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Hey all.

To make a long story short, I managed to destroy TWO (2) para EQ pedals in quick succession by putting them in the FX loop of an Orange Terror Stamp (pedal version of the Tiny Terror). The one had been working fine for a couple of weeks, but I was trouble shooting something else and in the process of turning things off/on, plugging and unplugging, etc, I'm fairly certain I broke it .

Initially both EQ's worked swimmingly, but after a the aforementioned plugging/unplugging now all they do when on is make awful sine-wave type sounds as I tweak the Q and level knobs. Overall volume still works to affect that terrible sine noise. (How I broke TWO: when the first stopped working I thought it was because of my poor wiring. I used the second in its place because I was still troubleshooting another problem).

I'm not sure if it's Orange's fault or my own. In my builds, I made subs on the resistors I figured were close enough, but did I end up making something burn out? (I always ask someone that knows what they're doing if my subs are OK; it figures if the one time I don't I break stuff).

My subs were: instead of 1.6K resistors I used 1.5K. Instead of 5.1K resistors I used 5.6K. And finally, instead of the 12n capacitors I used 15n.

You'll probably notice some electrical tape, which I used because initially the pots were shorting out against the PCB (when this happened the pedal wouldn't turn on at all. After the electrical tape it worked perfectly until today's unfortunate incident).

Any help/suggestions would be greatly appreciated. Both these pedals are intended to be used in live settings, so please also let me know if there's anything to be worried about when using them in FX loops. Thanks!

I don't know what's wrong, but my first guess would be something happened to the charge pumps. Take voltages of pins 4 and 11 of the op amps.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

All three op amps read 9.87v at pin 4 and 0.72v at pin 11.

Looks like Keith was exactly right about something happening to the charge pumps. The function of the charge pump in this circuit is to provide +9V to pin 4 and -9V to pin 11 of each of the three quad op amps. Looks like whatever was going on between the Para EQ pedals and that Orange Terror pedal blew out the -9V generation of the charge pump, though it's still passing along +9V. Not sure what would cause this (though Keith very well might), but I would guess that replacing the charge pump in each Para EQ will likely put them right again. If it was me, I'd go with an LT1054 instead of a 1044S or 7660S, if either of those are what came in them originally. The 1054 is a more robust chip. Mouser sells them for about $3 each.

I see that the Orange pedal uses a 15V center-positive power supply, where the Para EQ needs 9V center-negative. You didn't run both pedals daisy-chained off the Orange P/S, did you?

Your part substitutions wouldn't factor into this, since none of those components are associated with the charge pump and the power-handling portion of the circuit. They will, however, affect the function of the EQ circuit itself, though I don't know to what extent. The fact that the circuit contains 15x1.6K and 24x5.1K resistors is a bit concerning. Did you make these substitutions for ALL of them??

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

In this circuit, the charge pump isn't doing anything to the positive voltage supply. It's only acting as a negative converter to create a bi-polar power supply. So even with a bad charge pump you will still get +9v (or whatever your positive voltage supply is), you just won't get negative voltage.

I'm not familiar with this Orange amp pedal, but if you connected a positive 15v ground to the parametric EQ, that probably wouldn't be very good since you'd be connecting pin 3 of the charge pump to +15v.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

You may have damaged the op amps. I would remove the op amps from their sockets and measure voltages on pins 4 and 11 with the charge pump in. If you're still not getting negative voltage on pin 11 then you can assume that the charge pump is bad.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

I'm not running the pedals off the Orange P/S. I'm running the Orange from it's OEM power supply separately from my pedal daisy-chain (1Spot), which is only running BYOC stuff and a Boss TU-3. I do have an "outlet extender" that it's all plugged into: this is so I can have the two different power supplies (Orange and 1Spot) fed by the same extension cord, which is then plugged into a surge protector. In other words: wall -> surge protector -> extension cord -> outlet extender -> both Orange and 1Spot adapters. Is it possible the outlet extender is causing an issue when I turn the Orange on and off?

Regarding the resistors, yes I substituted all of them , but the EQ was functioning as I'd hoped up until then. The Orange only has a "shape" knob for tone, so of course it was welcome to have the power to control Lo, Mid, Hi (and of course the center freg and Q values )

Measurements on 4 and 11 are still 9.87 and 0.72, respectively without the op amp. Should I replace the charge pump and go from there?

Yes, that appears to be the clear indication based upon those results.

And don't worry about the component substitutions you made. The value differences are small and the important thing is that the pedal functions to your satisfaction. It sounds like it definitely was doing so, up until these mishaps.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

Ok, I've got my fingers crossed and some LT1054s on the way!

Assuming this will get the EQs up and running again, any insight on how I may have busted them in the first place so I don't repeat my mistake?

I would assume your problem has something to do with how you're powering the pedals.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

Something to check would be the actual output voltage on the power supply you're using. Some inexpensive 9V P/S's are not properly regulated and may put out as much as 15V. That's enough to fry some of these charge pump IC's. That's one reason I like the LT1054, because it's rated for 16V max. input voltage.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2

I'm using a 1Spot NW1-US adapter with an 8 plug daisy chain. I measured the adapter with a multimeter and it's giving a steady 9.44v. It says it's 1700mA max.

The Orange is being separately powered by its OEM power supply: positive tip 15.29v (measured), 2.0A.

Not sure if I put this clearly before, but both adapters were plugged into a small, cube-shaped outlet extender which is not a surge protector. Could that be the culprit? It was very cheap and it's an easy thing to replace in my power chain with a traditional surge protector (it's there so I can have just one extension cord coming from the pedalboard).

Measure the voltage of the ground of the Orange. Do this by powering both the BYOC and the Orange but keep them separate on their own power supplies. Red probe goes to the sleeve of the orange FX loop jack. Black probe goes to the sleeve of any jack sleeve of the BYOC pedal.

_________________
*patience is a virtue*

Please do not PM me. email is prefered. keith@buildyourownclone.com

I think I'm doing this right... I'm getting a number that's fluctuating from 0.09 to -0.09

LT1045s are installed and the pedals are both back up and running! Thanks so much.

Is there anything I should be concerned with now, or will the more robust charge pump prevent similar damage to the pedal in the Orange FX loop?

Excellent! Glad to hear the new charge pumps did the trick.


That's a good question. Wish I could provide good advice, but we really don't have a clear cause for what happened. If it was me, I'd go ahead and hook one of them up and see how the two get along now. Hopefully, the higher voltage rating of the 1054 (16V) will give you some added protection if the other charge pumps (10V) over-volted. Worst case you have to buy another LT1054.

_________________
“My favorite programming language is SOLDER” - Bob Pease (RIP)

My Website * My Musical Gear * My DIY Pedals: Pg.1 - Pg.2