Mark 1 - Master Volume Question

[kdove]

I have an original Mesa Boogie. At home I have to run it between 1 & 1.5 on the master volume. I almost never run it above 2.5 even on stage. Very sensitive ... but I can usually get it set.

Got me to thinking:
- Are the master volumes audio or linear taper?
- Would it make difference to change the volume pot?
- Wondering if I could move the range where it was not so sensitive on the low end

Never really thoughy about it before but ... any comments?

:?

 

[guitarsawicki]

Answer to your first question:

Human ear is non-linear. So I assume that volume pots of guitar amps are always non-linear. At least Mark series amps.

I have seen a linear volume pedal. Most volume pedals are non-linear. With linear master volume pot you probably go to 7-8 until you hear anything.

 

[kdove]

Same is true for guitars but both audio and linear pots show up on guitars ... so does anyone know for sure what Mesa/Boogie uses for master volumes for sure?

I've heard that sometimes that was a strategy that is sometimes used on amps ... making it seem that they seem louder than they really are ... "man it was really loud in the store and it was only on 2" ... that sort of thing. For example

Now the Boogie's loud ... no doubt ... that's not a problem. The 60w/100w is surely no going for that strategy.

But I'm thinking that on 10 both audio and linear would be the same ... maybe the pattern might be an advantage on the sensitivity on the low end. Maybe it's just the opposite and make it worse.

 

[guitarsawicki]

But I'm thinking that on 10 both audio and linear would be the same ...

That's true

 

[Boogiebabies]

Hi Ken,

I feel your pain. In most cases, I find the Master sweet spot on 4-5. This is where some incredible harmonics start blooming out. The down side is I have to run my lead master at 1.5, hence there is no clean channel unless I want deaf dogs and paralyzed hamsters. It's a hard balance, but basically I bring two amps or balance the two. I personally don't like lead master setting above 3 or 4 or a totally different charachter reveals itself. I don't know what the benefit of a linear taper would have as eventually, to balance the outputs they will end up being close to the original audio taper to produce the same effect. Judging on how good you amp sounds, I might just live with it.

 

[kdove]

Fair enough ... so you confirm the Boogie has already an audio taper. I figured as much but just wanted to check. Thanks again ... you know my amp about as well as I do by now. :wink:

 

[Boogiebabies]

I bought 2 CTS replacement pots and two Mesa mini pots and they read with an even taper from 0 to 10, or 0 to 1M. If they were linear I would probably only hit 100K at 4.5.

 

[kdove]

I bought 2 CTS replacement pots and two Mesa mini pots and they read with an even taper from 0 to 10, or 0 to 1M. If they were linear I would probably only hit 100K at 4.5.

Do you mean "if they were audio"? I would expect that if they read evenly from 0 to 10 they'd be linear ... wouldn't they? Apologize if I'm just not following well. :roll:

 

[kdove]

bump ... just want to confirm my last question ...

 

[yettoblaster]

Audio taper is logarithmic because of how we hear.
In audio gear (like guitars and amps) passive circuits are almost always audio taper.
The schematic I downloaded from a link here at The Boogie Board to freeinfosociety.com shows the master in a Mark I preamp as 1meg.
Unless otherwise noted (and it's not otherwise noted) I'd assume all pots to be audio taper.