Convert a Marshall Guvnor Mk2 to a Mk1 and save ££££

equalsql

If you own a mk2 version and want a mk1, want to save some money and are good with a soldering iron then do this..

C12: replace with 22nF
R12: replace with 10KΩ
R25: replace with jumper
R26: remove (leave open)
R5: replace with 220KΩ
C22: replace with 47 pF
R19: replace with 10KΩ
R21: replace with 150KΩ
R9: replace with 220KΩ
C23: replace with 47pF
D1: add 2 1N4007 in series


Part list:
1 x 22nF capacitor
2 x 10KΩ resistor
2 x 220KΩ resistor
2 x 47pF capacitor
1 x 150KΩ resistor
2 x 1N4007 diode

Source

thermionic

Interesting video. I’d read about the 10x scaling in the eq section with C22 not being scaled correctly, but that was a good explanation. Also being able to turn the deep control down so that it’s effectively off seems like a very sensible idea. Tempted to try this on mine, and I could borrow a stock one for comparison.

ICBM

Well... yes and no. That's "sounds subjectively like a Mk1", not "converts a Mk2 to the same circuit as a Mk1". The two circuits are significantly more different than just swapping a few component values - the Mk2 uses a version of the Mk1 circuit at the start, but it has a whole extra dual-IC stage for the Deep control - you would need to fit a switch to bypass that if you didn't want to just disable it completely. In fact, the very first change listed - C12 in the Mk2, equivalent to C9 in the Mk1 - should *not* need changing if you're doing an accurate circuit conversion since they're the same value (220nF).





(Ignore the red circles, they relate to a different mod.)

randella

I looked into this a while ago - I'm handy with a soldering iron and have a bit of electronics background (although quite rusty these days through lack of use )

Thing is though, I figured I quite like the GV-2 as it is. Plus mine was a leaving gift, so it has sentimental value. I did consider dipping for another to try this out, but then the whole reissue saga gathered pace. Decided in the end to just wait out the feeding frenzy over that and go for a used (new) Mk. I once they start inevitably hitting the classifieds.

Not to say I wouldn't be interested to follow if someone else tried it. I think the video comparison I watched was Johan Segeborn's here: