Using different voltages - advantages?

[RandomRedLetters]

So what are the advantages to using different voltages? 1.5v vs 9v vs 12v vs 18v?

All I can figure is more voltage equals more headroom in boost circuits

Anything I should know?

[niftydog]

well, I think you hit the nail on the head with that one... but how much headroom do you need!? (rhetorical!)

Other than that you can drive op amps better with a decent voltage, you can acheive more gain, although too much gain is pointless... anyone ever tried putting a 18V peak to peak sine wave into their guitar input... it's really freakin' loud, so don't bother!      

[gez]

And in the other direction:

Where stages are being overdriven, less headroom = more distortion

Convenience of using 1.5V batteries/3V lithium jobbies *

Some op-amps/chips consume less current at lower voltages so battery life is longer

*ICL762X range of amps will run off 3V and have miniscule current consumption.  Simple diode clipping circuits could easily be implemented with these chips.

[petemoore]

I use 18v [12'd do I think] for the Splitter Blend, it's much nicer as clean.
 9v works fine for most distorters, because headroom isn't what they're about at all.
 I use LM317 regulators to drop the voltage when I want the voltage dropped, check out AMZ 'lab notebook' for low voltage circuit designs.

[Sir H C]

Remember many traditional op-amps can not get within about 2 volts from the supply rails (2 or 3 Vbe drops).  So with a 9V supply, you have only 4-5 volts that you can swing on the output.  Double the supply and now you get a 14 volt swing, triple the swing for doubling the voltage.  

As to the different voltages, 2 easy ones 1.5 and 9 come to mind as single battery voltages.  Cheap and easy to do.  The first pedal (Maestro FZ-1) used 3 volts, then dropped to 1.5V for the FZ-1A and up to 9V for the FZ-1B.  So just with one pedal you get the whole range of supplies out there.

[DDD]

Oh,
what about tube circuitry that has 350 Volts power supply and hevily and beautifully distorts signals at the same time? I'm surprized...

[Transmogrifox]

Oh,
what about tube circuitry that has 350 Volts power supply and hevily and beautifully distorts signals at the same time? I'm surprized...

Much higher gain in your average heavy tube distortion unit.   Try 4 tube stages at 100V/V each stage, you have a gain of 100^4, or 1x 10^2^4 = 10^6

You have a gain of one million Volts/Volt.

This is pretty heavily clipped even at a headroom of ~100-200 Volt swing (P-P)

For an op amp type circuit, this is like putting 4 tubescreamers in a chain.

It just gets to be too much.

[gaussmarkov]

well, I think you hit the nail on the head with that one... but how much headroom do you need!? (rhetorical!)

Other than that you can drive op amps better with a decent voltage, you can acheive more gain, although too much gain is pointless... anyone ever tried putting a 18V peak to peak sine wave into their guitar input... it's really freakin' loud, so don't bother!      

some folks like push their preamp.  perhaps niftydog is not one of those folks. :twisted:  :wink:  i have to agree, though, 18v is more than i have ever needed.  (edits in green)

[niftydog]

well, there's pushing your preamp, then there's running up as fast as you can behind it and shoulder barging it over a 300 foot cliff!  :shock:  

My (rhetorical) question to those folks is then this; why go to the trouble of giving your booster lots of headroom when all you do is drive the following input stage close to overload?!  :?

Headroom is good, I like headroom, but traditionally it's been an important factor in power amplifiers - not necessarily signal processing gear. As I say, I wonder if there's any point in having high headroom in your processing gear if you run your power amp just on the clip light all night.

[gaussmarkov]

My (rhetorical) question to those folks is then this; why go to the trouble of giving your booster lots of headroom when all you do is drive the following input stage close to overload?!  :?

Headroom is good, I like headroom, but traditionally it's been an important factor in power amplifiers - not necessarily signal processing gear. As I say, I wonder if there's any point in having high headroom in your processing gear if you run your power amp just on the clip light all night.

yeah, i wonder about that, too.  i have not figured out the popularity of zachary vex's super duper either.   :?  gonna work on that.

but one case is when the booster is a tool for manipulating the amp.  you put a booster in front of your preamp for the sole purpose of cooking those tubes because you like the sound your (master volume?) amp produces under those conditions.  there may not be any other signal processing in such a rig because amp clipping, and no other, is the goal.

So what are the advantages to using different voltages? 1.5v vs 9v vs 12v vs 18v?

just to be sure this did not get overlooked:  boosters are not the only place to think about headroom.  petemoore explained that blenders may need more headroom than 9v will deliver.  if they get a hot signal, blenders can be driven into unwanted clipping.  robert keeley designed his blender (page 2) for 18v supply.  sean m also suggested this might be a good idea for his b. blender, especially in guitar applications.[/u]

[Joe Hart]

I get a little clipping out of my Phase 90 reissue. If I use a 12V adapter, could that cure it or would it cause more problems because the circuit is designed for 9V?
-Joe Hart

[gez]

I get a little clipping out of my Phase 90 reissue. If I use a 12V adapter, could that cure it or would it cause more problems because the circuit is designed for 9V?
-Joe Hart

The clipping is most likely due to the FETs and not a headroom issue.  Easiest way to check would be to disconnect the wet signal and listen (I'm assuming an op-amp input buffer is used and this amp is the same as the others used in the wet chain - can't remember the schematic).

[petemoore]

Phase 90 does respond to different v+ input.
 It 'can sound good post boost/fuzz, but it gets 'gnanky' distortion if you try to drive a tube amp with it. Voltage *May help this.
 I tend to just connect the phase 90 preboost/fuzz.
 I like the dropped voltage sound of Jfets. limiting the swing using low voltage as V+ renders...you guessed it...a tube *like OD sound. It's real nice because it aslo does the 1trik pony compression thing.
 FF's sound a little different at 7v or so than 9v, I run them at 9v till the battery drops some, which I notice as decreased output and 'spongier' tone.
 All the opamp stuff I've tried [haven't done much messing with the LM741 which adds distortion to DIST+ Types] likes being at 9V or above...probably just a memory remnant of undesirable OA clipping artifacts from early basic OA experiments...didn't mess about with getting clipping directly in an opamp.
 Lowering voltage has it's merits, I like the way Jfets work at lowered V+'s, bipolars can be cool. Combining boosters with the last stage at LV...I'm getting the 'goods' from that. EZ, works great, does a couple neat tricks the other distortion/compression techniques don't do.
 Starvin' Munster ... LM317 regulating voltage supply to Mu Amp post Mu Amp or post Fuzz stage...very nice fuzzes from these.