Operate at 12V or 9V?

[bufftonz]

Hi everyone,

I just recently acquired a good condition DOD FX96 Analog delay pedal off of eBay a few days back (the one with Tape Quality knob). Everything works good, but I read the reviews at Harmony Central and from what I understand, the later purple version FX96 (the one I got) does not perform so well at 9V, but when using a DC power brick running at 12V(i.e. Dunlop DC power brick), one can get the FX96 to do more things, like self-oscillations, longer-brighter repeats when 'Quality' knob on max and darker,longer-lasting repeats when 'Quiality' knob is at min...basically all these things it would do at 12V which can't be done at 9V. I was wondering if anyone here who has a DOD FX96 can attest to that, or can suggest me otherwise?

Here is another kicker, the DOD FX96 were made before 1998, so the pedal itself is of the unregulated electrical-satndard type, so a few units of voltage deviation is alright, but is this true? Has anyone ever powered a 9V pedal with 12V and achieved better results from such use? If anyone has any suggestions or stories to tell, please let me know, I'll b e happy to drop an ear. 

The reason why I'm asking this is  because I want to know if its worth getting the Dunlop DC Power Brick, that I may run the FX96 at 12V vs. 9V. If anyone is not sure what I'm talking about, you can visit the reviews at Harmony Central; some reviewers there claim that the FX96 performs more and does more things at 12V versus 9V. But I"m not so sure...

Please let me know what you think.

Thank you.

--Chris

P.S. The specific FX96 I have does very little at 9V, like it cannot self-oscillate like the earlier blue FX90, and the 'Quality" knob on the FX96 appears to have limited tonal-control range at 9V, but I assume it to be more versatile at 12V?

[demonstar]

Has anyone ever powered a 9V pedal with 12V and achieved better results from such use? If anyone has any suggestions or stories to tell, please let me know, I'll b e happy to drop an ear. 

I have no experience with what you mention but supplying anything with more power than it was designed for without modification sounds a BAD idea. With mods then go for it but without I wouldn't!

I'm sure I've read on here (it may have been an R.G. comment but can't be sure) that quite often manufacturers will use 10V (or similar) rated caps to keep the cost down. That would mean if you plugged in 12V you could be seeing fireworks.

To conclude in my opinion before just plugging 12V in there I check out it's guts and reference a schematic then make an informed decision based on the evidence. So it could work but I wouldn't chance it because chances are it won't!

Remember safety glasses when exceeding electrolytic caps voltage rating.

[darron]

i wouldn't say that it's necessarily a bad idea. something that self oscillates at a few more volts could be sus'. not sure that it will all of a sudden become brighter etc. like you described.

also, that pre 1998 thing doesn't really make sense to me. it's not like pedal manufacturers are now building their boxes with built in regulators. also, voltage regulators are not a new thing and people could always have used them in the past. even a 9V batter usually puts out a tiny bit more than 9V fresh.

it's not too hard to check if you will wreck it though. you mostly just need to find the schematic and check the rating on the parts. demonstar is right in that some manufacturers do for example use 10v caps, but these are usually in pedals with SMD parts who are really cheaping out or who want to save on space. make sure the capacitors are all rated over 12V and have a bit of safety margin. take a look at the datasheets for all the ICs in there. opamps and stuff are often rated to around 18V. i'm not familiar with the schematic, but the delay chip may not handle the 12V, but it probably would.

some pedals can benefit from a bit more voltage, but 9V is the convention these days for pedals as that's what most power supplies run at, and they will usually take A 9V battery.


track down a schematic first if you want to be safe. i wouldn't be assuming that it's going to make much sound difference, but it may.

[Paul Perry (Frostwave)]

The only pedals I don't like to risk at a higher voltage are ones that are digital - and ones with BBDs!
Digital, because there are always regulators & (possibly) analog inputs to micros that have to be kept below certain levels. And some digital stuff with DSP chips use a lot of current & a higher input voltage might overload the regulator.
And BBDs, because some of these seem to be pretty fussy in their supply requirements.

[bufftonz]

I read the schematics, it appears that the minimum component value that I see so far, is 16v. Perhaps I can show the link to the FX96 schematic here below:

http://www.schematicheaven.com/effects/dodfx96_echo.pdf

Other than the voltage issue, is there any other way to maximize self-oscialltions on the FX96? There must be a circuiut upgrade from the previous FX90 that allows this newer FX96 not to self-oscillate like the older FX90. Has anyone ever performed such a mod to an analog delay pedal to achieve more repeats/infinite repeats?

There is only 1 trim pot inside the FX96 and that only adjusts max delay time-range,  but thre is no other internal tweaking components.

What do you guys think about self oscillations/infinite repeats?

--Chris

[zombiwoof]

I am awaiting the arrival of the same model DOD pedal from Ebay (we were probably bidding against each other!), and was wondering the same thing.  I've read in more than one place about using 12 volts on these things, so I hope you post your results if you try it.  I have gotten a few DOD pedals lately, and I noticed on some of the older ones, even though it uses a 9 volt battery, it calls for a 10 VOLT adapter!  Are those even around?  Was that a DOD part?

Al

[demonstar]

You look like you got everything you need to check if it's ok to run at 12V. Looks like it could well be O.K. off the schematic. I checked the odd IC but I'd check them all.

By the way did you see the parts list... 1/10 watt SMT resistors. WOW they must be tiny! Can you see them? 

Good luck!

[frequencycentral]

Dunno if this is relevant but I accidentally ran my Boss pedals at 12 volts at band practice the other night, having used the powers supply to tinker with something else at home earlier. I didn't realise until the next day. No harm done, didn't notice the differance.

[bufftonz]

Yes, those resistors are tiny, and unfortunately, if one really had to perform a mod on th board, one who owns a FX96 (to include myslef) must be aware that the computer board is multi-layered, like on the bottom side there are etchings, but there are also some trail etchings on the component side in certain areas. I am curious though, say for instance, if I didn't want to try the 12V thing, perhaps coiuld perform a mod on the Repeat portion of the circuit: if you read the schematics posted earlier you can see that the Repeat pot has three lugs of which the middle lug has a capacitor and a resistor coming before in-route to that lug, I'm suspecting that 0.22uF cap or the 10K resistor might effect the maximum duration of the Repeats, however, I'm not sure as to which component is actually responsible for the Repeat durations. What do you suppose of this?

--Chris