Suggestions for 1960 Mercury mods

[journeyman]

I got a 1960 M-12 Mercury and put a nice Weber alnico speaker in it; got it all ship shape and it works great. But...it has too much midrange for my tastes. My reverberocket also has lots of mids, but not like this; I'm very happy with that amp as an alternative to my Fenders.

I'm thinking of having this M-12 Mercury scooped out a bit; not to try and make it into a Fender blackface, but I'd like it to sound different, definately with less upper midrange. It would be nice if it would break up a bit earlier as well. Any suggestions for mods would be welcomed.

[Hangman]

I got a 1960 M-12 Mercury and put a nice Weber alnico speaker in it; got it all ship shape and it works great. But...it has too much midrange for my tastes. My reverberocket also has lots of mids, but not like this; I'm very happy with that amp as an alternative to my Fenders.

I'm thinking of having this M-12 Mercury scooped out a bit; not to try and make it into a Fender blackface, but I'd like it to sound different, definately with less upper midrange. It would be nice if it would break up a bit earlier as well. Any suggestions for mods would be welcomed.

Regarding the general frequency response/Tone, I think the biggest change you can make to the tone/response of an amplifier is the Speaker. Have you tried it with other speakers? It may be that the Weber doesn't suit you like you hoped it might?

I tend to believe that these old amplifiers shouldn't be forced to be what you want them to be, you should just get the amp that you want, or build it.

There are dozens and dozens of small vintage amps like this one that might suit you better, why modify a piece of vintage gear when you could sell it and buy something you actually like? There is nothing inherently wrong with the circuit, its not like the amp is unstable, or noisy. you just don't like the way it sounds.

[journeyman]

I got a 1960 M-12 Mercury and put a nice Weber alnico speaker in it; got it all ship shape and it works great. But...it has too much midrange for my tastes. My reverberocket also has lots of mids, but not like this; I'm very happy with that amp as an alternative to my Fenders.

I'm thinking of having this M-12 Mercury scooped out a bit; not to try and make it into a Fender blackface, but I'd like it to sound different, definately with less upper midrange. It would be nice if it would break up a bit earlier as well. Any suggestions for mods would be welcomed.

Regarding the general frequency response/Tone, I think the biggest change you can make to the tone/response of an amplifier is the Speaker. Have you tried it with other speakers? It may be that the Weber doesn't suit you like you hoped it might?

I tend to believe that these old amplifiers shouldn't be forced to be what you want them to be, you should just get the amp that you want, or build it.

There are dozens and dozens of small vintage amps like this one that might suit you better, why modify a piece of vintage gear when you could sell it and buy something you actually like? There is nothing inherently wrong with the circuit, its not like the amp is unstable, or noisy. you just don't like the way it sounds.

I hear what you are saying, but any mods that I do to any of my amps are reversable. I always save the original parts and keep a record of what was done. It helps that I have a great amp tech. Sometimes a change of one resistor or cap value can make all the difference.

[Hangman]

Understood on the modifications, I have modified plenty of vintage amps myself in the same way. (always reversible)

I've posted an M12 schematic in the DOCs page. regarding more gain, you could adjust the gain of the paraphase phase inverter. assuming the supply would allow for it. You might take measurements of the supply voltage there, do some calculations and find out.

regarding tone shaping, I would mess with the values of the tone stack C6 and C3. Currently they should be .002uf and .01uf first try dropping c6 to .001uf and see if that solves it.

if that didn't quite do it you could try more values that you would find in a fender. c6=500pf C3 = .005uf

[Hangman]

Journeyman, did you end up doing any mods to your mercury?

I would be interested to hear what you did.

[journeyman]

Journeyman, did you end up doing any mods to your mercury?

I would be interested to hear what you did.

Haven't had the time yet, but later this summer I'll get to it. I did use my Reverberocket on a gig and it worked great. I'm so used to the sound of Fender amps that the midrange of the Ampegs really throws me. I'm not touching that RR though; very cool amp. I'll post when I've done the mods on the Mercury.

[journeyman]

Well, it's been a while, but I did make a small change in the Mercury. Being so used to the Fender scooped tones, the Ampeg M-12 with its midrange bump has been a slowly aquired taste for me; I found that it was really something I was always trying to dial out. I took it to my amp tech and we tried changing out different component values but that didn't do it for me. I left it with him and after looking over the schematics again, he decided to remove the bright cap. The amp still sounds like an M-12, still has lots of mid range, but the harshness of it is gone. Now I'm kind of embracing the sound; still a challenge, but there is something about it that I really like. I'm using this amp for quiet jazz gigs so have no reference with the amp turned up loud. It was a very simple 'mod' if it can even be called that, but I really feel that it sounds better. The Weber Alnico speaker is a nice addition as well. I'll get a sound clip or a video up in a week or so and post the link.