Not yet

[jaudio]

Thanks to Russ and Brian for the guidance and the PIC🙂

Today I got the preamp and headphone sections working. I have two question

1. Has anyone measured the dc output at max volume?

2. Brian any chance I can buy a few of those -95 to 0 and 95- to +24 PICs

 

[jaudio]

another view

Im hoping to test it with bpa opa549 this week.

 

[jaudio]

Testing with the opa552 gain set at 7.

 

[jaudio]

with the cap bewteen the opa552 and 549s. the offset more than doubled,It still not a problem. Kinda made me rise an eye brow.

 

[digi01]

i like your nice work.forward😉

zang

 

[jaudio]

i like your nice work.forward😉

zang

Thanks

Doing alittle testing with a 7.5watt bulb in series with supply

 

[jaudio]

with +/-9volt ,I dare not go higher(no heatsinks and all). The offset is low with caps after the opa552.

The highs are crisp and clean,no hum some hiss at about a inch from tweeter. Vocal are clear. Im looking forward to the full supply test,hopefully sometime this weekend.

 

[jaudio]

This is my selector. It has

4 RCA inputs
3 XLR inputs with bal to single converter
2 buffered tape loops

I plan to use 4 transformers

1 for left,1 for right and one for led plus relays. A addital transformer for the #2 tape loop.

Tested today,all work as it should

 

[jaudio]

I had a little time to work on my amps. Everything but the heatsinks are salvaged. Still have to work on the fronts,hand file! 😡

 

[jaudio]

I need help with this one!

I getting voltage between speaker terminal and case. I measured between power supply including both rail and ground,no voltage and resistance is more than 20meg. The chips are isolated. The voltage start at about 1.5mv and increases as temp go up to 17volts.

The voltage at both terminal start at .05mv and increases to 25mv.

 

[jaudio]

Decided to test the amps with a fuse instead of the lightbulb between the mains and powersupply. I had one chip go boom. Tested the same amp with chips gone works fine,I guess that where the high output voltage came from. Iam going to replace the chip and see what happens.

 

[jaudio]

🙁