Toroids as output transformers....

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Another approach might be to opt for a design that doesn't require large output impedances. The Circlotron or the Philips SEPP OTL designs come to mind - half the output swing and fourth the output impedance, compared to a conventional PP amp with the same pair of tubes and the same output power. And it doesn't need a tapped primary winding.
Best regards!
 
Hi

Using PTs as OTs is nothing new, but even for guitar where functionality rules over performance, PTs can sound pretty awful even if they are toroids. The reasons why this is the case have been described accurately in this thread. Lots of people podge together little amps for background music using PTs as OTs and that works okay.

Pete Traynor tried noninterweaved OTs as an experiment and never used them in production as they sounded too bad even for his simple music taste of clean tones. For a distorted tone, the intermodulation produced by a PT is horrendous - not musical at all - where the normal THD prodiuced by an over-driven EI OT can be smooth.

As KOC points out, because toroids are nearly perfect in their designed function, they fail in a nearly perfect way, too. Too much bass through even the best high-fidelity toroidal OT will cause a "clink" sound. Totally nonmusical. kevin uses toroidal OTs in his amps and they sound fantastic. He says it matches the use of Power Scaling better as the OT imparts no sound of its own so the loud sound and quiet sound are the same.

The DC imbalance issue is not so much of a problem as people say UNLESS the OT has crazy high inductance. Vander Veen's OTs are like this, so maybe they are sensitive to such imbalance. Even a "bad" or not critically designed toroidal OT will sound much cleaner than the best EI OT, but will not be any more sensitive to DC imbalance than an EI. Again, I have to refer to Kevin O'Connor 'cause he uses toroids for output but you can run the amp with just one tube if you want and it still sounds awesome.

So, I think there's a lot of warning against toroids all around just because people don't know how transformers work? Fender didn't use toroids so they can't sound good, right?
 
rifraf50 said:
I knew that i was gonna get a fair slapping for entertaining the thought that these can actually sound quite good in guitar amp service.....but it did !!!

What i did was a very quick and rude application to prove whether it was worth evaluating even further ......and my ears told me it was
You talk as though you had a bright idea which nobody has ever thought of before, and when you suggested it everybody said it wouldn't work and you were daft to even try it but you forged ahead as a pioneer anyway.
None of this is true. People have thought of it, tried it, and found it works - to some extent. We have pointed out some potential problems; if this is what you call "slapping" then your cheeks will often be red on this forum.
 
hi , this is all about the use of toroid transformers and changing them to suit your needs.... which is surprisingly simple to do and with good results ....

I went this way because i found more critics condemning them because they are not" HIFI" but neither are guitar amps...

No i'm not someone who thought i was the first to come up with this idea nor am i trying to be some sort of hero or whatever....when i looked for practical information on this issue i found very little....hands on stuff that is ....

So i asked myself ....how bad can they be ? ....and how hard is it to do ?

i did find some notes about how some folk used them in low power situations or how some used them in hifi situations and wasnt pleased with the outcome...and there are some hi end makers utilising the toroid trannys...made to their spec of course...

Well i wanted to make another guitar amp and thought if i dont like the converted toroids i will swap them out ......simple

the amp in the video was bought for $60 ...it was a blown solid state amp .....these make good bases because they are loaded and come with speakers and a chassis ....a great starting point

The tubes used are 6cz5 / 6em7 television valves....and 6av6 as preamp tubes with the addition of a brimar 6br7 on its own channel ....the PI is a 6c4 cathodyne style

A pair of 6cz5 ar good for 21 watts

Thing is you can make your tranny to suit whatever tube you have....

This amp is load , its sweatly clean and filthy dirty ...it ticks all the boxes needed for gigging , of course sound is subjective so some are going to refute what i have done here .......but its simple

Toroids can be utilised in this manor effectively ...and at low cost

this whole thing was about building a cheap affordable tube amplifier utillising parts that may have not been considered in the past, and this was less than $150.00AUD all up

if you want to see it then follow link , YouTube



cheers rifraf
 
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The transformers...

The transformers...
 

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