GU-29 headphone amplifier schematic

[giorgos]

Hello,
I have a lot of NOS gu-29 tubes with sockets. I want to make a simple headphone amplifier. Just a quick project for fun. I have seen some chinese stuff with a ONE tube for both channels. I will drive the amplifier with the output of my preamplifier QUAD-33

Any schematics for a simple project? Need to be small, thats the reason for one tube. I want to use real HV not the chinese 12-24 versions on anodes.
Any help please would be great!!

Thanks
George

 

[PRR]

Not 12V so.... 100V? 600V?

Output transformers or no?

What range of headphone impedances?

Using a HIGH power radio tube for a small headphone amp, you have to do these decisions.

 

[aspringv]

Neith of these is a gu-29 but we're closeish... I have one of these mid build that I can send the schematic for that may suit? I've collected the parts for this however thats not a headphone amplifier either. I do have plans to also build this though which answers the problem of impedance. I mention the latter as getting or improvising an output transformer is easier with a push pull setup!

 

[giorgos]

Hello,
yes for output transformer and the impedance is around 55 ohms
Thank you for the answer
The plan is to use each tetrode for each channel, need to be small and one tube, any help please

 

[PRR]

200V plate and screen, couple-K load, makes a couple Watts.

That's way more than headphones need. So you could probably go 100V for about a third of a Watt.

I have no idea where to find 2.5k:55r sub-Watt transformers.

Note that the heater requirement of 12 Watts seems absurd for a part-Watt amplifier.

 

[giorgos]

200V plate and screen, couple-K load, makes a couple Watts.

That's way more than headphones need. So you could probably go 100V for about a third of a Watt.

I have no idea where to find 2.5k:55r sub-Watt transformers.

Note that the heater requirement of 12 Watts seems absurd for a part-Watt amplifier.

i will ask a friend here with a transformer shop if he can wound one output transformer
yes the heaters are little overkill for that amplifier, but its a project for fun