Why do some pedals have volume drop when switched on?

[opaline]

Not why as in a technical resistor transistor electrical sense, but why in a design/philosophical sense?

It's bad on both my 70s E/H Small Stone and newish MXR Blue Box. I know there are pretty easy mods to deal with all of this and also playing with pedal arrangements regarding gain pedals in the signal can be a workaround but why don't some pedals even have unity levels on their output?

Why make a volume drop inherent in a pedal and therefore severely limit it's usability? Especially something like a Blue Box where there is no real reason for it's existence except to blast obnoxious glitchy noise?

 

[midwayfair]

Not why as in a technical resistor transistor electrical sense, but why in a design/philosophical sense?

It's bad on both my 70s E/H Small Stone and newish MXR Blue Box. I know there are pretty easy mods to deal with all of this and also playing with pedal arrangements regarding gain pedals in the signal can be a workaround but why don't some pedals even have unity levels on their output?

Why make a volume drop inherent in a pedal and therefore severely limit it's usability? Especially something like a Blue Box where there is no real reason for it's existence except to blast obnoxious glitchy noise?

The "technical reason" and "design/philosophical sense" are usually the same. But there are multiple explanations.

Many modulation pedals are built without a volume control on the output. On things like Flangers, which use bucket brigade chips, there's a lot of filtering and volume limiting inside to avoid distortion and noise. The work around often results in a LOT of extra circuitry, usually in the form of a "compander," which is a compressor and expander. The Deluxe Memory Man has one, and it can STILL have a volume drop (one of AnalogMan's mods to the DMM is to tweak this).

Let's say you've got an effect that can only be produced with a chip that will distort if it sees 100% guitar signal. You don't want the signal to be distorted so you cut the volume at the front of the circuit. You might make up the lost gain elsewhere, but you have to be careful: amplifying that signal too much might make the pedal noisy. Make-up gain circuitry is one of the easiest places to introduce noise from the pedal itself, so you want to limit its use. So you design your circuit to be hardwired at something that's a compromise between hitting unity volume and making a noisy effect.

But let's say you're okay with the guitar signal distorting. You'd be able to hit unity volume then, right? Wrong. Because the signal will clip, and you won't get more output volume, you'll get more distortion.

There may be other things going on, however. Since you can amplify the signal at the cost of introducing some noise, you can add filtering -- cutting the highs will also cut hiss, and the pedal will sound quite. The problem is, even if the overall amplitude is the same, the human ear hears treble frequencies as louder than bass frequencies. It can still sound too quiet.

Some circuits are designed to hit unity volume, but by using resistors and capacitors in series. The resistor might have 5% tolerance (common) and the capacitor might have 20% tolerance (more common -- and in caps the tolerance tends to fall on the low side). Having a trimpot to individually adjust each pedal would be a lot of labor costs and take up room on the circuit board. So it's usually hardwired. Some pieces are sure to have a noticeable volume drop, with an unlucky few having a pretty severe one.

Finally, some circuits simply might not hit unity volume because they weren't meant to be turned on and off on a whim or because of the limitations of the parts to achieve a very specific sound. Old Fuzz Faces are notorious for this. There are ways to increase the volume output, but then it won't sound exactly like a fuzz face without that correction. (Usually it'll have more mids.)

 

[opaline]

Thanks Jon, all makes sense. Sometime in this lifetime I hope to get at least a working knowledge of the electronic world, starting to wonder why things work they ways that they do is a first step I guess...

It's surprising that components can have that wide a tolerance but I guess that's why a person pays more for hand-picked and/or matched stuff. I've read Germanium was horrid in that regard.

P.S.: Love the pedals on your webpage!