I'm looking to build a small low gain or even unity buffer pre-amp to feed a low power class-A power amp (Sugden Musicmaster). I would like to keep it in the same footprint as the power amp, probably looking very similar to the current pre/headphone amp (Sugden Headmaster) which I hope to replace/improve on. This gives me a working area of about 200mm wide, 230mm deep and 50mm height to work within, hence I'm looking at miniature valves. I would like remote input switching (4 inputs, this can be simple switched relays) and remote volume (motorised Alps blue probably).
My skill level is more accurate copying than looking to come up with anything novel, hence I'm looking at SRPP designs and the Aikido and Aikido Cathode Follower designs. I can get away with very little gain, my current Headmaster has a gain of about 16.5dB which is more than I need (a 10dB pad would be handy). My main digital source has a 2V output which is enough to clip the power amp (1v input I believe) so a simple buffer with volume control and input switching could be viable. I have no intention of driving headphones from this, just the power amp.
I've looked at:
The Lampizator SRPP scribblings on his site: http://lampizator.eu/LAMPIZATOR/MIKRO/Mikrolampizator.html
The Aikido and ACF pages of the glassware site: https://glass-ware.stores.yahoo.net/newhardware.html
This Preamp: https://www.diyaudio.com/community/...wer-with-printed-circuit-board-design.206415/
Does anyone have any suggestions or experience they would be willing to share?
Many thanks.
My skill level is more accurate copying than looking to come up with anything novel, hence I'm looking at SRPP designs and the Aikido and Aikido Cathode Follower designs. I can get away with very little gain, my current Headmaster has a gain of about 16.5dB which is more than I need (a 10dB pad would be handy). My main digital source has a 2V output which is enough to clip the power amp (1v input I believe) so a simple buffer with volume control and input switching could be viable. I have no intention of driving headphones from this, just the power amp.
I've looked at:
The Lampizator SRPP scribblings on his site: http://lampizator.eu/LAMPIZATOR/MIKRO/Mikrolampizator.html
The Aikido and ACF pages of the glassware site: https://glass-ware.stores.yahoo.net/newhardware.html
This Preamp: https://www.diyaudio.com/community/...wer-with-printed-circuit-board-design.206415/
Does anyone have any suggestions or experience they would be willing to share?
Many thanks.
You don't need to use subminature tubes, your 50mm height restriction means you will need to turn tubes sideways anyway. Fitting 7- or 9-pin tube sockets on 90-degree brackets will probably be necessary. The height restriction also means you will need a toroid mains transformer.
The preamp I show below is 115 x 185 x 53mm. I use a remote power supply but at least it gives you an idea of how compact it is.
7-pin tubes are smaller but you will need 9-pin for a twin triode like a 6CG7 which is more compact because both triodes are within the same tube.
You should be able to fit your size requirement but it will take some design tweaking on your part.
Matt
7-pin tubes are smaller but you will need 9-pin for a twin triode like a 6CG7 which is more compact because both triodes are within the same tube.
You should be able to fit your size requirement but it will take some design tweaking on your part.
Matt