4 4 0 PPIMV

[mehfuzhoss]

how can i get a PPIMV on my ax84 4 4 0 amp. detailed instruction would be great.
Thanks

[pompeiisneaks]

There are tons of howto's and documents on the web of installing a master volume. The Rob Robinette page has a good list.

https://robrobinette.com/Generic_Tube_A ... ter_Volume

Your amp has a typical 100k to the bias adjustment that allows a Post Phase Inverter MV, which is one of the better type, but you can just as easily stick one in pre PI

~Phil

[mehfuzhoss]

nice article. I am going with the type 3 PPIMV. i drew a diagram that i plan to mod with. please adivse if this is correct wiring for my 4 4 0 amp

[Ten Over]

I would feel better with the 1M pot on the low voltage side of the capacitors.

[mehfuzhoss]

Hello,

I have 0 and -11.9 volt on lower sides. higher sides are 192 volt each. so i should go ahead solder on 0 and 011.9 sides to the 1M pots 1 and 2 lugs and leave lug 3 empty. Am i right on this?

also, i am curious what if i ground the lug 3 of the 1M pot!

Thank you.

[Ten Over]

I have 0 and -11.9 volt on lower sides. higher sides are 192 volt each. so i should go ahead solder on 0 and 011.9 sides to the 1M pots 1 and 2 lugs and leave lug 3 empty. Am i right on this?

also, i am curious what if i ground the lug 3 of the 1M pot!

You should have around -12V on each of the lower sides. Better check that out. Then connect like you said.

Don't ground lug 3. It will foul-up your bias.

[mehfuzhoss]

Hello ,

I wired according to the diagram with 1M. great volume control.

i turn the volume (existing one) at full for good distorotion

and then i merely have to turn up the 1M (PPIMV) pot to get the amp at low output. even at 2/3 the amp goes on full bloom and very loud. i was thinking of getting a little bit more sweep from 0 to 2/3. you know what i mean? i tried 100K and the amp sounds very fizzy and thin. any suggestion for this?

Thank you.