My Pearl II Build
While the build has progressed slowly, I finished the power supply last night. I used cheap cases from Amazon given my build confidence, though they are in a cool blue color. The hardest part of the process was mainly putting the order together and assembling all the most helpful posts. Don't forget to bookmark! Anyone thinking of building a Pearl II, don't hesitate to reach out. More to come as I get into the RIAA boards this week / over the weekend.
Beginning of the case work
Initial layout
Finished board (used this kit: https://www.ebay.com/i/232849708899?ul_noapp=true)
Final layout which thankfully measured +/- 31 volts
While the build has progressed slowly, I finished the power supply last night. I used cheap cases from Amazon given my build confidence, though they are in a cool blue color. The hardest part of the process was mainly putting the order together and assembling all the most helpful posts. Don't forget to bookmark! Anyone thinking of building a Pearl II, don't hesitate to reach out. More to come as I get into the RIAA boards this week / over the weekend.
Beginning of the case work
Initial layout
Finished board (used this kit: https://www.ebay.com/i/232849708899?ul_noapp=true)
Final layout which thankfully measured +/- 31 volts
Where did the little power supply board come from? I'm considering knocking up a bunch of power supplies for Pearl, Korg and ACA pair. If I use the DIY Audio boards for the Pearl it will be quite bulky. Just chewing over all the options. I'm thinking hard over the options of one or multiple boxes bearing in mind the advice to keep the pearl power supply away from the pearl RIA itself.
it is this one from ebay, which comes with all the parts:
https://www.ebay.com/i/232849708899?ul_noapp=true
Finally I finished the build today and all the voltages checked out. Once i adjusted the trim plot I played it and so far it sounds very good. I would say much better than the bellari that it will be replacing.
One question: My speakers woofers seem to be working overtime with this pre. Any ideas as to why that might be?
One question: My speakers woofers seem to be working overtime with this pre. Any ideas as to why that might be?
Are they oscillating or pumping in/out a lot at higher volumes? I had that problem early on, and reworking some of the grounding scheme took care of it for me. I also lowere the gain a bit and added the zobel on input resistor, which may have helped too.
The ground is on one of the RCA leads. Normal for as Rega.
What’s you turntable resting on? What cartridge are you using? You are either picking up some resonances back into the table or you have a bad compliance mismatch which is resonating in the arm.
Your previous phonostage most likely had a subsonic roll-off to stop the woofer pumping.
What’s you turntable resting on? What cartridge are you using? You are either picking up some resonances back into the table or you have a bad compliance mismatch which is resonating in the arm.
Your previous phonostage most likely had a subsonic roll-off to stop the woofer pumping.
The turntable is on a marble bakers board which is on top of a built in cabinet. The speakers rest on the tile floor in front of this cabinet. I am just using the cartridge that came with the table which is the Rega Carbon. I did not have the woofer pumping issue with the bellari which does have a subsonic roll off filter but i usually did not have that switch engaged. Either way my woofers don't pump when using that pre-amp.
It could be that the better bass extension of the Pearl 2 is exposing other issues. The Pearl 2 does have a low frequency rolloff.
Is in an extremely consistent pumping, or does it change a bit with the record? Mine was extremely consistent and always started at a precise volume level. FWIW, I didn’t change anything with my player to resolve the problem. For mine, it was a combo of the extra gain and some poor grounding on my part that seemed to make it happen. As mentioned, I went through all of the grounding and lowered the gain a little, which ultimately seemed to resolve the problem. It’s very possible that I simply ‘muted’ the problem and didn’t fix it, but like you it was a new problem that came with building the Pearl. I had experienced rumble/wobble in the past, and this was different.
I found an error in how I’d wired the safety bridge in the PSU chassis and fixed that. Then I scuffed up the anodized aluminum case in a few places where panels, Star ground, etc come together. I also had used a bit of shielding for my power wires in the RIAA case, and it ended up causing more harm than good.
No mods really, just trying to optimize the grounding as much as I could. Out of curiosity, if you turn your volume all the way up, is the Pearl still quiet? Any hum, white noise, etc?
When I turn the volume all the way up there is a fair amount of hum. I cannot really hear it at my normal listening level which is not even at one quarter volume. A few things I have tried:
Moved signal and power wires closer to the chasis floor - minimal difference
Tried floating the ground wire in the phono section - made the hum louder
Since I am still testing the pre-amp, I didn't have the chassis cover on. Adding it made little difference.
I tried picking it up and moving it around which changed the hum, for example if I put it on top of my tube amp's power transformer, the hum increases substantially.
Should the pre-amp be dead quiet even at full volume on my integrated? Thanks again for all the advice from everyone in the thread.
Moved signal and power wires closer to the chasis floor - minimal difference
Tried floating the ground wire in the phono section - made the hum louder
Since I am still testing the pre-amp, I didn't have the chassis cover on. Adding it made little difference.
I tried picking it up and moving it around which changed the hum, for example if I put it on top of my tube amp's power transformer, the hum increases substantially.
Should the pre-amp be dead quiet even at full volume on my integrated? Thanks again for all the advice from everyone in the thread.