Moderators: pompeiisneaks, Colossal
Kind of makes me wonder what a modified one would sound like without the MM iron.rock_mumbles wrote:The stock circuit is fine clean at low volumes but pushed into distortion it's horrible with the DC biased second preamp triode, fizzy, fuzzy horrid ...Masco wrote:...
Wow! I guess just replacing the iron wasn't convincing enough for MM.
If the stock transformers are of poor quality and shrill sounding, modding isn't going to make that better. A pretty bottle does not improve a bad vintage.Masco wrote:[Kind of makes me wonder what a modified one would sound like without the MM iron.
yes, the original when pushed reminds me of a diode clipper distortion pedal.rock_mumbles wrote:The stock circuit is fine clean at low volumes but pushed into distortion it's horrible with the DC biased second preamp triode, fizzy, fuzzy horrid ...Masco wrote:...
Wow! I guess just replacing the iron wasn't convincing enough for MM.
The tone control stock is basically a Marshall 18Watt Tremolo tone control with a wrong value of treble cap it should have a 500pf treble cap not 220pf, the 18W control works pretty well.headstack wrote:...
the Merc Mag "Upgrade" removes nearly all the original components, and builds a very different circuit.
...
When I was stripping the board, it had me thinking "Why not keep this stock and just build a new turret board to load in here?"
Overall it sounds way better!
Loads of headroom, good chime, nice harmonic content, but the tone stack is basically kaput atm.
The modified control is a treble cut control sort of like the control in a Spitfire ... although I don't understand where the added resistor goes ???
Evidently, a pretty bottle was needed AFTER changing the iron.Colossal wrote:If the stock transformers are of poor quality and shrill sounding, modding isn't going to make that better. A pretty bottle does not improve a bad vintage.Masco wrote:[Kind of makes me wonder what a modified one would sound like without the MM iron.
I would love to try this, but the inner holes for for C4 and R1 now lead to a trace that is not in the circuit.rock_mumbles wrote:The simple circuit mods I did on my brother's AC4TV made it a much better amp ...
It's interesting that there is a lot of similarity to what I ended up with, from trying to do the bare minimum mods and what Mercury does ... except I modded the tone control to be a LiteIIb tone control.
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I'm still having a bit of a hard time making sense of the Mercury tone control ???
As a tone control option: make it into a LiteIIb control.
Put a 4.7nf (or 10nf) cap in C3, use a 500pf cap for C4, and jumper R1 . Then you will have some control of both lows and highs.
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