(No edit button found, apologies for multiple posts)
So it looks like the board itself isn't toast; managed to extricate U1/2 and still have good continuity. I did discover that R1-4/30-33 are all five Ohms instead of 10. Not sure why; I can't find my documentation and this was a forlorn project that was left by the wayside after my son was born. My other board is identical, though, and seems to function. I haven't taken any proper measurements yet, though, and am going strictly by the fact that the LED lights up. I know, amateur hour...especially since I'm cheating and feeding the boards via DC power supply instead of the UltraBibs I built for them ("known good" and all that).
I'll get new 7824/7924s installed and report back. I'm hoping I didn't accidentally zap the little ZTX/ZVPs during install, but we'll see.
So it looks like the board itself isn't toast; managed to extricate U1/2 and still have good continuity. I did discover that R1-4/30-33 are all five Ohms instead of 10. Not sure why; I can't find my documentation and this was a forlorn project that was left by the wayside after my son was born. My other board is identical, though, and seems to function. I haven't taken any proper measurements yet, though, and am going strictly by the fact that the LED lights up. I know, amateur hour...especially since I'm cheating and feeding the boards via DC power supply instead of the UltraBibs I built for them ("known good" and all that).
I'll get new 7824/7924s installed and report back. I'm hoping I didn't accidentally zap the little ZTX/ZVPs during install, but we'll see.
Thinking more about this...if I'm getting clean 25V from the UltraBib, do I really need the onboard regulators? Could I not simply jumper the U1/2 pads or, even better, simply use the downstream pads of R3 and R33 as Vin?
My plan has been to use one chassis for a BA-3 preamp with two sets of Ultrabibs and a shielded 22V Antek transformer. One set of 'bibs for the BA-3 and the other output from the chassis to the Pearl 2 chassis. I'm pretty sure one set would power both the BA-3 and the Pearl 2, but I like the separation and may go insane later and go for dual-mono BA-3.
My plan has been to use one chassis for a BA-3 preamp with two sets of Ultrabibs and a shielded 22V Antek transformer. One set of 'bibs for the BA-3 and the other output from the chassis to the Pearl 2 chassis. I'm pretty sure one set would power both the BA-3 and the Pearl 2, but I like the separation and may go insane later and go for dual-mono BA-3.
Good morning to the great DIY community. I would like to build the pearl 2 phono and from the passdiy site I followed what is reported: To build your own PCB boards download both Pearl files: file 1 and file 2.
I downloaded the two files and created a single zip uploaded to jlcpcb. I received this email asking:
As shown below, there is only one solder mask layer, where we can use it for both top and bottom sides?
Unfortunately I'm not the least bit expert on PCBs, could anyone help me on what kind of answer I should give? I thank in advance anyone who can help me.
Paolo
I downloaded the two files and created a single zip uploaded to jlcpcb. I received this email asking:
As shown below, there is only one solder mask layer, where we can use it for both top and bottom sides?
Unfortunately I'm not the least bit expert on PCBs, could anyone help me on what kind of answer I should give? I thank in advance anyone who can help me.
Paolo
I don't have the board in front of me, but the 4 mounting holes in the corners are fine unless you want to electrically connect to the chassis, which you don't,
Then I think I see the 4 holes for the two pins on each of the 2 heatsinks. Again, you don't want those connected (the heatsinks are isolated electrically).
Not sure about the others without a photo of the original board, but that's at least 8 accounted for.
Then I think I see the 4 holes for the two pins on each of the 2 heatsinks. Again, you don't want those connected (the heatsinks are isolated electrically).
Not sure about the others without a photo of the original board, but that's at least 8 accounted for.
@lillo: As Albert pointed out, the 4 PCB and the 4 heatsink mounting holes are isolated.
The other 'red holes' are all connected to ground.
I have a pair of unused boards from PL and I just poked around with a multimeter and that's what I found.
I also had some boards made using the available gerbers (and adding the solder mask) and they came out fine. In fact, I used these boards in my build since I was convinced I would somehow mess it up and didn't want to risk the original set.
Good luck.
The other 'red holes' are all connected to ground.
I have a pair of unused boards from PL and I just poked around with a multimeter and that's what I found.
I also had some boards made using the available gerbers (and adding the solder mask) and they came out fine. In fact, I used these boards in my build since I was convinced I would somehow mess it up and didn't want to risk the original set.
Good luck.
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Sorry, just to be clear. I meant that those 4 PCB mounting and heatsink mounting holes are electrically isolated from the circuit.
The 4 corner PCB mounting holes, for example, have metal on the inside (thus you can say they are plated), but the plating does not extend beyond the height/depth of the hole and is not connected to anything else.
The 4 corner PCB mounting holes, for example, have metal on the inside (thus you can say they are plated), but the plating does not extend beyond the height/depth of the hole and is not connected to anything else.
I don't know if it is possible to purchase in Italy, (but I know people like cookies all over the world), my original Pearl 2 boards are mounted in cookie tins within an aluminum chassis. This really prevents "mains" radiation from leaking in. The idea came from a low noise amplifier design I saw on a Linear Technologies application note.
I did the Minnie-Pearl boards with the ground plane on the bottom layer, signal layer on top and the two power planes sandwiched in the middle. They are about 1/3 the size of the Pearl 2 boards.
In any event, you will love this phono preamplifier.
I did the Minnie-Pearl boards with the ground plane on the bottom layer, signal layer on top and the two power planes sandwiched in the middle. They are about 1/3 the size of the Pearl 2 boards.
In any event, you will love this phono preamplifier.
