Used ED combo standby popping and other issues.

[Drone_Monster]

Hi all,

I'm new here. This is my first post, though I've been following the forum for a while.

I recently bought a used ED wide body combo after falling in love with it after a month long amp search.
(I recently immigrated to Canada and had to leave my amps with friends.)

While I did check that everything is in working order before I bought it, there are a few things that have now become a concern. I just wanted to see if anyone else has experienced the following with their EDs:

- There is a loud pop when switching the amp to standby, even with the Volume and Master all the way down. I understand this is normal in some amps but it seems a little loud.

- When the Master is all the way down, I still get a bright, brittle signal coming through ie. it's not silent. This only presented itself as a real problem when i moved my volume, delay and reverb pedals into the fx loop - with the volume pedal all the way off, I get the same brittle signal bleeding through (regardless of what channel i'm on).

- There is a noticable hum with my pedals in the loop. (This hum isn't there when the same cables and pedals in front of the amp. And, yes, my pedals are supposted to be able to handle line level.)

I'm aware, from reading through the threads here that the fx loop on the ED is post Master control and I wonder if the popping with volume off and the volume bleed are connected in some way. Is this a design issue or do I need to have mine services?

Please, if anyone could shed any light on this I'd be really grateful.

 

[screamingdaisy]

- There is a loud pop when switching the amp to standby, even with the Volume and Master all the way down. I understand this is normal in some amps but it seems a little loud.

It’s normal, and I agree the ED is worse than most. Mesa uses mechanical relays in their amps. It improves the sonic quality over other methods, but it comes at the cost of popping.

- When the Master is all the way down, I still get a bright, brittle signal coming through ie. it's not silent. This only presented itself as a real problem when i moved my volume, delay and reverb pedals into the fx loop - with the volume pedal all the way off, I get the same brittle signal bleeding through (regardless of what channel i'm on).

I’ve never noticed this, but I don’t typically play my amp with the master on zero and I’ll suggest that Mesa likely didn’t design the amp to be used in this manner.

Normally I’d double check on my own amp before responding, but I can’t right now so I’ll post what I suspect is going on...

In tube amps some bleed through between tube halves isn’t uncommon. Each 12AX7 preamp tube is two separate triodes in one bottle, and if the signal is hot enough in one half it’ll bleed through to the other. It’s normally not an issue since people generally don’t play their amps with the volume all the way off and the amp functions fine when used in a typical manner.

The other thing it might be is the reverb. I’m pretty sure that on the ED the reverb is in parallel to the effects loop, so even you mute the loop using a volume pedal the reverb may still be bleeding across. If this is the case bypassing the reverb should eliminate it.

- There is a noticable hum with my pedals in the loop. (This hum isn't there when the same cables and pedals in front of the amp. And, yes, my pedals are supposted to be able to handle line level.)

Sounds like a ground loop. What kind of power supply are you using to power your effects? Do you have effects out front and effects in the loop? And are they all powered off a single power supply?

I'm aware, from reading through the threads here that the fx loop on the ED is post Master control and I wonder if the popping with volume off and the volume bleed are connected in some way. Is this a design issue or do I need to have mine services?

The ED is a loud as hell amplifier that does weird things when you try to use it at very low volumes. The quirks that tend to present themselves when used at bedroom levels go away when the amp is turned up to stage volumes. Hiding three channels behind a single set of controls caused some design limitations, and they chose to have the amp fire on all eight cylinders when the volume is at concert level.

 

[Drone_Monster]

Thanks for the reply!

I'm glad to here the popping is normal. I thought it might be but wasn't sure.

Regarding the bleed, the only reason it's an issue is that I'd like to do post pre-amp volume swells with the volume pedal and it doesn't go completely silent. I have checked and the reverb is already bypassed. Seems strange that an amp wouldn't be able to completely cut the signal when the volume is down. This can't be by design, surely. If it is bleed from the tubes, would replacing them help?

As for the ground loop, yes, I am running pedals in front and through the loop all off a Strymon Zuma and an Ojai linked together.
It doesn't seem to be a cable issue. Will try each pedal again one by one in the loop but this time no other pedals in front.

I actually love that this amp is so **** loud and clear, but, yeah, it does make things awkward and weird at lower volumes. Hoping to meet some people to play with so I can get it out of the **** apartment!

 

[screamingdaisy]

Seems strange that an amp wouldn't be able to completely cut the signal when the volume is down. This can't be by design, surely. If it is bleed from the tubes, would replacing them help?

Replacing them likely won’t change anything.

IMO, the bleed is mostly noticeable at very low volumes in an isolated environment. Once you get the amp up to stage volume with a snare drum and cymbals in the room... the little bit of bleed is a non-issue.

IMO/YMMV

 

[Drone_Monster]

Hmmm. I would agree with you if it was just a little bit of bleed but this is fairly loud, so volume swells (which I do fairly often) are not possible on the pedal, it’s more of an eq/wet mix.
I was hoping no one else was experiencing this and that it isn’t just part of the amp design.

I’ve at least discovered that my Strymon Timeline isn’t playing nice with the fx loop, apparently the pedal gets its ground from the loop. Not sure what to do with that info but at least I know the cause.

 

[screamingdaisy]

Try using an isolated power supply on the Tmeline. The supplied wallwart should be good enough to test with. If the hum goes away with the wallwart then the issue is likely that the Zuma/Ojai is your second path to ground.

Most of my ground loop issues have been power supply related, usually from the pedals before the preamp sharing a supply with the pedals in the loop. The Zuma/Ojai advertise individually isolated outputs and shouldn’t be causing this, but that ground loop isn’t appearing out of thin air and there’s a limited number of cables attached to your Timeline.