What are the trade offs? PUSH PULL vs. pure SET

Is the triode circuit of a push pull design compromised because of its ability to go to Pentode/Tetrode? Is the triode circuit in a push-pull even considered to be single ended. ?

If not what differentiates the design from pure SET?

Thank you

Groovey Records

Listening to
The Rolling Stones- Rolling Stones Records 10C 06:063616-w/ "Let it Rock" live -Spanish Pressing & Cover-Fowlers Treacle Sticky Fingers in a Can
Yes, the triode operation of an amplifier that has tetrode or pentodes is compromised. Such tubes in triode mode are not as linear as real triodes.

In triode mode, a push-pull amp still differs from a triode amplifier that is single-ended. Push-pull has greater power and wider bandwidth, but also *more* distortion at low power levels. SETs have vanishingly low distortion at low power levels, on account of the way the output transformer behaves when operating single-ended (no hysteresis loss) as opposed to push-pull (where hysteresis loss causes a loss of low-level detail due to increased distortion).

Of course there is more but that's a good place to start...
Thanks Atmasphere

it is always a compromise

look at this link from Steve Vaughn's Home page


best to you


Listening to Simon & Garfunkel-Bridge Over Troubled Waters- the Only Boy Alive in NYC
Hi Groovey, thanks for the link. In general Eddy is on the money. He does leave out some details that *I* think are important- namely OTL amplifiers.

Take away the output transformer and you remove most of the arguments for SE. So it then becomes possible to have more of the best of both worlds- low harmonic generation along with power and bandwidth. Negative feedback remains optional (in my case I disdain it as it robs the music of soundstage depth and adds and undesirable 'sheen' on top).

All the Best!
Hi Atma-Sphere
After you responded to my thread your moniker rang a bell and i remembered hearing about your designs elsewhere (Arthur Salvatore's woofer in sheeps clothing) so I looked in on your site and read alittle here and there.

I am still at the research stage and will leave my final decision a while longer.

When I asked Arthur specificly about OTL he said "Everything being equal, I still prefer SET amps or amps using DHT output tubes, but a good OTL amp can be an excellent choice depending on the speakers."

In that context my room is very large with a cathedral pine ceiling walls and floors. I have 89db 8ohm JBL 240 Ti that I enjoy very much. They are a full frequency speaker, not as low as a sub but claim 37hz- 27k. For now they are my systems strength not its weakness.

As for the present thread where does DHT output tubes fit into the big picture
Are they a design option for SET alone or are they more VERSITILE fitting into PP, SET,and OTL design parameters ?

I only have enough knowledge to be dangerous so please share what you can.

Best Regards

Groovey Records

Listening to- Charlie Mingus-Blues & Roots-Atlantic SD 1305