Sorry if this question does not belong in this thread ... but I would like to build the Pearl 3 and I want to make sure that I purchase all the necessary parts. From what I can tell if I purchase the DIY kit from DIY Audio Store ($150) and I purchase the Modushop kit "Wayne's Pearl III Chassis Kit" (230 Euros), that is all I need. Is that correct? Thanks, Ed
^ No. The build document (the .pdf in post 1) provides a list of all the other necessary (and optional) components.
@EGlaser I am going through the BOM and buying all the same stuff today and had the same questions. Most of the part numbers are in the BOM in the directions.
1. You need to head over to DigiKey and Mouser and purchase quite a few things to finish the power supply and case.
-From Mouser I got this stuff: RCA connectors, XLR connectors, Ground Post, AC plug, Caps for C1-C11, Resisters for R3-11, LEDs for D3-5, rectifier for D1, 2, and 6 ~ $115 at mouser
-From DigiKey I got: U2 (if XLR), Transformer (on backorder right now, shipping August) Fuses, 2 and 3 slot terminal blocks, cable gland, IEC fuse holder, and switch ~$65 at Digikey
2. You will need wire/cable for internal power, umbilical cord, and signal wires. I picked up some Mogami from Performance Audio. ~$20
3. You will need M3 5mm standoffs with screws and nuts ~$10 at Amazon
4. Stuff for ground wires however you want to hook them up including misc screws, star washers etc.
5. Sandpaper to scratch the paint off the case panels to connect them all together electrically
I will still need to order some 16 gauge wire from Amazon for the power box, some spade connectors and spade terminals for the board, probably use some old Cat 6 wire to extend the LEDs out to the front of the case, random shrink wrap, electrical tape, solder, soldering iron, crimp fittings etc.
This might not be everything, but this will get you started for sure. I up to about $575 of stuff right now (including the diyAudiostore kit and the Modushop case). I'm thinking I will need a few more things once I get into it.
1. You need to head over to DigiKey and Mouser and purchase quite a few things to finish the power supply and case.
-From Mouser I got this stuff: RCA connectors, XLR connectors, Ground Post, AC plug, Caps for C1-C11, Resisters for R3-11, LEDs for D3-5, rectifier for D1, 2, and 6 ~ $115 at mouser
-From DigiKey I got: U2 (if XLR), Transformer (on backorder right now, shipping August) Fuses, 2 and 3 slot terminal blocks, cable gland, IEC fuse holder, and switch ~$65 at Digikey
2. You will need wire/cable for internal power, umbilical cord, and signal wires. I picked up some Mogami from Performance Audio. ~$20
3. You will need M3 5mm standoffs with screws and nuts ~$10 at Amazon
4. Stuff for ground wires however you want to hook them up including misc screws, star washers etc.
5. Sandpaper to scratch the paint off the case panels to connect them all together electrically
I will still need to order some 16 gauge wire from Amazon for the power box, some spade connectors and spade terminals for the board, probably use some old Cat 6 wire to extend the LEDs out to the front of the case, random shrink wrap, electrical tape, solder, soldering iron, crimp fittings etc.
This might not be everything, but this will get you started for sure. I up to about $575 of stuff right now (including the diyAudiostore kit and the Modushop case). I'm thinking I will need a few more things once I get into it.
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Have now got one channel working fine. The channel with the intermittent LED, however, is not working. The red LED comes on but goes off again and even when it's on there's no sound. I'm scratching my head to work out where the issue is. In addition to the basic tests in the build guide are them some further diagnostics I can perform? I have the functioning board to compare with. The channel that works sounds great so am keen to fix the one that's not working! Is it possible that it's the LED that's actually faulty?
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Update on diagnostics - I've painstakingly been through the malfunctioning board to test all continuity between the joints and components. Every thing is fine except R19 on the bad board is measuring 750R on the meter not 1K. This is despite the banding being correct on the component. I have also performed some diagnostics with power on and compared the values on boath boards. It seems there are some discrepancies on Q5, Q7 and Q8. Please see the image attached. If anyone has any clues as to the issue it would be most appreciated. The board that's functioning sound sgreat and I'm keen to get both channels humming....
Some of your measurements are not clear. For instance, the output of U1B is -8 volts, but R25, which is physically connected to U1B output, is not the same. Yet Q7 E is -8 volts, did you mean Q7 B? There are not that many components around Q7, D1 and Q6. Double check the pin orientation, resistor values and solder connections.
For the output circuit to be working properly the output of U1B should be around+0.95 volts and the other side of D1 should be -.95 volts. If you measure across D1 you should see about 1.9 volts. My pearl 3 was +.93v and -.93v and across D1 was 1.84v
The other issue you are having is with capacitor multiplier Q8 and should be resolved. Check R19 and R20. A simple voltage divider. Is R20 possibly 1K?
For the output circuit to be working properly the output of U1B should be around+0.95 volts and the other side of D1 should be -.95 volts. If you measure across D1 you should see about 1.9 volts. My pearl 3 was +.93v and -.93v and across D1 was 1.84v
The other issue you are having is with capacitor multiplier Q8 and should be resolved. Check R19 and R20. A simple voltage divider. Is R20 possibly 1K?
Thanks for the reply. I've retested and there were one or 2 mistakes (see image). Part of the issue I think is that Pin7/R25 seems to oscillate between the correct value (-0.93 and -8). This I think is what is turning the LED at D1 on and off. As advised I tested R19 and R20 and I htink there's an issue there. R19 on the malfunctioning board measures 772R despite the banding being the same as the R19 on the good board (which measures 1k as it should). R20 on the bad board takes a long time to measure with the meter and levels off at 12.5k ohn. R20 on the good board also takes a long time to reach a value and levels off at 33k ohm. Along with this, R2 and R3 on the bad board are taking a very long time to reach their value compared to the one on the good board which measure immediately. I'm planning as a next step to replace R20 on both boards, R2, R3 and R19 on the bad board. Is it possible there was a bad batch of resistors?
Locky - it looks like you need to go back and flow some solder. I would guess there's an open connection somewhere. Give those connections some more solder and heat and let the solder flow through to both sides of the board.
The slow measurements are from the capacitor in parallel charging. Difficult to get accurate measurement in circuit.
No need to replace the resistors with the good voltage readings.
Did you check LED D1 orientation? The LEDs I got from the kit I can't tell which is the flat side. We know the LED works because it lights up, but with -8v from U1B, I think it is reversed in order to light up.
No need to replace the resistors with the good voltage readings.
Did you check LED D1 orientation? The LEDs I got from the kit I can't tell which is the flat side. We know the LED works because it lights up, but with -8v from U1B, I think it is reversed in order to light up.
Then that´s what you use 😉
DON`T trim the legs. Just cut them after soldering.
Or replace with new....... the short leg (big electrode inside the housing) being Cathode.
If the LED is lighting momentarily, it is installed properly.
The error is elsewhere.
The error is elsewhere.
Have resoldered components, ensuring that there's solder on the top of the board also and have tested the DC volts using the pdf values provided by 6L6. The good news is that the LED is remaining on and I have the required voltage across D1 on both boards. The volts on the good board are also in line with the values on the pdf. There remain some discrepancies on the bad board, however, around Q8 and Q5 which I'm not sure how to resolve. I've reattached an image of the values I'm getting. Is the next step to replace Q5 and Q8 and then retest?
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Thanks. The joints look ok and I have good continuity through to the associated joints. I'll replace Q8 and then retest. My BOM came with ZTX457 rather than the ZTX851 on the schematic... I have a few of the following in my spares box and am wondering if any of these will do? BC557BG/BC547CG/BC550CG/BC560CG.