gibson medalist 4/10

[ianmarks]

anyone have a schematic, mods, suggestions, advice.....etc......

picked one up at a yard sale for 50 bucks but its missing tubes and needs some work.

this is a double post but I think it might get more attention here.....


thanks and take care,
Ian

[TD_Madden]

maybe this is it?

You didn't give a model number, so I'm just guessing....there's a Mercruy Medalist.

http://www.schematicheaven.com/gibso...L6_mercury.pdf

[ianmarks]

Thanks TD, but that's not the right schematic. Medalist 4/10 is the model. This one had six tubes in the preamp section and two el34s and another tube in the power section. It has a chassis for each section....dates june 6 1969

[TD_Madden]

One of the Medalist 4/10 entries on Harmony Central mentioned that Gibson offered him the schematic.....have yout tried them?

[ianmarks]

gonna call them first thing in the morning....thanks!

[Resonator Guy]

Hey it is an old thread, but I have just been reading through some on a drowsy summer day. If you never got your schematic, here you go.

[ianmarks]

Thanks a lot. Looks better than the version I had. I am still messign with that dreadful beast. Got it up and runnng but it's got a bit of hum.

[Resonator Guy]

Those came out of one I used to own. I never could get it sounding very good so I sold it many years ago. I took those out to work on it and forgot to put them back. hope they help.

[Gtr_tech]

I had one through here some years ago. I didn't care for it. The 12az7 PI sounded like shit. The owner didn't want it changed so it was left as is. Theres lots of tone shaping between preamp stages that can be altered/removed to get a more traditional tube amp tone. Gibbo amps in general miss the mark. Some of the earlier ones were better tho.

[Enzo]

Youo know, I often feel that way about Gibson amps, and the Epis. I find myself thinking "who would WANT to make an amp that sounded like this?"

[ianmarks]

So yeah, it's been awhile, but I am back working on this beast. I believe my reverb transformer bit the dust. I get sound when I rattle the tank, but that's it. The two tabs that are on the transformer itself, should they be tied together and go directly to the reverb pan input? I see no grounding on the schem (see above) until the output of the pan. Is there anyway to tell using a multimeter to see if the transformer is working? I have read a bit and it seems if this is the case, I should probably go with a fender replacement driver and tank. Could you all recccommend a model # for the driver and pan?

Thanks!!

[ianmarks]

Well, I got it sorted out. Reverb has returned! My RCA wasn't connected properly coming off the transformer.

I still have hum, enough to make me want to tinker more with it. All the can caps were replaced. I am thinking about replacing the "chocolate" caps. When I lift channel two out, via cutting r56 the hum becomes much more bearable. Too bad channel two is where the goodies are. I ran across the premier guitar article on cutting out the junk in the duo medalist and will be implementing on channel one. Looks like I will lose the mid control in the process. May look at a way of changing the tone stack up a bit.

Any other mod recommendations are welcomed!

[riz]

If you post a picture of the guts, you might get more help on hum-chasing ideas. I have never worked on a Gibson amp, so I can't really make solid recommendations offhand, but it likely could be wiring/layout issues. Maybe have a look at the heater supply? Search the forum for "hum" and hip yourself to the various issues your amp could be having.

[Jazz P Bass]

You have stated that all of the cap cans where replaced.
I would still check the assorted voltage junctions for undue Vac ripple.
I have had new cap cans where one or more of the capacitors where not up to snuff.

[ianmarks]

Here are the guts.

If I don't get hum when disconnecting channel 2, wouldn't that mean that the problem with the hum would be limited to that section? I would assume that the power amp would be fine as channel 1 runs through with no hum.

I am going to check voltages at all the key pints and see if anything is off.