A2 driving boards (for tube amps)

[Wavebourn]

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.

 

[ArcticBrew]

How many are available?

I would like to acquire 4 boards.

Steve

 

[Wavebourn]

How many are available?

I would like to acquire 4 boards.

Steve

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:

 

[d to the g]

I’d like a pair.

 

[Wavebourn]

I’d like a pair.

PM your address.

 

[Wavebourn]

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.

 

[Wavebourn]

Power supply board:

 

[evanc]

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

 

[Wavebourn]

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.

All 3 in a row.

 

[evanc]

Thanks

 

[evanc]

I wanted to say a thank you to wavebourn for the driver boards. They are a very compact, taking up much less space then my previous set up. Plus the price is very fair.

Cheers
Evan

 

[Wavebourn]

I wanted to say a thank you to wavebourn for the driver boards. They are a very compact, taking up much less space then my previous set up. Plus the price is very fair.

My pleasure!

 

[dady]

Hi dear friend and venerable diy, could I use sk2700 in this circuit?
Best Regards

 

[Wavebourn]

Hi dear friend and venerable diy, could I use sk2700 in this circuit?
Best Regards

Yes;

you can use 2SK2700 for the upper part, a source follower. But for the lower part, CCS, you need a depletion mode MOSFET.

 

[dady]

Thanks dude

 

[Wavebourn]

Thanks dude

You are welcome dady

 

[Wavebourn]

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.

 

[gillougillou]

Mistake

 

[Wavebourn]

I still have some boards if you want. Email me at info@wavebourn.com
I do not visit the forum frequently, my apologies.

 

[gillougillou]

Hi thank you, you got an email.

Gilles.