Master Volume pot

[dorrisant]

Ok... I built it this way... Works great. The psuedo-linear taper is much better. This would be pretty easy to clip-lead test an existing build. TRY IT! I think you will like it.

I want a catchy phrase for naming this thing... "The D Mod", that works. I can hear it now... Some dude over at TAG did this mod to his Lar-mar MV... It's called "the D Mod"... Works great... Solved all of my Master Volume needs...

Just kidding. But seriously, you guys should try this and let us know what you think. I think I did this all wrong. Maybe not.

[rooster]

Another thing here regarding the wiring? If you use a twisted pair with a shield (Teflon encased #22 is nice) you can skip the single wire carrying the bias voltage up to the pots - just use the shielded wire for this. It's very tidy plus you have the benefit of the bias voltage serving as a shield as it leaves the board. I do this and it is stone quiet.

When you connect to the tubes, use the same wire but cut the shield wire off at the tube end - just like the drawing shows.

[rooster]

[dorrisant]

Dorrisant, your 4th sentence needs an edit I think?

Yep, I edited it for clarity.

[M Fowler]

Installed PPIMV in TW Rocket combo I had sold so he could turn down a bit when at band practice. I said I usually turn it up.

Not so sure about all that Audio verses Linear in this situation sounds same as all the 250kA versions I've done. I can't really tell about linear verses audio tracking of the volume?

What's the big difference again?

[M Fowler]

Martin Manning provided a drawing showing the bias wiring on a Marshall JTM45.

[rooster]

Mark, you should easily hear the difference between the different pot tapers. Are you being funny?

[M Fowler]

Works great per customer. Here is his report back: The rocket is sounding great! That mv really makes it versatile for clean and dirty. The marshall HRP #39 clone on the other hand is one of the best distortion sound I have ever played, Though wattage is way too much still at 50watts.

No I don't do much amp stuff anymore because of many health issues including my left ear finally decided it was tired and with years of multiple surgeries. It goes from no hearing to slight, ENT don't know what exactly is wrong.

The right ear is completely swollen shut with an infection but can't get back to ENT to get that fixed.

The tinnitus has increased dramatically too so for me to rely on my hearing to tune amps would be a joke.

Trying not to be too funny

[Littlewyan]

Sorry to hear that Mark. Hope it all gets sorted soon.

[M Fowler]

Thanks my problems are minor compared to so many less fortunate souls.

[rooster]

Ah, Mark, I have been away from this post and just now read your post about your hearing and ear problems, I'm very sorry to hear this. An ear infection is nothing to mess around with, I hope you can get this taken care of soon. All the best to you, Sir.

[M Fowler]

Thanks I got the ear drops and swelling went down nicely and no more pain but tinnitus increased and still decreased hearing. See the GP on the 19th for med renewal day and I'll get back into ENT on referral.

I am going to continue the use of Linear pots for the Lar-Mar PPIMV the customer is still talking about the change to his Rocket combo.

I want 3/8" shaft and 3/8" long threads like the way Mojo CTS are built it works best for my chassis with faceplates to get that extra thread length.

Mark

[cbass]

doug hoffman sells a conversion bushing for the 8mm shafts to 3/8

[M Fowler]

Yeah I have some washers that work for that as well but the problem isn't 8mm verses 3/8" it's the length so I can use an internal star washer behind the chassis and get enough thread length to screw on the nut.

Those short pots work well if you have a silk screened chassis like the Dumbles and Tweed Fenders but not if your going face plate like on most of my builds.

Mark

[angelodp]

Martin, just found this PPIMV for JTM45, I assume it will work equally well for the 100W Super Lead.

Ange