Rocket too much gain

[yalesmith]

I just finished a rocket build and I am a bit surprised by how much gain/distortion there is. I was thinking it was more of a clean amp. I was wondering what i can do to reduce the gain yet still keep the volume...I would like some warm breakup when cranked but that's it, (like a fender). I have tried the PIG control but that seems to lower volume too much. Any help would be appreciated.

Thanks

[xtian]

I just finished my first Rocket build. See https://tubeamparchive.com/viewtopic.ph ... 4&start=15

Have you checked voltages against the chart? That's probably a good indicator of too much gain in the preamp tubes.

I haven't been able to turn mine up yet, but at low to medium volume, it's clean and spanky.

[yalesmith]

the voltages are good.

Thanks

[sliberty]

Not sure of course if there is something wrong with your amp or not. But if it is all OK, and you just want less gain, you could try some lower gain tubes, like 12AT7's, in V3 and even in V1. You oculd also try the split plate load resistor trick that I have used on my Express. It cleaned up the Express considerably.

[yalesmith]

what is the split plate load resistor trick? and how do you do it?

thanks

[M Fowler]

Just either put in lower gain tubes or do what I do changed the V1a 220k plate resistor to 100k-150k this will set the gain lower for more headroom.

Mark

[sliberty]

what is the split plate load resistor trick? and how do you do it?

thanks

Replace a plate load resistors with two resistors that add up to the same total value. Move the wire that usually connects the plate of that stage to the grid of the next stage so that it connects the junction of the two resistors to the next grid. Depending upon how you divide the total plate resistor, that will determine the amount of clean up it will do.

[gktamps]

Hmm. Any chance of a drawing or photo of this?
Thanks

[yalesmith]

Mark - do you mean V1b 220k plate resistor?.

Thanks

[sliberty]

I've done it on a switch in the past, so that is how it is drawn. The example in the diagram is from an Express (V2a).

[yalesmith]

I changed the vb1 from 220kj to 100k and it helped alot...will fool around a bit more

[M Fowler]

I changed the vb1 from 220kj to 100k and it helped alot...will fool around a bit more

See it works

I was talking about R4 220k.