Why, Priboy is only PP big power, not with good sounding. Tubes are bad, people change it to GU50 for better sound.
I have first layout PCB v1.0 for GU50 same schematic .
Attachments
Thank you for the nice comments.
The circuit designs are all from Bronski's web sight.
The power supply consists of a twin, tube rectified designs with filter chokes. (5AR4/GZ34)
The heater supply is twin 6.3VDC regulated at about 4.2 amps per side.
In the centre, with the stinger heat-sink, is the 12v linear regulated supply for the accessories.
The iron is Hammond. EH tubes
The pre-amp case contains a p to p Aikido Balanced Octal circuit.
Two T Reg s from the DIY store.
Driver boards for the magic eyes.
Khozmo remote and attenuation.
Electro Harmonics 6SN7.
The machine work is mine, a semi retired guy with way too much spare time on his hands.
It glows in the dark too...
The circuit designs are all from Bronski's web sight.
The power supply consists of a twin, tube rectified designs with filter chokes. (5AR4/GZ34)
The heater supply is twin 6.3VDC regulated at about 4.2 amps per side.
In the centre, with the stinger heat-sink, is the 12v linear regulated supply for the accessories.
The iron is Hammond. EH tubes
The pre-amp case contains a p to p Aikido Balanced Octal circuit.
Two T Reg s from the DIY store.
Driver boards for the magic eyes.
Khozmo remote and attenuation.
Electro Harmonics 6SN7.
The machine work is mine, a semi retired guy with way too much spare time on his hands.
It glows in the dark too...
Beautiful job! I can appreciate all the time and effort that went into the design and construction. I've never been able to get my wiring harnesses to look like that.
Does including the heater wiring in the wiring harnesses increase hum at all?
Does including the heater wiring in the wiring harnesses increase hum at all?
Thanks.
I have to go through the challenge to get great results and I am happy for this.
I don't have a noise tester, but with my ears listening, I'm fine.
Member
Joined 2009
Paid Member
Here's a new build I did this week.
I show the metal work because it's so easy if you use a silver acrylic pen... If you make a mistake, you can correct it with spit. When you're finished, IPA wipes it off.
It uses a Hammond 278CX PT, 1650N OPT, 193Q choke. The SMPS in the back powers the heaters and the DC-DC boost converter for the front end.
Schematic is in the Modular Amplifier 1 thread (https://www.diyaudio.com/community/threads/modular-amplifier-1.375206/) (My typical 6F12P - 6SN7 front end) - the only difference if PSU which is in this case 560V for the outputs and 560V from the boost for the front end, and the OPTs.
It started as UL but there's too much gain (and the Hammond transformers have more phase shift at HF than the toroid setup I usually use) for my NFB set up and it was "marginally stable" so it's now a triode connection. It's auto biased using 600R dale and 23000 hour @ 105°C Kemet 470uF cap per tube, Then it was "hummy". There was 1V RMS of hum which in a good transformer CMRR would cancel. These aren't like the toroids I usually use though as I said, so I had to add the choke. PSUD sim said ~3V without the choke, and 30mV with it and it shows - no noticeable hum - and I told off my Guinea pigs for chewing too loudly earlier LOL
I was tired of the old build on it's flimsy aluminum chassis and with it's poorly done point to point wiring from years ago. I'm also trying to get rid of it and I think it's nicer now then ever and it has new 6550 tubes 🙂
If you're near Toronto and want a working 6550 amp with new tubes for 1000$ (the coils alone cost that - I just don't want it) it's on offer.
EDIT: Underside pic was taken before I installed the choke, but there's nothing to see. Also, the boost with the silver heatsinks failed in 2 minutes - so did a second one. I swapped it in for one with the black heatsinks (older version?) and it's fine as expected (like the other 20 odd units I've used already). Bad batch maybe, but I'd avoid the silver heatsink version.
Happy Sunday!
I show the metal work because it's so easy if you use a silver acrylic pen... If you make a mistake, you can correct it with spit. When you're finished, IPA wipes it off.
It uses a Hammond 278CX PT, 1650N OPT, 193Q choke. The SMPS in the back powers the heaters and the DC-DC boost converter for the front end.
Schematic is in the Modular Amplifier 1 thread (https://www.diyaudio.com/community/threads/modular-amplifier-1.375206/) (My typical 6F12P - 6SN7 front end) - the only difference if PSU which is in this case 560V for the outputs and 560V from the boost for the front end, and the OPTs.
It started as UL but there's too much gain (and the Hammond transformers have more phase shift at HF than the toroid setup I usually use) for my NFB set up and it was "marginally stable" so it's now a triode connection. It's auto biased using 600R dale and 23000 hour @ 105°C Kemet 470uF cap per tube, Then it was "hummy". There was 1V RMS of hum which in a good transformer CMRR would cancel. These aren't like the toroids I usually use though as I said, so I had to add the choke. PSUD sim said ~3V without the choke, and 30mV with it and it shows - no noticeable hum - and I told off my Guinea pigs for chewing too loudly earlier LOL
I was tired of the old build on it's flimsy aluminum chassis and with it's poorly done point to point wiring from years ago. I'm also trying to get rid of it and I think it's nicer now then ever and it has new 6550 tubes 🙂
If you're near Toronto and want a working 6550 amp with new tubes for 1000$ (the coils alone cost that - I just don't want it) it's on offer.
EDIT: Underside pic was taken before I installed the choke, but there's nothing to see. Also, the boost with the silver heatsinks failed in 2 minutes - so did a second one. I swapped it in for one with the black heatsinks (older version?) and it's fine as expected (like the other 20 odd units I've used already). Bad batch maybe, but I'd avoid the silver heatsink version.
Happy Sunday!
Attachments
Last edited:
Wow, a nice amp! do you have volume control or just 2 channels input selector?