The two images I recently posted were the actual results using the AP Analyzer. The above post by 6L6 is a simulation with National Instruments "Multisim". The simulated results with Wayne's values closely approximates the illustration on the PASSDIY website.
You can keep tweaking the values until the cows come home for perfection against the RIAA curve, but the most important thing to remember is that the channel-to-channel match is more important than getting a result better than 0.3dB relative.
Well I received my .22uf for the snubber on the power PCB and than I stumbled across the “Quasimodo the bell-ringer”.
So now I will go through and read up on it and probably end up making one so I get the snubber portion correct since I am going pretty much all out on this build, may as well.
So now I will go through and read up on it and probably end up making one so I get the snubber portion correct since I am going pretty much all out on this build, may as well.
Last weekend I got a Rega Planar 3 with an Audio Technica AT33 PTG/II cartridge. This combo did not seem to get along with the Pearl 2. After connecting the TT the noise (hiss) increases and a soft fast clicking sound is audible through the speakers. Disconnect the TT and hiss decreases again and the clicking sound is gone. I noticed the clicking sound before with a Bugle 3 in 60dB gain modus and Thorens TT with a Goldring Elite cartridge. The Pearl on the other hand has no problems with the Thorens/Goldring, I have been playing with this combo for years. Or is 60dB gain for these stages just a tad on the high side?
Is the cartridge picking up some interference? Would adding a Zobel network on the input help with this? (In another thread I read 680R in series with 1000 pF across the input; are these values specific to the Pearl, or could I use these for the Bugle as well?)
Is the cartridge picking up some interference? Would adding a Zobel network on the input help with this? (In another thread I read 680R in series with 1000 pF across the input; are these values specific to the Pearl, or could I use these for the Bugle as well?)
Doesn't the Rega Planar 3 use a switch mode 24 V power supply? If you have one, place a A.M. transistor radio near the Rega and see if you can hear the power supply.
Also, the copper pour/ground plane on the Pearl 2 input seems to act like an antenna for noise and hum.
One of my cartridges is an AT33PTG, and there's no noise associated with it and the Pearl 2. I added the Zobel but only because I had ringing with a HOMC cartridge.
Another question: what effect will the use of a low noise voltage regulator (/shunt etc) have on the Pearl 2? Will there be less audible hiss? First I used the stock 7x24, then I changed to LM3x7 with bypassed adjust pin which are supposed to be quieter, but I could not detect a decrease in hiss. Or is CRCRC filtering and additional filtering on the board as described in the pdf already good enough and is there not much to be gained?
I had a regulated supply on mine for years before I built the standard one from Wayne's paper, and I didn't notice any noise increase.
I compared the Pearl 2 using both the Jung Super-Regulator and the LMxxx units in the PASSDIY design -- there is no difference that I can discern and the LMxxx units should be quite satisfactory.