CRATE V18 Optimisation

[HELLORAPH]

I looked into thegearpage forum, unfortunately it is not active anymore and many schematics and pictures disappeared. Can someone tell me how to get a cleaner amp ? I already swapped R4 R10 and changed the speaker but still not enough - I'm wondering about reducing resistor R3 to 100 k and change Both V1A and V1B cathode resistors and capacitors to come back to Fender type 1.5k and 25µ/25V ?

[Daviedawg]

Please post a schematic of your amp for people to see the circuit you are asking about.

Dd

[HELLORAPH]

here it is
https://www.thetubestore.com/lib/thetub ... OZQEekb_n4
This is a PDF where on page 1 and 2 the schematic is shown.

[Daviedawg]

Ok schematic is there

Dd

[Crabman]

How clean do you mean?

This is a 4 gain stage amp with plate driven tone stack. This is one more stage than an 800 … probably not the most ideal circuit to mod for a cleaner tone. They dropped the cathode follower and created a 4th gain stage so i don't think clean was in the design plan.

On top of that you are pushing the EL84s hard with hot bias on the PI and low value tail resistor. There are certainly things you can do to tame this circuit … perhaps convert to 3 stages plus CF but it will still be “gainy” and it will probably make a mess of your PCB.

[HELLORAPH]

Yes you are right, there are too many stages, I'm thinking about 2 options.
1 would be to build a 18W + Reverb TMB Gain Master directly on tourret
2 to change on PCB (includes the suppression/change of some stages).
Unfortunately on the gearpage forum I can't get all info I need : Is the SLO mod a lot cleaner ? Would the JCM800 mod work well ? I'm more a Fenderish looking for some manageable crunch - so I would try to reduce gain changing components and tubes.... If someone did and is satisfied I'm clearly interested.