Simplest Master Volume EVER

[snide]

I tried this on a wreck clone and it only lowered the volume of the amp a small amount, even when dialed all the way down. Is this normal for this application?

Eric

[Craig Reid]

Nope. When dialed all the way down the PI receives 0 signal.

You might want to check your wiring. Is it possible you put it on the feedback side vs the PI input side?

[snide]

Craig,

Your right! I just went by David's schematic and the pin numbers are backwards in relation to the preamp layout in the download section (which I used in the build). I should have double checked it first. Thanks for the reply.

Eric

[Darkbluemurder]

That is the MV from the "800" chapter of The Ultimate Tone, Volume 3.

I have used it in several amps. I agree, it works great.

Craig

I used it also in several amps (Fender, D-clones, Marshalls Plexi style and 800 style) and indeed it works well. The only minor drawback is that the Presence control becomes less effective. In my hot rodded Marshall I addressed this problem by replacing the Presence control with a "Cut" control a la AC 30.
I really like Kevin O'Connor's books. I am looking forward to TUT 4 to complete the edition.

[Snapcase]

I came up with this MV design when building my first TW clone (I wanted to tame the volume a little for home use). I won't swear it's original, but I've never seen it anywhere. The sound is pretty much flat,..nothing missing, just a little high end boost starting about 3KhZ.

The only minor drawback is that the Presence control becomes less effective.

I was about trying boot-strapped master in a couple of amps. It's nice finding comments about its performance in advance.

At least for the amps I intend to mod, a couple of Soldano I always run with presence knob fully off, this could be a welcomed drawback. Thank you, guys.

[sliberty]

For what its worth, I installed this MV in my Express, and found that it got loud a bit too fast for my taste. So I replaced the 1MA pot with a 1ML pot, and it behaves a bit more to my taste.

I came up with this MV design when building my first TW clone (I wanted to tame the volume a little for home use). I won't swear it's original, but I've never seen it anywhere. The sound is pretty much flat,..nothing missing, just a little high end boost starting about 3KhZ.

David Hicks

[jelle]

look at a 5F6-A schematic, at the phase inverter. The first 1Meg the signal sees is replaced by a pot (wiper has grid connected to it). That's it.

Just wondering..Can this design be improved by using a dual 1M pot for both the 1M resistors of the phase inverter? Some amps use smaller values for this resistors like silverfaces and some mesa's.

Thanks,
Jelle
The Netherlands.

[vantamp]

Howdy to everyone from a newby. I was looking at this mod and have a question. Does the 250k phase balance pot have to be installed for the master mod to work properly? It may be a dumb question but I am still learning.

[keithrick]

Howdy to everyone from a newby. I was looking at this mod and have a question. Does the 250k phase balance pot have to be installed for the master mod to work properly? It may be a dumb question but I am still learning.

No, this is not a Express schematic BTW.


BTW- I know I ranted about attenuators and MV in a previous post. Well, I had to rewire my clone in a new chassis and I did add this MV circuit. It was a toss up between the MV and the spit load plate resister. For me it works great but only when I run it a certain way. For example, Normally I run all the dials at noon with the exception of the volume which could be a liitle lower. With the master volume circuit I am able to run the gain at around 2pm and the MV at betweem 12-2pm. At these setting there is NO loss of dymnamic in the amp! Yes, I did notice that the presence was less effective, but the bright switch became useable and quite enjoyable. Another added benifit was that I am able to dial all the hiss!!!

Again, The amp runs silent with no loss of dymanics!! I am glad I tried it! Having stated that I must confess that the amp is NOT any lower in volume.

Luckily my neighbors drink alot of my beer!!!

[arfy]

I just finished my Express over the weekend and the sound is just what I'd hoped for but the volume is freaking me out, I haven't used anything bigger than 2 x EL84 amps in a long time and this is a whole other thing.
So where are you putting the 1 Meg pot? There's room between the presence and bass pots in the Ceriatone chassis I used, that would have the extra advantage of using rather short wires to connect it.
Anyone?

[sliberty]

I used a salvaged chassis, so my situation is a bit different. But, having said that, I put mine on the back of the chassis. My expectation is that I will set it once during a jam session and leave it, so being on the back is no hardship. And there was already a hole there that I needed to fill somehow

[Normster]

I just finished my Express over the weekend and the sound is just what I'd hoped for but the volume is freaking me out, I haven't used anything bigger than 2 x EL84 amps in a long time and this is a whole other thing.
So where are you putting the 1 Meg pot? There's room between the presence and bass pots in the Ceriatone chassis I used, that would have the extra advantage of using rather short wires to connect it.
Anyone?

If you want to "try before you buy" you can temporarily remove one of the speaker jacks and stuff a pot in there. I tried the 1M pot but will probably pull it out this weekend. Short of an attenuator, there's just no way to reduce the volume without reducing the power tube breakup (which is what I love about the tone).

[daz]

would this master volume mod be any more effective than the matchless master volume in a matchless style amp? I've built a dc-30 clone and IMO it's master volume is crap - it sounds terrible at low volumes.

[sliberty]

I looked at a schematic of the dC-30 online to be able to compare. One clear difference is that the Matchless MV is Post Phase Inverter and the MV described here is pre PI. So, this one will reduce any overdrive in the PI as well. If you like EL84's, maybe thats a good thing. A little more chime and a little less grind. But if you are looking for a way to keep all tubes groaning, and still reduce the level, you'll need an attenuator.

[daz]

Thanks sliberty - yeah that's why I thought this mastermod might be more effective.
I guess that's why Mark sampson designed it post PI - to keep the grind.
I actually like the crunch of the ef86 channel.
Might experiment and see the difference.
thanks!