vintage EHX frequency analyzer question

[ham_phist]

Hey all,

Long time no post, but I haven't been able to do a lot of pedal stuff. I got this pedal on a steal, but it's powered by an AC cord and has the transformer inside it.

I would really like to bypass the transformer and supply DC to the circuit for use. If you were me, what would you do in order to find out what voltage that needed to be?

From the date of the pots, this appears to be from 77 or so. I tried asking EHX on twitter as well as the EHX forums. Thought I would check here and see if anyone knows any magic.

[ham_phist]

here's a pic of the guts:

[BuGG]

I would go to the original schematic.

From the looks if it you're going to need a +15VDC and -15VDC supply.   You should be able to add a small charge pump circuit and power the thing from a standard 9VDC supply.

There's a whole thread about this very subject over at the Madbean forums:
http://www.madbeanpedals.com/forum/index.php?topic=13084.15

[rocket88]

figured i would add a video of this thing in action.



like all EHX stuff, definitely something worth building since it's hard to find at a reasonable price. post the schematic in the requests, maybe we'll see a layout for this beast.

Madbean's version works well with 18 volts + charge pump...

 http://madbeanpedals.com/projects/freekout/Freekout.pdf

[ham_phist]

hey all, thank you much for the replies!

Had some gigs this week, so my audio time was limited. Just took this thing apart to take stock of what would be good to do aside from the power scenario. Being from around 76 or 77, I figured it wouldn't hurt to recap this thing. No big deal at all, but I do have one question.

These two axial caps here are 100uf at 25v. They are a good size. I have radial caps rated the same, but they are significantly smaller, just the kind you get from Tayda. Are these different and would it be better to replace them with a specific similar type of electrolytic cap?

Second- I am looking at the charge pump that will supply +/- 18v using an LT1054 below; would it be possible to make this happen with the 1044 or 7660? Just curious, I have some of those laying around but no 1054s. I need to use a 1n4001 to drop it to 15 v also.

http://tagboardeffects.blogspot.com/2014/01/providence-stampede-od-sov-2.html

I added the gunshots of this beast. I would like to convert it to true bypass, but it's got some goofy stuff going on with the power switch as well as a footswitch and I just don't know if I care enough to mess with that.

gutshot with the big silver caps: https://www.dropbox.com/s/fzrkjyipwuebp7a/20160610_224021.jpg?dl=0