Got up early to find the problem. Might have been the jacket on the 30 gauge output wire was soldered over.
That make any sense? I have a headache.
Also changed the parallel resistor to a 294 ohm, reducing the total resistance to 193 ohms for R14.
Subsequently, the output is about the same as my previous phono's MC setting.
The sound is real nice, even with no warm up. It has quite a bit more soul than my IC based phono.
Wayne, thanks for putting this great phono pre together, and to everyone for their support!
Vince
That make any sense? I have a headache.
Also changed the parallel resistor to a 294 ohm, reducing the total resistance to 193 ohms for R14.
Subsequently, the output is about the same as my previous phono's MC setting.
The sound is real nice, even with no warm up. It has quite a bit more soul than my IC based phono.
Wayne, thanks for putting this great phono pre together, and to everyone for their support!
Vince
channel balance problem
I posted earlier about my balance problem and it showed up on the scope looking at the output mosfet, so I replaced it and they are spot on now.
I have to agree on the sound, it is more spacious and 3d than anything else I have had ( classe\threshold\crown\paracass ). a fantastic and educational fun piece, Thank You Wayne.
jjacks4x
I posted earlier about my balance problem and it showed up on the scope looking at the output mosfet, so I replaced it and they are spot on now.
I have to agree on the sound, it is more spacious and 3d than anything else I have had ( classe\threshold\crown\paracass ). a fantastic and educational fun piece, Thank You Wayne.
jjacks4x
Problem with pearl power supply
Found the pearl II off this morning. Found that the ps filter cap had leaked.
Replaced with 50v 10k uF. Voltages seem to be off but from what I read somewhere, the circuit draws from the plus and minus differently.
Not connected to the circuit the ps gave 38v neg and 23v pos.
Connected to the circuit, had a reading of -50 and +7v at the ps caps.
Everything was quite, no noise and it sounded a bit better than before.
Unsure, I unplugged it and awaiting some advice on what could be happening.
TIA
Vince
Found the pearl II off this morning. Found that the ps filter cap had leaked.
Replaced with 50v 10k uF. Voltages seem to be off but from what I read somewhere, the circuit draws from the plus and minus differently.
Not connected to the circuit the ps gave 38v neg and 23v pos.
Connected to the circuit, had a reading of -50 and +7v at the ps caps.
Everything was quite, no noise and it sounded a bit better than before.
Unsure, I unplugged it and awaiting some advice on what could be happening.
TIA
Vince
So did you get the erroneous voltage before or after the on-board regulators?
Oops - then I saw this...
Which means you have something miss-wired, if you have the full psu negative voltage at one of the rails.
I am looking at your PSU photos and am getting confused because there isn't enough resolution... Can you take a close, well-lit, in focus photo and post it here? Thanks!
Oops - then I saw this...
vdi_nenna said:
Which means you have something miss-wired, if you have the full psu negative voltage at one of the rails.
I am looking at your PSU photos and am getting confused because there isn't enough resolution... Can you take a close, well-lit, in focus photo and post it here? Thanks!
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Hi 6L6,
since I am building the Pass Pearl 2 Phonostage currently myself, I am just curious to know what is wrong in the PSU schematic? Can you tell us, please?
I am using a different PSU, but anyway would be good to know to learn something.
BTW: Is there anything else wrong in the Pearl 2 schematic or any other pitfalls?
Thanks a lot!
Cheers
Poli
I did not know that the PS is wrong. The PS looked different to me, but assumed it was Pass Labs ingenuity.
The voltage problem came back! I decide yesterday to simplify the F4/F5 PS schematic.
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It's minor, but there is a missing ground connection from the bridges to the caps. Here is a corrected drawing -
In your photos it looks like you have no ground connection from your bridges to the caps, and that your connection to your ground-breaker is on the PSU positive rail. But it's hard to tell for sure. That's why I've been asking for a photo with more resolution...
