Which is Reverb In / Out on Mark IV?

[Russ]

I just got my Mark IV head put back together after installing my reverb tank. What a chore. I had to take the sucker completely apart. Anyhow here is the problem I am faced with.

Being that the amp didn't have a tank in it when I got it, which is send and which is return?.

The tank is clearly labeled send and return but the chassis says nothing. I want to be sure I have this thing in the right way. It is a brand new tank and would hate to mess it up or worse my head.

I am not sure you will need this info but:

1990 Mark IVa

Both jacks are green on head.

They are situated one closer to the front of the amp and one closer to the rear. Both sit next to the tranny.

 

[t0aj15]

The wire that goes to the INPUT of the reverb tank comes from the jack closest to the transformer.

 

[shack]

Man, I'd just call Mesa Tech support to be safe. 5 minute call, no chance for error.

 

[Russ]

Shack you're right. It was just too late last night to call them. I'l call them in a few minutes.

 

[chedgeco]

Russ,

They are not there on Friday's, Monday through Thursday's only. This lets the boys and girls to take their Boogies out to the local North Bay area clubs and pubs and turn them up loud...

Chris... 8)

 

[Boogiebabies]

http://mesaboogie.com/manuals/Mark%204.pdf


Page 21.

 

[t0aj15]

As I said, the send (input on the tank) wire is the one closest to the transformer.

 

[Russ]

I ended up calling Mesa Hollywood and they were able to help me out. I was not doubting you toaj, I was just a little scared to burn anything up if I got it in incorrectly. I forgot it was Friday and wasn't able to get a hold of Petaluma. Chedgeco, you are right they are closed today. I already knew that but like I said I forgot what day it was. Boogiebabies, thank you for posting the link to the manual. I already had it but what I didn't have was the original RCA cables. That and I had just gotten done installing the new tank with the replacement non-Mesa branded cable(Generic Stereo type). There is no color coding on the tank. It is just labeled Input and Output. It would have helped if they were color coded. The chassis doesn't say input or output. They aren't even color coded other than both are a common green color. This is why I needed help.

After installing the reverb cable to the chassis, I found that the reverb isn't really very strong. I am wondering if a change to 12ax7 might be in order as the EH12ax7 that I have in there tests pretty strong (almost new). Has anyone with a version a head tried this? The version b head has all 12ax7s. The version a head was designed with a 12at7 that is supposed to be there in V4.

I think I asked this before but I don't remember getting a big response...

 

[t0aj15]

I didn't have the original RCA cables. That and I had just gotten done installing the new tank with the replacement non-Mesa branded cable(Generic Stereo type). There is no color coding on the tank. It is just labeled Input and Output. It would have helped if they were color coded. The chassis doesn't say input or output. They aren't even color coded other than both are a common green color. This is why I needed help.
After installing the reverb cable to the chassis, I found that the reverb isn't really very strong. I am wondering if a change to 12ax7 might be in order as the EH12ax7 that I have in there tests pretty strong (almost new). Has anyone with a version a head tried this? The version b head has all 12ax7s. The version a head was designed with a 12at7 that is supposed to be there in V4.

I assumed from your original post that you didn't have the original reverb cables, that's why I explained it the way I did.
As for the weak reverb, I'm not a tech but perhaps you just need a different model reverb tank.

 

[Boogiebabies]

I will take a loo at my MK IV and see where the reverb cables go from the chassis to the tank. The MK IV B needs a 12AX7 in the V3 and V4 because they each share a triode with the Lead channel and Reverb.

 

[t0aj15]

I will take a loo at my MK IV and see where the reverb cables go from the chassis to the tank.

That's what I did before I posted.

 

[Russ]

I just snagged a newer Mark IV case on ebay that includes the reverb tank. I plan on swapping the cases and tanks to see if it helps. If the reverb doesn't improve I will just assume that the reverb is just on the mellow side for this amp. I would still like to see whether or not a 12ax7 would make any difference.