Buzz when switching on Dual Recto

[enuenu]

When I flick the power switch on in my 3ch DR I hear a loud buzz from the head that lasts for about one second.

1) I then flick the power switch off and wait a few seconds, a quick "rattle" can be heard when I flick the power off.
2) I flick the power switch back on and the "buzz" noise does not occur.
3) I then flick the power switch off and wait a minute or so. Again, a quick "rattle" can be heard when I flick the power off.
4) I flick the power switch back on and the "buzz" noise occurs again.

Are all these mechanical noises while flicking the power switch normal?

I have only had this used head for a few days and it just started doing this. The "buzz" noise doesn't sound right to me at all. The "rattle" is not as bad , but should it be there? The head is a couple of years old and has had little use according to the person I bought it off. It's condition backs this statement up.

I also notice that when I switch the power on, all 3 channel lights on the footswitch light up and stay that way until the channel is changed using the footswitch. At the same time (when power switch first flicked on) the orange channel light on the head always lights up, regardless of the channel last used and the fact that all 3 lights on the footswitch are on. Is this normal? I have the FX loop control on the rear panel set to "Bypass Loop", the channel selector on the rear panel set to "Footswitch", the power set to "Spongy" and the rectifier to "Vacuum Tubes"

This all happens before I touch the standby switch (which is in the standby position). It happens with all 4 combinations of power (bold, spongy) and rectifier (diode, tube) selections on the rear panel.

 

[enuenu]

I have done some experimenting and seem to have isolated the source of the problem. It only occurs when the footswtich is connected AND when FooTSWitch is selected on the rear panel channel selector. Leave the selector on FTSW and disconnect the footswitch and the problem dissapears. Leave the footswitch connected and change the rear panel channel selector to anything but FTSW and the problem goes away.

I also notice that it is usual that the little green light on the rear panel slowly dims to black when the power is flicked off. With the FTSW connected and FTSW selected, if this light is black when the power is flicked on the noise happens to maximum effect. If the power is flicked on, then off for 3 seconds and then on again, not allowing the green light to completely dim, the noise is abbreviated to about half a second in duration. If the power is flicked on, then off for 1 second and then on again, not allowing the green light to dim at all, the noise is further abbreviated to about 1/10th of a second.

 

[enuenu]

I just found this. Exact same problem I have. Maybe it is normal?? If all DRs don't do it, can it be considered normal?

 

[enuenu]

I will contact Mesa and see if they have heard of this.

 

[enuenu]

Haven't had a chance to talk to Mesa yet but talked to another tech. He said he didn't think the electro-mechanical buzz when switching the power on was right. I also told him that if the footswitch is connected when the power is flicked on, all 3 channel lights on the footswitch light up and stay lit and the orange channel light on the head ALWAYS lights up. He said he remembered that the footswitch lights should flash on and off when the power is flicked on and that the channel light on the head that lights up should reflect the last channel used. Maybe I have a footswitch or footswitch circuit problem?

Any 3 ch dual recto owners feel like doing an experiment for me? Connect the footswitch and select it at the rear panel (and select FX bypass) then turn the power on (leave standby off). What do the footswitch's lights and the head's channel lights do? Thanks.

 

[gmcelroy]

From what I can gather this is normal on the newer models. I too am a new 3 ch DR owner and noticed that my amp does the quick "buzz" when turning it on and the footswitch does the exact same as yours but I have not heard the "rattle". The guy I bought mine from had two DRs and he said both amps did the same thing when the footswitch was attached. I spent a couple of hours last night going through old posts here on the board and from what I found this is pretty common. Please post what Mesa has to say.

 

[MetalMike]

yea i got a 3ch dual rec and it does the buzzing it quieted down when i put gz34r rectifier tubes in it but it still makes it. i took it as normal.

 

[enuenu]

Just called Mesa and without any hesitation the guy said the buzz was normal and that the way my lights first illuminate was also normal. Seems all is well. However if I was producing this amp I would say to my design team "Get rid of that goddamn buzz on power-up, it sounds like ****." I've never heard an amp (that is not busted) make such a horrible sound, so I'm sure it could be designed out. I wouldn't have though a company like Mesa would let such a thing slip through the cracks and then accept it when they discover it.

 

[songrider]

If it has no affect whatsoever on the sound/tone/feel/performance or stability of the amp then I dont see it as a big deal.

Ive had amps that have done all kinds of crazy things over the years during powerup or shutdown. As long as it does what its supposed to do when its powered up and off stanby not a biggie...

 

[phyrexia]

Just called Mesa and without any hesitation the guy said the buzz was normal and that the way my lights first illuminate was also normal. Seems all is well. However if I was producing this amp I would say to my design team "Get rid of that goddamn buzz on power-up, it sounds like sh!t." I've never heard an amp (that is not busted) make such a horrible sound, so I'm sure it could be designed out. I wouldn't have though a company like Mesa would let such a thing slip through the cracks and then accept it when they discover it.

i told you it was normal but you didn't believe me I guess

sounds you want mesa to go twenty years in the past and start using LDRs instead of relays. although i think the reason they switched from LDRs to present methods was because of "those goddamn unreliable LDRs" essentially. 8)

 

[enuenu]

Sorry if I offended anyone in my pursuit of the truth . I really appreciate all your input. One thing I have found in life is that if you ask a few experts the same question and get different answers you have not found the truth. Ask a few experts the same question and get the same answer from them all and chances are you have the truth. Ask one expert and take their answer as gospel and move on and you may run into trouble. That's just my research style, I can see some may see it as excessively manic. If someone asks me a question in my field of expertise and they then ask someone else the same question I don't feel offended, hey maybe they might find out something new.

The amp is a ball tearer and am happy with it, I just wanted to be sure that I didn't have a technical problem that could fester and cause damage. I am now resting easy. Thanks again.

How did you do with the experiment? Did the lights act in the way I described? (There I go again, I know what curiosity did to the cat but a leopard can't change its spots)

 

[phyrexia]

Connect the footswitch and select it at the rear panel (and select FX bypass) then turn the power on (leave standby off). What do the footswitch's lights and the head's channel lights do? Thanks.

Sorry for the fuzz. Camera lives in my pocket.

 

[enuenu]

Thanks a lot for hanging in there with my manic research! I think only the three channel lights illuminate on my footswitch on power up, but I can't quite remember. I'm at work now and will check when I get home.

 

[enuenu]

All 3 channel lights on the footswitch light up on power up. The FX light assumes the state it was in when the amp was last powered down and the solo light never illuminates on power up. The orange channel light on the head always lights up. The only difference between mine and the one you photographed seems to be the behaviour of the solo light. The reason for the difference in the solo light illumination on power up has got that curiosity going again!

I haven't used the FX loop yet so I guess I should test it and the solo function to see if it all works. The only pedals I have are an old DOD overdrive and a Boss SD. I guess I just take a lead from the rear panel FX socket and plug it into the input on the pedal then take another lead from the pedal's output back to the other FX socket on the rear panel.

This amp is utter filth. The more I play with it the better it sounds. Yes tweaking does make a huge difference. My favourite at the moment is a tone on the orange channel in modern mode. Mean as hell.

 

[enuenu]

It has stopped buzzing on start up now. Maybe my DR is alive and has healed itself?