18v compressor power troubles

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18v compressor power troubles

crw414
I've just built a philosophers tone compressor using sabro tone's layout. It works great at 9 and 12v but as soon as i plug in 18v [ recommended supply voltage ] it cuts out unless I play very gently. I've used 5532 , opa2134 and a ca3140[ lm741 replacement ] and the datasheets all say 18v's ok. All capacitors are also rated at 25v or higher.
Anyone seen this before or have any ideas ?
I also have tried 4558/tl072and 5534/tl071 for dual and single ic's and no change.
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Re: 18v compressor power troubles

induction
Are you sure your 18V supply isn't defective?
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Re: 18v compressor power troubles

crw414
thanks , yeah I checked with another compressor and 18v  works fine . I also just tried a 5k pot inline with the 18v supply to try to adjust the voltage to where it doesn't cut out. It works fine up to about 13.5-14v then it starts cutting out .
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Re: 18v compressor power troubles

induction
I think we need pictures and voltages to be any help with this.
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Re: 18v compressor power troubles

negativefx
In reply to this post by crw414
Is there a smaller layout than Harald's?  I suspect that mark/miro/johnk can shrink it down a bit... there's a ton of dead space on Harald's.  Harald does great pot layouts if you don't like wiring, but I like small boards more than less wires as it allows me to smash them into smaller boxes and/or double up in 1590BBs.
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Re: 18v compressor power troubles

inefficiency
I don't think it will be of any use, but I have the original pedal if anyone needs any gut-shots to confirm anything.
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Re: 18v compressor power troubles

crw414
I got out the multimeter and checked some voltages , and they are :
U2 tl072 [ I used 2134] . LM741                    NE5532                   4558
12 V   18v                   12v   18v                 12v    18v                12v    18v
1. 5.9 - 8.95                .07                          6.4 - 9.45                7.9 - 11.1
2  5.9 - 8.95                  9      6                   9.05- 6                    6.5 - 9.5
3 .5.9 - 8.95                  9      6                   9.05- 6                    6.35 - 9.3
4. 0                              0                               0                          0
5. 5.97- 8.95                .07                         5.6 - 8.5                  6.35 - 9.3
6. 5.97 -8.95                 6     9                    5.95 -9                    6.5 - 9.5
7.5.97 -8.95                11.5 - 17.3               5.9 - 9                     6.5 - 9.5
8.11.5- 17.45               7.4 - 10.4               11.6 - 17.3               11.5-17.3

I don't pretend to understand what these all mean , but according to the schematic on FSB http://www.freestompboxes.org/viewtopic.php?f=7&t=11954&start=80
Pins showing around 17 v should be 15 v.So should I adjust the 10r limiting resistor on the power input to get 15v ? Would this in turn effect the 9v supply bringing it down to 7.5v?

I do agree there is some empty space on the layout , but it was done to allow all 5 pots in a row apparently , I ended up wiring the pots because for some reason the pot tabs were lifting the copper traces off the board
thanks to harold for the layout  I wasn't brave enough to attempt my own
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Re: 18v compressor power troubles

negativefx
Yep, that's exactly why I avoid mounting pots directly to vero.  The slightest tilt in the pot or shifted drill hole and your board gets destroyed.  My ol drill press and I work well together but we aren't perfect.
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Re: 18v compressor power troubles

induction
In reply to this post by crw414
Are you sure those tantalums are rated for 25V and are oriented correctly? (Just a wild guess, I can't tell from the picture.)
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Re: 18v compressor power troubles

crw414
yeah all caps rated 25v or above and oriented properly.checked with my bbe supercharger at 16v , as I was using my joyo at 12, 18v and it still cuts out , yet works great at 12v.only other thing I've seen is the 2200uf cap is only rated at 10v on the schematic but mine is 25v , not sure if that would make any difference.
Thanks for the help anyway