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DIY Stompboxes => Building your own stompbox => Topic started by: sjaltenb on January 19, 2009, 01:07:17 AM

Title: help location position on PCB based on schematic
Post by: sjaltenb on January 19, 2009, 01:07:17 AM
hello,

i fixed my PT-80 and it sounds very nice indeed! There is a soft whistling coming from it however I do not have it in an enclosure so i'm guessing thats the culprit, other than that, no noise whatsoever!

anyway, I would like to add an SPST switch to this circuit to kill the dry sound. I was told I needed to place it at "A" on this schematic:

http://www.generalguitargadgets.com/diagrams/pt80schem.pdf

Which I see is coming off the TL072 into a 10K resistor, but I am not sure which one of the two it is on here:
http://www.generalguitargadgets.com/diagrams/pt80schem.pdf

Once I find out which one it is, i should simply intercept the signal off the opamp and place teh switch between the opamp and 10K resistor, right?

Thanks so much!!!
PS-what is the approx stock delay time of the pt80 at max time?
Title: Re: help location position on PCB based on schematic
Post by: Andre on January 19, 2009, 04:32:21 AM
The arrow in the picture points towards the lead of the 10k resistor you have to lift.

(http://www.xs4all.nl/~jvcn0028/pictures/PT-80%20Dry_Lift.jpg)
Title: Re: help location position on PCB based on schematic
Post by: sjaltenb on January 19, 2009, 02:04:55 PM
why thank you very much Andre! I had suspected that was it, but...I was not sure. Thanks again.