Princeton reverb master

[phsyconoodler]

Anyone tried the train wreck type 3 master volume on a princeton reverb?
  Im thinking it should work but...

[phsyconoodler]

Tried it. It gets resl gritty but has a hair trigger. On or off almost.
  Grinds really cool however.
i want to install the master that Merlin uses but its confusing me.
 It looks like the coupling cap from the previous stage is disconnected and hooked up to the pot.
   Anyway it eludes me how to implement it. Brain block.

[tubenit]

Keith,

Nice to see you on the forum! 

You're presenting an interesting challenge given the PR has vibrato and fixed bias.  I probably would do a VVR and use it as the master volume.
http://www.hallamplification.com/main.html?src=%2F#2,2


With respect, Tubenit

[tubenit]

Edited info and reposted further in thread after help from Sluckey.

[sluckey]

That PPIMV circuit by Bruce Collins should work just fine in a PR.

[tubenit]

That PPIMV circuit by Bruce Collins should work just fine in a PR.

Steve, THANKS for the input on this!   I am understanding this to mean the vibrato will still work OK with the PPIMV.  Correct?

What about the other idea in reply #4 moving the vibrato ................ think that might also work OK?

Thanks! With respect, Tubenit

[sluckey]

I am understanding this to mean the vibrato will still work OK with the PPIMV.  Correct?

Correct. Your draft circuit in reply #3 should work too.

What about the other idea in reply #4 moving the vibrato

This may work but will likely need some tweaking. If you had another triode you could copy the Vibro Champ circuit exactly.

I would try both of the other MVs before moving the trem.

[Ed_Chambley]

A LARMAR will work and the tremolo will also.  I have a PR build with one.  I do not care for it because the sound I like coming from a Princeton is not preamp.  It is not smooth at all.

I believe this is the perfect candidate for a VVR if someone is wanting a bedroom amp. 

[sluckey]

Tubenit, you need to redraw that 68K and intensity pot sitting below the MOSFET.

[DummyLoad]

That PPIMV circuit by Bruce Collins should work just fine in a PR.

Sluckey's  response to my question whether the vibrato would still work:   

Correct.

With respect, Tubenit

your bias tap (PT to 100K to 1n4007) is connected to supply mains directly. it will work but is not safe. 


--pete

[DummyLoad]

corrected.


btw: in SCH if you set your snap to grid to .025" things fit better.


--pete

[tubenit]

Corrected the schematics I previously posted.  CHECK for ERRORS!

With respect, Tubenit

[phsyconoodler]

So i ended up using the 5e3  style master.
one meg pot with one lug to coupling cap after first stage,wiper to pin 7 and end lug to the junction at the pi. It works pretty good. A little tweaking and it will be really good. I was going to use vvr  but didnt have therright mosfets on hand. Overall im happy. My brain got by its block! Thats the most important  thing.
merry Christmas  to one and all!