well as proper tube matching to get symetrical output .
Still very worthwhile if another lifetimes use can be gotten out of it though . Fingers crossed the transformers are good in the ones I ordered .

CJ

Re: Transformer Varnishing methods
« Reply #24 on: October 30, 2018, 05:43:45 PM »
i put a phone jack on mine with a resistor divider so as to get 0 to 500 mv range when turning the knob all the way up, otherwise it is hard to get instrument level signals dialed in.   this makes guitar amp testing a lot easier, dial it in for 50 mv and it sticks.

the light bulb regulators are what made these things famous.
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Re: Transformer Varnishing methods
« Reply #25 on: October 30, 2018, 06:49:49 PM »
Ahhh right I was wondering what the jack socket was for , looks like a handy mod.

I found a few Veeder counters on ebay , all 5 digit ones  , one perfect ,one with  jammed up reset,and the small one with key operated reset, but no key . Hopefully these things are servicable , and not just a bunch of springs and wheels that fall all over the place if opened ,

I might try mount the smaller one on my handcranked winder instead of the clockwork counter ,and maybe think about using one of the larger ones on the cnc winder when I get it , of course its got digital counters already , but Im not sure if it counts unwound turns in the same way as an analogue counter . I'm slowly tooling up with various other bits and bobs too ,  adhesive tapes, a nice pair of CK scissors for cutting papers and insulations , an electricians scissors  for tougher jobs .
The boss in the motor winders is apparently having a clean out soon too , so any scraps of papers,nomex ,insulated tubing ,and piles of reclaimed phenolic boards of all thicknesses , theres a lifetimes worth of off cuts and scraps that would do the small transformer winder just fine , he's also got magnet wire in just about every size from .08mm or 40Awg up to 5mm or what ever that is in Awg , so hopefully I can strike a good deal on some copper too .

I have to say Im bitten by the winding bug , its actually quite therapeutic hand winding and guiding  ,does take a bit of practise though. Thank you all once again for the inspiration ,encouragement and accumulated empirical know-how .
 

Re: Transformer Varnishing methods
« Reply #26 on: March 11, 2019, 07:50:06 AM »
Hi,

Sorry to drag up an old post, but this seemed like the place to ask.......I am going to start making my own transformers. I am going to start out with a couple of sets of gtr amp transfos, but would like to wind my own mic input, and line output ones at some point.

I see that varnish is the "standard" way to seal these up. Does anyone have any experience using beeswax? It seems like it would be easier on the lungs, and doesn't have to be baked.

Also, what kind of tapes, and insulating papers exactly do I need to get to use? I have heard the term "presspaper" a lot, but I don't know what that is. I will probably get my lams & bobbins from Edcor to start out, as I couldn't find anyone else that deals in small volumes here in the U.S.

Thanks for any and all comments / advice!

George

Re: Transformer Varnishing methods
« Reply #27 on: March 11, 2019, 04:43:16 PM »
Theres a kind of spray we use at work in the motor place , Ultimeg anti tracking varnish , its also used for transformers , a quick spray as the layers go down on transformers holds everything in place , it is smelly though . Ive seen wax impregnated windings ,trouble is wax melts at around the ambient temp of your tube amp , so it tends to ooze over time . I you want to try wax its easy melt it in a pot and dunk it into the wax until the bubbles stop coming up ,dont let it  get too hot or damage the bobbin material etc ,same way as you might impregnate a guitar pick-up .

Mini ovens dont cost a lot nowadays , and would easily have enough space for a few guitar amp sized transformers in one go , might be worth considering in the longer run .

Theres a few papers and tape types , Nomex being the main one we use nowadays also a blue paper with a shinny and matte side , theres a number of different binding materials and cord for strapping up windings ,insulated tubing for where the taps attach to the coils , Nylon bobbins are common ,but fibreglass and bakelite are also used . Tissue and kraft paper for interleaving I dont see much of in my line or work , but presumably any art suppliers will have these . Masking tape is most often what we use , and ocassionally Kapton tape . The flexible glass tape is also sometimes used ,once its varnished and baked off its very tough.

Re: Transformer Varnishing methods
« Reply #28 on: March 11, 2019, 05:52:49 PM »
Hi Tubetec,

Thanks for the info. I think I will skip the wax idea. I was wondering about heat over time with that.

So basically the Nomex paper is used as the insulator between layers, and regular 'ol masking tape or Kapton tape (I actually have a big 3" wide roll to use on my 3D printer) to fasten the insulation?

As far as the tubing (or spaghetti as a lot of people seem to call it) will regular heat shrink work to use to bring the magnet wires out of the bobbin, or do I need a tubing that will not shrink?

Thanks again for the response.

George

Re: Transformer Varnishing methods
« Reply #29 on: March 11, 2019, 07:34:50 PM »
The tubing we use is fibre/textile with a sillicone layer on the outside , its all hi temp stuff that goes in really so in the event of overheating things dont break down quickly .I have seen some bits of heavy duty heatshrink at the connections in a Toroid,
but regular heatshrinking no not really , if it was heated it would be too easy for the strands to poke through or if there was a sharp edge , The sillicon tube goes nice and flat too when you wind over it ,so minimising lumps and uneveness .

Might be worth watching someone on youtube making a big transformer , just to see how they do the lead outs off the coils , a piece of tubing is slipped over the wire first the wire is then soldered on ,the tubing is slipped over the solder joint its then  insulated with paper and  then taped flat then you might wrap with a layer of nomex ,tape again and continue .Magnet wire insulation is better than what it was years ago , everything we use is high temp high voltage stuff ,but you still need to ensure pri /sec is well insulated as the voltages between the windings is high in tube amps .


Re: Transformer Varnishing methods
« Reply #30 on: March 11, 2019, 07:42:56 PM »
OK, so no regular heat shrink.

Do you have any idea where I could buy some small quantities of this stuff?

Thanks again!

George

Re: Transformer Varnishing methods
« Reply #31 on: March 12, 2019, 02:43:42 AM »
The fibre tubing comes in many colours and diameters , but usually on a large roll , its probably the smaller diameter stuff you want for audio transformers . A transformer winding place should be able to sell you a small quantity ,alternatively a motor rewind shop might have it too .

Re: Transformer Varnishing methods
« Reply #32 on: March 12, 2019, 09:36:31 PM »
Heres an ebay seller with the kind of stuff you want ,

https://www.ebay.ie/itm/1-25mm-200-C-HIGH-TEMP-Silicone-FiberGlass-Sleeving-Wire-Cable-Insulating-Tube/153142660289?hash=item23a8038cc1:m:mkuIKjaSMaL496mIb_nTI5Q


Im lucky ,at work theres piles of off cuts of this and all the other materials for winding, I can take away more or less what I want of the surplus with the ok from the boss  of course .

Re: Transformer Varnishing methods
« Reply #33 on: March 13, 2019, 07:03:51 AM »
Thanks very much for the link! I talked to a few places here in the U.S., and either they didn't sell to individuals at all, or their min was 1200' or some other huge length.

George

CJ

Re: Transformer Varnishing methods
« Reply #34 on: March 15, 2019, 12:39:59 AM »
just type "fiberglass sleeving" on evil bay and it spits forth 4000 links

https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313.TR1.TRC0.A0.H0.Xfiberglass++sleeving.TRS0&_nkw=fiberglass++sleeving&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=vinyl+glass++sleeving&LH_TitleDesc=0

usually you splice PVC wires to the enameled winding wire right on top of the coil, 

if it is heavy wire for ther sec spk wind, then it makes senses to bring it out , leave it long  enough to reach the output jack, then just throw a sleeve on it,

If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Re: Transformer Varnishing methods
« Reply #35 on: March 15, 2019, 03:49:05 AM »
Just a quick tip for those who might need a small amount of slieveing but dont feel like waiting ages for a package of it , electric cookers often contain some of the heat resistant tube to protect the wires , it can easily be re-used .

CJ

Re: Transformer Varnishing methods
« Reply #36 on: March 15, 2019, 06:48:08 AM »
we have an abandoned no-tell motel with kitchenette's in every room, the tweekers ripped the copper out of the walls but there is still sleeving under the stove burners,  alcohol gets rid of the hamburger grease and pork and beans,

but you have to be careful, the cops now use it for swat team practice,

google "Holly Hotel  OlyWa if you don't believe me,
« Last Edit: March 15, 2019, 06:53:34 AM by CJ »
If I can't fix it, I can fix it so nobody else can!
Frank's Tube Page: www.mif.pg.gda.pl/homepages/frank/vs.html
Guitar Amps: http://bmamps.com/Tech_sch.html

Re: Transformer Varnishing methods
« Reply #37 on: March 15, 2019, 07:16:34 AM »
Thanks for the link CJ. Knowing what to call the stuff & actually search for is usually half the battle!

George


 

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