More 'life' to high plate cleans

[norburybrook]

thanks Martin, well I'd say there's plenty of bass on the clean side anyway so I wouldn't want any more. So are you saying leave the 5uF's as doubling them to 10 will add bass?

Marcus

p.s. I 've also realised there different mid pot values for the EQ on the #124, I'll swap that out tomorrow as well.

Marcus

[Structo]

In another thread I mentioned a mod that switches the bypass cap on V1a.

It consists of a .68uF and 5uF cap on a switch.
This helps with single coils and humbuckers.

You can also put the LNFB on V1b on a switch to see if you like it with or without.

Another tweak is to put a switch on the Presence pot (full CCW to off) so I can turn off the global NFB.

It makes a louder output and is much more raw sounding.
I use this sometimes when playing real low volume.

The rest of the cathodes have 5uF caps on them.

I fought too much bass as well with my amp.

I also lowered the PI coupling caps to .05uF.

[Charlie Wilson]

Marcus, the 10uf bypass caps also adds more gain in the bass and mids. I had 10uf(V1 only) on my low plate classic and switched them out for 5uf. I prefer the 5uf. The sound on the clean is a little more relaxed sounding and Fender like to my ears. You lose a little gain and fullness in the OD but I still prefer a leaner sound there also. I think most the guys prefer the 10uf.
CW

[martin manning]

thanks Martin, well I'd say there's plenty of bass on the clean side anyway so I wouldn't want any more. So are you saying leave the 5uF's as doubling them to 10 will add bass?

Marcus

p.s. I 've also realised there different mid pot values for the EQ on the #124, I'll swap that out tomorrow as well.

Marcus

Partial bypass of the cathode resistor makes a roughly 6dB high-pass shelf. You can ball-park where the middle of the bass roll-off will be by using the 1/(2 Pi RC) formula where R is Rk and C is Ck. For 5uF and 1k5 that's 21Hz, but it will be 1-2dB down an octave higher than that at 42Hz. You can see that doubling the value of the cap will move it down by a factor of two, or one octave. It'd be easy to test by tacking another 5uF across the existing one. Worth a try.

[ToneMerc]

Has anybody tried a hybrid low-high-plate configuration? Marcus if you are going to convert your 102 to low-plate you could change V1 first and see how that sounds.

I have a build what I called a Mo-plate, 100k/150k in both classic and skyliner configs At first tried 10uf on both v1 and v2 and in both configs I found the OD to be too muddy, so usually I put a 4 or 5uf on v2.

TM

[norburybrook]

I'm going to swap the bass and middle pots to #124 spec tomorrow, what can I expect from that? bass is moving to 250k, losing the cap and changing the resistor to 1.8k and middle to 100k pot.


Marcus

[Charlie Wilson]

Marcus, I think you are going off of the #124 as a low plate classic with the values you mentioned. Might as well try the .047 mid cap also. You are going to get less bass and mid range.
CW

[norburybrook]

Marcus, I think you are going off of the #124 as a low plate classic with the values you mentioned. Might as well try the .047 mid cap also. You are going to get less bass and mid range.
CW

cool, I think less bass and mid range will definitely make the clean sound more fender like.


Marcus

[Structo]

Is it a 25uF that qualifies a fully biased cathode?

I think that takes it down to 4Hz.

[aflynt]

FWIW, I tried upping the cathode bypass caps and the lowplate-clean/highplate-od and preferred lowplate across the board with 4.7uF bypass caps. I thought upping the v1a or b bypass caps made the clean sound more like it did highplate. I basically tried a bunch of this stuff with alligator clips last winter before I settled on my current values. I've had the best luck trying things in place and listening like that.

-Aaron

[Charlie Wilson]

Aaron, I remember that you liked the 10uf on the clean side for the low plate classic. Did you go back to the 4.7uf? I found that by going back to the 5uf on the clean my strat sounded nicer and the OD was less harsh and buzzy.
CW

[aflynt]

Aaron, I remember that you liked the 10uf on the clean side for the low plate classic. Did you go back to the 4.7uf? I found that by going back to the 5uf on the clean my strat sounded nicer and the OD was less harsh and buzzy.
CW

I wound up at 8uF on v1a/b on my Low Plate Classic. It's still kind of bassy, though especially with deep engaged. My main amps are Lowplate Skyliners that I kept at 4u7. I've kept the other amp as a LPC because it's so versatile. That comes at the expense of being a bit more difficult to dial-in, though.

-Aaron

[Charlie Wilson]

Wow 8uf. Cool, sounds like your are as picky as I am. Have you tried reducing the V1b coupler to .02 or so. I noticed Dumble did that with the Carlos Rios amp(SRV) and the Borderline. It really limits the effect of the bass control but it does reduce the boomy bass. I have a .02 in mine and I may go up just a little to .03. I also have a 330pf treble cap and I may reduce that to 300pf or 270pf so the high e doesn't jump out quite as much. I found if you go too low your lose the high end punch in the OD.
CW

[aflynt]

Wow 8uf. Cool, sounds like your are as picky as I am. Have you tried reducing the V1b coupler to .02 or so. I noticed Dumble did that with the Carlos Rios amp(SRV) and the Borderline. It really limits the effect of the bass control but it does reduce the boomy bass. I have a .02 in mine and I may go up just a little to .03. I also have a 330pf treble cap and I may reduce that to 300pf or 270pf so the high e doesn't jump out quite as much. I found if you go too low your lose the high end punch in the OD.
CW

Never tried anything but .05uF in the v2b coupler spot. I'll give that a shot sometime. Thanks!

-Aaron

[Guy77]

I've got a 50W high plate, non-HRM that is lacking a bit on the cleans, single coils and buckers. Sounds a little too 'flat' dark and a bit too much compression. I like the somewhat 'singing' violin like quality, but the cleans dont sound '3D' and lively enough, especially with more mids dialed in (which I like for the OD)
Had a new production tung sol in V1 Plate voltages were roughly 10V low, swapped it out for a brand new one, and the plates went back up to about 190V. Sounded better, but still lacking. bright switch helps a bit, but causes ear fatigue and can get a bit harsh, so I often flip it back off within a few minutes
What's the best course of action to liven the cleans up? Should I add the NFB back to V1? I'm considering just dropping the plates to 180K/150K because I'd like some more dynamics from the clean channel, too. I dont think it needs to go all the way down to 100k, though. Thoughts or suggestions? Should I attack this one triode at a time? I attached an image of what I believe to be a fairly accurate representation of the preamp in my amp.

My 50 watt 124 high plate had the same issues. I tried many different values for V1 and V2 (100k to 220K) there was always a sacrifice with the Clean and OD channel. In the end I placed everything to stock 124 high plate values and placed the B+ rail on a 3 way switch with diodes and heat sinks and each positions changes the B+ by 20v. I found that when I ran the B+ at 430v cleans and OD were to my liking.

Cheers
Guy