Higher Voltage Supply or Voltage Divider on input

[Bill Mountain]

I have a Mesa Bottle Rocket as part of my rig and the 12V AC is becoming troublesome on my small pedal board.  I tried to replace it with a ZVex Box of Rock but my high output low tuned bass pummled the input into splatty submission.

I think part of the reason the Bottle Rocket works so well for my bass is the that 200V+ power supply provides plenty of headroom to receive/amplify/clip my signal.

I had hoped to ultimately do a MOSFET conversion of the Bottle Rocket but I'm trying to decide if I should do a high voltage supply (30-60V) or just a big voltage divider on the input so the 9V supply looks much bigger by comparison.

Before I had this design in mind it was suggested to me on this forum to use a voltage divider instead of higher voltage but I worry about increased noise by dropping a signal 30dB then boosting it back up.

I have also considered crossovers and clean blends but through many many many many many listening tests I've discovered that I prefer the sound of a full range signal being clipped.

I've also considered a small box that will take the 12VAC power supply and output 12V AC and 9V DC for my other pedals or modding the pedal to work off of a voltage multiplier.  If I can't make a good FET solution then these are my other best options.

So...I guess my question is...Higher Voltage Supply or Voltage Divider on input?

Also as an aside...I have tried to use standard dirt boxes and only turning the drive up slightly but to me it doesn't feel/sound the same as turning the drive up higher on a quieter signal.  I think it has to do with blocking distortion (or the SS equivalent).  I think I need the supply big enough or the signal low enough that the low end in my signal does not create undo side effects.  The relationship between all of this confuses me to no end!!!

[Bill Mountain]

Maybe regardless of other factors bass signals are not meant to be clipped gracefully.  Maybe the universe is against it.

Edit: and by bass signals I mean sub 100Hz.

[R.G.]

Before I had this design in mind it was suggested to me on this forum to use a voltage divider instead of higher voltage but I worry about increased noise by dropping a signal 30dB then boosting it back up.

Well, it only costs a couple of resistors to find out if the increased noise is a problem, right? Sounds like a mighty cheap test. It's probably faster to do it and then listen than it is to do the noise-voltage calculations, not to mention the forum-typing.

Note that attenuating the signal coming in also attenuates any noise coming in with it by the same amount. All you pay is the noise voltage in the attenuators and then the reamplification. That may be horrible, but in most cases, the added noise is either unnoticeable or very tolerable.

I had hoped to ultimately do a MOSFET conversion of the Bottle Rocket

I know you know this, but it needs saying again - a MOSFET conversion of the Bottle Rocket won't sound the same. Similar maybe, but not the same.

So...I guess my question is...Higher Voltage Supply or Voltage Divider on input?

Since doing a voltage divider on the input is so cheap and fast, I say do that first, and you may not need to do the high supply voltage.

[Bill Mountain]

Before I had this design in mind it was suggested to me on this forum to use a voltage divider instead of higher voltage but I worry about increased noise by dropping a signal 30dB then boosting it back up.

Well, it only costs a couple of resistors to find out if the increased noise is a problem, right? Sounds like a mighty cheap test. It's probably faster to do it and then listen than it is to do the noise-voltage calculations, not to mention the forum-typing.

Note that attenuating the signal coming in also attenuates any noise coming in with it by the same amount. All you pay is the noise voltage in the attenuators and then the reamplification. That may be horrible, but in most cases, the added noise is either unnoticeable or very tolerable.

I had hoped to ultimately do a MOSFET conversion of the Bottle Rocket

I know you know this, but it needs saying again - a MOSFET conversion of the Bottle Rocket won't sound the same. Similar maybe, but not the same.

So...I guess my question is...Higher Voltage Supply or Voltage Divider on input?

Since doing a voltage divider on the input is so cheap and fast, I say do that first, and you may not need to do the high supply voltage.

Thanks for the input.  I know they won't sound the same but I'm out to prove that most clipping "sounds the same" and the secret is in the frequency shaping.  I chose FETs simply because it will be easy to mimic the gain stages of the tube overdrive.  With other quieter guitars and pickups I can get a Tube Screamer clone to sound almost exactly the same as the Bottle Rocket by boosting the bass.  When I tried my bass through the same TS clone it decimated it and turned it from a smooth overdrive to a clacky sounding fuzz (not in a good way).

This is the exact reason I got into DIY.  I wanted to build an overdrive/distortion/fuzz that can handle a wide range of basses (especially mine) and I'm nowhere closer than when I started.

[defaced]

I had hoped to ultimately do a MOSFET conversion of the Bottle Rocket but I'm trying to decide if I should do a high voltage supply (30-60V) or just a big voltage divider on the input so the 9V supply looks much bigger by comparison.

From my work on high voltage MOSFET conversion of tube circuits, you'll need to do a good bit of stage by stage tuning to get things right.  The MOSFETs being better at turning on and off than a tube are the driving factor here.  I am at the beginning of this process with my MOSFET SLO preamp project.  I expect this to take alot of scope time to get right, and I suspect I'll get a slightly "harsher" character to the distortion than with a tube, but we'll see.   If you decide to go this route, I'd say go the high voltage path, and even so far as to do a 200v supply.  Which brings me to...

If there is enough room in the bottle rocket, you could build a 200v SMPS and stick it in there.  This will allow you to run the Bottle Rocket off of 9v DC.  The possible problem here is that you risk heterodyning of the switching frequency of the 9v supply (assuming it's a switcher) with the 200v SMPS.  I use two different supplies and one plays nice with my MOSFET SLO while the other dumps buzzing in the audio.