diyAudio Power Supply Circuit Board v3 illustrated build guide

[richluvsound]

…. on my boards I have 390r at R18 .

This http://www.diyaudio.com/forums/pass-labs/249554-beginner-build-aleph30-needs-some-help-22.html

post 221

 

[jwilhelm]

I don't see an R18 in the schematic. The resistors you are looking for will be the largest ones on the amplifier board. They will be very low resistance and will be hot when the amp is operating. I can tell you which ones you are looking for if you post a picture of the amp board.

 

[richluvsound]

Close up ...

Here you go J !

 

[jwilhelm]

It doesn't look like your schematic matches your boards. Those big blue ones to the right side would be your source resistors. Looks like there is 5. There should be an even number. One for each output device. You should find the proper schematic so you know what the bias setting is supposed to be. If the bias is set too high you will melt your amp.

 

[richluvsound]

There is another underneath . The stuffing guide would probably be more help.

Aleph 30 BoM
Resistors


R0 3R optional Order quantity
R1 ?
R2 10k 3R 1 3W mf only if needed
R3 10k 10k 2 Phoenix Passive Components MRS16S
R4 100k 100k 2
R5 68.1k 68k1 2
R6 68.1k 221R 11
R7 100k 4k75 1
R8 ? 392R 2
R9 221R 1k5 2
R10 221R 47k5 1
R11 221R 1k 1
R12 221R 820R 1
R13 4.75K 0R47 12 3W mf PD
R14 392R
R15 221R
R16 392R
R17 1.5k
R18 1.5k
R19 47.5k
R20 1k
R21 820R
R22 0.47R
R23 0.47R
R24 0.47R
R25 0.47R
R26 0.47R
R27 0.47R
R28 221R
R29 221R
R30 221R
R31 221R
R32 221R
R33 221R
R34 0.47R
R35 0.47R
R36 0.47R
R37 0.47R

 

[jwilhelm]

You need to find the ones that are connected to the source leg of each output device. Looks like the output devices are remote mounted. Follow the wire from the source leg of the output device to the first resistor they connect to. Those are your source resistors and where you measure your bias current. I can't say for sure what the bias current is supposed to be without the proper documents for your amp.

 

[Marra]

Is this the schematic that you are working too Rich.

https://www.google.co.uk/search?q=a...pass-labs%2F197848-aleph-jango-2.html;637;466

When I built an Aleph 5 some years ago everything was set by fixed value resistors is this not the same?

 

[Marra]

Whoops wrong image.

https://www.google.co.uk/search?q=a...topic%2F6579-aleph-3-vs-calor-gold%2F;641;550

It's in there somewhere

 

[Tape Echo]

Would like to purchase and build a PCB but the Store's link is currently dead. Sorry if this is already a known issue.

http://www.diyaudio.com/store/ampli...ries/universal-amplifier-power-supply-v3.html

 

[AndrewT]

That link is not dead.

 

[Tape Echo]

It's fine now, but multiple attempts last night resulted in an error.

 

[chrismercurio]

Hi,

Easy question I'm sure, but asking anyway:

If you don't need a split rail supply, how do you treat the (-) board differently to get (+)?

Best,

Chris

 

[6L6]

Ground is relative... and also where you decide it to be.

So if you were to split the PCB and make two single-rail supplies, stuff everything as labeled, but attach the output "backwards" -- what's marked as GND will be V+ and what's marked as V- will be GND.

If you stuff as labeled the lower voltage will be on the V- marked output pad and the higher voltage will be on the GND pad. (This is also true when it's a bipolar PSU...)

Your lower voltage you will call GND, and the higher voltage will be called V+ .

 

[chrismercurio]

Thanks for the clarification. I thought it was as you describe, or I would need to stuff the diodes 180 degrees out from what is suggested.

Best,

 

[valley711]

value of filter resistor

will .51 ohm. 4 watt resistors work in the filter instead of .47 ohm 3 watt?

 

[AndrewT]

yes

 

[chrismercurio]

Hi,

I'm curious if anyone has used the Perforated Riser Panels -

Perforated Riser Panels - Accessories & Spare Parts - Chassis

With these?

Best,

 

[Renron]

ChrisM,
I have not used these exact panels from DiyAudio, but this is my preferred design, especially on the bottom for all of my projects. Excellent way to get air flow and I use the holes to attach the boards with PC standoffs. I've also used a very thin piece of plexiglass underneath a component board as an insulator.
I didn't even know we had these for sale. Thanks!
Ron

 

[chrismercurio]

I found them on accident in the links on the pcb page. I'm going to use tin snips to cut them to size in a tube project but think it's awesome the this stuff is so readily available now. It is so much easier to make professional looking projects these days.

 

[dmtparker]

KUDOS!

The "Mains" refer to the wires connected to the AC wall plug. The "Primaries" of the transformer connect to the mains. The transformer then transforms the wall voltage down to out transformer voltage, in a Pass amp something like 18V - 24V. The wires with the lower voltage (which is still AC, just lower voltage) are the "Secondaries"

The lower voltage AC needs to be turned into DC - diode bridges do this - the array of 4 discrete diodes with heatsinks (per channel, totaling 8) take the AC on the secondaries and make it DC, which is not particularly clean and smooth, which is what the filter section is for - The big capacitors and resistor banks will make the rippily DC into very smooth DC.

The "Monolithic bridges" are the little square packages that have 4 diodes in the one package, and take the place of the diode section of the PCB. They have 4 connections so AC goes in, and DC comes out.

In the below photo you can see, from left to right -

Transformer and transformer secondary wires, connected to;

(2) monolithic bridges, connected to;

Filter section of the PCB. (which has the diode section removed)

This page has TONS of awesome info that will help you figure out your PSU - although it's specific to a chipamp, the Pass style PSU is essentially the same, just much bigger. Building a Gainclone chip amp power supply.

6L6 you are the BEST! This is as nice, straight forward and helpful an explanation as I have seen. Answers like this encourage Newbies to continue to ask questions and LEARN as they create great products. We are all indebted to you for your caring, helpful, and lucid explanations.
Note: I just chose this one to reply to as it was particularly great. ALL of 6L6 replies that I have read anywhere on this forum are GREAT! Three cheers for 6L6!