Hi!
Who wants A2 driver boards (boards only, no components), please PM me. I ordered a batch and expect to have them in 1 week. The bottom MOSFET is depletion mode, for a simpler CCS. The top one can be either enhancement, or depletion mode MOSFET. The board contains an anode load
resistor of a previous stage tube, a coupling capacitor, and a source follower loaded on a constant current source. One trimpot sets idle current of the source follower, another one sets bias of the power output tube. For SE amp you need one per channel, for a PP amp, of course, a pair per channel.
They were designed for my Gubernator-71 amp, to drive grids of GK-71 tubes. They would be handy as well driving GM-70 or 300B that would be a waste of precious tubes if to drive in A1 only.
Who wants A2 driver boards (boards only, no components), please PM me. I ordered a batch and expect to have them in 1 week. The bottom MOSFET is depletion mode, for a simpler CCS. The top one can be either enhancement, or depletion mode MOSFET. The board contains an anode load
resistor of a previous stage tube, a coupling capacitor, and a source follower loaded on a constant current source. One trimpot sets idle current of the source follower, another one sets bias of the power output tube. For SE amp you need one per channel, for a PP amp, of course, a pair per channel.
They were designed for my Gubernator-71 amp, to drive grids of GK-71 tubes. They would be handy as well driving GM-70 or 300B that would be a waste of precious tubes if to drive in A1 only.
Attachments
No problems. PM me your address. I expect them to be delivered this Saturday, so can ship the next morning in an envelope. The shipment will cost such a way under $4, instead of $32.25 in the package.
Here are assembled boards, just for the reference:
Attachments
I received boards, packed and shipped them. Based on what I paid for shipment, you can get 4 boards including shipment worldwide for $10 total in an envelope. For more boards worldwide shipment would cost $14.
Also, I can share some power supply boards, $1 each + $4 shipment of 1 or 2, more would not fit into an envelope. The board contain places for 2 dectifier diodes, 3 filter caps (external choke, and 1 resistor on the board), plus a MOSFET for a voltage regulator, with an external VR tube. Also, Shottky rectifier can be mounted with up to 4 filter caps for a filament DC, like 8.4V for compactrons from 2x6.3V.
All my boards are designed to fit under 1U chassis.
Also, I can share some power supply boards, $1 each + $4 shipment of 1 or 2, more would not fit into an envelope. The board contain places for 2 dectifier diodes, 3 filter caps (external choke, and 1 resistor on the board), plus a MOSFET for a voltage regulator, with an external VR tube. Also, Shottky rectifier can be mounted with up to 4 filter caps for a filament DC, like 8.4V for compactrons from 2x6.3V.
All my boards are designed to fit under 1U chassis.
Attachments
Could you show an unpopulated board. I'm thinking about the footprint for the trimmers. All three pins in a row or the center pin offset.
Thanks
Evan
Thanks
Evan
Yes;
you can use 2SK2700 for the upper part, a source follower. But for the lower part, CCS, you need a depletion mode MOSFET.
By the way, 2SK2402 that I use in the upper position have internal Zener to protect it's gate from overvoltage. If you use MOSFETs that do not have Zeners, I strongly suggest to add one on the rear side of the board.
I still have some boards if you want. Email me at info@wavebourn.com
I do not visit the forum frequently, my apologies.
I do not visit the forum frequently, my apologies.