New member, new Express 5:50+, four different problems!

[AxeOfSpades]

Hi everyone, I'm a new Express 5:50+ owner and glad to be a new member of this board. I just received my new head/cab on Friday and have been running it through it's paces. When it’s working properly the sound is amazing. But unfortunately, I have to say that I'm glad I kept the shipping cartons! I have the following four issues that I'm hoping you can help me with:

1) Horrible intermittent crackling and hissing noise (with occasional squealing too) on both channels on all modes and at all power settings. These sounds are audible at all Master volume levels AND with no guitar plugged in. Also, it seems to be worse with Gain around the 2-3 o clock position. So far I haven’t noticed any pattern as far as when the crackling occurs and it seems random so far.

After reading and re-reading the relevant manual section, I guessed it might be the driver preamp tube (V4) causing this since it occurs on both channels and all modes. So, I swapped it with V5 and it seemed to fix the problem on channel 1 but not channel 2. Channel 1 is now quiet but channel 2 is as bad as ever. Not sure what to do at this point since it seems possible I have more than one bad tube! Unfortunately, I don’t have any spares to use for swapping.

On a side note, very similar symptoms (the difference being the additional symptom of significant volume loss) occurred on my Carvin Legacy 3 immediately upon using it the first time. Swapping tubes made no difference, so the Carvin tech had me ship it back because he suspected cold solder joints somewhere. They sent me a replacement head which has worked perfectly ever since. I wonder if this could be the same issue or at least partly to blame. But what are the odds of that happening twice with heads from 2 different manufacturers?! BTW, this is definitely NOT just the normal hissing sound that can be expected by cranking the master on any tube amp and that has been the subject of other threads on this board.

2) Loud electronic popping sound coming through speakers when using toggle switches (kind of like what happens when you turn on a bad light switch). It’s worst when switching channels - both via the head and via the footswitch - but other toggle switches make this sound too. This is another intermittent problem which seems to get worse the longer the amp is on. I would expect the use of these switches to be relatively silent but maybe this is normal for these amps? If it is in fact normal, this baby is getting returned permanently.

3) This one may just be me not understanding how channel switching works on this amp, but I don’t think so. When the head is set to "FW SW” and I use the footswitch to switch to channel 2, I am UNABLE to use the head to manually switch back to channel 1. It just stays on channel 2 on both the head and the footswitch. The only way to get back to channel 1 is via the footswitch. However, if I do the reverse, and use the footswitch to switch to channel 1, I AM able to use the head to manually switch to channel 2. This makes no sense to me. It should work the same in both directions, channel 1 to 2 and vice-versa. Or is there something counter-intuitive to how this is supposed to work?

4) Additionally, I AM able to use the footswitch to switch channels when the head is in the “Ch 1” position but not when the head is in the “Ch 2” position! This not only seems like inconsistent behavior but I thought you were only supposed to switch channels via the footswitch when the head is in the “FT SW” position. Am I wrong about this?

Since I’ve only had it for about 3 days, I guess I’ll call the place I bought it from first and if they can’t help, then Mesa. Hopefully, I can get someone to send me a few replacement tubes to eliminate tubes as the problem.

Of course, any useful advice any of you can provide would be hugely appreciated! And thanks for listening!

 

[Stinger22]

Mine is a 5:25+ but should be same.

1. Sounds like a tube problem, have you gone through and tapped each tube with a pencil eraser to see if they make noise and cracking?
2. Could be a result of the bad tube(s).
I'd take it back to where you bought it and have them pop in a couple of known good tubes.
Tubes can get damaged in handling, I always carry a couple with me.

3. Yep same with mine. First noticed that when I was sitting close to the amp trying different settings
4. And again same here.

 

[AxeOfSpades]

Mine is a 5:25+ but should be same.

1. Sounds like a tube problem, have you gone through and tapped each tube with a pencil eraser to see if they make noise and cracking?
2. Could be a result of the bad tube(s).
I'd take it back to where you bought it and have them pop in a couple of known good tubes.
Tubes can get damaged in handling, I always carry a couple with me.

3. Yep same with mine. First noticed that when I was sitting close to the amp trying different settings
4. And again same here.

Thanks for your response Stinger22. That is very interesting info and hopefully some of this will help you out with your amp. I spoke with Humbucker Music (where I bought it from) several times today and did some more debugging and here is what I discovered..

1) Yes, it's probably multiple bad tubes. I removed each tube and reset it. Everything seemed fine actually. But when I switched from 5W to 25W for the first time it started acting up again and stayed that way. Then, I used the pencil eraser to tap them under various settings. Tubes V4 and V5 seem to be the noisiest and, depending on the current amp settings, are each microphonic some of the time. Something definitely seems out of whack with the preamp tubes. Fortunately, the awesome people at Humbucker offered to send me a full-set of new tubes, rather than having me try to figure out exactly which tube(s) are bad! :shock: Hopefully that'll fix this issue once and for all.

2) In addition to channel switching, this issue also occurs when switching power levels (esp. when going from 25 to 50) and when using the standby switch. And based on what I've been told and read on here, it seems like that may be somewhat normal - although bad tubes might be making it worse. Also, it seems like the Reverb level might affect how loud this popping is - which, I'm guessing could be because of the microphonic V5 tube. This issue is still kind of hard to pin down as far as what switches are affected by it and what settings cause/allow it to happen. I can sort of accept it occurring to some extent when switching power levels or even when using the standby switch. However, it's pretty hard to accept during channel switching (both via the head and via the footswitch)! Hopefully swapping tubes will magically fix this problem too.

3, 4) Apparently this is normal for these amps. I guess I'll just have to throw logic out the window on this and get used to the way it works. Although I absolutely HATE this expression, "It is what it is" seems appropriate in this case.

I'll post an update when I've had a chance to swap some more tubes.

Thanks

 

[AxeOfSpades]

Well, I received the replacement tubes and finally got a chance to try swapping them out. While doing so, I realized that my original post was incorrect where I said swapping V4 and V5 fixed the crackling on the channel 1. Actually, it did not. The crackling still was audible on channel 1 crunch mode, although not as bad as on channel 2 burn mode. Also, I was wrong in that it was V1 and V2 that I actually swapped - not V4 and V5.

Anyway, after I got the 5 new preamp tubes and 2 output tubes, I spent about 2 hours trying out different combinations. As expected, swapping the output tubes had no effect at all. Neither did anything else. After a couple hours, I finally found a new preamp tube that when swapped with the original V1 tube, seemed to reduce the crackling significantly - enough to where I can live with it. So that's it for now. Hopefully, that wasn't just a temporary fix but we'll see.

So, other than some of the idiosyncrasies I mentioned before regarding the weird channel switching and popping sounds, I'm beginning to like this amp a lot and have been able to dial in some great tones pretty easily - especially in channel 2 burn mode. But, it is still a little disappointing that an amp of this caliber seems to be so.. I guess flaky is a good word.. and so relatively difficult to use compared with any other amp I've owned.

At least it looks cool and sounds great - obviously the two most important factors. :lol:

 

[bunny.lapin]

I bought a used Express 5:50 recently and the buzz/hiss was disappointing. I changed V1 & V2 with the Doug's tubes recommendations and have a full set of preamp and power tubes shipping from him now.

It made a big difference on the hiss for me - the clean channel was louder than 'crunch' before and now it's not - burn is pretty buzzy but at the same time I'm not surprised. Once the amp is cranked up a bit all I can hear is sweet tone!