The PPIMV (Post-PI-Master-Volume) thread.

[CoffeeTones]

Generally. http://www.rig-talk.com/forum/viewtopic ... 0#p1058235

[peter25]

I was looking for a dual PEC A250k to exchange the alpha pot I have installed now. These are very hard to find in Europe, if not at all. If u buy them from an online American store the posting charges are not worth it. Total price would add up well over $60 for one pot.
Now I heard some great things about Tocos Cosmos. Does anyone have experience with these pots maybe?
Here's a link to a site with some info.
Link

Any info would be much appreciated!

[JimmyR]

Now I'm a little confused! I just ordered some pots to try the dual 250KA + 2M2 resistor PPIMV, then is see the demo of the dual 500KA pot MV. Which do I try??

I guess what I want is purely the tone of the amp turned up - but not as loud. I don't need any more dirt than the amp already has, just less volume. So the Lar-Mar one is for me?

[CoffeeTones]

The dual 250KA + 2M2 resistor PPIMV will do that, if you are replacing a pair of 220k output grid resistors. It can add a little more dirt if the PPIMV is turned down and the pre is up. You can dial that effect out for the most part. It's easy to find a balance in volume and dirt. This PPIMV is most useful some where between the 5 an 9 settings, with the pre set to taste.

[JimmyR]

Thanks! Too many options...

[JimmyR]

Well I just tried the dual 250KA pot/2M2 resistor PPIMV on a 5F6-A Bassman. Sounded pretty ordinary on that amp. But I'll try it on a 1987 soon. Marshalls seem to work with MVs better than Fenders for some reason. I had beefed up the filtering to almost Marshall levels on the Bassman too.

[Silvio55]

Hi guys! I have my 18 watt clone in wich I added the Paul Ruby mod (the 1N4007 in series with zeners across the power tube grid leak resistors) to get rid of the nasty crossover distortion at full volume, I also added a crossline master volume, wich works but I don´t like a lot, so I wanted to try a LarMar master volume type, I have installed it in my 50W Plexi clone and it's amazing, but I have some questions: Do I have to solder the diodes directly oh the pot or can I keep them on the board? does the diodes have to run across the outter lugs of the pot or between the ground lug and wiper?

[CoffeeTones]

http://music-electronics-forum.com/t33314/
http://music-electronics-forum.com/t255/

[JimmyR]

Well I tried this Lar-Mar PPIMV in my 1987 clone - nah, not for me. I thought it sounded awful, actually. I twisted the wires tightly and it was dead quiet. No need for shielded cable.

So everything was great except I just didn't like how it sounded unless master was on full. I prefer the 2204 MV. But plain ol' 1987 sounds best. It's just very, very loud.

[rockgod212]

this may be a dumb question, but has anyone put their ppimv in an unused normal (low input) channel jack hole? is it possible to put it there without noise, as that is where I want to put it.

[rockgod212]

this may be a dumb question, but has anyone put their ppimv in an unused normal (low input) channel jack hole? is it possible to put it there without noise, as that is where I want to put it.

[CoffeeTones]

It invites problems. Output components should always remain as far away as possible from the input.

[rockgod212]

ok then, scratch that idea. back of the amp it goes then.

[RagnarMarGunn]

Yeah i guess you are right
and i believe the PPIMV works just as good as all people has said here, i'll just have it installed and be happy.

BTW i read on Metros facebook page in a recent post that George uses type II PPIMV with the 500k dual pot because he thinks (hi George! ) it is the best... that made made me a little confused since i hade just read this whoooole thread! (yeah when you're sick home from work, then thats what you do )
link: https://www.facebook.com/MetropoulosAmp ... 37/?type=1

"My favorite master is the type II PPI-MV using the PEC dual 500k pot. Most transparent and even at lower volumes"

any comments on the 500k? i mean, you got me convinced about the 250k+2.2m but if George uses it then it must be good right?

Sounds good at least:

Well .. i finally pulled the trigger and installed PEC Dual 500K pot and left 220K on the board. I've had Lar/Mar in various forms for the past 5 or 6 yrs, never going back. If you decide to try, fist try measuring the resistance of Alpha + safety resistor with standby on, after you replace with 500K Dual PEC pot and have 220K on board, measure again and see the difference while turning the knob. The sound is so much better that it's hard to describe, my Metro 1987 turned into 2204 is finally the beast it was supposed to be .... at all volume. I guess it's got something to do with less resistance.

[CoffeeTones]

Post removed.