New Mark IV - Rhy1 Channel very low

[kbourque]

Hey guys,

I just got my brand new Mark IV medium head at home and everything works fine except the RHY1 channel is VERY low. All other channels are normal volume. I'm new to tube amps so a little help would be appreciated.

Thanks in advance.

Kris

 

[Platypus]

Where are your volume settings?

CH1 is quieter than the rest of the channels but not by a huge amount, if you're turning the knob past 7 and it's still quiet I would look into checking your preamp tubes for a problem.

 

[kbourque]

yeah I can almost put it full blast and it's still low, the other channels are CRANKED.

Is there a certain pre-amp tube I should switch first?

 

[kbourque]

i switched out all the pre-amp tubes and it's still happening

I tried with and without the EQ and its still the same difference.The only way to get the same volume compared to the Lead channel is to crank the master and gain on 10 on the Rhythm 1 channel,and thats with the Lead Channel master on 1.

 

[shredding]

something's definitely wrong here. What's your R1 gain set at? It's going to affect the volume a great deal.

I set my R1 channel vol to only 3-4 and it will match the L channel at volume 2 and gain at 8 pulled.

 

[edward]

Hi Kris,

If this just happened (when all was working fine beforehand), and your R1 gain setting is up where it was when all was good, then you definitely have a problem which requires a tech.

FWIW, I had your same prob with my MKIII head, except with the Lead channel. Turns out it is a component called the LDR (there are several in there) which handles the signal and how it gets switched. I'm *not* saying that is your problem, but after speaking with a Mesa Tech, the MKIII and IVs are the last of the Boogies that use LDRs for switching, and they are a known to fail. Some fail and you get zippo; others fail and you get a % of the signal. I fixed one of my LDRs and got the signal back up to about 70%, so obviously more work is needed, but at least I confirmed my issue. A trusted tech (who knows boogs well) is what you need here

Edward

 

[kbourque]

something's definitely wrong here. What's your R1 gain set at? It's going to affect the volume a great deal.

I set my R1 channel vol to only 3-4 and it will match the L channel at volume 2 and gain at 8 pulled.

My Rhy1 gain is on 10 (not where I would normally have it but just for testing purposes here), and if i put my Rhy1 Master anywhere from 1-5 it's barely audible while the other channels are shaking the room

And you're right something is definately wrong.

 

[kbourque]

Hi Kris,

If this just happened (when all was working fine beforehand), and your R1 gain setting is up where it was when all was good, then you definitely have a problem which requires a tech.

FWIW, I had your same prob with my MKIII head, except with the Lead channel. Turns out it is a component called the LDR (there are several in there) which handles the signal and how it gets switched. I'm *not* saying that is your problem, but after speaking with a Mesa Tech, the MKIII and IVs are the last of the Boogies that use LDRs for switching, and they are a known to fail. Some fail and you get zippo; others fail and you get a % of the signal. I fixed one of my LDRs and got the signal back up to about 70%, so obviously more work is needed, but at least I confirmed my issue. A trusted tech (who knows boogs well) is what you need here

Edward

Hi Edward,

It's actually a brand new amp and this was the first time I ever turned it on so the Rhy1 Channel has never worked right.

I'll be bringing it back to my dealer this weekend, I am no amp tech lol.

Thanks a lot for the info though I'll keep it in mind!

Kris

 

[kbourque]

I brought my amp back to the dealer and they thought the output on the Rhy 1 channel seemed low also so it's with their tech department now.

Can someone do me a favor and let me know if using the factory sample settings from the manual gives each channel about the same amount of volume. This way I can tell the guys at the store what to try after their techs look at and/or repair it. This would be a huge help! The store is 3 hours away if anyone is wondering.

Manual (Page 15): http://mesaboogie.com/manuals/Mark%204.pdf

Thanks

Kris

 

[kbourque]

Hey guys,

So I had my amp sent back to Mesa to get it checked out and here’s what they said:

This amp was tested at Mesa Boogie and found to have No Faults—it’s working very well—it will be shipped back to the store. As a customer service they changed the output tubes—in case there was a tube malfunction. You should receive the amp late next week…..

I’m not sure what to think about this, hopefully it works, I can’t see them just ignoring the problem if it was happening while they had it.

I guess I’ll just have to see.

Thank you for the replies btw, very appreciated.

Kris

 

[kbourque]

Hi Kris,

If this just happened (when all was working fine beforehand), and your R1 gain setting is up where it was when all was good, then you definitely have a problem which requires a tech.

FWIW, I had your same prob with my MKIII head, except with the Lead channel. Turns out it is a component called the LDR (there are several in there) which handles the signal and how it gets switched. I'm *not* saying that is your problem, but after speaking with a Mesa Tech, the MKIII and IVs are the last of the Boogies that use LDRs for switching, and they are a known to fail. Some fail and you get zippo; others fail and you get a % of the signal. I fixed one of my LDRs and got the signal back up to about 70%, so obviously more work is needed, but at least I confirmed my issue. A trusted tech (who knows boogs well) is what you need here

Edward

You we're right, Mesa just called me and said this was exactly what was wrong with my amp.

Thanks

Kris