nashville 112 reverb

rpetersen · Post by **rpetersen** » 21 Jan 2016 1:47 pm

I know this isn't the only amp doing this, getting the hum when set above 3 1/2 - 4. Cleaned plugs on both ends and just got through putting the "Mod" reverb in it - - still sounds the same.
Moved the reverb around to different locations - no change -
Just bought a DD-3 that was still in wrapping with power supply - Now thinking about selling it and just going to an RV-3 as I miss the reverb - Any thoughts??

George Kimery · Post by **George Kimery** » 21 Jan 2016 4:28 pm

The first 112 I had suffered this problem. I called Mike Brown and he said they had a bunch of them escape with the reverb cable wires reversed INSIDE the amp. He said to take it to my local Peavey dealer and they should be able to take care of it. I took it in, they threw it up on the counter and pulled the chassis and reversed the wires inside. Problem solved. If your's is a new amp, I wouldn't think this is the problem, but I am just throwing in my experience with the same problem and what was done to correct it.

rpetersen · Post by **rpetersen** » 21 Jan 2016 5:09 pm

It is a 2007.. I need to check what you are saying yet. ... I'm surprised Mike didn't mention that to me

ajm · Post by **ajm** » 22 Jan 2016 7:04 am

George wrote: "....the reverb cable wires reversed INSIDE the amp."

I don't understand what you mean.

If the cables are reversed to/from the reverb pan, and the pan is mounted in the bottom of the cabinet, couldn't they just be switched without removing the chassis?

However, if by "reversed" you mean that the signal and shield connections are reversed on the cable(s), then that would probably require swapping connections inside the chassis.

George Kimery · Post by **George Kimery** » 22 Jan 2016 7:08 am

AJM, you make a good point that I had never thought about. All I know is what I was told to do and it worked. It didn't take but a couple of seconds for my dealer to reverse whatever was wrong. Perhaps it had to do with the wiring to the knob control and not to the pan itself. All I know is, it worked and that's my story and I'm sticking to it.

Carl Mesrobian · Post by **Carl Mesrobian** » 22 Jan 2016 7:53 am

ajm wrote:George wrote: "....the reverb cable wires reversed INSIDE the amp."

I don't understand what you mean.

If the cables are reversed to/from the reverb pan, and the pan is mounted in the bottom of the cabinet, couldn't they just be switched without removing the chassis?

However, if by "reversed" you mean that the signal and shield connections are reversed on the cable(s), then that would probably require swapping connections inside the chassis.

It seems obvious that the chassis has to be pulled -

Lane Gray · Post by **Lane Gray** » 22 Jan 2016 11:03 am

Given that the two leads are of different lengths, it probably just made sense to someone to reverse at the chassis (swapping leads AND turning the tank around could accomplish the same thing).

rpetersen · Post by **rpetersen** » 22 Jan 2016 11:29 am

Update...
Pretty hard to do without removing the chassis
the leads are quite different in length and after I pulled it what I found was the 2 leads (4 wires)all go into one plug - A Peavey technician told me to just turn the plug around in the opposite way - it can be plugged in either way - I tried that and that didn't work!!
I am trying to get a schematic from Peavey because it might be that the 4 wires going into the plug is where the problem might be if something is plugged in wrong anywhere
I'll keep you posted
thanx for the input guys
If this doesn't work, I'll probably be looking for a RV-3

Lane Gray · Post by **Lane Gray** » 22 Jan 2016 11:43 am

Yes, the leads are different in length, but can't you turn the tank around?

Howard Parker · Post by **Howard Parker** » 22 Jan 2016 12:23 pm

How long have you owned the amp? If the amp had been working correctly and if the problem just recently occurred then the leads are not your problem.

h

rpetersen · Post by **rpetersen** » 22 Jan 2016 1:53 pm

Lane - I'm guessing turning the plug around does the same thing

Howard - I just bought the amp so I don't know for sure If it was doing this earlier, but I think the previous owner used other effects, but it has also been sitting around for a while

ajm · Post by **ajm** » 22 Jan 2016 3:42 pm

Carl wrote: "It seems obvious that the chassis has to be pulled."

With all due respect, no it's not 'obvious", and it wasn't really the question. My question was really pertaining to what is going on electrically.

Since I don't have a Nashville 112 to look at I'll make some assumptions.
1) The reverb tank is in the bottom of the cabinet, probably screwed to the cabinet, and in a bag of some sort.
2) The reverb send/return cables go through a hole in the metal chassis and connect directly to the circuit board. It sounds like this may be done with a connector plug, 4 pin single row.

If true, it sounds like the connections on the plug may be hot-shield-shield-hot. One hot is the send to the tank, the other the return.

Therefore, if the plug is not polarized or keyed, turning it around would indeed accomplish the same thing as swapping the connectors at the tank.

It's possible that it might be easier to pull the chassis and reverse the connector. As some have said, the cables being a different length, along with the tank being in a bag, and screwed down to the cabinet, might end up being harder than just removing the chassis, sliding it out, reversing the connector, and sliding the chassis back in. Maybe that is the reason for the instructions George got from Peavey.

Rpetersen seems to have tried "the fix" and for whatever reason it didn't work. So I guess we're in limbo until we hear more.

Carl Mesrobian · Post by **Carl Mesrobian** » 22 Jan 2016 4:53 pm

"Seems obvious", sir

Carl Mesrobian · Post by **Carl Mesrobian** » 22 Jan 2016 5:00 pm

George Kimery wrote:The first 112 I had suffered this problem. I called Mike Brown and he said they had a bunch of them escape with the reverb cable wires reversed INSIDE the amp. He said to take it to my local Peavey dealer and they should be able to take care of it. I took it in, they threw it up on the counter and pulled the chassis and reversed the wires inside. Problem solved. If your's is a new amp, I wouldn't think this is the problem, but I am just throwing in my experience with the same problem and what was done to correct it.

I'm with George on this one, good luck troubleshooting!

rpetersen · Post by **rpetersen** » 22 Jan 2016 5:12 pm

Nuther Update!!!
Working with a Tech named Grant from Peavey who was as stumped as me - he finally said there is one more thing to try, but doubting if it would work -

I turned the speaker 1/4 revolution clockwise as you look in the back (making longer leads)
No Change

Turned the speaker 1/4 turn counter clockwise
Almost dead quiet!!!! played through it and turned it as high as 7-8 -Just a very little noise
Now I have an extra "Mod" reverb 3 days old if anyone is interested
Hope this might help someone else!!!
Thanx all... Ron

George Kimery · Post by **George Kimery** » 23 Jan 2016 2:29 pm

Ron, I am glad that you got your problem solved. It's a little late to ask this, but you didn't by any chance have the DD-3 hooked into the amps effects loop and have it siting on top of the amp did you? I did this with my RV-3 and got a hum. If I moved it to the end of the amp away from the transformer, the hum was significantly less. I solved the problem by just using longer cords and placing the RV-2 on the floor, away from the amp, which was on an amp stand.

ajm · Post by **ajm** » 23 Jan 2016 3:34 pm

Glad you got your amp working. But rotating the speaker?

However, this is a bizarre phenomenon happening (I've never heard of it anyway). So now the real questions are: What is going on and why did this fix the problem? Or is this fix rather klugey, and the problem is just waiting to come back again at the worst possible time?

rpetersen · Post by **rpetersen** » 23 Jan 2016 4:46 pm

George - I didn't have the DD-3 near it when changing things around

AJM - I know it sounds weird, But that was kinda the last thing the Peavey tech told me to try before sending it in and there was no doubt of the difference -
I know magnets can do strange things - My amp sitting in the back of a Ford Excursion on a trip made the built in compass in the vehicle go nuts - Couldn't figure that one out either until we unloaded it and put it back in!!
Also when my son and I wired my shop, we had two sets of wire in conduit running next to each other and when both were powered we got a hum - Had an electrician stop by and he called it Feral Resonance (sp) we used the same conduit and changed the wiring around a little bit and it stopped - that was another weird one and was fairly loud!!

Clyde Mattocks · Post by **Clyde Mattocks** » 24 Jan 2016 9:21 pm

I have a thought and it's pure speculation. You know when you are getting hum from a single coil (especially tele) pickup and you turn your body in relation to the amp, the hum goes away. By rotating the speaker, you are moving the speaker connection wires in relation to the chassis and possibly some inductance from the transformers. Who knows?

rpetersen · Post by **rpetersen** » 25 Jan 2016 6:24 am

Been wondering how this works too and I should mention, this almost sounded like a 60 cycle hum -

2 things I noticed:
1. The speaker wires are now closer to the transformer which I would think could make it worse
2. The speaker wires are now on the opposite side of the reverb wires that go up inside the cabinet. Maybe?

ajm · Post by **ajm** » 25 Jan 2016 7:39 am

I do not have access to a stock "unmolested" Nashville 112 to compare. Just a thought based upon another recent comment, regarding the location of the wiring.

When the reverb wires come out of the chassis and drop down to the tank, how are they routed in a stock amp?
- Do they just drop down arbitrarily to the tank, or
- Are they routed over to the side of the cabinet, maybe held in place with a screw hook thingy, then routed down the side and bottom of the cabinet to the tank?

Speaker wires: How are they routed?

Then, how are they routed in the amp that has the problem?

Maybe there is a way that the wiring is supposed to be routed for proper operation, and somewhere along the way this was altered in the "problem" amp.

And as a side note: Regarding the original "fix" of switching the reverb cable plug around inside the chassis........

After you switched it, and it didn't fix the problem, did you switch it back? Reverb tanks have an in and an out. How do we know which way it is supposed to be? Is there stenciling on the circuit board that can be correlated to the jacks on the tank?

Granted that it probably won't hurt anything regardless of which way the wires are. And it will probably work much better one way over the other. But that isn't the question.

rpetersen · Post by **rpetersen** » 25 Jan 2016 10:22 am

Reverb wires run almost all the way along the bottom of the chassis (and still do) to one side and then fastened to the sidewall and down to the bottom and then to the reverb tank

Speaker wires just sort of drop down in the middle of the amp
this isn't my first 112 and it looks like it was wired like others

FYI - I just got an email from the tech that told me to do this and he doesn't have a clue why this worked either

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