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The SLB (Smooth Like Butter) Active Rect/CRC/Cap Mx Class A Power Supply GB

I built one PSU yesterday. The board is very high quality and nicely laid out! I’m really looking forward to using it in my M2X build.

I have some questions:

1. For the LEDs, is the square solder pad the cathode (-)?
2. When installing the transistors, should they be oriented so that the face with the printed markings has the left-most pin in the square pad?
3. I’m using the large heat sinks for Q9 and Q11. I haven’t put the screw in place but it looks like it’ll be difficult to adjust RV2. Is there enough clearance?
4. Q10 and Q12 mount on a heat sink, connected to the board via J5 and J6. I’m curious about why there are also solder pads for those transistors?
5. Is there a testing and adjustment procedure somewhere in this thread?

TIA
 
Member
Joined 2014
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I’ve got a single SLB built powering my Alpha20 amplifier. I removed the conventional bridge rectifiers/CRC psu board and replaced them with the SLB psu. My Alpha20 had a small amount of hum that I could not get rid of, with the SLB in place it’s almost silent! Very nice improvement.
Each amp board is pulling 1.3A bias current, at this current draw the BJT’s do not get hot enough to require a dedicated heatsink. I will remove the flying leads and edge mount them under the SLB board and fasten them to the aluminum base plate.
 

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Received my boards as well! Planning on putting 2 boards with 2x200va (Antek AS-2222) in one case for dual mono power. Very excited about this and seeing how it works with my Alpha 20 as well as future Pass amp builds. M2X is next.

I'm hoping for similar results in getting rid of the last bit of power supply noise too, Vunce!
 
Founder of XSA-Labs
Joined 2012
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Sorry about the tape residue guys. I used to tape all the boards with 3M tape and I guess it was a better quality and left no residue as I never got a complaint before. But definitely won’t be using that tape on any more boards. Hope you guys are all able to remove the tape residue. I think mineral spirits paint thinner works well.
 
We have a product here in Oz called Eucalyptus Oil and it will easily remove any sticky residue - but your packaging tape residue was a challenge even for that, plenty of elbow grease also helped - but boards are now very nice and clean.

I hope that tape you used is already in the bin!
 
Founder of XSA-Labs
Joined 2012
Paid Member
I have 6 rolls of it but will reserve it strictly for taping the paper labels on the envelope and for reinforcing the envelope with tape bumpers and cross-straps.

A story behind why I reinforce the envelopes: I sent a package once to an address in the US. The post office delivered to a GB participant, in a clear baggy, a bubble mailer envelope that I had sent, ripped in two with contents missing with a note that said: "Sorry for the inconvenience but we had an equipment malfunction in the sorting machine." That's all I got was "sorry". No recourse since it was not insured. Of course, I ended up eating the lost PCBs and sending a new set to the member who got the "sorry" note and and an empty ripped up pakage. So now I put extra tape to make sure a machine can't rip the envelope in half so easily. This cheap tape will serve that purpose well. But I will use a different (more expensive 3M) tape for the boards, or use 3M blue painters' tape which leaves no residue.

Here is another story about a package I sent to Shenzen China. The member never got it and the tracking said "In transit". After 1 month and a few days, I sent the member a new board at no charge and he got it in 7 days. A month later (over 60 days) I receive in the mail, the original package, stamped "undeliverable, return to sender" and it had postal stamps from around the world on it: Frankfurt, Adelaide, Tokyo, Hong Kong, Shenzen, and back to US, New York, Chicago, finally Dulles Virgina. That thing went around the world and through the ringer and envelope was beat up but still intact.
 
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