Alternate First Watt Power Supply Schematic

[dBel84]

You have also used the hot CL60 which is an option for 220 V.

Hard to see exactly how you have it all wired up.

 

[vdi_nenna]

To test ps board alone, I disconnected from amp boards. Reading plus and minus 26.6v. That's ok.
I guess that's unloaded dc.

When amp boards were connected, output dc was way off and varying up and down.
I had just biased and zeroed out output dc the other day. Only difference is this new board.

Th2 is going to chassis ground like the schematic says.

 

[vdi_nenna]

Board is trashed. Won't survive removing parts.
Vias gone. Going back to store supply. Have too.

 

[JeffYoung]

That's a bummer. Where did you get the board made? Usually they'll survive several removals....

PS: if you do try it again, reset your bias. Using the 0R47 power resistors will change the voltage slightly and necessitate a re-bias.

 

[twitchie]

That's a bummer. Where did you get the board made? Usually they'll survive several removals....

PS: if you do try it again, reset your bias. Using the 0R47 power resistors will change the voltage slightly and necessitate a re-bias.

The red board is from PCBWay. I will test mine in F5 and report back.

 

[twitchie]

Hooked up one side to one channel F5 and it looks good. Any post-mortem on that board or is it already history?

I am not using any on board thermistor yet or not for this test at least

 

[vdi_nenna]

The red board does work as designed.
Just don't unsolder parts from it.

I build up the PS on another version of this board and is ok too. Not sure why there was a wild offset. My be it was just me.

 

[JeffYoung]

Glad you got it working, Vince!

 

[darrr]

I have several pcb that I can sell at cost (9 euros) plus shipping. outside Europe, the cost is probably too expensive. More info by PM.

 

[Juntuin]

Rectifier boards are still on their way, but got 5pcs of these today. Thanks Jeff!

 

[vdi_nenna]

Got a chance to listen to two simulate F7s: one with shared power supply and the dual supply from this thread.
There is a distinct difference and I think the advantage goes to the dual supply.
I can elaborate more but that's really it.

 

[Zen Mod]

surprise .......

 

[rhthatcher]

I built up some boards for some projects. First one done is a Rawson built F5 that I recently bought. I measured “as-found” voltages and then gutted it. It sounded great on my bench speakers, and voltages, bias, and gain all check out great.

 

[vdi_nenna]

 

[rhthatcher]

I re-rebuilt my Aleph J Mini (original rebuild was to fix the hum and mess from the original Rawson build). The boards I pulled out are going into a buddy’s aleph j monoblocs.

This amp checks out on the bench: PSU voltage, dc offset, bias, gain. Sounds great on test speakers.

 

[rhthatcher]

I have now built 4 amps with these boards. The 4th was the last one I had, and I may have another project requiring another.



@Jeff - I really like the boards. Quick, straightforward, very nice work!!!



Question to everyone: I'm thinking of making another run of these boards. Anyone interested?

 

[darrr]

I still have few PCBs but delivery is from Poland

 

[Wishborn]

I would love to buy a board or two. To Norway. Who do I contact?

 

[darrr]

I have few. PM please

 

[rhthatcher]

I have decided to build a couple more amps, and I'm having a batch of these boards fabricated. I expect I will have them mid-August. If you're interested in buying board(s), please let me know.