• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

UL Push-Pull Tube Amp (mono combo)

Hi Guys,

i just got a recommendation to join this forum, the perfect place to get some advice for my project they say ... so here i am, greetings to you all :)

Short information about me: My normal domain is technical acoustics which i study as a major atm. Electrical engineering comes as a side effect but is more a hobby than a profession, so my knowledge is still limited. I built my first amp two years ago, an ultralinear Push-Pull Design after Williamson (ECC82, ECC83 and 2 KT88 per Channel) and the result was very satisfying. As it was the first project, i chose a 'lego-like' kit. All parts and housing included, circuit boards already soldered, so i basically just assembled and wired everything.

Now, two years later, a whole lot smarter :rolleyes: and finally some awesome speakers in the living room, i think i am able to realize my original plans. I want to build a new amplification system with the following specs. The speakers are Dali Epicon 6 (88dB/2.83V/m, very linear impedance around 4 Ohm, no srs peaks or drops).

-quite simple mono block design (no knobs at all, except for power on of course)
-around 50-100W per channel
-ultralinear Push-Pull design
-no volume control (via preamp)
-no input selector (via preamp)
-tubes: KT88 (the only one i know really good yet) or some new KT Models (90, 120, 150) to get some Power (i am absolutely no expert yet, always open to suggestions)
-solid state can definitely be used for Bias, Power Supply, etc. signal path tube only if possible.
-if possible i would like to use point to point wiring in all tube stages

I think i am able to manage a proper layout, understand the circuit and of course i know how to handle the high voltage etc. I can use all the instruments in the laboratories of the university, so that should not be a limiting factor.

What i CAN'T do is develop a circuit by myself, so i rely on an existing (and community proved) one. Unfortunately my time is quite limited atm, so i cannot just read the whole forum (would be interesting though). I would really appreciate some tips regarding useful threads and topics to read, or other recommendations.

Cheers,
Robert
 
Last edited:
After a lot of reading, especially the threads above, i realised that it might be not a good idea to try a community created project without proper documentation. I understodd not even half the techtalk :eek:

The archives revealed some threads mentioning the the M-125 Monoblock Kit from tubes4hifi.com (tubes4hifi amplifier KITs page).

They look pretty much like what i want. Push Pull Design, some srs power for my 88db/2.83, 4 Ohms and most importantly, a complete documentation is included.

A quick check brought mostly very positive opinions of other forum members, what do the experts think about this kit? Some changes to be made? Some parts to change?

After some other opinions, i would contact Bob to discuss a plan. As i live in Europe, shipping the whole kit from the US might kill the idea, especially with the heavy transformers...

Cheers,
Robert