My PIMETA v2 plays music but the buffers get very hot within a few seconds. I have almost no experience with building amps so I'm posting pictures and the components I used hoping that you guys can spot what I'm doing wrong much faster than I can debug it. I visually inspected all solder joints and they look OK to me but I could try to get a close up of some parts if needed.
top
I didin't realize those red caps are so bulky until they arrived. They fit OK though.
bottom.
I really wish I used headers for all wiring. I tried soldering twisted copper wires from the power supply wires directly to the board and they eventually ended up touching and throwing sparks. There are burn marks on the board but I think it's OK.
side.
I wanted to make C6 replacable so I "hacked" the header you see on the left from an old 28pin DIP socket. For the moment I'm using 10pF caps for C6.
I followed the suggested values on the schematic for the most part. The only deviations I chose were 10pF for C6 and .12uF for C1, C3 and C5.
Here is a list of the components I used:
- power supply 1
24V VDC 1A linear regulated 2.1mm jameco
- R1L/R 2 4.32 KOhm .4W 1% digikey PPC4.32KYCT-ND
- R1G 1 = R1
- R2 2 499 kOhm 1/4W 1% digikey 499KXBK-ND
- R3 2 1 kOhm .1% have it
- R4L/R 2 4.75 kOhm 1/4W 1% digikey RNF14FTD4K75CT-ND
- R4G 1 = R1
- R5 2 3.32 kOhm 1/4W .1% digikey RNF14FTD3K32CT-ND
- R6 2 = R2
- R7 3 100 Ohm .5W 1% digikey PPC100XCT-ND
- R11 3 = R5
- RBIAS 1 5K trim pot digikey 3296W-502LF-ND
- RBLIM 1 1 kOhm .1% have it
- RCCS not used
- RLED 1 10 kOhm have it
- C1 2 .12 uF 1% 50V digikey p3874-nd
- C2 3 470 uF 20% 25V digikey 493-1553-nd
- C3,C5 4 = C1
- C4 2 6.8 uF webshop
- C6G-L-R 3 10 pF 5% digikey 490-3678-ND
- LED1,2 2 3.7V digikey 404-1175-ND
- D1,2 1 (D1) diode digikey 1N4001FSCT-ND
- Q1 1 PNP transistor digikey 2N5087
- Q2-4 4 NPN transistor digikey 2N3904BU
- IC1 - not used
- IC2 1 TLE2426 rail splitter digikey 296-1994-ND
- BUF* 3 LMH6321MR buffer newark LMH6321MR
- OPALR 1 AD8620 dual sm digikey AD8620ARZ
- OPAG 1 AD8610 single sm digikey AD8610ARZ
- vol pot 1 50 K webshop
- input 1 3.5mm .125" 3way digikey CP1-3513-ND
- output 1 6.35mm .25" 3way digikey SC1317-ND