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leonard d rock
Silver Member
Philippines
301 Posts |
 Posted - 05/16/2008 : 10:50:00
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hi guys. i'm posting this here rather than opening a new thread. my od-1 which was doing fine after i did the aca to psa mod was doing fine and doing duty primarily as a solo boost to the hm-2 or ds-1. however, this week, when i turned it on, a crackling sound comes out from the pedal and increases as i turn either knob to max. i isolated it from the board and the crackling sound definitely comes from it. any known causes for this? thanks for your help.
LDR |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 05/16/2008 : 13:51:03
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quote:
Originally posted by leonard d rock
hi guys. i'm posting this here rather than opening a new thread. my od-1 which was doing fine after i did the aca to psa mod was doing fine and doing duty primarily as a solo boost to the hm-2 or ds-1. however, this week, when i turned it on, a crackling sound comes out from the pedal and increases as i turn either knob to max. i isolated it from the board and the crackling sound definitely comes from it. any known causes for this? thanks for your help.
LDR
Hi LDR! Not quite sure what ou mean by "i isolated it from the board and the crackling sound definitely comes from it"? |
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zentropa
Gold Member
USA
837 Posts |
Posted - 05/16/2008 : 16:24:07
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i think he means he took it off his pedal board and is going guitar -> od-1 -> amp and he isolated the problem as definitely being that pedal.
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 05/16/2008 : 17:56:41
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| Gotcha! Well... if it's crackling, its almost certainly one of the amplifiers (cant recall if it has opamps or transistors - need to check when I get home), or a blown cap. Probably and amp. I'll check out the schematic tonight. |
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Laurie
Double Platinum Member
Canada
4854 Posts |
Posted - 05/16/2008 : 20:33:56
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OK... so I looked it up and it's a 4558 opamp.
Forgot to ask - is the crackling over the top of the normal sound, or is there just crackling with nothing else?
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leonard d rock
Silver Member
Philippines
301 Posts |
Posted - 05/17/2008 : 04:09:08
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hi zentropa and laurie, guys. the crackling sound comes out louder when the pedal is turned on and mixes with the overdriven sound. i tried resoldering some of the bad solder joints, but sound/ noise is still there. would a dead component be the cause?
LDR |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 05/17/2008 : 04:36:40
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Hi leonard d rock
Are the input output sockets tight, loose sockets can cause this problem as well.
Also clean the sockets with a cotton bud & some switch contact cleaner.
You will be amazed at the dirt that gets into these sockets.
Also look inside for any loose wires, there was one recently (Member On-Way) that had a broken blue wire, & then a few more of the wires broke off as well.
Good luck
regards Dr. Bob |
Edited by - Dr. Bob on 05/17/2008 13:45:18 |
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leonard d rock
Silver Member
Philippines
301 Posts |
Posted - 05/17/2008 : 11:24:10
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thanks dr. bob, guys. i'll be opening it up again and examine everything more closely (wires, solder spots etc.)
LDR |
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One-Way
Bronze Member
New Zealand
104 Posts |
Posted - 05/17/2008 : 11:59:25
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| Yeah those old wires work harden and get brittle with age and break off their connections easy. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 05/17/2008 : 13:50:58
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quote:
Originally posted by leonard d rock
thanks dr. bob, guys. i'll be opening it up again and examine everything more closely (wires, solder spots etc.)
LDR
Hi leonard d rock
Don't forget to check the in out sockets.
Also --- sometimes the nuts on the pots come loose & the pots can turn-twist, so that the outer lugs on the pots touch the chassis/case or some other part of the circuit & insides.
And One-Way:
Just little off topic for a minute.
Nice to see you back, How is that lovely Strat you made?
We should find that old thread, so that new members can get a look at your wonderful workmanship.
Regards Dr. Bob |
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One-Way
Bronze Member
New Zealand
104 Posts |
Posted - 05/18/2008 : 06:19:50
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Hi Doc Bob,
The strat is going great and still my no 1 guitar because it plays and sounds great. I still like to break out my LP every once in a while for some high octane distortion and shredding.
On my home recordings I generally like to use a range of guitars to get distinctly different sounds.I usually end up with too many guitar tracks. Cant help myself. |
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leonard d rock
Silver Member
Philippines
301 Posts |
Posted - 05/21/2008 : 02:41:20
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Hi everybody! i finally found out what was causing the crackling noise.  the brown wire connected to pcb point #1 had only about two strands connected.the rest were already broken tho i don't know why. probably has been that way with the previous owner. i cut and stripped the wire to make a new end and soldered it to the pcb. the od now has a stronger, fuller sound, probably due to the complete connection. thanks for your suggestions, i tried them all, almost decided on rewiring the whole thing, or letting a pro tech o it. MABUHAY!
LDR |
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One-Way
Bronze Member
New Zealand
104 Posts |
Posted - 05/21/2008 : 08:12:36
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| Yeh those old work hardened wires break easy. When i pulled mine apart to examine it another couple of wires broke off as well. |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 05/21/2008 : 10:44:41
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quote:
Originally posted by leonard d rock
Hi everybody! i finally found out what was causing the crackling noise. the brown wire connected to pcb point #1 had only about two strands connected.the rest were already broken tho i don't know why. probably has been that way with the previous owner. i cut and stripped the wire to make a new end and soldered it to the pcb. the od now has a stronger, fuller sound, probably due to the complete connection. thanks for your suggestions, i tried them all, almost decided on rewiring the whole thing, or letting a pro tech o it. MABUHAY!
LDR
Hi leonard d rock
That's really good news...
I had a rough guess that it was a bad connection.
Can you tell me what revision it is, A-B-C-D or E?
I Have a couple of later Rev-E's, but keep looking for one of the earlier ones with the Quad op-amp.
Regards Dr. Bob |
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leonard d rock
Silver Member
Philippines
301 Posts |
Posted - 05/21/2008 : 11:49:25
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hi dr. bob, guys. i don't know what revision it is but i ran its serial number 102500 and it says it was made september 1981. the opamp is a nec 4558d which was stock. i installed a chip adaptor so i could experiment with different opamps. i tried an rc4558p i found in an old betamax but it gave a some medium-high pitched whine/hum at almost full gain. i had better results with a jrc 4558, 4560 and rc4558d, even a ta 75558 but i use the stock opamp since it sounds best.
LDR |
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Topic |
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OD1 playing up again
