Cap upgrade in an MTS module?

[Whoopysnorp]

Has anybody tried doing an all-around upgrade of any of the components in an MTS module (e.g. all the caps)? I have an XTC module, which I like, but I could imagine it being better. I've just looked and saw that it uses the .0047u cap in C3, when according to this site the .0022u value is supposed to be stock on XTCs (mine must be an early one). I think it would benefit from the tighter pick attack, and it definitely doesn't need the amount of low end that it has now. Would I benefit by going one step further and replacing all of the caps with Orange Drops or something like that?

I'm planning on getting an SL+ soon, and possibly either a Recto or a Grail, and any advice on upgrading components in those would be appreciated as well.

 

[djd100]

The caps in the audio path are good to replace (coupling, tone stack, bright), though the caps used by Randall in these locations aren't bad excepting the bright and tone stack ceramic caps (though to be fair many tube amps had ceramic caps in the same locations as well). You can get a sweeter top end by replacing the ceramics with silver micas.

IMO you can get a little benefit with orange drops but it's subtle, though if you can solder PCB's safely then it's cheap and easy to try.

Has anybody tried doing an all-around upgrade of any of the components in an MTS module (e.g. all the caps)? I have an XTC module, which I like, but I could imagine it being better. I've just looked and saw that it uses the .0047u cap in C3, when according to this site the .0022u value is supposed to be stock on XTCs (mine must be an early one). I think it would benefit from the tighter pick attack, and it definitely doesn't need the amount of low end that it has now. Would I benefit by going one step further and replacing all of the caps with Orange Drops or something like that?

I'm planning on getting an SL+ soon, and possibly either a Recto or a Grail, and any advice on upgrading components in those would be appreciated as well.

 

[Mattfig]

Yeah...Changing everything to 22u is a good call...As for caps...I've been experimenting with them...Tried several Orange Drops and really can't hear a major difference at all...However, getting all tone caps to 22u will help your cause...Silver MICAs are supposed to be nice...Red WIMAs too...

 

[Whoopysnorp]

OK cool. I'm not too experience with reading schematics or tracing circuits...how do I tell which are the caps I want to replace?

 

[eedude]

Has anybody tried doing an all-around upgrade of any of the components in an MTS module (e.g. all the caps)...

The components used on the MTS modules are of high quality. Just subbing them our for some other manuf with the same value will not yield much.

Some modules do have ceramic caps for the anode bypass and for the treble cap. In hi-fi ceramic caps are bad...because they have some non linear properties. In a guitar amp, their characteristics may or may not be bad... it's up to your ears to decide.

as mentioned by others the "c3" cap vale has a significant effect, but I think on the XTC module the reference designator is actually c1....or at very least it may have changed numbers over the years.

 

[Whoopysnorp]

Ah ok, I see that the C1 cap on the XTC is in the same location as the C3 on the Recto (which is a .0047u). I don't know enough to be able to tell whether it's serving the same purpose or not (is that the coupling cap?), but it would make sense that this is the cap in question, since .0022u is supposed to be the stock value on the XTC. Between what you and Mattfig have said, I have decided against doing any total component swaps on the module. I may change the C1 to a smaller value to get some more tightness. I'll have to play with it some more and decide whether I really want it to change.

 

[warlok]

Here's the deal with C3 (or C1 in your case it seems.)
http://www.grailtone.com/guitar-tone-articles/randall-modules-modifications.html
Bottom of page.