Help - Installing Reverb Tank w/ IIC+ Head

[Persepolis]

Hi,

I got around to installing a reverb tank with my DRG IIC+ today and am having some problems. Specifically, the reverb is pretty faint and once it gets turned to about 8 or 10 a weird oscillation and distortion starts. Also, if I turn the guitar volume up I get some very weird noises (like a loud overwhelming hum).

Any help would be appreciated - even on something so simple as to actually install the tank (for instance the washers aren't really making sense to me). Thanks!

 

[lovetoboogie]

Hi...

Couple of things first...Is this a head or combo? what tank did you get? Are the cables in the right orientation? The reverb return cable should be shielded, coming from the output of the tank to the RCA jack closest to the front of the amp...

Let's take it from there and see if we can get rid of the issue...

 

[Persepolis]

Hi...

Couple of things first...Is this a head or combo? what tank did you get? Are the cables in the right orientation? The reverb return cable should be shielded, coming from the output of the tank to the RCA jack closest to the front of the amp...

Let's take it from there and see if we can get rid of the issue...

Hey,

Thanks so much for your reply. It's now a head, formerly a combo. I got all items from Mesa directly (the tank, cover, cables, etc.) - so I would be surprised if they sent the wrong items (however, I did notice the tank is a Ruby tubes tank). I wasn't able to find any diagrams on how to install correctly, so I went all options of cable connections until I got some reverb.

When I purchased the amp I left the combo shell and tank with the original owner; but I do believe the reverb was working correctly then.

Thanks again.

 

[lovetoboogie]

Okay...so first thing. When Mesa or an aftermarket company ships a new tank there is often a piece of foam insulation in the tank under the springs to protect them during shipping. It would be prudent to inspect the tank and the springs carefully to make sure the foam is removed and that there are no pieces loitering in the Springs. Make sure they are clear and clean.

Next...the orientation of the new tank is important because it is now a head. The reverb output, the one with the shieded cable needs to be away from the power transformer. On combos this is usually a non-issue but on heads this is critical. Especially if your head shell does not have the reverb tank cutout as factory heads do. If you don't have a tank cutout then the tank should go open side down, RCA Jacks on the tank facing forward(toward the control panel)..make sense? If per chance you have a head cab with the cutout for a tank then the tank will sit open side up, RCA Jacks facing backwards(towards you looking from the back of the amp). If you have the tank facing up in the cutout you need to have an aluminum or steel shield covering the tank opening...

Sorry for being long winded, but that first bit is crucial for getting the noise/hum floor down and then deal with the actual reverb circuit next....

 

[Persepolis]

Okay...so first thing. When Mesa or an aftermarket company ships a new tank there is often a piece of foam insulation in the tank under the springs to protect them during shipping. It would be prudent to inspect the tank and the springs carefully to make sure the foam is removed and that there are no pieces loitering in the Springs. Make sure they are clear and clean.

Next...the orientation of the new tank is important because it is now a head. The reverb output, the one with the shieded cable needs to be away from the power transformer. On combos this is usually a non-issue but on heads this is critical. Especially if your head shell does not have the reverb tank cutout as factory heads do. If you don't have a tank cutout then the tank should go open side down, RCA Jacks on the tank facing forward(toward the control panel)..make sense? If per chance you have a head cab with the cutout for a tank then the tank will sit open side up, RCA Jacks facing backwards(towards you looking from the back of the amp). If you have the tank facing up in the cutout you need to have an aluminum or steel shield covering the tank opening...

Sorry for being long winded, but that first bit is crucial for getting the noise/hum floor down and then deal with the actual reverb circuit next....

Not at all long-winded; I greatly appreciate the in-depth help.

I bought the cab from Mesa, so it does have the bottom cutout. I oriented the tank as you suggested (after the removing the foam inserts). Tried the all orientations of the cables and I believe only one worked. However, it works in the sense of subtle reverb from 0-8, then anything beyond 8 introduces distortion and ghost notes (almost like a delay or harmonizer). Additionally, if you increase the master volume, you start getting a pronounced - and overpowering hum. I've since removed the tank and cables and the amp is back to normal functionally.

 

[lovetoboogie]

okay...so with the tank face up in the cutout, do you have an aluminum or steel shield covering the tank opening? the hum is coming from one of several places...so we'll work backwards from the tank since that is the new factor...the interference from the proximity of the open side of the tank to the transformers and power tubes is going to cause problems...hum for one, but it will also dead and/or inhibit your reverb output as well...

after this we'll move on to the under chassis RCA jacks. usually very poor grounds there...

 

[Persepolis]

okay...so with the tank face up in the cutout, do you have an aluminum or steel shield covering the tank opening? the hum is coming from one of several places...so we'll work backwards from the tank since that is the new factor...the interference from the proximity of the open side of the tank to the transformers and power tubes is going to cause problems...hum for one, but it will also dead and/or inhibit your reverb output as well...

after this we'll move on to the under chassis RCA jacks. usually very poor grounds there...

Yes, had the shield installed - but frankly, the washer layout and (gold inserts) didn't make sense in terms of how to install. Perhaps that's a cause as well.

 

[lovetoboogie]

here's a rough orientation of the tank placement direction and correct cable location...





and here is a rough cut of aluminum showing how the shield should ride on top of the gromet...

 

[lovetoboogie]

the shield rides on top of the rubber gromets...if you have eight(8) washers, then a washer underneath and above the shield, if you only have four(4) washers, then the washers on top of the shield...the shield is floating, technically, and should not make contact with the tank...

 

[Persepolis]

the shield rides on top of the rubber gromets...if you have eight(8) washers, then a washer underneath and above the shield, if you only have four(4) washers, then the washers on top of the shield...the shield is floating, technically, and should not make contact with the tank...

That's very helpful. I moved the washer so that they would line up with the cabinet's mounting screws - so as to screw in (i.e. 2 on one side are wider than 2 on the other). It appears that's incorrect from your picture. Also, where do the gold grommets go? Presume into the wood itself?

Thanks again for all of this help!

 

[lovetoboogie]

the shield rides on top of the rubber gromets...if you have eight(8) washers, then a washer underneath and above the shield, if you only have four(4) washers, then the washers on top of the shield...the shield is floating, technically, and should not make contact with the tank...

That's very helpful. I moved the washer so that they would line up with the cabinet's mounting screws - so as to screw in (i.e. 2 on one side are wider than 2 on the other). It appears that's incorrect from your picture. Also, where do the gold grommets go? Presume into the wood itself?

Thanks again for all of this help!

the gromets on your tank should go where the holes in the cab are. disregard gromet location in the above tank. i just grabbed that one for reference. please see the picture i added to show how the aluminum should float above the tank. four screws, four gromets, four washers....should do the trick. the gold inserts are a newer thing that slide through the hole of the rubber gromets to help keep them from deteriorating prematurely.

additionally, the screws should be machine thread and match up with t-nuts that are on the underside of the cab...do you have those?

no problem with the help. I happen to be doing a reverb mod on a 79' Mark IIA tonight...so i am in the reverb frame of mind

 

[Persepolis]

the shield rides on top of the rubber gromets...if you have eight(8) washers, then a washer underneath and above the shield, if you only have four(4) washers, then the washers on top of the shield...the shield is floating, technically, and should not make contact with the tank...

That's very helpful. I moved the washer so that they would line up with the cabinet's mounting screws - so as to screw in (i.e. 2 on one side are wider than 2 on the other). It appears that's incorrect from your picture. Also, where do the gold grommets go? Presume into the wood itself?

Thanks again for all of this help!

the gromets on your tank should go where the holes in the cab are. disregard gromet location in the above tank. i just grabbed that one for reference. please see the picture i added to show how the aluminum should float above the tank. four screws, four gromets, four washers....should do the trick. the gold inserts are a newer thing that slide through the hole of the rubber gromets to help keep them from deteriorating prematurely.

Ok, so this is likely where some of my confusion stems from.

The cutout at the bottom of my amp is roughly like the following (could be inversed since going off of recollection):

.................... X...............X
X ................................................. X

Whereas the tank-cutouts, like the one you pictured, allows only for the following orientation:
X.................X

X.................X

Unfortunately, the grommets don't fit correctly for proper alignment.

 

[lovetoboogie]

okay...so the holes are offset. and the actual holes on the tank are not all big enough to fit a gromet into? correct? not a problem...that's an issue with the Ruby tanks...they don't have the offset holes to match the mark series t-nut location...or they are not big enough to accept a gromet....there's a work around


here's a mark I with the offset holes. the t-nuts are kind of dark but you can make it out. in this case the screw, washer and gromet all go into a hole on the tank base that lines up perfectly. it's an older accutronics tank so they are flexible with the holes pre-drilled...

you can put the gromets in the four corner holes...but then when you go to screw the tank in it will compress the shield down and make contact with the tank. i would drill new holes in the tank to line up with the t-nuts...is this confusing? could you post a picture of the tank you have? that might be helpful....

 

[Persepolis]

okay...so the holes are offset. and the actual holes on the tank are not all big enough to fit a gromet into? correct? not a problem...that's an issue with the Ruby tanks...they don't have the offset holes to match the mark series t-nut location...or they are not big enough to accept a gromet....there's a work around


here's a mark I with the offset holes. the t-nuts are kind of dark but you can make it out. in this case the screw, washer and gromet all go into a hole on the tank base that lines up perfectly. it's an older accutronics tank so they are flexible with the holes pre-drilled...

you can put the gromets in the four corner holes...but then when you go to screw the tank in it will compress the shield down and make contact with the tank. i would drill new holes in the tank to line up with the t-nuts...is this confusing? could you post a picture of the tank you have? that might be helpful....

You're 100% spot on. Thinking I should just track down the correct Accutronics unit and perhaps return this to Mesa (the cables are also MUCH shorter than pictured).

Again, I really appreciate all of your help on this!

 

[lovetoboogie]

okay...so the holes are offset. and the actual holes on the tank are not all big enough to fit a gromet into? correct? not a problem...that's an issue with the Ruby tanks...they don't have the offset holes to match the mark series t-nut location...or they are not big enough to accept a gromet....there's a work around


here's a mark I with the offset holes. the t-nuts are kind of dark but you can make it out. in this case the screw, washer and gromet all go into a hole on the tank base that lines up perfectly. it's an older accutronics tank so they are flexible with the holes pre-drilled...

you can put the gromets in the four corner holes...but then when you go to screw the tank in it will compress the shield down and make contact with the tank. i would drill new holes in the tank to line up with the t-nuts...is this confusing? could you post a picture of the tank you have? that might be helpful....

You're 100% spot on. Thinking I should just track down the correct Accutronics unit and perhaps return this to Mesa (the cables are also MUCH shorter than pictured).

Again, I really appreciate all of your help on this!

Not a problem...we can pick up whenever you like. You can get a perfect replacement from Amplified Parts. They use MOD tanks and I believe the holes all line up. For reference when ordering your tank # should be: 9AB2A1B

 

[Persepolis]

okay...so the holes are offset. and the actual holes on the tank are not all big enough to fit a gromet into? correct? not a problem...that's an issue with the Ruby tanks...they don't have the offset holes to match the mark series t-nut location...or they are not big enough to accept a gromet....there's a work around


here's a mark I with the offset holes. the t-nuts are kind of dark but you can make it out. in this case the screw, washer and gromet all go into a hole on the tank base that lines up perfectly. it's an older accutronics tank so they are flexible with the holes pre-drilled...

you can put the gromets in the four corner holes...but then when you go to screw the tank in it will compress the shield down and make contact with the tank. i would drill new holes in the tank to line up with the t-nuts...is this confusing? could you post a picture of the tank you have? that might be helpful....

You're 100% spot on. Thinking I should just track down the correct Accutronics unit and perhaps return this to Mesa (the cables are also MUCH shorter than pictured).

Again, I really appreciate all of your help on this!

Not a problem...we can pick up whenever you like. You can get a perfect replacement from Amplified Parts. They use MOD tanks and I believe the holes all line up. For reference when ordering your tank # should be: 9AB2A1B

Thank you again, you really went above and beyond to help.

So additional question if I can trouble further, is this ultimately and ill advised effort - am I better just running my Intellifex in the loop?

 

[Persepolis]

In addition to the great help here, I contacted Mesa and Gary was very helpful. It's just really cool that - in this day and age - outstanding customer service still exists.

My many thanks to all.

 

[gts]

the shield rides on top of the rubber gromets...if you have eight(8) washers, then a washer underneath and above the shield, if you only have four(4) washers, then the washers on top of the shield...the shield is floating, technically, and should not make contact with the tank...

Nice try but not quite right......

Remove the grommet/ washers from the tank.
Literally squeeze/ push them through the holes in the tank they are sitting in.

These washers will go underneath the tank (between the tank and the cab).
The metal cover/shield sits on top of the tank in full contact. (no air space between like if you leave the grommet/ washers in the tank).

The Screws that hold the tank in the head cab go through the cover, tank, grommet/ washer and into the t-nuts.