Both chanels at full power with sinus, drain 620 watts from the wall. 400W AT IDLE.
1200W peak at startup.
Here is my new build after 40+ years of abstinence. Nothing to brag about, but I'm happy with the result. It's based on a Eico HF-89 schematic, everything worked out of the box, sounds great, revs up to 26W cleanly before distortion appears, mainly clipping on both sides. Sounds very good too, at least to my untrained ears.
Thank you for your kind words!
Here are some more pics. I'm not the tydiest builder in the world, so please go easy on me 😁
Hmmm, pics did not get attached, let me try again
Where do I start...
Physicist by education (Odessa State University), sold to the capitalists in 96 because science was not paying the bills, since them working for companies that design and manufacture Point Of Sale terminals (a.k.a credit card machines in the UK). Mostly as a system engineer, 90% software, 10% hardware. That job pays for the hobby.
I've been thinking about building a single ended amp, triode based. But I want something straightforward and cheap, no fancy tubes like 300B or those high voltage monsters like GM-70 etc. I've got a bunch of 6N6 triodes, been simulating in LTSpice, looks like I can get 10W from 4 tubes in parallel with a 6N2P driver, with reasonable distortion. But simulation is one thing, real build will probably be more challenging. Also, decent single ended transformers are not cheap. Will probably make a prototype first.
6CK4 octal base triodes. Two per single ended channel.
They do work great in push pull, but single ended should work well too.
Save money . . .
Take a medium to large sized used Push Pull output transformer, remove all the E and the I laminations.
Re-stack all the E's on one side, put a layer of Kapton tape (or other tape) on the open end of the E's, and stack all the I's on the tape.
(Kapton tape becomes the air gap).
Have fun building and listening to a single ended triode amplifier.
They do work great in push pull, but single ended should work well too.
Save money . . .
Take a medium to large sized used Push Pull output transformer, remove all the E and the I laminations.
Re-stack all the E's on one side, put a layer of Kapton tape (or other tape) on the open end of the E's, and stack all the I's on the tape.
(Kapton tape becomes the air gap).
Have fun building and listening to a single ended triode amplifier.
I thought about it, but has a weird socket, high heater currents, gets extremely hot. Too troublesome for me. I also realised that 20W stereo makes my living room vibrate. 10 should be enough.
Is a good choice, but not for me.
Interesting... I may end up doing that, thank you!
It may be challenging to find a cheap used PP with the right impedance though. Time for some e-Bay browsing.
----
Just looked around for 6CK4, nothing in the UK, all options are from the USA, cheapest around £22 delivered. Pity because it looks like an interesting tube.
I have also looked at the 6N13, but I get better simulation results with the 6N6. Real build may be different though.
Last edited:
SE in not a complicated tube and straightforward design?
Check out George at tubelab and his website (he has a forum here also under the manutacturers/vendor section) and his SimpleSE (SSE). KT88, EL34, and 6550 if you want to push it. The KT88 and EL34 setup does the trick for me and you can switch between the two.
Check out George at tubelab and his website (he has a forum here also under the manutacturers/vendor section) and his SimpleSE (SSE). KT88, EL34, and 6550 if you want to push it. The KT88 and EL34 setup does the trick for me and you can switch between the two.
Thank you, had a look there some time ago. Is all good, but I'm fixed on using triodes, not pentodes/tetrodes in triode mode. I'm not saying they are not good, but is not what I'm looking for. Also I want sometbing easy to drive, no mosfet drivers, no class A2. A CCS is fine though 😁
