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GSG Output Transformer Sticky Thread

PostPosted: Sun Sep 12, 2010 7:42 am
by Shannon Parks
Please post your output transformer recs here. While I've always intended to try some other iron due to James products unavailability at times, I do see an eBay seller selling them cheap:

http://electronics.shop.ebay.com/Vintag ... 86.c0.m282

PostPosted: Sun Sep 12, 2010 10:45 am
by Ty_Bower
The award for the best budget class OPT has to go to Edcor, for their single ended GXSE transformer. I put a pair of the 15W models into my get*set*go and have been extremely pleased with them. Just mind the primary and secondary impedance ratings, as these units don't come with multiple taps.

http://edcorusa.com/Products/BrowseSeri ... eriesID=36

PostPosted: Sun Sep 12, 2010 1:40 pm
by TomMcNally
I've built a bunch of g*s*g's with the even cheaper
Edcor XSE15-8-5K with good results.

They hide real well under a Hammond 12x8x3 chassis.

Image

TCTubes http://www.tctubes.com/ has good
deals on James transformers also.

... tom

PostPosted: Sun Sep 12, 2010 8:53 pm
by Quad
Transcendars are another option.

PostPosted: Sun Sep 12, 2010 9:13 pm
by TomMcNally
I built one with the Transcendar TT 212-OT's ...

Image

PostPosted: Mon Sep 13, 2010 11:23 am
by EWBrown
While they're not exactly "budget" priced, the Magnequest RH-60 SE OPTs sound excellent with the GSG. These have 5K primaries, and 8/16 ohm secondaries. THese are about the same size as the Hammond 125ESE or the 15 Watt GXSEs. The output power will be somewhat lower than with a 2.5 or 3K OPT, but the THD is also lower, which is a good trade-off. These are about $100, each. Higher quality iron at a price that won't break the bank...

I've used the GXSE OPTs in other SE amp projects and they sound very good, and give the best "bang for the buck" of any OPTs I've ever used.

I have a pair of the 3K, 10W Transcendars, I'll have to try them out on a GSG, and the other test I want to try is to run triode strapped 6AV5GAs.
Ditto, with a pair of Edcor GXSE15-8-3.5K. Or use Soren's method, with using the GXSE15s with 8K primaries, and 16 ohm secondaries, and run them as 4K:8 ohm OPTs, that might offer a higher primary inductance, at no extra cost.

/ed B

PostPosted: Wed Sep 15, 2010 8:06 am
by Shannon Parks
I wouldn't mind a pair of these one day:
http://www.magnequest.com/030.htm

O:)

PostPosted: Wed Sep 15, 2010 12:37 pm
by EWBrown
Those are the "gold plated Cadillacs" of the SE OPT world :)) $) ;)

Image

And at 360 smackeroos each, they better darn well be!

/ed B

PostPosted: Thu Sep 23, 2010 2:42 pm
by Francois_G
[quote="Ty_Bower"]The award for the best budget class OPT has to go to Edcor, for their single ended GXSE transformer. I put a pair of the 15W models into my get*set*go and have been extremely pleased with them. Just mind the primary and secondary impedance ratings, as these units don't come with multiple taps.
[/quote]

This transformer seems to come in 2.5k or 4.5/5k near the operating point for GSG. What did you use?

PostPosted: Thu Sep 23, 2010 6:27 pm
by Ty_Bower
Francois_G wrote:This transformer seems to come in 2.5k or 4.5/5k near the operating point for GSG. What did you use?

The 15 watt rated GXSE is available with many different primary and secondary impedances:

http://edcorusa.com/Products/BrowseSeri ... eriesID=36

I chose the GXSE15-6-2.5K. At the time I built the amp, the impedance of my speakers seemed to spend a lot of time around 6 ohms. According to the spec sheets, the 6B4G tube delivers a reasonable amount of power at an acceptable distortion level when operating into a 2.5K load (similar to a 2A3). I'm happy with my choice, but if I did it again I might think about choosing a different primary/secondary impedance (but perhaps the same ratio) to get a little more inductance on the primary side.

PostPosted: Sun Oct 24, 2010 3:42 pm
by Ty_Bower
Almost forgot... wasn't the James Audio JS-6112HS the "original" preferred output transformer for the Get*Set*Go? Or was it the JS-6113HS?

PostPosted: Sun Oct 24, 2010 4:14 pm
by TomMcNally
James 6113HS were what we used.

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PostPosted: Thu Jul 28, 2011 12:29 pm
by Thatch
Edcor will wind anything but they have a setup fee of 40 dollars, still they are a bargain, I have some tubes that are supposed to go with a 2.5K and either they were not making those or I just wanted to change the secodary and it was the same thing, $40 and they will wind, nothing is on the shelf so I am not sure the $40 is a one time thing if you want to get more or not, I haven't gotten that far yet.
I figured if I went with 2.75K I could use a lot more tubes like 6L6Gs in triode, 300Bs etc, and I am hoping that a beam power from 50 and some late 60s 9pin pentodes will both work well and most important sound better than average which I guess I will go for a triode strapped pentode running on low octane fuel with the same OPTs.
I listen mostly to a Heil AMT/Altec 15"bass running free with a huge PIO cap from the 40s, maybe before as a high pass, so I am looking at 11 ohms or somewhere around there depending on what is running the most at how loud and figured I could get a 12 ohm secondary, putting me smack between most high efficiency speaker setups and it will play with anything, use a lot of power tubes.
I need a tube rectifier and can't decide about using 6J5s as drivers so I can have more tubes and a bit more rolling opportunities. A bit less gain, more like a 6SN7 than a 6SL7, but 2V coming in ought to be enough with 98 or so db SPL. If it isn't I will put 6SL7s in there with different halves wired and just trade them around for even wear.
Thatch

PostPosted: Wed Aug 10, 2011 2:01 pm
by kku
Starting from $54/pair, quite a lot of choices. Only downside is the seller is in HK.

http://www.analogmetric.com/category.php?id=36

Tomiko OPT

PostPosted: Thu May 10, 2012 1:41 pm
by LMAN