Ry an Rx are 1 Ohm so 4.3mA should only drop 4.3mV across those. No DCSTB that I remember reported gave +/-18V (36V across) they usually give no more than 17.5V.
One is near to max permissible for the op-amp. Use that one on the right side DCG3 power input. That side powers the delay circuit that doesn't mind.
Never do diy when tired. I was checking psu boards today- same as two days ago- one is around 18 v another is 17.6. Bench supply shows a similar current drain.
Then I think I have put dmm in the wrong mode (mA) and possibly shorted something. One part of the board is now showing 19.57V .
I feel stupid now :/
Then I think I have put dmm in the wrong mode (mA) and possibly shorted something. One part of the board is now showing 19.57V .
I feel stupid now :/
Since I used J113 in CCS, and the voltage is little bit high at 18.3V.
I jumped a LED and got +/-16.4VDC.
I jumped a LED and got +/-16.4VDC.
The Id of the VAS is about 140mA with 10 ohm R10. The offset +/5mv without DC server and +/- 1-2mv with DC server.
I use DCG3 to drive my DIY SIT MU follower.
I use DCG3 to drive my DIY SIT MU follower.
Check all transistors Vbe with DMM in diode mode. Especially the BCxx ones.
Not bought a scope yet. Haven't tested yet.
It is on my next big item list to purchase.
The speakers are Harbeth c7es3. They may not be the best fit ones for the SIT amp.
I tried 3 front end to drive the SIT amp and still looking for.
https://www.diyaudio.com/community/...ff-and-defisit-amplifier.392733/#post-7278660
The 1st is headphone IC amp LM4562+LME49600 + an Edcor 150:300 autotransformer;
The 2nd one is Pass BA-3
The 3rd is your DCG3.
I listened your DCG3 for few days now. So far it is the best if I could say.
First few days, I was using +/-18.2VDC + 140mA Id, I liked the sound better but it got too hot with my heatsink. I also worried about the IC for the DC server. So I lowered the PW to +/-16.4VDC and have listened it for few days. I might be wrong and have subjective feel that the high voltage PW would have better sound.
My purpose is not headphone amp or a regular preamp but FE with higher output swing. What I am think is a higher PW voltage version of your DCG3.
What I would like to do are
1. lower Id of the VAS stage from 140mA to around 100mA.
2. increase the power supply voltage to 20VDC, I searched and found OP285. It might be the alternative of the original IC. And my SIT amp has a capacitor at input. In the worst case, I could get rid of the DC server at all.
3. The ultimate goal is to use +/-24VDC power supply to maximize the swing to suite the SIT amp.
I tried 3 front end to drive the SIT amp and still looking for.
https://www.diyaudio.com/community/...ff-and-defisit-amplifier.392733/#post-7278660
The 1st is headphone IC amp LM4562+LME49600 + an Edcor 150:300 autotransformer;
The 2nd one is Pass BA-3
The 3rd is your DCG3.
I listened your DCG3 for few days now. So far it is the best if I could say.
First few days, I was using +/-18.2VDC + 140mA Id, I liked the sound better but it got too hot with my heatsink. I also worried about the IC for the DC server. So I lowered the PW to +/-16.4VDC and have listened it for few days. I might be wrong and have subjective feel that the high voltage PW would have better sound.
My purpose is not headphone amp or a regular preamp but FE with higher output swing. What I am think is a higher PW voltage version of your DCG3.
What I would like to do are
1. lower Id of the VAS stage from 140mA to around 100mA.
2. increase the power supply voltage to 20VDC, I searched and found OP285. It might be the alternative of the original IC. And my SIT amp has a capacitor at input. In the worst case, I could get rid of the DC server at all.
3. The ultimate goal is to use +/-24VDC power supply to maximize the swing to suite the SIT amp.
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More rail voltage makes the Mosfets internal capacitance less. Up to 25V, then their reduction rate is negligible. But take care to also arrange drop for suitable coil voltage at the DCG3's output relay. Not to overshoot its max spec. With 17V rails the three LEDs do that. Maybe replacing one of them with a resistor to create a voltage divider with the coil's DC resistance.
I suggest you examine this Siglent series. Regarding high value of features vs price.
There is also instruction in the pdf manual for 4X gain setting if it can be useful when with more swing.