Lar-Mar or Watts control... ?

[dorrisant]

Going to put a MV in a Rockster build. Have any of you guys compared both in a Rocket or Rockster?

Tony

[M Fowler]

Yes I have messed with both designs. The Watt's control works very well but not without affecting the tone.

It certainly reduces the volume to get bedroom levels but is better used in conjunction with the MV rather then alone like in my Reverb Rocket build that has no MV.

I think colossal has put both the Watt's control and PPIMV in one of his amps.

Mark

[kwijabo]

would you mind pointing me to the watt's control? i tried looking for it online but couldn't find anything for "Watts volume control" or "watts tube amp volume."

i had a lar-mar in my rocket style build. the thing about it is that i really liked the way the thing sounded as is. when i turned it down to say 7/10, the amp still sounds good. only because you know how good it sounds out of the circuit will make you want to have it cranked. then below 7, i think the tone actually stays pretty good. but the low end percusiveness, character, and feel of the EL84's go away.

FWIW, i like installing lar-mar's for use like i mentioned, just rolling off the control to 7 or 8/10. very usable.

[Colossal]

would you mind pointing me to the watt's control? i tried looking for it online but couldn't find anything for "Watts volume control" or "watts tube amp volume."

The Watts control is taken from the Egnater Rebel 20 although the idea has been around in several forms for a lot longer. This amounts to placing a 25kB-50kB pot (depending on the wattage of the amp and desired attenuation) in series with the shared bias resistor on the phase inverter. So in the example of a Marshall where the PI bias resistor is 470R, the Watts control goes in series with the resistor. Everything else is as normal. For a better taper, a resistor can be added in parallel to the pot. I've used 25kB || 33k in an application on a 6V6 Plexi. I like the result in Marshall amps, but not Trainwrecks. As MFowler mentions, there is a tonal change after a point. If you think about what it does (cold biases the PI), this reduces the magnitude of the output of the PI. It warms up and compresses the signal at low settings of the pot. This is good for true bedroom level jamming but the tone will get fatter but more muddy. This might be to the liking of some. I find that the Watts control works well in conjunction with a PPIMV but again, this is on Marshall style amps. If I had to pick one, it would probably be the PPIMV.

i had a lar-mar in my rocket style build. the thing about it is that i really liked the way the thing sounded as is. when i turned it down to say 7/10, the amp still sounds good. only because you know how good it sounds out of the circuit will make you want to have it cranked. then below 7, i think the tone actually stays pretty good. but the low end percusiveness, character, and feel of the EL84's go away.

Yes, I find the Lar-Mar PPIMV does work will in Voxy style amps as we are not looking for gobs of preamp distortion working in conjunction with output distortion and global NFB.

Tony, that would be my opinion, I'd use a PPIMV in a Rocket or Rockster. I think it will be more tonally transparent since the Vox PIs are already pretty cold and crispy sounding (Tag's rain of nails description fits here), but that is its signature quality.

FWIW, i like installing lar-mar's for use like i mentioned, just rolling off the control to 7 or 8/10. very usable.

Yes, they are great for taking the edge off although I really like the tone of an Express with the PPIMV backed off to noon. The crunch is great.

[Firestorm]

The term "watts control" can be misleading. There's the Egnater version described, but VHT has been offering a Watts control, which is a true VVR/power scale control on the output tubes. In some VHTs, they did not have an MV (which you must have for the power tube scaling to work properly).

[Colossal]

The term "watts control" can be misleading. There's the Egnater version described, but VHT has been offering a Watts control, which is a true VVR/power scale control on the output tubes. In some VHTs, they did not have an MV (which you must have for the power tube scaling to work properly).

Yes, it is a misleading term for sure.

[dorrisant]

Thanks for the responses guys. I think I will order a few of the dual pots and do some experimentation.
FWIW... I put a Watts control in my Frankenstein Rockster. It is a bit different with about 470 plate voltage, but is very useful along side a Rocket Booster pot... lots of versatility that way.

Tony

Here is a diagram of the Watts Control:

[Gaz]

The term "watts control" can be misleading. There's the Egnater version described, but VHT has been offering a Watts control, which is a true VVR/power scale control on the output tubes. In some VHTs, they did not have an MV (which you must have for the power tube scaling to work properly).

Yes, it is a misleading term for sure.

Eh, I dunno, it does technically lower the watts. I think any control labeled as such is marketing gimmick. For the Rocket and serious db reduction, power scaling of some variation is a must or the EL84s loose their griiiiiiiind.

[Reeltarded]

$75 variac. Tenma copy. Works on every amp. I have one for every amp. I have almost every amp.. I am surprised you guys have an amp. I thought i had all the amps.

Damn. I need more money.

[dorrisant]

$75 variac. Tenma copy. Works on every amp. I have one for every amp. I have almost every amp.. I am surprised you guys have an amp. I thought i had all the amps.

Damn. I need more money.

Hey! I thought I was missing something...

[Reeltarded]

I just bought your amps for a song and a dance. Good song, terrible dance if I'm honest.