I would say, just try it out. I like the 68k resistor, although I don't know if the difference I hear is the resistor or the LNFB... Anyways, it was an easy mod. We just snipped the old resistor and didn't have to get the turret board out. If you do it, make sure you record soundclips of both variants

Thilo didn't you make a switch for LNFB? Why not switch it on and see what the 68k slope did?

I should re phrase my post. I read back the thread and I think I get it better how the 180k slope resistor concept could work well. Perhaps I'm just a bit baffled cause I am about to do the new Dr. Ika (Pickmaster) FM ME / OTS "TR" mod with the suggested 68k slope.

I just hope bluesking could read this and shed some light into other aspects of the mod like is it more punchy or what other than being more scooped. And also I hope Pickmaster could chime in too so he could share his ideas on this.

THats very interesting on the alligator clips. Could I just clip it on and off while amp is operating ? Better to turn off?

a couple of points:

1. placing a resistor in parallel will always decrease resistance. therefore to get an increase in resistance you either need to  change the resistor or add another resistor in series
2. a correction on the parallel resistor formula posted earlier:

 1/R1 (Existing Slope) + 1/R2 (secondary test value) = 1/Total R.

lowering the slope resistance will decrease the overall insertion loss of the tonestack and therefore provide more signal to the overdrive section. hence giving more bloom, however also with an increase in bass and mids
increasing the slope resistor has the opposite effect, it increases the insertion loss and there the result will be a more pristine signal to the overdrive section, with less bass and mids, but the overall tone is much more natural. to compensate for the loss, i have turned up the overdrive somewhat when needed, however the sound is tighter and clearer.

each to his own.... however a customer has heard my amp many times before, however after hearing it last week with the resistor mod, has decided to place an order.

i cannot stress enough for those using EV12L's, putting them in a tuned box such as the TL606 makes the world of difference to the overall sound and response too ....tightens the bass up without loss of highs

Hi there tone lovers,

Once again:
Low slope resistor (not very low though!). Fat sounding Bluesmaster has 47k but there is a  0,02mf after it which cuts down to much bass in comparison to 0,1mf on OTS.
68k slope on OTS is MY PERSONAL favourite which introduces little bit more bass and low mids but most importantly adds natural clean compression to the first tube, so clean gets so called CHIRP and singing quality. I’m a very light touch player and I use very thick pick 3mm Stubby. Compressed clean sound allows me to have less drive on OD trimmer which is kind of clean but fat singing, bloomy, touch sensitive drive tone which does not need PAB to sound great.
In short lower slope resistance and less or no  capacitance on NFB gives me more TWEED tone enhanced in high frequencies with higher capacitor value on the clean volume pot. Personally I always prefer TWEED to Blackface, more correctly tweed fatness with blackface glassy tone added.

Mr. Fabulous is right in case that higher slope resistor gives you more clean, less fat non compressed (more classic blackface) tone and I’m sure many players love this tone but not me. I like rubbery, spongy, fat, wet, syrupy, singing clean and drive tone.

But I totally agree!   Tone is very individual and you have to try to find the best for yourself, tone which makes you play and feel better.

I love my amps. No D-lator in the loop !!! just Digitech RP200

 
 

Thanks I think I will indeed go with the 68k and I will try to do a before and after sound demo.