No, I have not performed a formal test, but some simple bench tests show something like 50 WPC. I just do not have the distortion figures at those levels.
Thanks Loren, not so interested in the distortion level just rough output power, the distortion IMHO is secondary to how the amp really sounds
Sandy
Let me see what the cost of each board is for various quantities and I will report back.
It all depends on how many boards are ordered and how many people want these boards.
There are three boards to the set (Power supply, HV Delay Board, Driver Board), but you need two of the power supply boards to make one stereo amp since the amp uses a power transformer for each channel.
The Driver Board contains both channels, but you can always cut it in half if you want to make two separate mono blocks. However, you would need an extra Delay Board.
I did a quick price check on the power supply boards and at quantity 10 (5 stereo amps) it runs $33.66 per board.
The driver board costs the same price for the same 10pc quantity, but I only need one per amp, which a 6pc order quantity would be $50.38 per board.
The delay board costs $46.33 per board for an order of 6 PCBs.
All boards are 1 oz, 1/16" thick double sided glass boards. 2 oz will cost more, but I have no idea how much more. I use Express PCB and their software program to make the boards. Transferring this design to Eagle (which I have) would a bit more work as I am not fluent with that program. So, I am really stuck with Express PCB for these boards.
The Delay Board could be hand wired if you want to save money. It is simply a 555 timer, relays, power condition components for the timer, and some power resistors to elevate the filament supply.
I'll probably add one extra set of boards for my self to the total order as I keep thinking I might want to build a second amp and biamp my system.
The Driver Board does not have PCB holes for the filament pins of the 6SN7s, but I can easily add them and associated pads to run the filament wires to the board.
I elevated my driver board over the sockets and placed a metal shield between the PCB and the tubes with the filament wires running under the shield, thus I did not need to bring AC to the PCB. Adding those extra pads is no big deal. I just have to move a few traces.
The driver board costs the same price for the same 10pc quantity, but I only need one per amp, which a 6pc order quantity would be $50.38 per board.
The delay board costs $46.33 per board for an order of 6 PCBs.
All boards are 1 oz, 1/16" thick double sided glass boards. 2 oz will cost more, but I have no idea how much more. I use Express PCB and their software program to make the boards. Transferring this design to Eagle (which I have) would a bit more work as I am not fluent with that program. So, I am really stuck with Express PCB for these boards.
The Delay Board could be hand wired if you want to save money. It is simply a 555 timer, relays, power condition components for the timer, and some power resistors to elevate the filament supply.
I'll probably add one extra set of boards for my self to the total order as I keep thinking I might want to build a second amp and biamp my system.
The Driver Board does not have PCB holes for the filament pins of the 6SN7s, but I can easily add them and associated pads to run the filament wires to the board.
I elevated my driver board over the sockets and placed a metal shield between the PCB and the tubes with the filament wires running under the shield, thus I did not need to bring AC to the PCB. Adding those extra pads is no big deal. I just have to move a few traces.
Yes!
However, you still need to elevate the filament AC voltage relative to the high tension. That circuitry is also on the delay board. There is no reason you could not do that with point to point wiring.
I use the delay board because it is automagic. I just flip a switch and go about my business and the unit starts after the timer times out.
I have a shear, so if you request it to be sheared I can do that for you no charge.
I purchased the Studio Version of this program:
Copper Connection PCB Editor - Robot Room
You can import ExpressPCB files and then export Gerber files in order to use a board service like this:
PCB prototyping
Quite a cost savings. I used the Copper Connection program itself to generate a few boards. Works great.
Scott
Copper Connection PCB Editor - Robot Room
You can import ExpressPCB files and then export Gerber files in order to use a board service like this:
PCB prototyping
Quite a cost savings. I used the Copper Connection program itself to generate a few boards. Works great.
Scott
Quite late with this remark - happy new year everybody!
.... The final balance of signal is not only dependant on the plate load resistors. The following stage grid resistors plus the equality of the triodes in each twin triode also plays a role. As a practical aspect I ofien include a suitable pot in series with both load resistos (tap to B+) if I want the signals particularly equal. Even then the final result is still dependant on the equality of the KT88s! Only a spectrum analysis can be the final judge.
Somewhere one must stop in the interest of practicality, and these days 1 - 2% resistors are normal. Just to mention.
Being unable to find one I was starting a BOM. A bit of a chore when you don't know cap voltage values.
Are the components on the relay board (Filament board) shown on the relay board schematic? Between the 3 schematics, the 2 photos and interconnect .pdf I have a good handle on the parts except for the parts listed as R1›R4 (assuming R5 is the 470K of the relay system), R6›R11 and C3&C4 . What is the role of C5? There are appears to be an extra diode on the board as well.
Also what do you mean by "you still need to elevate the filament AC voltage relative to the high tension"? What relationship are you trying to establish?
This project has really caught my attention. Even my wife thought the amp looked cool ("What are those big blue things at the back?").
Are the components on the relay board (Filament board) shown on the relay board schematic? Between the 3 schematics, the 2 photos and interconnect .pdf I have a good handle on the parts except for the parts listed as R1›R4 (assuming R5 is the 470K of the relay system), R6›R11 and C3&C4 . What is the role of C5? There are appears to be an extra diode on the board as well.
Also what do you mean by "you still need to elevate the filament AC voltage relative to the high tension"? What relationship are you trying to establish?
This project has really caught my attention. Even my wife thought the amp looked cool ("What are those big blue things at the back?").
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