OTL guitar amp...

I've been doing OTL guitar amps for some time. Such as this one of many prototypes (my amps dont seem to get past the prototype stage;))
Tube OTL by Devildogamps - YouTube
They are a little different than the classic transformer coupled pentode amps. The OTLs I build using triodes have very little 'tube compression' in the output stage. This is great for highly dynamic styles of playing, but can be a bit 'handful' for styles that require a more steady volume. Of course, that just makes for an excuse to get a good compression pedal, and one can't have enough pedals.

Atmasphere even had an OTL for guitar under the brand 'Rendition Audio' but I cannot find it when googling, so perhaps it no longer is?
 
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Just for interest,
<snip>
I guess it will get moved to the Instruments forum...I think it would interest some here!

Its only for interest they can be made..

Regards
M. Gregg

Yep, it will since that is where it belongs per forum policy.. :D

It is interesting, and I'd encourage any members who are into guitars and amps to mosey over to the Instruments and Amps forum whenever they can..
 
I've been doing OTL guitar amps for some time. Such as this one of many prototypes (my amps dont seem to get past the prototype stage;))
Tube OTL by Devildogamps - YouTube
They are a little different than the classic transformer coupled pentode amps. The OTLs I build using triodes have very little 'tube compression' in the output stage. This is great for highly dynamic styles of playing, but can be a bit 'handful' for styles that require a more steady volume. Of course, that just makes for an excuse to get a good compression pedal, and one can't have enough pedals.

Atmasphere even had an OTL for guitar under the brand 'Rendition Audio' but I cannot find it when googling, so perhaps it no longer is?

We still do. The website is being moved.
 
As I said in another similar conversation about OTL guitar amplifiers, this is my personal contribution of research and dedication for more than five years on guitar amplifiers 0TL.

The solution to a complex problem and its practical realization is not so much in the difficult way to solve it, but in the incredible simplicity of its simplicity, that can be before our eyes and go unnoticed, until this is achieved.

Sounds of some guitars whit my OTL Amps,
All in higth impedance:

Amplificadores de Válvulas OTL sin Transformador de Salída, Muestras de Sonido.
 
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You are naughty Fahey. You made me look and I have to contribute😊:
1. Does OTL mean a tube amplifier type that is cheaper because it doesnt need an output transformer?
2. The mentioning of less compression in the output stage makes me think; Why not transistor or class D then? For me an electric guitar sounds dull and thin, has eardamaging attack, very little sustain and is really just an unpleasant instrument without the distortion and compression from an amplifier. Some few transistor amps like Roland Jazz Chorus were popular with yeah; Jazzplayers. I think they strike very softly to make the sound bearable. Roland Cube was just not great at all. Bad sound of transistoramps could be remedied to some extent with pedals or other effects but nothing beats a tubeamp. Today Its different I think with all the simulation software, but then why not just play through a monitor/PA?
Cheers!
 
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Oh, contributing to a thread with useful information is FINE.

Not for the troll who in´t really interested on advice , just rocking the boat for fun, but for somebody else who reads it.

Now, wasting time trying to convince him about his errors?
Waste of time, by definition he won´t listen or will twist meanings so another good Samaritan tries to explain and so on, attracting more and more well intentioned people into the fray.
His maximum goal/pleasure would be to have 2 or 3 Forum members arguing each other to death, for dozens of pages.

FWIW I DID answer, wasted time, researched data and pictures, tried to maake it simple.

But did that once.
When I saw it was just a (bad) joke ... bye bye Baby,
 
1. Does OTL mean a tube amplifier type that is cheaper because it doesnt need an output transformer?
Haha. You wish.:ROFLMAO:

By eliminating the transformer the topology just adds myriad of new problems and solving them doesn't come cheap.

2. The mentioning of less compression in the output stage makes me think; Why not transistor or class D then?
Yes, why not?

Futterman, one of pioneers of OTL design, even admitted that MOSFET devices basically rendered his tube designs obsolete. The device was just superior for the particular application. In same topological design (we don't even need to change circuit architecture) they solve the difficult issues of e.g. decreasing output impedance, very high drive voltage requirements of output devices and complex drive arrangements of unipolar devices.

Look at, say, Moscode. It's a Futterman amp that replaces the complex, unreliable and expensive output stage with simple, reliable and cheap Mosfet circuit that essentially isn't much different from the original.
Now some hybrid musical instrument amps from Randall or Ampeg/Crate are basically clones of the Moscode topology. It's actually commercially sane design.
 
Both M Gregg and efeemeka were writing about OTL for 800 Ohm loudspeakers. With 2 x EL86 you can construct a very simple, low partscount OTL output stage for such loudspeakers (see page 3 of the attached datasheet for the EL86).

I'm a bit puzzled about this thread. I don't see a clear reason for the accusation of being a troll. But probably (?) the reason for it lies (mostly) outside this thread.
 

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@teemuk That is interesting. I knew a guy who wanted to design a "Mosfet tube amplifier"

I was given a Crate 12" combo with very noisy pots. Sounded very good when I finally got to try it out. Ive since cleaned the pots to perfection, but had no time to play with it. I wonder if its a Moscode type.
Ive never experiensed tubeamps as unreliable though. -Ive never seen one fail, but then I almost only used them for instrument amplification and no diy.
@PFL200 Im puzzled too. Maybe the troll post was deleted.
Cheers!
 
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