Sure, I should get the resistors in early next week. They aren't going to be super easy to change out because I used those big 25V electrolytics for the heaters instead of 16V, so I need to take the PCB out and solder them to the top of the PCB... I'll text you when its ready.
Here's my version of Aikido. It uses 6N1P-EV and 6N6P tubes.
B+ 220V, 6.3V heaters, cathode resistors - 430R, transformer - dual primary, secondaries 250V, 2x7.5V (in parallel for 4A).
Sounded excellent while in my possession. Building another one, this time I intend to keep it. Will post pics later.
B+ 220V, 6.3V heaters, cathode resistors - 430R, transformer - dual primary, secondaries 250V, 2x7.5V (in parallel for 4A).
Sounded excellent while in my possession. Building another one, this time I intend to keep it. Will post pics later.
Attachments
Yet another build...
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Finishing another Aikido, this time with elevated AC filaments. Initial test show that this is the path worth taking - less heat, less load on transformer, and absolutely no hum, plus it sounds great.
Transformer - Edcor dual primary, 250V @ 200ma + 6.3V @ 3.5A secondary. B+ adjusted to 240V with 230V at the anodes. Tubes 6n1p and 6n6p, cathode resistors - 330R so the tubes are biased for a bit more current.
I had to cut some traces in order to do elevated AC filaments. It would be just great having such option ready on the board, something JB could probably work into his next design.
Now it is time go start fabricating that chassis.
Transformer - Edcor dual primary, 250V @ 200ma + 6.3V @ 3.5A secondary. B+ adjusted to 240V with 230V at the anodes. Tubes 6n1p and 6n6p, cathode resistors - 330R so the tubes are biased for a bit more current.
I had to cut some traces in order to do elevated AC filaments. It would be just great having such option ready on the board, something JB could probably work into his next design.
Now it is time go start fabricating that chassis.
Attachments
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I am just basically documenting my own work here.
Here testing new configuration of Aikido with CLCRC power supply and 6N1P - 6N6P tubes. Voltage on the plates +270V, Rk - 360R on both tubes. Used Kiwame for Rk, Allen Bradley CC for grid stoppers, TDK CM2 as power resistors in final RC stage, Dale precision is the rest. Coupling caps - Auricap. Overspecked power transformer, Hammond 10H 100ma choke. Elevated AC heaters (JB, please put jumpers on the board for AC heater elevation)
Preamp sounds excellent, much better than with any regulated power supplies I used in the past (a lot of help from PSUD2). Also tests show that 6N6P sounds better when biased "hot".
Everything will be put in a nice chassis.
Here testing new configuration of Aikido with CLCRC power supply and 6N1P - 6N6P tubes. Voltage on the plates +270V, Rk - 360R on both tubes. Used Kiwame for Rk, Allen Bradley CC for grid stoppers, TDK CM2 as power resistors in final RC stage, Dale precision is the rest. Coupling caps - Auricap. Overspecked power transformer, Hammond 10H 100ma choke. Elevated AC heaters (JB, please put jumpers on the board for AC heater elevation)
Preamp sounds excellent, much better than with any regulated power supplies I used in the past (a lot of help from PSUD2). Also tests show that 6N6P sounds better when biased "hot".
Everything will be put in a nice chassis.
Attachments
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Let's see:
aluminum chassis - $82
power transformer - $52
transformer cover - $29
tubes - $40
Hammond choke - $24 ($19+$5 shipping)
Relay volume control - $37
3 pairs of RCA - $15
Alps pot - $14
PS-7 power supply - $19
Aikido noval PCB - $39 (+shipping)
Angela tube sockets (4) - $20
Kiwame, Allen-Bradley, TDK, and Dale resistors - $60
Auricaps (2) - $76
misc caps, resistors, wire, cable, heatshrink tubing, hardware (torx bolts) ~ $50
I also added the remote control to this preamp - $24
The raw cost of parts comes out to ~ $600. Add tools (drills, hole punches, etc.) and lots of time.
The cost of parts depends on the quality of them. You could use Russian K40-Y9 coupling caps that sound excellent and are a bit cheaper than Auricaps, dispense with remote and relay volume control, use cheaper transformer without cover. Cost of parts would go down under $450.
aluminum chassis - $82
power transformer - $52
transformer cover - $29
tubes - $40
Hammond choke - $24 ($19+$5 shipping)
Relay volume control - $37
3 pairs of RCA - $15
Alps pot - $14
PS-7 power supply - $19
Aikido noval PCB - $39 (+shipping)
Angela tube sockets (4) - $20
Kiwame, Allen-Bradley, TDK, and Dale resistors - $60
Auricaps (2) - $76
misc caps, resistors, wire, cable, heatshrink tubing, hardware (torx bolts) ~ $50
I also added the remote control to this preamp - $24
The raw cost of parts comes out to ~ $600. Add tools (drills, hole punches, etc.) and lots of time.
The cost of parts depends on the quality of them. You could use Russian K40-Y9 coupling caps that sound excellent and are a bit cheaper than Auricaps, dispense with remote and relay volume control, use cheaper transformer without cover. Cost of parts would go down under $450.
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That's a really good deal. I spent $600 using mid grade components, and no stepped attenuator or remote control.
Can you share which attenuator (if you bought it) and remote control unit you used? I've been hesitant to do this as I was concerned the rc unit wouldn't have enough oomph to turn a stepped pot.
Can you share which attenuator (if you bought it) and remote control unit you used? I've been hesitant to do this as I was concerned the rc unit wouldn't have enough oomph to turn a stepped pot.
Look for "relay volume control" on eBay, they sell for $36-40 single ended. This relay volume module is controlled by a simple 50k pot, so any RC with 50k pot will do - I see some on eBay for $20...
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