MK 3 reverb tank

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Cubanjoe
Bottle Rocket
Posts: 3
Joined: Fri May 06, 2016 11:50 am

MK 3 reverb tank

Post by Cubanjoe » Tue Jan 22, 2019 10:53 am

The reverb on my MK III Red stripe combo needs to be on 10 or you can’t tell that it’s on. I’ve had the amp from new, and I suspect that it has degraded over the years. I have a spare tank from a Mk v. Can anyone tell me if they are compatible?

Cheers
Vince

woodbutcher65
Mark III
Posts: 180
Joined: Fri May 04, 2018 10:36 pm

Re: MK 3 reverb tank

Post by woodbutcher65 » Tue Jan 22, 2019 10:01 pm

Don't assume it's the tank that's the problem. It's far more likely to be a tube problem. And has the amp ever been serviced and recapped? Any Mark III should definitely have had that done by now, and I say it should have been done twice by now. It's amazing how much better the amp works when it has fresh strong glass and good capacitors that work like new.

lovetoboogie
Mark II
Posts: 119
Joined: Tue Mar 25, 2014 10:14 pm
Location: New York City

Re: MK 3 reverb tank

Post by lovetoboogie » Tue Jan 22, 2019 10:25 pm

Mark IV tank is compatable...

Little known or discussed fact about the Mark III...need more verb'? Use the footswitch... Has to be a TRS(stereo cable) with a 2-button footswitch(for models with EQ & Reverb). Reverb/EQ jack is on the underside of chassis(looking from back it is the one closest to the power tubes). Other jack is R2 on/off.

The Mark III reverb circuit is almost non-existent without the footswitch...


"....The Mark III's reverb is by far the best we've ever had; its performance is hard to equal even with
expensive outboard effects. And the Reverb Footswitch also works uniquely: rather than merely switching the Reverb on and off, it
allows you to maintain a good background level then footswitch up to a dramatic, fully drenched reverb for a special effect"

jrb32
Mark III
Posts: 193
Joined: Wed Jan 31, 2018 8:32 am

Re: MK 3 reverb tank

Post by jrb32 » Thu Jan 24, 2019 10:52 am

After you've swapped the preamp tubes over (V4 does Reverb) to rule out a bad tube, you can try taking the reverb tank apart after you take it out of the amp to check if it's corroded or there's any gunk inside.

Won't be caused by old filter caps but good to replace these if they've never been done.

Another thing is the reverb is pretty weak anyway on the III once you've gone back from another amp with strong reverb, but I'm guessing it was never like this before?

Supposedly a Mk V tank should work though to save you taking the old tank apart to diagnose? Worth double checking with Boogie first though.

https://store.mesaboogie.com/products/r ... cuits.html

Let us know how you get on!

Cheers,

Jon

Cubanjoe
Bottle Rocket
Posts: 3
Joined: Fri May 06, 2016 11:50 am

Re: MK 3 reverb tank

Post by Cubanjoe » Fri Jan 25, 2019 2:56 pm

jrb32 wrote:After you've swapped the preamp tubes over (V4 does Reverb) to rule out a bad tube, you can try taking the reverb tank apart after you take it out of the amp to check if it's corroded or there's any gunk inside.

Won't be caused by old filter caps but good to replace these if they've never been done.

Another thing is the reverb is pretty weak anyway on the III once you've gone back from another amp with strong reverb, but I'm guessing it was never like this before?
EV bee
Supposedly a Mk V tank should work though to save you taking the old tank apart to diagnose? Worth double checking with Boogie first though.

https://store.mesaboogie.com/products/r ... cuits.html

Let us know how you get on!

Cheers,

Jon
The amp did have a Cap replaced a few years ago, over the years it’s had several sets of valves. The reverb has always been not very intense. It is a nice gentle reverb. I have been thinking about getting it re capped. I wasn’t aware that the footswitch made a difference to the sensitivity.

Cheers guys.
Vince

Promethean
Mark II
Posts: 82
Joined: Wed Nov 13, 2013 7:53 am

Re: MK 3 reverb tank

Post by Promethean » Sat Jan 26, 2019 2:39 am

The default reverb level in a MKiii is very low.

Def. try using the foot switch.

I also did the reverb level mod (super simple) that increases the relative volume of the reverb sound. I can go all Dick Dale now.

There is a black wire that comes from the PCB that terminates on one of the fx loop socket tabs. Drop a resistor (10-15k I think) in line and you will have loads more reverb.

If I was doing it again I may use a 50k trimmer to fine tune it.

woodbutcher65
Mark III
Posts: 180
Joined: Fri May 04, 2018 10:36 pm

Re: MK 3 reverb tank

Post by woodbutcher65 » Sat Jan 26, 2019 10:35 am

I had to go out and buy a stereo cable for my rev/eq footswitch for my MK III.

Yes, it's true! I now have SURF REVERB. PLENTY.

jrb32
Mark III
Posts: 193
Joined: Wed Jan 31, 2018 8:32 am

Re: MK 3 reverb tank

Post by jrb32 » Fri Feb 01, 2019 6:42 am

You can also try moving the 220K resistor in the reverb circuit so instead of going to ground it goes around the 1.5M resistor instead. That will increase the reverb a lot! You might need a new 220K resistor though I'm not sure the original 220K will have enough length on its legs to fit around.

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