Running pedals at 18V

[vondran]

I'm wondering if I can run some pedals at 18V's.  Specifically a tonepad built Ross compressor, tonepad TubeScreamer, MXR Phase 90, and a Dunlop Crybaby GCB-95 Wah.  Any thoughts?  I figure I have to double the LED resister so it will not draw too much, but other than that any problems?

[RaceDriver205]

That would not be a good idea, you'd likely fry the circuits. Why do you want to use 18Vs?

[petemoore]

  As long as all the components are rated for the voltage applied you're ok.
 A little bit of elbow room, like a couple volts is a good idea.
 *The electrolytic capacitors are likely rated @ 16v, if so they will not like 18v one bit.
 Resistors, if 1/4w, won't care. I would bet all of them are.
 The active components in these...I think are cool @18v, see data sheets for more info...
 With a close in light and mag-glass, you can probably make out the voltage ratings on the small caps, most of the ones I've seen are rated above 25v.
 An option is using a 9vdc wall wart into a MAX1044 to get ~17.2vdc, then run a Voltage Regulator to bring that under what the caps are rated for, running small signal effects at 12v or 14v should attain most all, or at least the lions share of higher voltage supply benefits.
 

[petemoore]

Why do you want to use 18Vs?
  Ross compressor...not sure..haven't heard about HV supplying a Ross, I Do have an OS Comp I read/now think could benefit from higher voltage supply = more headroom = no clipping with HB output on hard low note attacks.
  tonepad TubeScreamer...might change it's character a little? It's a distorter...
MXR Phase 90..I'd be interested to hear what HV'ing a Ph90 does to the headroom and sound.
   and a Dunlop Crybaby GCB-95 Wah.
  In my case I hypothesize I'd hear no difference, I go Guitar>Wah, because the signal output is near equal to the signal input, headroom shouldn't be an issue. This hypothesis doesn't take into account 'anything else' that might end up mattering in application...
  Maybe someone's tried this and can correct my calcs...
  The Green Ringer seemed to perk up nicely @ 17.2v, my testings on the GR made for less than clinical analysis as I use 'schtuff' w/settings to boost it's input and output. I have a Ge booster/Dist+ type also with a MAX1044 bumping the V supply up, they sound fine.

[vondran]

I'm asking because I have a tight pedal board with 6 pedals running off one 9.6V supply and 1 pedal running off a 18V supply.  I definitely am at the max rating of the 9.6V wart, so was thinking of moving one or two to run of the 18V.  Several things I did notice was the compressor and TubeScreamer sound better running off a 9.6V supply rather than a 9V battery.  Compressor is definitely cleaner and the TubeScreamer is a little more bright.

[RaceDriver205]

But if the circuit is designed for 9Vs, won't things over heat from the greater current created by 18Vs?

[JHS]

Most 9V FX-boxes sound sterile, harsh and cold when powered w 18V.

IMHO most circuits must be slightly modified to run on 18V for more headroom w/o sounding harsh (reducing the input impedance often kills this harshness but the FX will sound muddy when powered w 9V again). On a lot older FX the caps must be upgraded too, so check the caps first before running the FX on 18V.

JHS

[vondran]

Things should only be hotter for DC paths from supply to ground, mostly bias paths which are a small amount of the pedal current.  But when I look at most of the pedal schematics, most stages are DC isolated and current swings are based on the signal swing range and not the supply voltage.  Supply voltage does however effect the headroom.  This is why I believe the compressor is cleaner when I use the slightly hire voltage (9.6V vs. just a 9V battery).  Note high output humbuckers definity have more noise through the compressor than single coils which makes me believe the CA3080 is clipping a bit when supplied with 9V and driven.  So the question is, is even higher voltage better and will it hurt anything.  I guess I'll just have to check the ratings and give it a try.  Or maybe I should just regulate down some of the 18V to get more 9.6V supply taps.

[RaceDriver205]

Well you could just place a zener diode between the 18V supply to drop it down to a lower voltage. If you used a 8.2V 1W zener it can take a max current draw of about 120mA, or with a 5W you'd get 610mA.
I don't really know much about the headroom thing, I just know that a few circuits I made which I accidentally connected to +12 instead of +9 started to run hot.

[MartyMart]

I would agree in general with the "sterile" sound of most things at 18v
I have had some units sounding good at 12v and have recently been trying a
regulated 10v PSU, which Boss/Line6 pedals seem very happy with.

IMO, if it is not "designed: as an 18v circuit, then dont run it as one without
some serious circuit changes to accomodate the voltage change.

OD's etc that can take it ( 25v min caps ) seem to clean up too much for me
as the headroom increases, you may like that though ?

MM.

[petemoore]

  I can tell that I feel lucky.
  I messed around with 18v, -9v from 9v+, multi-ple DC Jacks daisy chained Im at lllllllllll yupp 1 dozen units' powered off a VS One Spot adapter [1700ma of pure clean 9.4Vdc].
  That's alot of places to make 1 error on a long line.
  Mess ups on the power supply in the past...well...it's messy...
  I pre-test every thing I can...re-think everything through a few times before applying power to any change made.
  Do tell if Phasers accept higher input Voltage sources more gracefully using upped Voltage Supply...
  My D/Ross Comp Seems 'powerful enough to handle high level inputs, the OS is better at it with the NE5532, and sounds great I think...might have room yet for improvement...seems to do well...?
  It's due for a new box, perhaps I'll get one, test the OS with a little booster in front to mimic say an active guitar, use MAX to get ~2 x V, and a 317 to regulate, put a nice 3pdt w/LED indi on it...compare results by memory-ear.