Matchbox top cut

[Ge_Whiz]

Just finished building the ROG 'Matchbox'. I don't like it as much as the 'English Channel', but the friend I've built it for will. I used a BS170 and two 2N5457s and had no trouble at all, except the 100k trimmers are right at the extreme end of travel.

However, I have the same issue with this circuit as I did with the EC - again, I couldn't hear the effect of the top cut. Since the MB has no traditional tone controls, I wanted more effect from the top cut circuit, and ended up reducing the pot down to 47k and upping the capacitor to 47nF. Now I can tame the brightness and get a good blues tone from it.

I'm still intrigued as to why the 'original' tone circuit values don't seem to do enough in these emulations - different impedances, perhaps?

Come Christmas / New Year, I'll be building the 'Prof Tweed' and 'Supreaux' together in one box, for myself this time! But I may still have to build another EC for myself, too...

[B Tremblay]

I'm with you on this one - there may be some "impedance voodoo" at work within the amps that doesn't translate to FETs.  I'm sorry that Cut control has turned out to be an electronic vestigial tail in those circuits.

[bwanasonic]

Sounds like *scaling* the values works? Either */ by 4 or 5. Have to keep that in mind when I finally build an EC or Matchbox. Any chance of putting that info on the appropriate ROG pages, so when I do the build I'll remember?  :lol:

Kerry M

[Ge_Whiz]

Heck, no need to apologize, Brian! Just a footnote may save folks some experimentation, that's all. For future builds I'll ensure that I socket the capacitor at the trial stage and hard-wire it after selection (the joy of stripboard  ).

[B Tremblay]

I've added a note to both the EC and MB articles.  Thanks!