Effect of different plate and cathode R values for HRM amps

[Tonegeek]

I have the ODS 101 HRM plate and and corresponding cathode values (220k, 150k, 180k, 120k) with the exception that I lowered the v1a plate to 180k. Anyone messed with these values and what is your experience? I have seen 220k, 150k on V1 and V2 and especially wonder what the experience is for those people. Also I have seen 150k, 120k on v1 and 220k, 150k on v2. What is that like?

My immediate goals are:
1) Drop a tiny bit of high end overall
2) Make my clean channel a little fatter (warmer). It sounds great now in that it is balanced, with all frequencies accounted for and no harshness except very slightly in the 1k hz area (This may be my speaker choice doing that). My Strat sounds like a Strat- especially in the 2,4 pickup position, but it is almost too clean if that makes sense - like a Twin but not quite so scooped in the mids. I notice with the d'lator in circuit with no fx, that it sounds even better due to something I can't even put my finger on (slight breakup maybe?). I tweaked my d'lator so that it is totally transparent when in circuit except for that magic something. I want more of that sound.
3) And finally I want more growl from my OD channel. My OD sound is very useable now, but it is not big enough. My Reverend Roundhouse HB is easier to get a good OD sound with, but it is still not growly the way I want. Referring to the Bonnamassa clip on youtube I just felt completely enclosed by the sound regardless of what amp he was using. The notes were thick, had definition and character, and sounded clean and distorted at the same time. (It sounded like the Jubilee was not only doing the delay, but the main note too- he wasnt clear about that). The Steelbender Dumble clips are the same way. I am not sure it is possible to get a sound like that out of one amp in a small space, but those sounds are what I shoot for.

For now I am just mainly interested to hear from builders about the plate, cathode relationships and if experimenting with these will help meet some of the stated goals. thanks.

[talbany]

I had somewhat the same issue with my early builds and though I tried many differant configurations there I did notice some slight changes in frequency responce as well as point of breakup they were to subtle for my strat to really satisfy me and couldn't really do much with the bypass caps as they effected the tone of the OD. The Les paul with a JB in the bridge was happy but the strat lacked the warmth and some chime I thought.
Then I went with the standard 220 150k and tried a pair of NOS GE 6550's and wala plenty of bottom end bloom more clean headroom and the OD was BIG and had great throat to it. Even at lower volumes it was sweeter. I dont know why more people don't recommend or use 6550's or KT 88's they go great in this design I think.


Tony VVT Amps

[Tonegeek]

I had somewhat the same issue with my early builds and though I tried many differant configurations there I did notice some slight changes in frequency responce as well as point of breakup they were to subtle for my strat to really satisfy me and couldn't really do much with the bypass caps as they effected the tone of the OD. The Les paul with a JB in the bridge was happy but the strat lacket the warmth and some chime I thought.
Then I went with the standard 220 150k and tried a pair of NOS GE 6550's and wala plenty of bottom end bloom more clean headroom and the OD was BIG and had great throat to it. Even at lower volumes it was sweeter. I dont know why more people don't recommend or use 6550's or KT 88's they go great in this design I think.

Interesting... It makes sense in a way as Dumble gets the OD from the preamp, so the 6550's give you a nice clean power section. I have not thought of using them because I had a JCM 800 with them and it was the loudest amp you could imagine and I have no need to ever play that loud again. I am contradicting myself a bit here because the players whose tone I admire the most all play very loud (not sure about Robben, but his tone seems like it would still be great even at low volume) The other thing is I think my OT is too close to the tube sockets and although a 6L6 will fit, I doubt a 6550 will. Not sure about a KT-88. I could move it a suppose. Did you go 220k, 150k on both V1 and V2? I am tempted to try that before I do anything else.

thanks

[groovtubin]

I had somewhat the same issue with my early builds and though I tried many differant configurations there I did notice some slight changes in frequency responce as well as point of breakup they were to subtle for my strat to really satisfy me and couldn't really do much with the bypass caps as they effected the tone of the OD. The Les paul with a JB in the bridge was happy but the strat lacket the warmth and some chime I thought.
Then I went with the standard 220 150k and tried a pair of NOS GE 6550's and wala plenty of bottom end bloom more clean headroom and the OD was BIG and had great throat to it. Even at lower volumes it was sweeter. I dont know why more people don't recommend or use 6550's or KT 88's they go great in this design I think.


Tony VVT Amps

i used KT-66`s in a bassman reissue w/D circuit 4 years ago, i AGREE!

jim@Omegaamps

[talbany]

In my very humble opinion what works best in this design that I have found for STRAT's are from favorite to least are.

KT 88's 6550's 7027's KT 66's Fave
4 5881's 2 or 4 6L's Nice
KT'77's pretty cool but better with Humbuckers
4 6V6's Not bad
EL 34's Dont like
2 6V's really dont like

Sorry D Lite fans 2 6V's DO NOTHING FOR ME Especially the Clean channel of this design.

Once again this is just my opinion take me out back and shoot me if you like, my wife will be the one handing out the BULLETS.

Tony VVT Amps

[dogears]

Lots of HRM amps have 220K/150K on both V1 and V2. Never trust what you read. I have never personally seen 150K/120K so it does not count as truth for me. Stick with the 220K/150K. It will fatten and smooth.

Make sure you have a 4.7uf on V2B.

[Pete]

I have never personally seen 150K/120K so it does not count as truth for me.

You mean on V1?

Stick with the 220K/150K. It will fatten and smooth.

I take it you mean on V2? . ... sorry, I'm just not clear on this, I don't think I've ever heard you (or anyone here) stress this before.

[Tonegeek]

Lots of HRM amps have 220K/150K on both V1 and V2. Never trust what you read. I have never personally seen 150K/120K so it does not count as truth for me. Stick with the 220K/150K. It will fatten and smooth.

Make sure you have a 4.7uf on V2B.

so if I go 220k/150k on v1 and v2 for rP, I should also use 3.3k and 2.2k respectively for the rK?

thanks,
w

[Pete]

I would say yes, as that is the Doctor's rule. Always 3.3k with 220k etc.

Lots of HRM amps have 220K/150K on both V1 and V2. Never trust what you read. I have never personally seen 150K/120K so it does not count as truth for me. Stick with the 220K/150K. It will fatten and smooth.

Make sure you have a 4.7uf on V2B.

so if I go 220k/150k on v1 and v2 for rP, I should also use 3.3k and 2.2k respectively for the rK?

thanks,
w