Adding Lar-Mar type II master volume to my Rocket

[Doxie man]

After converting my Liverpool over to a Rocket I am left with an extra hole in the front panel so I am going to add the Lar-Mar type II master volume. Since this circuit is cathode biased, are the two 2M resistors that are soldered across the 250k dual-gang pots still required ? They are there when this MV is installed in a fixed bias circuit as protection to the bias circuit should the wiper on the pot(s) fail but in a cathode biased circuit such as the Rocket, bias is not set there ....grid reference is. I have never done a MV before ( if you can believe that !) so I am taking things slow and carefull

[M Fowler]

There is no difference installing a Lar-Mar or PPIMV on the Rocket cathode bias verses Express fixed bias.

I use a 250k Liner dual gang pot, 2m2 resistors (2) and shielded cable to power tube grids and bias caps where the two 220k resistors used to be. Out of the dual pot to ground.

[Doxie man]

I thought so but wanted to get confirmation....thank you Sir

[M Fowler]

No problem glad to help out.

Here is a Rocket combo thread with a nice layout showing how he wired his. https://tubeamparchive.com/viewtopic.ph ... hanneedles

https://tubeamparchive.com/download/fil ... &mode=view

[Doxie man]

I only have 2M resistors on hand.....NOT 2.2M but I would think it won't be an issue. WOW !.....that layout is freaking NICE ! Lots of cool mods going on

[M Fowler]

Reverb Rocket 002.JPG

I've built so many Rockets and some I've added three switches just for fun.

Reverb Rocket Panel3.jpg

50W Reverb Rocket.jpg

[Roe]

the larmar is perfect for ac30 type amps w/o negative feedback. it works great

[Doxie man]

Installed the LAR-MAR PPIMV and really like it I also set my signal caps to .022uf to reduce the low end a tad and dropped the input cap on the PI to .01uf to smooth out the drive. This ones done folks.....sounds FANTASTIC

[Doxie man]

[M Fowler]

Looks very good.

[Bob S]

Congrats - very nice build. They can be loud so a PPIMV helps a lot for lower volume situations.
I understand about the Liverpool not being your thing. Not really a pedal friendly platform either, whereas the Rocket is a great pedal platform.
The Liverpool is on the edge of stability when it sounds great.
Well done!