OPTs with 16 ohm secondary

[bigmm79]

I'd like to build a GSG with 300b tubes and OPTs with 16 ohm secondary.
Are there any OPT options other than the Edcors out there with 16 ohm secondary and other appropriate specs?

Not that there's anything wrong with Edcor, just want to know options.

Also what OPT primary impedance should I be looking for in a 300b config?
Does the wattage rating of the OPT matter?
Those are a couple of beginner questions I know - but I am a beginner

[Shannon Parks]

I'd like to build a GSG with 300b tubes and OPTs with 16 ohm secondary.
Are there any OPT options other than the Edcors out there with 16 ohm secondary and other appropriate specs?

Not that there's anything wrong with Edcor, just want to know options.

Also what OPT primary impedance should I be looking for in a 300b config?
Does the wattage rating of the OPT matter?
Those are a couple of beginner questions I know - but I am a beginner

Look for 3.5k. The stock build (with the 1.5 ohm filament droppers) will output 4W while ditching the 6AX5GT for a pair of 1N4007s will up you to almost 7W. So a 10W tranny is OK. Do keep an eye on the frequency specs, though. A higher rated output may be needed to get the low or high frequency spec you require.

Shannon

[bigmm79]

Thanks. Edcor doesn't have 3.5k to 16 - 2.5 or 5 - so I guess it would have to be a custom job.

James js-6123h appears to be an option but it looks like they are fairly expensive. Anybody know a good reputable source for those?

[Shannon Parks]

No worries - I would opt for a 2.5k before a custom tranny. It will work fine.

Shannon

[Thatch]

It seems the James is no longer made, and for what it would do it was a bargain. I want to buy a pair and now can't.
Edcor is good, but anything, no matter how trivial like getting a 16 ohm secondary vs an 8 is going to cost you $40 for them to "set it up" as it is a special order for all their transformers because they do not keep any on the shelf I think it is BS, but what can you do if you use 16 ohm drivers?

Thatch

[Shannon Parks]

Try the One Electron UBT-3: 3K with 4,8 & 16 ohm taps. Also plenty of James outputs are on eBay, but I'm not sure which ones support 16 ohms.

Shannon

[Ty_Bower]

I guess it would have to be a custom job.

Electra Print will wind you whatever transformer you want. A 65ma rated 3.5K:16 would cost you $115.50 each. Of course, for that price you could pay Edcors custom fee and have pretty much the same thing in their CXSE line. I've not done business with Jack myself, but have heard some people say good things about his transformers. I've also heard one negative report, too. My impression is that his products appear to be designed with a fairly conservative margin - plenty of iron, generous windings.

If you're inclined to do a bit of research, there are many vendors listed here:
http://www.diyaudio.com/wiki/TransformerSuppliers

[weeves]

I just purchased my James outputs from ayumitubes on ebay - No problems and good customer service- He has 6123's on sale

http://cgi.ebay.com/JS-6123HS-JAMES-AUDIO-TUBE-OUTPUT-TRANSFORMER-2A3-300B-/250866907306?pt=Vintage_Electronics_R2&hash=item3a68d538aa#ht_5599wt_850

$265 + $85 shipping makes them a little pricey -

There are sellers cheaper on ebay if you do a search.

[bigmm79]

ok, still thinking about a 300b gsg project.
Would like to use off the shelf edcor opts cause the price is right.
Also would like to use the cxse because of the extended frequency response. Those only are available off the shelf with 1.25k or 5k primaries (with 16ohm secondary).
Would either of those work and which would be preferable?

Not sure how that primary impedance affects things - if its preferable to go higher or lower than the ideal 3.5k and how far one can deviate before impacting sound.

[Shannon Parks]

The easy answer is the 5K to 16 ohm output. Just a little less power, but an even more linear amp. The 1.25K to 16 ohms would produce an unacceptable amount of distortion.

Shannon