Lar/Mar PPIMV power tube saturation?

[mickeydg5]

I would rather the one I mentioned.

Like this except different capacitor values can be used along with the a 1M dual potentiometer.
Amp Archives/Marshall/Schematics & Layouts/PPIMV's/Improved PPIMV

 

[Ed A]

Hey Oatie, I went ahead and ordered the parts before seeing your post about the Rich II mod. I ordered everything that my Amp tech would need to do the Larmar including a Pec 250K dual. So at this point it will be the Larmar that I try. Interesting back in the 90s I tried the rich mod at Rich's Home, the guy who actually it is named for. I absolutely hated it, but may be the particular amp itself wasn't doing it for me. I'm sure the Rich mod II is different but fingers crossed that this LARMAR with the 250k pot will do it for me, sure seems to be a lot of love for it out there. Thanks!

 

[matttornado]

NO.
Gain must be up high - master must be up very high
to get power tube saturation.

No, not really. It depends on the amp. I get Power Tube saturation with my LARMAR master up at around 4. Presence control works at that point as well. That's with my volumes at about 6.

YMMV

 

[Oatie]

Here is the Rich II PPIMV that George installed in a new Metro Amp, it's the 500k PEC Pot and since this is a Bass Spec amp it has the .1/400v. caps for the Phase Inverter Coupling Caps. If it was a Lead Spec. amp it would have the two .022/400v. caps jumping to the PEC Pot.

The two 220k Bias resistors stay in the amp, and the shielded wire has 2 wires inside, the red and black, yoiu can see the black wire going to the PEC, but you cannot see the red wire to the PEC because it's hidden behind the black wire. The red wire goes to the back center (Wiper) of the PEC pot.

You know if George is using it in his amps, it's got to be good.

Because the Mil Spec quality of the PEC pots are available now for these Mods, the quality of the MV has gone way up vs. the cheaper Alpha pots.
The Sweep and slight adjustments make the PEC Pot well worth the extra money.

 

[danman]

I have also noticed a much better sweep in the PEC pot over the Alpha when used in a PPIMV. They are pricey but seem worth it!

 

[kamran]

I had a PPIMV on my superlead for a while and loved it. Wish it still had it but I sent it to LA Sound Design for a mod that utilized a different kind of master volume so they removed it. I love the amp a whole lot more now but it still doesn't do low volumes like it did with the PPIMV.

With a PPIMV you're not getting power tube overdrive, but you're distorting the phase inverter, and you'd be amazed how much gain and compression actually comes from the PI, that you may have thought was solely coming from the power tubes.

Also, if it's a true style lar/mar PPIMV then when the knob is set to ten it actually is out of the circuit.

 

[AndyK11]

I am getting a JTM50 clone that I'll be installing a PPIMV on. I was going to do the LarMar, but since George likes the Rich II mod, and since it's WAY less invasive than the LarMar, I'm going to give it a try.

Not sure what the 'II' is, but George's demo sounds pretty goo to me!

[ame="http://www.youtube.com/watch?v=vypgBhGQwJA"]www.youtube.com/watch?v=vypgBhGQwJA[/ame]

 

[sweaty v]

Ive ordered all the parts for this mod, my '72 metal face SLP is opened up on the bench and its wondering whats going on. Its bone stock to this point. My question is, has anyone who has done this mod ever regretted doing it.I'll never sell it but right now its hard to use it in the basement.
Any thoughts??

 

[FutureProf88]

No, not really. It depends on the amp. I get Power Tube saturation with my LARMAR master up at around 4. Presence control works at that point as well. That's with my volumes at about 6.

YMMV

I agree. I have two PPIMV amps and I can get a very good power tube saturation sound at 4-5 on the dial. Not the same as with it cranked further up but definitely good enough. As said, at that point the presence control works fine and I only run my channel volumes on 2.5 and just over 6.

I think that 4-5 is a nice sweet spot for PPIMV amps, and the nice thing is it is still taking a bit of stress off your tubes at that point.

 

[tweedman8758]

Ive ordered all the parts for this mod, my '72 metal face SLP is opened up on the bench and its wondering whats going on. Its bone stock to this point. My question is, has anyone who has done this mod ever regretted doing it.I'll never sell it but right now its hard to use it in the basement.
Any thoughts??

I've done this mod to a couple of vintage amps. I used existing holes and saved all the original parts. I will never go back but they can be put back to stock if needed after I'm gone. The only difference will be the solder joints won't be original.

 

[yladrd61]

I put a Lar Mar PPIMV in my 1970 Super Lead which already had a Pre PI MV, I didn't like the added distortion, or the loss of the tone and presence controls at lower settings, so I removed the Lar Mar and went back to the Pre PI MV....