another Gainclone build - PTP PA100

[gadut]

I had an ambitious gainclone project to welcome my first children 🙂 twin boys with birth expectation on mid Aug'12. BPA200 mono block using shine7 PA100 parallel with DRV134, but during the build of this gc, Aleph30 stole my attention. When I had already collected all parts for 8 ICs, I finally chose to build PA100 with upcoming Aleph30 😀

Design

amplifier design based shine7 PA100 with some changes :
- remove R20,C20,C4,C8,C3,C7,R12,C10
- change C1 into 2.2uF, C12&C14 into 680uF

psu design based on carlosfm with some changes :
- R3&R4 are changed into 0R075 10W (copy from nelson CRC design)
- additional 100uF parallel with C7&C8 (copy from tnt-audio)
- C9&C10 are changed into 680nF (copy from tnt-audio)

Parts Selection
Amplifier parts
- all resistors are hand-matched <0.1% by using Sanwa PC500a (example with R 1K are selected from around 30 resistors with 987 ohm displayed on DMM over 3 times measurement). Is it silly? 😀
- Resistors-> 1k,22k: kiwame carbon, 10k,47K: takman carbon,0R1: dale lvr 5W
- Capasitors-> C1 2.2uF: gad viva, C2 100uF: nichicon muse bp, C5 10uF: nichicon muse, C12&C14 680uF: blackgate f,C11&C13 0.1uF: wima mkp10

PSU parts
- 1 pcs talema encapsulated 2x25V 300VA
- 8 pcs mur860 heatsinked
- R1&R2 2k2 5W: dale cw-5, R4&R4 0R075 10W: dale lvr (0R15 5W parallel), R5&R6 0R5 10W:dale cw-5 (1R 5W parallel)
- C1&C2 4.700uF: nichicon gold tune, C3,C4,C5,C6 10.000uF: nichicon gold tune, C7&C8 100nF: wima mkp10 parallel with 100uF nichicon muse,C9&C10 680nF:wima mkp10, bypass caps 100nF wima mks4

Casing
the hardest part of building this amp is designing casing layout to make the best position,each heatsink is about 2,4kg. I just got 5mm alum sheet for downplate and backplate, but still need to be smoothed and anodized. Faceplate will be 15mm alum or curved wood, top cover will be transparent acrylic

any input and comment are welcome to enhance this project

 

[AndrewT]

I think the output Zobel should be located right at the output of the chipamp.

This will require two Zobels. Each one dedicated to it's own chipamp.

Where do the chipamps source their input offset currents from?
At the moment you do not show any DC blocking between the two +IN PINs.

 

[gadut]

I think the output Zobel should be located right at the output of the chipamp.

This will require two Zobels. Each one dedicated to it's own chipamp.

Where do the chipamps source their input offset currents from?
At the moment you do not show any DC blocking between the two +IN PINs.

currently each module is separated each other, not soldered yet. I only lay them to get the future placement.

I'm planning not to use Zobels circuit, i expect that no oscillation 🙂 but if needed, maybe I will use after mounting each modul.

do you mean C1? i'm using 2.2uF, but currently it's de-soldered during layout placement.