Done. Now #1578 is the right one.
Dear Salas, thanks for this greatly appreciated.
I would love to try your shunt reg with Pearl II one day
For now I use UGS style power supply by CheefdeGaar. I can say it gives a better sound than previous onboard 78XX/79XX ... But shunt reg would give an even better sounding unit I guess
Best,
nAr
Can't say about Pearl's particular susceptibility to PSU types, having no direct experience in Pearl, but experimenting is the holly grail of DIY, so good luck. Always use oscilloscope to know that different supplies cooperate OK for clean rail results before comparing.
Voltages across R21, R22, R23, R24 are:
L 69.4mV; 69,3mV; 69.8mV; 70.1mV
R 69.1mV; 69.6mV; 69.2mV; 69.8mV
Other voltages around the circuit are pretty close to Wayne's reference, the drain of Q4 with 20.5 instead of 21 being most "innacurate".
What is the safe margin for 0 DC point setting? While my DMM is set on averaging I manage to set it from 0 to 0.01V. How long I should watch the behaviour?
L 69.4mV; 69,3mV; 69.8mV; 70.1mV
R 69.1mV; 69.6mV; 69.2mV; 69.8mV
Other voltages around the circuit are pretty close to Wayne's reference, the drain of Q4 with 20.5 instead of 21 being most "innacurate".
What is the safe margin for 0 DC point setting? While my DMM is set on averaging I manage to set it from 0 to 0.01V. How long I should watch the behaviour?
Added 1K to R9 in parallel. Q3 reads:
C 10.8; 10.9V
B 9.4; 9.3V
E 8.75; 8.65V
Looks like more in the ballpark?
Yes, ballpark
Voltages across R21, R22, R23, R24 are:
L 69.4mV; 69,3mV; 69.8mV; 70.1mV
R 69.1mV; 69.6mV; 69.2mV; 69.8mV
Other voltages around the circuit are pretty close to Wayne's reference, the drain of Q4 with 20.5 instead of 21 being most "innacurate".
What is the safe margin for 0 DC point setting? While my DMM is set on averaging I manage to set it from 0 to 0.01V. How long I should watch the behaviour?
It always wander a little. Wanders less when in enclosed box. Don't worry, as you have capacitors series with output. It won't cut too high in the output swing either. 50 mV +/- are not a crime
Nex thing, wire in / out and listen ?
Best,
nAr
Thanks. I have input jFets mounted on supports, just in case I would want to adjust for tighter quads. But I suppose my values are alright and there's no shuffle to be made?
I would say so
nAr
finally
It's up and spinning
Pheew, it took time this build! So, firstly, thanks all for the help provided. I wouldn't be listening to it at the moment without you, guys. Special thanks to Anaël and Salas.
I've spinned about 5 LPs until now. First impression, it sounds better by a notch to my previous RIAA. If it was mechanics, I would say somebody has tightened the screws in the system. And of course it's tomb silent. So in general let's say the state is more solid right now
Other benefits may appear after more listening. It could be, that my rig is not helping to hear the full potential at the moment too. But I have to say, at least to myself, that my comercial, "dwarf" in comparison GSP unit wasn't bad at all. It might have some tiny benefits even. But as I said, I should better listen more and compare.
My cartridge loading resistors are 47.5K and my cartridge loading spec. resistance is 47K. Hope there's no mismatch? I've also lowered gain. R16 is set to 47K. I had way too much of it when with 100K. I wonder if I can measure my gain somehow now? Maybe it can even be lower? Chance of oscillation?
I don't have C9 installed. Wonder if it was there for any reason at the beginning.
HFN test record says the system is in phase. I swapped +/- leads on both channels on the cartridge.
Crikey, it's hot down here. About 30 deg. C. inside. So both DCB1 heatsinks and Pearl negative one is sweating around 50C. Closer to the winter, I would love to hear if upping CCS helps.
It's up and spinning
Pheew, it took time this build! So, firstly, thanks all for the help provided. I wouldn't be listening to it at the moment without you, guys. Special thanks to Anaël and Salas.
I've spinned about 5 LPs until now. First impression, it sounds better by a notch to my previous RIAA. If it was mechanics, I would say somebody has tightened the screws in the system. And of course it's tomb silent. So in general let's say the state is more solid right now
Other benefits may appear after more listening. It could be, that my rig is not helping to hear the full potential at the moment too. But I have to say, at least to myself, that my comercial, "dwarf" in comparison GSP unit wasn't bad at all. It might have some tiny benefits even. But as I said, I should better listen more and compare.
My cartridge loading resistors are 47.5K and my cartridge loading spec. resistance is 47K. Hope there's no mismatch? I've also lowered gain. R16 is set to 47K. I had way too much of it when with 100K. I wonder if I can measure my gain somehow now? Maybe it can even be lower? Chance of oscillation?
I don't have C9 installed. Wonder if it was there for any reason at the beginning.
HFN test record says the system is in phase. I swapped +/- leads on both channels on the cartridge.
Crikey, it's hot down here. About 30 deg. C. inside. So both DCB1 heatsinks and Pearl negative one is sweating around 50C. Closer to the winter, I would love to hear if upping CCS helps.
Attachments
Hey, Nice setup dude
I can see "my" Allen minimalistic replicas running at the outputs
Good to hear no noise at all. Gain setting is also absolutely relevant.
47k5 as cartridge load is perfect, no need to think for a load mismatch compared to 47k value
Best,
nAr
I can see "my" Allen minimalistic replicas running at the outputs
Good to hear no noise at all. Gain setting is also absolutely relevant.
47k5 as cartridge load is perfect, no need to think for a load mismatch compared to 47k value
Best,
nAr
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Hey, Nice setup dude
I can see "my" Allen minimalistic replicas running at the outputs
nAr
Another benefit perhaps. I can use them because of much lower Zout as compared to previous setup. Un grand merci for those and the caps. A good deed is not forgotten.
Another benefit perhaps. I can use them because of much lower Zout as compared to previous setup. Un grand merci for those and the caps. A good deed is not forgotten.
You're welcome hope you can have a good time listening to some nice lps
Anaël
Added 1K to R9 in parallel. Q3 reads:
C 10.8; 10.9V
B 9.4; 9.3V
E 8.75; 8.65V
Looks like more in the ballpark?
Changing R9 is a bad idea. It is part of the RIAA equalization network, as Wayne gently pointed out to me earlier in this thread. You should leave its value alone.
To adjust your bias you may instead lower R10. See my post #1180.
THEN report on the sound
By the way, congrats for a beautiful build.
Pierre
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Sounds about right (4k or so for R10). Don't forget to put 499 back in for R9.I've got some 6K8, I could try paralleling with R10.
Pierre
Oups, I'm terribly sorry ! I let out the wrong correction accidentally.
Luckily Pierre is here to correct my mistakes
Tomas please report voltages after mods (my repair mistake, sorry, I really apologise) and Pierre's right correction
Best,
nAr
You must be joking! There's nothing to regret. We live and learn and I've learned a lot from you.
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