Hi There,
Once again, here is a layout of the OTS FM mod.eagle. easiest platform for really great tone.
With offered mods (in green) you‘ll get clean as good as TR or Bluesmaster with 100-120pf High cap on volume push pull, fat but sparkly same time.
Important tip! When you use single coil pickups, you can switch OFF V1’s 0.05uF NLF cap for fatter, more compressed tone , but for the humbuckers better switch it ON otherwise you will have to much sug and early brake up.
Drive channel (ratio X – line mod) will give you fatter and more open drive tone which you can smooth with higher value snubbers and if you use 120pf cap on volume’s bright switch, accordingly you have to increase V2,2 snaber’s capacitance with 3 way switch with 470pf or 680pf caps (you can experiment and chose cap’s value according to your taste).
On the mid-boost switch increase cap to 470pf for slightly more high mids and remove 0.001uF cap on bass pot for slightly more lows and low mids (or better introduce a mini switch).
Finally change presence pot to 1K linear for better early and smoother action.
I hope this mods are easy to perform and you will have better sounding amp instantly.
Best wishes and good luck.
Hi Pickmaster,
Just wanted some clarification on a few pointers on your mods,
1. Above you recommend a 100 or 120pf on the preamp volume push pull, however it isn't on your schematics. Do you think it necessary to have this and also a 3 way bright switch with values 68 and 120pf? Perhaps having both will provide more flexible variations of all three values of brightness on the cleans, with a 1M A push/pull set with a 100pf, which will be me variation of all 3.
2. LNFB two way switch (on/off). This is standard on the FM ME so no change required here.
3. On your schematic, the V2,2 snubber’s capacitance is a 3 way switch with 470pf or 680pf caps, however I plan on going the rotary switch path, however only a 6 way is available for me. Which values for the 6 way do you recommend? If my understanding is correct of this function, with the bright switches engaged (both the 3 way switch and the push pull mentioned in point 1 above) creating glassy/two rock type cleans, this rotary switch will remove the highs on the OD channel only, but retain the high mids producing a rounder attack and fatter sounding note definition with the OD. V2s snubbers value static at 330pf & 250pf which is the value on the schematic (within the V2 socket/circle) or both at 330pf?
4. The change for the mid boost to 470pf is straight forward, although I'm looking at possibly getting a 500k A push pull pot on the bass pot to engage/disengage the bass cap.
5. Think the drive - ratio x line mod values are straight forward with the values 100k - cap towards X terminal ( to be paired with 100k L pot which is standard on the FM) and 0.01uf to be used with a 1000v ceramic cap and then 150k as per standard. My question here, is if I increase to 0.02 or 0.03, can I roll negate the added fatness of the OD by tweaking the V2,2 rotary switch implemented if i find it too fat?
6. 68 k slope resistor, 2w. Also ok here, although is there any reason why to choose 2w over 1w?
7. Lastly, the presence pot changed to a 1k linear.
If you could please confirm and provide some advice on the above would be much appreciated! Took me a while to study the schematics and understand the reasoning of the mods! Currently in discussion with Nik on the mods, so I want to make sure I'm relaying the correct information to him.
Thanks so much pickmaster for sharing these mods. To be honest, I was thinking of saving up for a Two Rock CRS at one stage.... But that would mean selling most of my beloved gear and saving up for a while further.... Damn too expensive they are....
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