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Posted by: Ajmurrell Nov 15 2008, 03:38 PM

Right then guys, the amp is here and for the most part I'm extremely happy with it, but I do have a couple of questions for anyone who has some Tube Amp knowledge.

This model has a Reverb section that is a tube powered spring reverb and the problem I'm having is that it produces a lot of buzz.

It's completly seperate to the guitar, master volume and volume controls. It still buzz's with the same volume regardless of whether or not the guitar is plugged in, or what volume settings you dial in. The more reverb you dial in, the louder the buzz but no other knob effects it.

When I got it home I thought this might well be a fault so took it back for them to look at, and to be honest, the buzz was much much quieter in the store. They still swapped out the tubes for me for new groove tubes and then thebuzzing was even less.

The guy was saying that it most probably was due to the electrics of the house, dimmer switches etc.

The problem is, I've tried it in multiple plug sockets, as well as turning off other sockets in the same room and tested with or without light's on and the buzz is too consistent from the reverb channel for me to assume its being affected by the surrounding electronics.

For example, turning the light on and off produces that well known buzz on the amp when the volume is turned on but turn the volume off and dial in the reverb and the amp buzzes - even with no volume, and the lights make no difference to the amount of buzzing.

Is this normal? If so, is there anything I can do to reduce the buzz?

The annoying thing is that the buzz from the reverb is just as loud when playing loud as when playing quietly, so it wouldn't be a problem in a gig scenario but for home practice it certainly is very audible.

Hope it's not a serious problem, with hopefully a solution!

Posted by: kjutte Nov 15 2008, 05:10 PM

Is it mechanical buzz, or does it come from the speaker?

Posted by: Ajmurrell Nov 15 2008, 05:15 PM

QUOTE (kjutte @ Nov 15 2008, 04:10 PM)

Posted by: Ramiro Delforte Nov 15 2008, 05:28 PM

It sounds like a problem in your electronic installation. Have you tried to plug the Amp in other rooms of your place? Could be that you haven't mass conection properly and that's what's causing the buzz.
If it's a mass problem you'll have to create a mass, it's not difficult but if you don't feel qualified to do it yourself call an electrician.

I hope it was useful.

Posted by: MickeM Nov 15 2008, 07:32 PM

Since you got one of these rare amps you have the benefit of contacting the manufacturer directly, or chat in their forum with other Dr Z fans about your problem.
I suggest you start there.

Posted by: Ivan Milenkovic Nov 15 2008, 08:53 PM

Maybe you can go into some store that has a power conditioner device and plug it in, see if the buzzing is gone then. If it is, then you might wanna consider buying such a device to keep your current flowing steadily.

Posted by: Ajmurrell Nov 15 2008, 09:15 PM

Thanks guys, I'll head over to the forum and ask over there. I've tried it in different rooms and the result is the same.

However after some more testing it isn't nearly as bothersome as I first thought.

At low volumes it is audible, but as soon as you start playing this beauty with a touch more volume its drowned out completely

I have taken a small break as my ear drums deserve it! It's a hugely addictive amp though I must say!!

Posted by: Noangels Nov 18 2008, 08:55 AM

I think in that review you listed in your 1st post on this amp is stated it was noisy-but I cant see how using the reverb like this at low volumes would produce a lot of buzz.If it doesnt produce that sound without reverb at the same levels then surely your power supply must be clean?I would think a dirty supply going into that amp would produce that sound as soon as you turned the amp on!I would say its must be the design of the reverb giving you this buzz,changing tubes wont do a thing-perhaps a compontent on the verb chain is faulty or this is a design fault!

Posted by: kjutte Nov 18 2008, 12:06 PM

QUOTE (Ajmurrell @ Nov 15 2008, 05:15 PM)

Posted by: Ajmurrell Nov 18 2008, 02:03 PM

Yeah, it's not a power supply issue I've discovered.

Searched through the forum and discovered a response to a similar question from the big DR Z himself (or at least, someone at the factory ) and it turns out this is normal problem on the MAZ jr head.

It's caused by the reverb unit being wired in close proximity to the transformers, which is unavoidable in the head unit. You wouldn't have the same problem with the Combo it seems.

he goes on to say: There is a compromise between eliminating the hum and squashing the tone of the amp. Ever wonder why Fender never made reverb heads in the 60s?

The tone is fantastic, and I was only really worried in case this was evidence of something being wrong with the circuitry or similar that would have been costly to repair at a later point.

I believe its just a characteristic of the amp and because the reverb knob is the only one controlling the buzzing (it's not amplified when turning up the master volume or volume controls) - as soon as you turn the volume above the threshold of the reverb buzz, you can't hear it at all. It's a loud little beast at 18W, so at home without an attenuator I have it on about quarter power - which is perhaps unfriendly to the neighbour's, but the buzz is inaudible at even that volume.

Thanks for your help though guys

Posted by: kjutte Nov 18 2008, 02:43 PM

QUOTE (Ajmurrell @ Nov 18 2008, 02:03 PM)

Yeah, it's not a power supply issue I've discovered.

Searched through the forum and discovered a response to a similar question from the big DR Z himself (or at least, someone at the factory ) and it turns out this is normal problem on the MAZ jr head.

It's caused by the reverb unit being wired in close proximity to the transformers, which is unavoidable in the head unit. You wouldn't have the same problem with the Combo it seems.

he goes on to say: There is a compromise between eliminating the hum and squashing the tone of the amp. Ever wonder why Fender never made reverb heads in the 60s?

The tone is fantastic, and I was only really worried in case this was evidence of something being wrong with the circuitry or similar that would have been costly to repair at a later point.

I believe its just a characteristic of the amp and because the reverb knob is the only one controlling the buzzing (it's not amplified when turning up the master volume or volume controls) - as soon as you turn the volume above the threshold of the reverb buzz, you can't hear it at all. It's a loud little beast at 18W, so at home without an attenuator I have it on about quarter power - which is perhaps unfriendly to the neighbour's, but the buzz is inaudible at even that volume.

Thanks for your help though guys

Posted by: Noangels Nov 19 2008, 02:37 PM

Any time mate:) Sounded to me like a design fault on the reverb,glad to know I was on the ball with this one

If you realy do want verb at low volumes then perhaps a pedal as sugested above may be in order,or you could get small multi FX pedal board with compression/delay/chorus/phaser/tuner ect as that could be be used for pratice and future gigs:)

Posted by: Ajmurrell Nov 20 2008, 02:09 AM

QUOTE (Noangels @ Nov 19 2008, 01:37 PM)

Posted by: Ivan Milenkovic Nov 20 2008, 04:00 PM

Then the simple solution is not to use the reverb at all. If you have GT8, you can use it in the loop.