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Old 24th December 2011, 12:21 PM   #1321
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Rich
I would guess the problem is with the solder joints... again.
You could fix this board - or start anew. Make sure you test your components because others beside R29 might be gone now...
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Old 24th December 2011, 01:44 PM   #1322
nar is offline nar
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Quote:
Originally Posted by PierreQuiRoule View Post
Rich
I would guess the problem is with the solder joints... again.
You could fix this board - or start anew. Make sure you test your components because others beside R29 might be gone now...
Or a short vs ground plane ...

I would get a new soldering tip, and remove all - resolder all new. With shiny / well done joints.

For a simple resistor/pad joint, heat with screw driver type tip, at 45 angle so it touches both component lead and pad. Heat for about 3 seconds or so, by tight contact. Pressure must be enough to transport the heat. So, holding the pcb in a vice is a good idea for this

Then, apply flux. It must go all over and flow, don't add too much at the same time; better joints are done with minimal quantity flux. Otherwise it takes more time to cool up, will overlap with ground plane adding complications later. When flux as "wetten" all wanted, quickly remove the soldering tip. It must consolidate in about a second. You should see the process with your very eyes !

Optional : After each soldering, verify there is no short between pad and adjacent ground plane/pad.

Best,

nAr
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Last edited by nar; 24th December 2011 at 02:00 PM.
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Old 24th December 2011, 02:01 PM   #1323
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thanks guys.

I'll remove everything from the output and test the input again . I need to order new tips and a couple of parts. Obviously , I would like to keep the board
if the input is still good , if not , I'll order a new board .
nAr , if you could spare a couple of ZVP 3310 that would be great ?
. I can't find them in the UK .

Thanks for your help ,Wishing you all a wonderful holiday , Rich
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Old 24th December 2011, 02:14 PM   #1324
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nAr - Very good advice.
Rich - Board should still be good. There is enough copper on this one for the traces not to lift.

Best wishes to all for the Holiday season!

Pierre
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Old 24th December 2011, 02:37 PM   #1325
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Originally Posted by Itsmee View Post
Just re-read your post, try connecting the turntable ground to the Pearl chassis instead.

6L6 beat me to it.
Here's an update on my grounding issue. I'm getting a buzzing sound from only one of my two tables (a Mitsu LT-30). All is quiet when using the other one.

Oddly, whether grounding the Mitsu to the star, or leaving it un-grounded, makes absolutely no difference in the noise level. Holding the end of the ground wire between my fingers reduces the noise quite a bit. This is strange, I never owned a table that behaved this way.

Update 2: This was happening with a Pickering XSV-3000 cartridge. Using a Grace F-9 cart, there is tremendous hum with the table left un-grounded. The one difference between the carts is that the Pickering uses a grounding strap between one of the pins and the metal cart body.

Update 3: Problem solved. Since the Pearl 2 reverses phase, I reversed the polarity of the cartridge leads to compensate. Apparently this causes grounding problems, since putting the leads back to the proper polarity eliminated the buzz.

Last edited by McQuaide; 24th December 2011 at 03:01 PM.
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Old 24th December 2011, 09:04 PM   #1326
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..... Input stage is un-damaged I have removed everything from the output ... I'll clean it good with solder braid and replace everything .
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Old 29th December 2011, 06:03 PM   #1327
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Default Final update on Pearl 2 grounding...

Grounding issues can be tough to troubleshoot, because the noise tends to come and go, is different with different turntables, and can change depending on the location of equipment and cabling, what's being touched, etc. I kept making changes based on the advice of various individuals, thinking they worked, only to find that the buzzing sound came back with a vengeance.

Well, I finally have a completely quiet Pearl 2, based on 6L6's advice. My config is what he recommended:
  • Earth only connected to the PS chassis
  • Output jack grounds connected to the PCBs (I had connected them to a star ground instead)
  • PCB starground and turntable ground to Pearl 2 chassis (I didn't know the PCB starground existed)
  • v+, v-, vground floating
  • Shielded turntable interconnect cable from the input jacks to the PCBs

So a hearty thanks to 6L6, this had been bugging me for some time!

Mark
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Old 29th December 2011, 07:35 PM   #1328
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Mark,

Where is the pcb star ground? Is it the pad between C6 & C4, above C12?
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Old 29th December 2011, 07:40 PM   #1329
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Yes, the unmarked hole between C4 and C12. Connecting these and the TT ground to the chassis killed the noise completely.

Someone also said to ensure the jacks are isolated from the chassis, which mine are.
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Old 29th December 2011, 07:41 PM   #1330
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Thanks.
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