Works perfectly. Sounds incredible. No noise. No pops. No heat issues. Running about 140V at the plates.
It even works well as a boost/OD pedal into another amp. I've mostly been using it into a Two Notes CAB M cab sim for headphone playing and it sings.
Been using it for a couple weeks but I just finished the faceplate today.
I've built a bass preamp with DI-out and an active tone stack with the very same tubes with pleasing results. My tubes are sticking out to the top for cooling reasons and are fenced by drawer handles. Got some PCBs left in case there is interest...(based in Germany)
Power Input is a standard 12V Wall-Wart or pedal supply, the V-Pump delivers around 240V (adjustable), heaters are 12V in series (the tubes are russian Mil-spec with tight tolerances, works fine)
by far not as pretty as yours, but it was an experiment very much worth the effort. Especially as a bass player you can have your sound with you, even if you leave the heavy gear at home.
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The sweet spot I've found with this is with the B+ at 210V and about 140V on the plates. That's with a 9V True Tone 1-spot plug. I've got a lead on a 12V plug that I need to order and try.
It really needs some stress testing and updates before I'd put any PCBs out into the wild. I wasn't sure what power supply I'd be using, so I went with 6V regulators for the heaters. These put out as much, if not more heat than the tubes. If the 12V supply doesn't oscillate with the SMPS, I'd change it up to run the 6V heaters in series from the 12V input.
There are also some other tweaks I'd have to make so it's easier to build.
chaccmgr wrote: ↑Tue Mar 02, 2021 12:29 pm
looks great! Any sound samples yet?
I've built a bass preamp with DI-out and an active tone stack with the very same tubes with pleasing results. My tubes are sticking out to the top for cooling reasons and are fenced by drawer handles. Got some PCBs left in case there is interest...(based in Germany)
Power Input is a standard 12V Wall-Wart or pedal supply, the V-Pump delivers around 240V (adjustable), heaters are 12V in series (the tubes are russian Mil-spec with tight tolerances, works fine)
by far not as pretty as yours, but it was an experiment very much worth the effort. Especially as a bass player you can have your sound with you, even if you leave the heavy gear at home.
I'd love to build one of those so please PM me for details. I'm in London by the way......UK.....remember? that country that used to be in the European Union !!!
Jubal, that turned out great, nicely done! I thought the same re using 12V input and powering the filaments directly; fewer parts and less heat. For anyone who might want to play with this concept, there are some pre-built boards available that can supply ~300V from 12 (basically the same SMPS circuit), so going with 2x 12AX7 and voltages very close to the full-size amp would be do-able. 12V 1A SMPS wall plugs are easy to find, too.
martin manning wrote: ↑Tue Mar 02, 2021 10:35 pm
Jubal, that turned out great, nicely done! I thought the same re using 12V input and powering the filaments directly; fewer parts and less heat. For anyone who might want to play with this concept, there are some pre-built boards available that can supply ~300V from 12 (basically the same SMPS circuit), so going with 2x 12AX7 and voltages very close to the full-size amp would be do-able. 12V 1A SMPS wall plugs are easy to find, too.
Martin,
Would you be able to give info on the power supply boards you are talking about? I am building an all pc board (except tube) dumblator that was originally going into a 124 based amp. After reading the issues others have had with an in the amp application, I've decided to house it in a separate box and use a separate power supply. I need 1 B+ point with 250-350v.
jcsifu wrote: ↑Wed Mar 03, 2021 6:54 amWould you be able to give info on the power supply boards you are talking about? I am building an all pc board (except tube) dumblator that was originally going into a 124 based amp. After reading the issues others have had with an in the amp application, I've decided to house it in a separate box and use a separate power supply. I need 1 B+ point with 250-350v.
The stand-alone D'lator supply is traditionally a small plate/filament transformer and rectifier/filter board, with rail voltages of 260 and 360VDC. You can find a schematic for that in the files section: https://ampgarage.com/forum/viewtopic.p ... 73#p413673
This SMPS has enough voltage for the plate supply, and includes a low voltage side for the filament: https://www.ebay.com/itm/DC-12V-to-150V ... Sw4qxap6GE
Its current capacity is far more than what is needed, but it's still cheaper and smaller than the original linear supply. If you look you may find others.
