.. and it sounds like music.
Music that is passionate, clear and moving
Music that is passionate, clear and moving
I had been too. I don't know if it's recent or if I just didn't notice previously, but blue specifically seems to have jumped up with 2oz copper at both PCBWay and JLCPCB. So... I might actually swap to another color. Red, Black, Green, and Purple didn't have the crazy bump last time I checked. Did you notice a bump in blue pricing?
Gary... I was leaning black too. I've got the red BA-3 boards, Randy's boards are Purple... hmmmmm.....
Black is sweet but it shows dust and even though the flex is real, the flux is too... They are hard to get clean enough.
Dust will settle no matter what the color, A good quality pcb cleaner wipes out the flux in no time with a gentle scrub with an old toothbrush.
Dust definitely shows faster on black for sure. However, regarding flux, I have only used isopropyl alcohol to clean flux. I need to invest in something better. What PCB cleaner do you use?
I use this product here in Australia, not sure if it is available in the US though.
https://www.chemtools.com.au/product/our-brands/kleanium/circuit-board-cleaner/
Otherwise, this is about the best but expensive here.
https://docs.rs-online.com/f428/0900766b8131b8ad.pdf
https://www.chemtools.com.au/product/our-brands/kleanium/circuit-board-cleaner/
Otherwise, this is about the best but expensive here.
https://docs.rs-online.com/f428/0900766b8131b8ad.pdf
Just checked pricing at JLCPCB, if you want 2 ounce copper than green is the way to go. All of the other colors with 2 ounce copper more than double in price for some reason.
All colors in 1 ounce are $10.00 for 5 pcb's.
Green in 2 ounce is $27.40 for 5 pcb's.
Blue, purple, yellow, white and red in 2 ounce are $59.79 for 5 pcb's
Black in 2 ounce is $75.99 for 5 pcbs. (ouch!)
All colors in 1 ounce are $10.00 for 5 pcb's.
Green in 2 ounce is $27.40 for 5 pcb's.
Blue, purple, yellow, white and red in 2 ounce are $59.79 for 5 pcb's
Black in 2 ounce is $75.99 for 5 pcbs. (ouch!)
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If anything, this one sounds more coherent than the breadboard version. The Diamond buffer circuit seems to benefit from a PCB implementation , better connection and power supply bypassing.
The whole amp runs better in this chassis. The dual-mono PSU is the best that I know how to build. It is absolutely silent.
The Diamond buffer seems to have a synergistic relation with the high transconductance Mosfets. The NOS Fairchild FQH44N10s have performed without fault. I would suggest that the group buy a tube of 30 and share among yourselves.
That is all good news as I do have a tube of those NOS Fairchilds, which I purchased a few years ago for a rainy day - thanks for the heads up on those.
Do you have some details on the dual mono psu you have implemented: transformer details, caps per rail etc, thanks.
Do you have some details on the dual mono psu you have implemented: transformer details, caps per rail etc, thanks.
Thanks Tungsten, this will drop into my NPXP very nicely! I'll just crank the bias since it is a 5U/400 chassis 
Best,
Anand.
Best,
Anand.
The power supply:
Transformers are Antek AS-3222
Boards are dual-rail SLB, enhanced with bipolar transistors selected for lower Vcesat. This allows the output voltage of the capacitance multiplier to be set closer to the voltage from the synchronous rectifiers. Mosfets used in the sync rectifiers are IPP040N06N.
The SLB boards are followed by Kemet 10,000 uF caps on each rail. This is vital. The seller of the SLB claims no output caps are necessary, but this is not the case.
The Anteks are bolted to 1/4” slabs of Acrylic, which are in turn bolted to the bottom plate. The donuts have rubber stoppers to isolate them from the steel mounting bolts.
Transformers are Antek AS-3222
Boards are dual-rail SLB, enhanced with bipolar transistors selected for lower Vcesat. This allows the output voltage of the capacitance multiplier to be set closer to the voltage from the synchronous rectifiers. Mosfets used in the sync rectifiers are IPP040N06N.
The SLB boards are followed by Kemet 10,000 uF caps on each rail. This is vital. The seller of the SLB claims no output caps are necessary, but this is not the case.
The Anteks are bolted to 1/4” slabs of Acrylic, which are in turn bolted to the bottom plate. The donuts have rubber stoppers to isolate them from the steel mounting bolts.
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This is basically the same path (psu, mosfets and amp) I will take. I don’t have scientific evidence, but one of my Class A’s with dual mono SLB psu has added capacitance at the output and I prefer it this way over the initial stock setup.
The smaller transistors of each cap multiplier pair were the KSC2690 and KSA1220. I don’t recall what the larger ones were. I wrote it up in the SLB thread a while ago.
The Etsy store that carries the SLB gives a basic parts list. It is pretty easy to find better transistors.
The Etsy store that carries the SLB gives a basic parts list. It is pretty easy to find better transistors.
