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

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SteadyEddie
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Re: The PPIMV (Post-PI-Master-Volume) thread.

Post by SteadyEddie » Mon Oct 26, 2015 12:44 pm

I've been using a Lar-Mar PPIMV for a while now. After I changed my wiring to a 2204, I tried the normal master volume and turned up the PPIMV all the way to take it out the circuit.

First thing I notice is that I have a huge boost in bottom end and more warmth.
I'm yanking out the PPIMV, even though I've lost some gain and sustain.

But before I give up on PPIMVs totally, does the Rich PPIMV have more of the bottom end that I've lost?

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

Post by CoffeeTones » Tue Oct 27, 2015 10:51 am

Brighten up and / or adjust for bass in the preamp. Reduce the NFB resistor value and listen. PPIMV reduces NFB. The Rich / Metro should be similar.

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

Post by Amp Healer » Fri Nov 20, 2015 7:54 pm

CoffeeTones wrote:Brighten up and / or adjust for bass in the preamp. Reduce the NFB resistor value and listen. PPIMV reduces NFB. The Rich / Metro should be similar.
:thumbsup:
Yes to get a PPIMV to work correct u need also to adjust the NFB value.
Get a triple potentiometers and adjust NFB at the same time as the volume.
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Doug H
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Re: The PPIMV (Post-PI-Master-Volume) thread.

Post by Doug H » Fri Nov 20, 2015 7:56 pm

I tried that :), it's tricky, I'd wager you are probably better off with a separate feed back control anyhow.

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

Post by Amp Healer » Fri Nov 20, 2015 8:11 pm

Doug H wrote:I tried that :), it's tricky, I'd wager you are probably better off with a separate feed back control anyhow.
Yes u are right, try something like this https://www.banzaimusic.com/MEC-M-87115 ... d-Pot.html
Not the right value but u get that I mean :wink:
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Re: The PPIMV (Post-PI-Master-Volume) thread.

Post by catalin gramada » Thu Dec 24, 2015 1:15 pm

Hallo, and Happy Christmas to All
Catalin

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

Post by Laurent Brondel » Thu Jan 21, 2016 9:12 am

Greetings, first post here.
I recently acquired a '73 JMP50 chassis that I progressively brought back to almost Plexi specs (I kept the split cathode, but changed the .0022 normal channel cap to a .022, and the .022 output coupling caps for .1 ones and increased the NGF). I also insalled a Lar-Mar PPIMV.
The PPIMV is great to bring the volume down just a bit with my trio, I have it at about 85%, otherwise it is just a tad too loud at the settings I use.
At home I use a Fryette Power Station in conjunction with the PPIMV to practice, and it works like a charm.
IME the PPIMV sounds really good between around 75% and 100%, below that it becomes a bit shrill and lifeless.

My question is, do you guys feel that even with the pot full up, it affects the tone of the amp, or do you think it makes no difference? Not trying to initiate a controversy, I am wondering if the Power Station alone wouldn't be a better fit, although it's great not to have to bring it, on top of the rest, for band practice.

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Loop and PPIMV on Blackstar Artisan 100

Post by henter2015 » Wed Feb 03, 2016 7:27 am

Hi Folks,

I recently bough a Metroamp V4 loop to install on an artisan 100, this am is a non-mv as well, reading around I can see that the loop is not recommendable to use it if you did the PPIMV instalation, what is the best approach to do both things on this amp? Im a bit lost on this... will it be better to forget about the PPIMV and use a volume pedal on the loop when installed? :rocker:

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

Post by sickman82 » Sun Oct 30, 2016 7:59 am

Couple of quick questions I have since I reinstalled my PPIMV..

1) I have a ZL Loop on its way.. reading the above question about it not being recommended to install the loop with the MV has got me a bit worried. Can somebody shed some light?

2) I have installed a Vox style cut control across the outputs of the PI instead of the Presence control (250k pot and 2200pf cap).. if I wanted to have a fixed presence control with presence maxed, would I just need a 4k7 resistor with a 100n cap to ground in series with the 4k7 resistor?

Hope somebody can help out. Cheers! :thumbsup:

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

Post by gsb » Wed Mar 22, 2017 3:48 pm

Hi !
I,m building jtm45 and i,m litlle confused .PPIMV with cut control and fixed presence control or PPIMV with variable NFB and normal presence control ? what is better for tone. :(

Thanks gsb

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

Post by neikeel » Wed Mar 22, 2017 6:32 pm

Gosh this thread is old, just noticed the three posts above unanswered.

In answer to the above question:

- for a JTM45 go stock presence and PPIMV
- the volume on a JTM45 just needs to be knocked back a bit and this will not affect the NFB (a JTM45 has a lot of NFB so can cope better).
- on the 73 JMP50 the tone is suffering at high levels of reduction because of loss of NFB ( I guess the poster is long gone. This can be compensated for with adjustable NFB or simply combining a good attenuator with PPIMV and using a bit of each judiciously.
Neil

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

Post by gsb » Thu Mar 23, 2017 2:22 pm

Hi Neikeel
Thanks for advice,i will leave Presence stock and put PPIMV in ,NFB 27k on 16ohm.I dont need bedroom level just for club giging .

gsb :P

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

Post by matttornado » Tue Mar 28, 2017 11:26 am

So who tried the Cross Line "Type 3" PPIMV from the Trainwreck pages?

I have it now in my 1974 JMP & I think it sounds awesome. I also tried the other types in the past.
I'm keeping it! :thumbsup:

I'm surprised I don't see this type talked about here or on other forums. :what:

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

Post by ledvedder » Tue Dec 26, 2017 11:29 pm

Hi, very old thread, but I'm hoping I can get some assistance installing the larmar ppimv in my Ceriatone Chupacabra 50. I've attached the layout for my amp.

The layout is here, http://www.ceriatone.com/hot-rodded-ple ... acabra-50/.

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

Post by neikeel » Wed Dec 27, 2017 7:04 am

The thing about the Chupa is that it has two bias circuits so that you can bias each output tube accurately if they are mismatched.

You will need:
A dual 100k pot and knob
2 feet of dual core (2 different colours, i.e. red and black) screened wire.
some shrink wrap correct size for the screened wire
2 2M2 carbon film 0.5w resistors

You apply the commonly found diagram with my amendments below:

n.b. these instructions are very specific to this amp because of the bias arrangement
Remove the two 110k resistors from the board (where J & K wires are hooked up) and the wires between both J & Ks.
Install the pot in one of the output jack holes (the extended one - not one with feed wires!)
Take the shielded wire and solder one end (i.e. red) to J on the board and other (black) to K turret, solder the red wire to the outer right (as you look at the amp front to back) and the black wire to the same lug on the other pot. Shrink wrap the shield at the board end so it cannot touch/short on anything. Extend the shield and solder to the back of the pot only.
Next take the other piece of shielded wire and solder red to J on the swamp resistor and black to K. Again solder the shield to the back of the pot. Take the red wire and solder to the wiper (middle lug of the pot you already have a red wire on and the black wire to the wiper of the other pot.
Next you take the bias feed to each pot, take a piece of wire, ideally red with a tracer from the turret where the other end of the 110k from K went and solder to the far left lug on the 'red' pot. Do the same with a wire from the other end of the 110k from K and solder that to the left hand (empty) lug on the black pot.
Last thing to do is solder a 2M2 safety resistor between the wiper on each pot and the individual wire from the middle of the board.
Check you work and you should be good to go.
Points to note, your individual wires are the bias feed to each half, the shield is not used as bias feed as you would with one bias pot. If you can get a high quality PEC pot I am advised these work best (by George)
Standard ones are here:http://valvestorm.com/Products/Componen ... /Amplifier
Other stuff here:http://valvestorm.com/Amp%20Mods/LarMar
Neil

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