You have to get the pearl 3’ from any transformer for it to be genuinely quiet. At that distance any hum is likely wiring issues, where under that it’s probably picking up transformer noise.
Forgot to ask you lacrossebowe8, what cartridge are you using?
As it sounds like you have things pretty well buttoned up, it might be worth trying that Zobel mod on the input resistors. See photo for values and instruction (photo is from 6L6 - he’s the real master at troubleshooting this stuff!)
As it sounds like you have things pretty well buttoned up, it might be worth trying that Zobel mod on the input resistors. See photo for values and instruction (photo is from 6L6 - he’s the real master at troubleshooting this stuff!)
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All set, I did not have the B1 grounded as I was using plastic standoffs.
I found the answer while searching through the B1 thread and 6L6 had mentioned it.
Just working on the volume control wiring right now.
I found the answer while searching through the B1 thread and 6L6 had mentioned it.
Just working on the volume control wiring right now.
I have a few more kits of components (genuine J74 and K170's). PM Me if interested. I stopped selling them a few years ago as it became too much work.
No pearl 3, he said you have to make sure the pearl 2 is 3 feet away from any transformers, thus the need for the long umbilical power cord between units.
Codyt - I am using the Rega Carbon cartridge. I plan to upgrade the table and cartridge one day.
Ooops, posted this in the wrong thread. I have F5 kits -- a few of them, not Pearl Two -- sorry for the confusion.
Sorry, I completely spaced that. Your setup sounds solid to me. Hopefully that zobel works out for you. The only other things I did to mine were reducing the gain, removing input cap (cable should have enough capacitance), and removed the output cap in favor of a bypassed electrolytic cap on the supply return (to stabilize offset and remove dc). Take a look at the last couple pages in the ‘Building a Pearl 2’ post for more info.
I took a look through that. I did not install the input cap or the R20 resister which looks like where one would install the input zobel.
I put the case together and situated on my shelf with the turntable in between it and the amp. It still hums at full volume but is not really audible at my listening volume. The woofers are still pumping some but seems to be less than before.
I put the case together and situated on my shelf with the turntable in between it and the amp. It still hums at full volume but is not really audible at my listening volume. The woofers are still pumping some but seems to be less than before.
I think R20 might be the optional input resistor spot. If that one’s empty, then your input resistor would be the 47k next to it.
So I added the zobel to the empty R20 (680 ohm and 1k pf) slot and my woofer pumping has stopped. Unfortunately it still hums audibly if the volume control is at a quarter or more. Listening levels are below that so it isn't bothersome while listening but I would love to get it a bit quieter if possible.
Also, anyone else who put the zobel in does the sound seem a bit thinner after? I hadn't listened much to the system with no zobel so I could have a poor sonic memory.
Also, anyone else who put the zobel in does the sound seem a bit thinner after? I hadn't listened much to the system with no zobel so I could have a poor sonic memory.
Sounds like you have a grounding issue within the Pearl 2 or somewhere in cabling to the TT or preamp.
I noticed no change in sound with the Zobel, and I think Wayne adds it to their commercial phono preamps. You can always remove it as it only affects one cartridge that I know of (SAE1000).
I noticed no change in sound with the Zobel, and I think Wayne adds it to their commercial phono preamps. You can always remove it as it only affects one cartridge that I know of (SAE1000).
I'm going to leave the Zobel in for now. I'm guessing it was just poor sonic memory. Any common grounding errors I should look out for? I did try floating the star ground in the RIAA chassis and it was noisier fwiw.
On mine I have the ground planes of the boards connected to a ground lug on the chassis, which the turntable grounds to. The ground side of the input jacks are also connected to chassis but not the output jacks. The jacks themselves are insulated from the case. Are you using shielded wire anywhere inside? If so the shield must be grounded at one end. You can also try grounding the Pearl to the preamp case.
There are a lot of variations of grounding schemes to try.
You can’t judge sonics until you get the hum solved. Start by isolating every connection from the RIAA chassis except the ground post.
I've collected most parts for this phono stage. I have matched pairs of k369 for inputs, i.e. two parallel jfets instead of four.
My question is regarding the pair Q4, Q5. Is it less critical to use low noise parts there? I was considering maybe k117 in that position instead of k369.
I'm sorry about yet another question about parts substitution, but I'm tempted to use what I have if possible.
My question is regarding the pair Q4, Q5. Is it less critical to use low noise parts there? I was considering maybe k117 in that position instead of k369.
I'm sorry about yet another question about parts substitution, but I'm tempted to use what I have if possible.
I'm not sure if it was discussed before. If i want more gain than 65dB, can R14 go lower than 300 ohm ? say R14 = 100 ohm ?
Or should I keep R14 = 300 ohm and start to increase R15 ?
I have 0.25 mV MC cart and low powered amp with low efficient speaker. 65 dB full gain from Pearl 2 is still not quite enough.
Do you see any issues with going higher than 65 db for Pearl 2 phono stage ?
Thanks guys,
Tom
Or should I keep R14 = 300 ohm and start to increase R15 ?
I have 0.25 mV MC cart and low powered amp with low efficient speaker. 65 dB full gain from Pearl 2 is still not quite enough.
Do you see any issues with going higher than 65 db for Pearl 2 phono stage ?
Thanks guys,
Tom
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