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Old 17th December 2011, 12:00 PM   #1241
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Quote:
Originally Posted by richluvsound View Post
ITS LIKE A DIFFERENT MATERIAL ... I can't get the whole clear !.... any suggestions ? I know a little about bonding metals ... I made my living fabrication St/St and Ally ... But ,
this aint right ... The exact same hole of the other board was like this too ! I seem to have got lucky with that one though.

R
Rich - If I were to guess, I would say that it is the connection of R7 to ground (bottom end of R7) right? If I recall correctly this pad connects to the ground plane and takes much more, repeat, much more heat and time to solder properly. There are a few others like this on the board. They are prime candidates for cold or marginal solder joints. I know because they gave me a hard time .

By the look of it, you are getting close to completing the first stage.

Pierre
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Old 17th December 2011, 02:16 PM   #1242
6L6 is offline 6L6  United States
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Rich - try a different brand or mix of solder when you re-flow old joints. Usually the flus is a different formula , and it can help make a clean joint. Also, you should get some paste flux and put a small dab on the pads before re-soldering. Use rubbing alcohol and an old toothbrush to clean the PCB after.
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Old 17th December 2011, 04:40 PM   #1243
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That makes sense pierre ! Its quite a heatsink area i'm trying to over-ride..

Pre-heat the board !
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Old 17th December 2011, 06:00 PM   #1244
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Originally Posted by richluvsound View Post
It's quite a heatsink area i'm trying to over-ride..
Exactly...
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Old 17th December 2011, 06:29 PM   #1245
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Default Grounding Question

I've been away from this thread for a while and could use some grounding advice.

I get a buzzing sound (not sure if it's 60Hz) when using one of my tables. Touching the output jacks makes the buzz go away; touching the input jacks makes it louder.

I'm using a star ground scheme recommended here. The Pearl 2 circuit grounds, output jack grounds, power supply circuit ground, and turntable ground all come together to a central star point. Earth is connected to the star through a 10 ohm resistor. Earth is also connected to the Pearl and PS chassis.

The fact that the buzz goes away when I touch the outputs jacks me to believe I have a grounding problem somewhere. Swapping headshells/carts makes no difference.

Any ideas?
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Old 17th December 2011, 07:54 PM   #1246
Itsmee is offline Itsmee  England
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Quote:
Originally Posted by McQuaide View Post
Touching the output jacks makes the buzz go away; touching the input jacks makes it louder.
Start with the simple checks first, you don't need to open the case yet. Do you have a buzz with the input disconnected and shorted out? Next check that you have continuity between input and output ground using a multimeter, also check that the input and output sockets are isolated from the chassis.
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Old 17th December 2011, 08:34 PM   #1247
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Quote:
Originally Posted by PierreQuiRoule View Post
Exactly...

What a PITFA .... !



C=9.33
B=8.53
E=7.90

things seem to have settled down .... I'll check every hour ...

Last edited by richluvsound; 17th December 2011 at 08:54 PM.
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Old 17th December 2011, 09:13 PM   #1248
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Quote:
Originally Posted by richluvsound View Post
C=9.33
B=8.53
E=7.90

things seem to have settled down .... I'll check every hour ...
The bias of your Q3 landed where it should. First stage is looking good .
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Old 17th December 2011, 09:35 PM   #1249
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Quote:
Originally Posted by McQuaide View Post
The Pearl 2 circuit grounds, output jack grounds, power supply circuit ground, and turntable ground all come together to a central star point. Earth is connected to the star through a 10 ohm resistor. Earth is also connected to the Pearl and PS chassis. [...] any ideas?
My guess... Because the Pearl 2 input, output and supply grounds are already connected together on the pcb, by connecting them all through wires to another star you introduced loops that pick up stray EM fields. The worst offender would be the input ground wire because any current induced there is amplified. Not good.

The Pearl input ground goes to input jack ground. Twist that ground wire tightly with the live input wire - so that there is no gap through which a stray EM field can travel through. The Pearl output ground goes to output jack ground. The two Pearl supply grounds both go to your star ground. Connect the turntable ground to that star.

Pierre

Last edited by PierreQuiRoule; 17th December 2011 at 09:53 PM.
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Old 17th December 2011, 10:29 PM   #1250
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Hi Pierre ,

what should be my next step ? Would you advise using 2.2k resistor @ Q2 and installing other parts first ... ?

Is there anything that i can check with each part I install ?

sorry about all the questions Sir

Rich
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