Pop on going to standby

[Jackie]

I had a similar problem on my Marshall and it turned out to be a dodgy PI tube.

 

[grc911]

Mine is still popping on going to standby.
Even louder when I have effects in the loop.
New tubes didn't help.
Even if I turn Master volume down it still pops.
No pop if going to off from standby.

Just cover my ears!

Greg

 

[CosmicDebris]

Bah, hissing and popping are back. Off to service it goes =(

 

[zGuitar7]

My Mesa Boogie Express 5 50 also makes a very loud pop when I toggle off my standby or power switch. Switching to standby first makes the loudest pop. And it's no better with the master volume off. I've had this amp for about one year and it started doing this fairly recently. The pop is so loud, it must be bad for the speakers? Any thoughts? Thanks!

 

[grc911]

"My Mesa Boogie Express 5 50 also makes a very loud pop when I toggle off my standby or power switch. Switching to standby first makes the loudest pop. And it's no better with the master volume off. I've had this amp for about one year and it started doing this fairly recently. The pop is so loud, it must be bad for the speakers? Any thoughts? Thanks!"

Welcome to the popping club.

Mine still pops. Less pop with no effects in the loop.
By coincidence I have taken up playing guitar direct into amp with no effects at all and the popping has diminished significantly so that I don't flinch when I turn to standby now.

No solution as yet and haven't had the amp back to a tech as that is a bit difficult in the land of Aus.

Greg

 

[dgr888]

Without seeing a schematic I believe once again "Mesa Engineering" forgot to put the bleeder cap on one side of the standby switch. I'd be willing to bet if you solder a .022/.047 600v cap to the switch and the other end to ground the pop will be gone. If you can't build em' right don't build em' at all.......

 

[EXPRESSLOVER]

Well we all seem to have the pop so it must be normal? Mine was ALWAYS there since I bought it from box new online. Maybe Mesa need to look into this? Give us a logical answer?

 

[alvaespa]

Hi all,

I own an Mesa Express 5:50 since 2008.
It did not pop at all during the first years.
It is not suppossed to do it as I have tested other amps in different shops and no one did so.

However, 3 years after these loud pops started when switching to standby in my amp.

I took it to an authorized MesaBoogie distributor in Spain and I had it repaired in a few days.

Capacitor C51 was damaged. That's all.
There are 2 capacitors preventing those pops, C51 and C43.
If your Express pops, it's more than likely that one or both capacitors are not working as they should.

The schematic can be found here:
http://music-electronics-forum.com/t22508/

Regards,