Master Volume in an Express

[Steve in Florida]

I have owned two Express clones, and both of them came with PPIMVs.

Glen (Geetarpicker) is exactly right, in my opinion. As much as I really want the MV to have some degree of use, it is really useless -- in the sense that you lose the reason that you want an Express.

With a MV, the beauty of the Express -- the increased fatness without increasing decibels as you turn up your guitar's volume knob -- is gone.

So I agree with Glen, that you are better off with an attenuator.

The best solution I've bought so far is a FluxTone speaker... giving a a very accurate sound at (nearly) bedroom volumes. (I have a 1x12 FluxTone cab with a Celestion Gold in it.) Be prepared for some sticker shock there... but it is amazing. Here's Brad Paisley talking about his: https://www.youtube.com/watch?v=_ABWwaxPgRI

Back to the topic of MVs... People say a MV works for them in an Express. It doesn't work for me -- it no longer does the Express thing right. With the MV at noon, the amp sounds significantly more nasal -- uninspiring at best. You lose Glen's mega-thick tones, and you lose the correct clean-to-mean effect.

My suggestion is to find a different way to cut decibels, or find a different amp.

Steve

[summitcity]

Nice looking build! What is the red stuff?

[rooster]

Since this is a current post and there are folks here who do not like the LarMar in their Express, I have to ask, are all of you here using the dual gang 250K LINEAR TAPER pot?

I was googling this MV and I noticed that there are quite a few references to the LarMar, pics, etc., and I only found one that sets the record straight: USE A LINEAR POT.

In my case, my first go round was with an audio taper pot and I thought the LarMar completely sucked. Just saying..

(Listen to my sound clip on the top of page 3.)

[vibratoking]

The VVR works really well for me and costs about $1375 less than the Fluxtone. The Fluxtone demo you posted sounds good, but there ain't much bang for the buck IMO.

[Paultergeist]

Rooster,

Honestly, your observation really does not make sense to me. The only thing different between a dual-gang 250K audio taper pot and a dual-gang 250K linear taper pot is the angle of taper. In practical terms, one type of pot might have a certain loudness (in an amp) at "5" on the dial while the other type of pot might achieve a similar loudness at a setting of "3," but the tone and volume range would be the same.

Your observation that the audio taper pot *sucked* -- compared to the linear taper -- makes me suspect other factors were involved......

[vibratoking]

It is pretty well known that the taper can make it physically difficult to adjust the pot get the performance that you want. I agree that conceptually there is no difference, but physically making it happen can be quite a different thing. This has been discussed many times with regard to pots in Les Pauls, volume pots in an Express, and many other places.

[rooster]

Ha! Let me be clearer: If you are using an Audio taper pot in the LarMar MV, then you have missed the boat.

(Listen to my sound clip on the top of page 3.)

[pleasantbullet]

I have the Dual LOG 250k pot Lar mar type PPIMV.
I find the log taper to give an accurate representation of volume increase.

1 to 3, its at moderate Bedroom / practice level.
4 to 5 is a perfect Jam setting to play along with live drums.
6 to 7 is loud, annoys the wife, but its not ear splitting.
8 to 10 brings it back into Beast Mode.

At half way (5) the master volume still allows the natural compression of the amp to speak and lets You grab your cleans from the guitar volume without it getting dirty.

This has been the perfect mod for me. I notice very little tonal difference, that affects my playing, or my EQ settings.

Do you have some sound samples at different levels to show how your MV sounds?

[rooster]

Well. at least you like what you have there. Maybe that's OK for you then. My guiding thought here in posting was to see if the LarMar haters had actually tried it as it was intended, with a linear pot.

I have some 2/12 boxes and speakers to record so I will do a MV clip while I am at it, no problem. Probably Monday at this point.

To explain why I think the LarMar MV is best with the linear pot vs. the audio taper, I can just report that the changes in volume are much more lineal. With the audio pot, going from zero volume to full, typically, at 12 o'clock, you are only looking at a value of 25K. With the linear pot the value is 125K. That's a huge difference and, in the case of a MV like this, it should make a great deal of sense.

(Listen to my sound clip on the top of page 3.)

[vibratoking]

...To explain why I think the LarMar MV is best with the linear pot vs. the audio taper, I can just report that the changes in volume are much more lineal. With the audio pot, going from zero volume to full, typically, at 12 o'clock, you are only looking at a value of 25K. With the linear pot the value is 125K. That's a huge difference and, in the case of a MV like this, it should make a great deal of sense.

I must be misunderstanding your explanation? The resistance required to transition from zero to full volume will be the same whether the pot is linear or audio taper. The only difference would be the amount of rotation that it takes to get there, correct?

[rooster]

Of course, vibratoking. My point being, the audio taper pot at 12 o'clock is not even loading the coupling section. From there it ramps up pretty fast - hardly offering any subtle control to the output. Basically an on/off switch IMO, and why - when I used this taper in error - t thought shitzbah.

(Listen to my sound clip on the top of page 3.)

[martin manning]

Of course, vibratoking. My point being, the audio taper pot at 12 o'clock is not even loading the coupling section. From there it ramps up pretty fast - hardly offering any subtle control to the output. Basically an on/off switch IMO, and why - when I used this taper in error - t thought shitzbah.

Must be something else. The loading on the PI and on the power tube grids (Lar-Mar) is the same either way at any given volume, and a linear pot should ramp up faster in aparrent volume than an audio taper.

[rooster]

MM: "The loading on the PI and on the power tube grids (Lar-Mar) is the same either way at any given volume, and a linear pot should ramp up faster in aparrent volume than an audio taper."

Haha, if you said 'in actual volume', and appreciated my use of the word 'loading' in my context, then we might be in agreement. Um, we might have found some common ground at least. Well, if you said this. Hm, complicated maybe but the PI is loaded, yes, but it is not driving the amp as the LarMar is turned down. (When I said 'load' I referred/spoke to the driving of the amp via the PI's output - which is reduced by turning the LarMar pot down). C'mon you guys, just admit that you have used an audio taper pot and see no reason to use a linear pot. At least this way your bias is out in the open.

(Listen to my sound clip on the top of page 3.)

[katopan]

Another thing to consider which might be contributing to your experience Rooster is that as you turn down the LarMar is the change in headroom. Turned up the power grids are clipping the PI output. Turned down the PI is allowed its full swing. In between is, well, in between. That would make the actual volume response different to what we expect from a volume knob, either log or linear pot.

[Bob S]

I'm careful using any 2 gang pot - linear or log. Measure both pots resistance at 10 degree intervals. Some are way out of whack wrt each other.
Not good for balancing the 2 halves.
Maybe that's just me.