1963 Gibson Mercury II

I got this amp at an auction about 30yrs ago.
Apparently there were only about 145 of these amps made.
Nice rare piece of history here.








1963 Gibson Mercury II. 2 channel tube amp runs about 35 watts. The speaker cabinet has one 10" and one 15" speaker. Tone stacks and tremolo, no reverb. The speaker box weighs a ton! It has a tilt-back leg built into the back. The speaker box and amplifier box are trapezoid shaped. Originally there were hooks to clamp the head onto the speaker box so you could tip it back with the head in place. the hooks were missing when I got it. There were also wheels on the bottom, which I also do not have. Other than that it is in superb condition, minimal wear to the tolex, grill cloth is in great shape, small amount of surface rust on the faceplate. There is a plastic logo plate that goes in the upper left corner of the speaker cabinet which I removed and stashed away a few years ago so it would not get broken. It has the original foot switch(for the tremolo) which uses an RCA jack instead of the now standard 1/4" jack. Very cool knobs too!

At this time I think it needs to have the filter caps replaced because it hums like mad when turned on, it worked great when I got it.
Nice warm tone, clean, full bodied sound and quite loud. Not much grunge to it, I feel like it was made for hollow body or semi-hollow body guitars. Good clean jazzy tones.

Very kewl amp Mike. When was it made? Duh! Read the title dummy.


Dig those knobs!

That is the goods, eh!!

Interesting that there is a 10" and a 15" in the cab. I don't think I've come across that configuration before.

Are these wired for frequency crossover perhaps?

Barry wrote:Interesting that there is a 10" and a 15" in the cab. I don't think I've come across that configuration before.

Are these wired for frequency crossover perhaps?

I don't know actually. It has been a long time since I had the back of the cabinet open. I'll have to open it up and have a look. The jack needs some fixing so maybe I'll do that and have a poke around inside to see what is the deal. I'll let you know what I find...

Barry wrote:Interesting that there is a 10" and a 15" in the cab. I don't think I've come across that configuration before.

Are these wired for frequency crossover perhaps?

i had a chance to open up the speaker cabinet recently and as it turns out, you are right, there is a crossover in there

two capacitors and two inductors
the unit is screwed and glued in place so I had to stick my phone inside to get a good look at the markings on the inductors

an elementary circuit, but not being a specialist, I can't really tell you what the frequency rollover is
It also appears that a previous owner may have swapped out the speakers, but apparently did not own or did not know how to use a soldering iron  

it looks like the change was made very early on because the code numbers on the existing speakers seem to indicate 1967

even the input jack was tampered with for some reason?

the hole where the jack is supposed to mount is damaged and will not support the jack any more so there will need to be some repair made in order to mount the jack in a way it can be used. i will probably get a piece of sheet metal to mount the jack and screw that to the inside of the existing hole. i will go through each of the connections and solder them properly and cover with some shrink tubing.

i found this schematic on the web that appears to be the setup in this speaker cabinet, (again, I don't know what the crossover frequency is, so the indication of 3kHz in the drawing may not be relevant to my speaker)
=========================================================================

>> link <<

Unlike electronic crossovers, normally they’re connected to the outputs of an amplifier and then to the speakers you’d like to use.

One of the most common speaker crossover types in use today: A 2nd-order 2-way speaker crossover with tweeter and midrange/woofer outputs. Inductors are represented with an “L” symbol and capacitors with a “C” symbol. A “2nd order” crossover just means that the second stage of parts is used to make the crossover filter out the unwanted frequencies even more effectively.
Capacitors and inductors have some interesting properties depending upon the frequency of a signal applied to them:

• Capacitors have more “resistance” (called impedance, in this case) to a low-frequency signal than a higher one. The lower the frequency, the less signal that is allowed to pass.
  
• Inductors are coils of wire that have more resistance to a high-frequency signal than a lower one. Therefore they filter out higher sound frequencies.
  

This works because when a capacitor or inductor has a signal applied to it that’s past the crossover frequency (depending on how it’s used), the resistance increases, which reduces the speaker voltage.

This means the speaker will receive less and less of the speaker signal that we want to block.
In all cases, the part value is chosen according to the speaker “Ohms” (impedance rating) it’s planned to be used with. That’s super important!
=============================================================================

at some point I will open up the amp and check out what it looks like in there. eventually I will look for an amp repair tech here in San Francisco to replace the filter caps and give the thing a look-over to see what else might need fixing.

for now it just sits in the fireplace opening and looks cool.

That's some pretty ordinary wiring together of components, eh! 
Interesting about the speaker swap; makes you wonder what was there ex-factory??

Thanks for the quick and dirty on crossovers - I was never exactly sure what they did, or what they were made up of, electronically.

Great pix Mike.

I reckon the second speaker was originally a tweeter located in the upper left corner where that plywood patch is. Very likely a horn type. That would make more sense.

I guess the guy who did the swap thought he'd get more volume by putting in a bigger speaker! Judging by the quality of his wiring that would seem to fit his electronic knowledge level.

Mike, why on earth would Gibson have built such a heavy thing as an amp with the ability to tilt back & potentially tip over?

Not unusual to see amps with "kick stands". Fender had them as well.

In my case, tilting the speaker upwards improved the dispersion of sound and avoided its being smothered by the drums and bass.

I always had my Roland Cube amp on a stand about 60cm off the ground and tilted back about 20-25 degrees. (Had to do something to compete with my Fender band mates!)

Westone wrote:Mike, why on earth would Gibson have built such a heavy thing as an amp with the ability to tilt back & potentially tip over?

i don't see much chance that this amp would tip over without something bashing it over, something which would probably knock it over even if sitting upright.

i think you have to consider when this amp was made. in 1963 the reality of live performance was that there was no such thing as stage monitors for the players, the tilt back feature was to help the player hear himself in the midst of a band full of brass instruments.

my 63 . I had it for 20 years . No idea what the value is

 by loonkiller Sat Nov 06, 2021 6:46 pm



these amps are not sought after the way others are. your bassman would easily sell for much more. old Gibson amps have a very limited appeal to collectors. they did make some really great ones but this model is mostly unknown.

i really love the unique knobs and the trapezoid shape of the cabinet. very much of its time period, even the name of the amp is indicative of its place in time.

do you have only the head or do you have the speaker box as well? is it functional?

I do not have the bottom  speaker cab for the Mercury.   It is very clean sounding amp . It can easy be turned up to 10 with little distortion or dirt as one would want for blues or rock. I used it in Jazz swing band because it fit the vibe. 

It even has the termolo on/off foot button.

Does anyone know what the original purchase price would have been back in 1963 ? 

I am sure it cost a lot . Gibson products were always expense . They were not your Sears / Mont Wards prices .

I paid $389 US for my Bandmaster in '63.  Ginsberg's in Roswell didn't have any Gibson amps in stock at the time and my band (D'Fenders ) had elected to use only Fender goodies.  I do remember that the prices were fairly close for comparable amps.

$390 in 1963 would be  $1500 today