Recommendation for Output Transformer

[TomCarlos]

Gents....

I am searching the old threads to see if I can find a recommendation for an Output Transformer (something I can easily find) for a small Champ like Class A build. The Power Transformer is rated at 250-0-250 @ 81ma with B+ around 300v. I'd like to build a prototype board where I can run either a 6V6 or 6L6 (this will be a test board with the appropriate biasing). I also have an 8 ohm speaker that I would like to use.

I found the Hammond Universal, 5 watt, 45ma transformer. The specs say that the Yellow and Black wires on the secondary will get me 8 ohms at a 5000 Primary Z. That sounds about right.

What say you... is this what you'd get or do you know of any other Xfmers that might fit the bill?

Thanks, Tom

[Pdavis68]

Edcor has this, which is quite a bit cheaper. They have a good reputation, but 1> I think they build the transformers to order and I think it's usually a 6 week wait and 2> Their shipping isn't cheap, so you may not save that much unless you're buying a few transformers from them.

Tubedepot has this one. Also cheaper and much more reasonable shipping rates than Edcor.

All that said, Hammond makes excellent transformers of course, and I'm a big fan of Antique Electronic Supply. Their shipping rates are also very reasonable and they ship fast.

[TomCarlos]

Thanks Pete.... The Classictone looks like a good option.

[eschertron]

Thanks Pete.... The Classictone looks like a good option.

+1
FWIW, I believe (calculated, not measured) the OT in my Champ to be about 6-7k on a 3.2R load. So the Classictone with 8k for a 6V6 and the 5k for a 6L6 aught to be worthy of consideration.

[olddawg]

If you can find an old record player, many had 5 watt single ended amps, one or two. Look around. The tape decks, hifi amps, and pas get a lot of attention and a few $. The record players are damaged and useless in most cases and go for next to nothing.

[Pdavis68]

I'm starting to discover what a treasure trove there is in recoverable parts from old electronics. Someone nearby is selling a Baldwin Orgasonic 54A for $25 and I'm so tempted to go buy it, but I recently got a Hammond L101 amp (with percussion & vibrato amps) and 3 old tube PAs a couple of weeks ago and my wife would not be pleased if I brought the organ home. But I could strip it and easily sell the parts for that organ for far more than $25. The amp alone has 6 EL84s and 3 12AX7s. And then there's the iron and the chassis. I'm not certain, but I think there may be another 40 or so tubes in the tone generator along with some big transformers...

Anyway, just sayin', I'm sold on this whole buying old amps and converting/scrapping for parts.

[TomCarlos]

Thanks again for the tips on the OT Recommendations.

Pete, there is a guy here in the Sacramento area who trolls Craigslist and runs his own "Wanted Ads" - looking for just the type of items you are talking about. If nothing else, it's like going on a treasure hunt. Is there tons of money to be made? Eh, probably not. But I bet it's a great hobby to many.

[olddawg]

Hammond amps, old tube PAs and such REGULARLY go for over $200 plus shipping on eBay without the tubes. They sell the tubes separately. Locally you can find stuff. That guy is probably making a small fortune.

[bluto]

If you want the option to run a 6L6 as well as 6V6 it would probably be best to get a xfmr with a higher current and power rating. FWIW the Hammond 125E (also A-D) will work for SE use as well as push-pull and they used to market them that way before the ESE series was introduced. I'm using one in a Gibson GA9 clone with a parallel dual 6V6 SE setup and it works well. Have used my 125E for many amp experiments over the years and it has been very handy for that.

[Pdavis68]

I've read a lot of negative stuff about using the 125E for SE amps (though there have been some positive words too, though harder to find). Hammond did originally market it as both, but they no longer recommend it for SE use and I suspect some of that has to do with all the negative feedback (no pun intended) they got about it. The general consensus has been that "it works" but it doesn't sound nearly as good as a real SE transformer. I'm also under the impression that it gets worse the more power you run through it. But it's probably a really good transformer for an experimental amp setup where you might go SE or PP and don't want to have to have two transformers.

[J M Fahey]

Didn't read the specs but if it's just a regular OT, *no gap* it will be a very poor choice for any SE amp.

I always wonder about posts in beginner's Forums about building an SE amp with a commercial Line transformer as OT and claiming "the best amp I ever heard".

Ok, let's factor in a little of builder's pride ... but not that much