Bought a used Dr. Z amp? Looking to breathe new life into an older amp?

We can bring your used Dr. Z amp up to spec. We offer the following services*:

(*prices do not include shipping costs)

Testimonials from happy customers updated frequently!


  • $105
    Includes a a full QA of your amp. We will check wiring, solder joints, caps, resistors, jacks, pots, ground points, tube sockets, transformers as well as bench and play-testing your amp.


  • $105+tubes
    Includes full check-up plus new tubes and bias

Mods and Updates

MAZ 18: Any 2014 and earlier (incl. w/ attached AC cord)

  • $199
    Mk. II Update

MAZ 18: Any w/ attached AC cord

  • $199
    Mk. II Voicing
  • $125
    Effects Loop Install
  • $125
    Reverb on/off (includes footswitch)
  • $150
    New output transformer with 4, 8, and 16 ohm speaker outs

MAZ 18 NR: Any 2014 and earlier (incl. w/ attached AC cord)

  • $175
    Mk. II Voicing

MAZ 18 NR: Any w/ attached AC cord

  • $175
    Mk. II Voicing
  • $175
    EQ bypass/boost mod (includes new variable boost footswitch)
  • $150
    New output transformer with 4, 8, and 16 ohm speaker outs

MAZ 38: Any 2014 and earlier (incl. w/ attached AC cord)

  • $199
    Mk. II Voicing

MAZ 38: Any  w/ attached AC cord

  • $199
    Mk. II Voicing
  • $125
    Effects Loop Install
  • $125
    Reverb on/off (includes footswitch)

MAZ 38 NR: Any 2014 and earlier (incl. w/ attached AC cord)

  • $140
    Current production voicing

MAZ 38 NR: Any w/ attached AC cord

  • $175
    EQ bypass/boost mod (includes new variable boost footswitch)


  • $225
    Half Power Switch (replaces Speed/Comfort switch. Speed or Comfort setting will be hardwired to customer’s preference)


  • $150
    Bass reduction & current production voicing


  • $175
    Post phase inverter master volume added on rear panel
  • $199
    Post phase inverter master volume added on front panel (new front panel included)

Prescription ES

  • $199
    Post Phase Inverter Master Volume installation


  • $325
    Post Phase Inverter Master Volume plus EQ Bypass (includes new front panel and variable boost footswitch)
  • $225
    Master volume (includes new front panel)
  • $175
    EQ bypass only (includes new variable boost footswitch)


“Hi Don,

Received my amp over the weekend and got it all bolted back up this morning. Fired it up and it’s working perfectly, the master volume is killer and much more usable, the reverb is just beautiful now (never liked it before) and the EQ seems more balanced. Thanks for everything and looking forward to many more years with my Z.”

Randy F.Owner of a 2003 MAZ 18


Amp sounds really good.  I’m really happy with what you did to it.  Great job!  I installed it back into the cabinet last night and played with it for about an hour.  Also, thanks for sending the clip.  It really helped me know what to expect.”

Andy Z.Owner of a 2005 MAZ 18 NR

“Hi Don,

Received my MAZ 18 today, reinstalled it in the combo and fired it up – it sounds great! There is plenty of low end available now (not as much as my Z-Lux, but it’s a VERY different design, eh?). The whole amp just seems more responsive and “bigger” now, and it’s very touch-sensitive on everything from sparkling clean to growl-y overdrive.

Thanks again – Iam a huge fan of Dr. Z amps!

All the best, ”

Steve C.Owner of a 2014 MAZ 18


Holy cow! Those upgrades are killer! Honestly, I rarely used the amp gain in the past, mainly because it was just slightly too harsh for my tastes, but this is perfect. I’ve run through several different guitars now, and they all sound fantastic. Money well spent – thanks!”

Ben L.Owner of a 2015 MAZ 18 NR

“Hey Don,

Got the MAZ, and boy, does it sound great. All my band members said how much definition it has. I can’t believe how much difference the mods you made helped.

Thanks, ”

Paul R.Owner of a 2001 MAZ 18

“Hi Don,

When I first got my 18 back I left the controls as you had left them. Pretty much all noon and a touch of reverb. Hooked it up to my Z 2×10. I guess I can sell my OD pedal collection!! Serious muscle and note definition. And when I kicked in the tone bypass I think I played it for an hour straight. Never touched anything but the guitar controls.”

Awesome job Don, ”

Jim R.Owner of a 2000 MAZ 18

“Hey Don,

I’ve had some time to sit down with my MAZ and wanted to let you know that I really dig it!

Firstly, I really like how the sweep of the master is way more even. Before, it felt like the amp achieved peak loudness around noon; now it’s peak loudness is when it’s maxed. I’m still exploring the benefits of that improvement in my bands and on my own.

I like the effects loop much more now too. Before the mod, I felt it neutered my volume and tone a bit; that is no longer an issue… With regards to the overall tone, it just sounds better. I’m still figuring out how to put this into words, but the biggest difference i notice right away was how the low end is less overbearing (particularly when played clean at high volumes).

If I have anymore revelations, I’ll be sure to let you know. Thanks again for your work and all that the good people at Dr. Z do for us tone-discerning guitarists!

Best Regards,”

John NorthOwner of a 2004 MAZ 18 NR

“Just put the amp back together and I am LOVING IT! Am I wrong or is there not only a lot more master volume output, but CLEAN output?! HOLY COW! Nice Work!”

Joel D.Owner of a 2008 Maz 38

“Don – sorry for the delay in getting back to you regarding the MAZ 18 mod.  I had a chance to play out with it recently and really love the new sound.  I think the revisions make the amp much more versatile.  The master volume is much more effective.  I am very happy with the amp.


Steve B.Owner of a 2000 MAZ 18

“Hi Don,

The amp sounds great, I just played a gig with it this weekend! Thank you for all your hard work.”

Erik N.Owner of a 2009 Maz 18 NR

“Amp arrived safely and VERY pleased! Good work. Thank you.”

David C.Owner of a 2004 Maz 18

“The amp sounds amazing and the reverb install was easy! Thanks for all your help. What goes into bringing the amp up to current spec? Thanks again!”

Paul F.owner of a 2007 Maz 38

“Hi Don, I just got back to the US last night and have played for an hour with the amp. Sounds terrific again! Much appreciated!”

Matt F.Owner of a 2001 Maz 38

“Don, I don’t know you how guys did it, but you managed to make a great amp sound amazing. I am very pleased. Glad I went for the upgrade, and glad I bought the Maz in the first place. Thanks very much.”

John B.Owner of a 2004 Maz 38

“Good Morning
I got the amp on Friday night….
Dude this thing sounds unbelievable…..
Reverb is definitely quiet and actually sounds deeper than previously….
The Amp itself sounds much more open and extremely touch sensitive than ever before….
The Bypass mode is insane….I can easily coax feedback and enhanced guitar volume control is killer…
I have owned three previous Maz 18’s all but one with reverb….this sounds better than any of the previous models
Thinking about buying a new combo version or at least in the 38 watt configuration….
Thank you for spending the extra time on this beast….will send you a picture with my other Z gear….”

Mike MartosOwner of a 2001 MAZ 18 Head

“Hi Don,

I’m very happy with my MAZ. It’s much quieter now and I like the updates. Best tone of any amp I’ve ever owned. Thanks.”

Dave H.Owner of a 2001 MAZ 18

“I got the amp yesterday and got to sit down with it last night. All I can say is wow!! It is EXACTLY what I was hoping it would be. Throaty growl with plenty of headroom. The EQ bypass is awesome. Anyway, thank you for all your work. I love it!!!”

John CantrellOwner of a 1995 MAZ 38 "Invasion"

“My MAZ 18 sounds better than it ever has! Clean and crisp as always, but with a touch of ‘hair’ at a lower volume than I have ever heard. And the reverb is the best ever!
Thank you very much for your efforts – I will be looking for opportunities to send more stuff your way!

Thanks again, and keep things hopping in Cleveland!”

Robert GruenlohOwner of a 2003 MAZ 18 head


Just to let you know, after I have given my amp several weeks of ‘field testing,’ that the amp works better than when it was new. Thanks much for fixing my amp.”

Russ C.Owner of a 2002 Maz 18

“Hi Don,

just wanted to write you back with my thanks for the great work. The amp is exactly how you described in email and what I asked for. Admittedly I was used to it being less bright, but I also noticed that mine was less bright then most other Maz 18’s I have played including the other one I own. However the range of control in the preamp section is much wider now, so I can dial in a warmer sound, which I tend to like. Also its back to having the power and physical presence that I’m used to. Its really one of the best amps ever made. Thanks again. Well done!”

Kevin C.Owner of a 2009 Maz 18

“Wow does it sound amazing! I only got to plug it in for 5 minutes but I’m taking tomorrow off and I don’t think I’ll be shutting it off all day. The tone in that thing was already amazing but it is just unbelievable now! And running super quiet too! I cranked it up, it sound awesome. I turned the master all the way down, sounds awesome. Thank you so much! Amazing work and you were incredibly helpful along the way. Your guys customer service is next level.”

Luke P.Owner of a 2005 Maz 38

“Hello Don,

I’ve had a chance to play the amp for a while now and it sounds amazing. It’s really night and day and now there is actual reverb.

Thanks again for your help you guys do great work!!”

Hugo C.Owner of a 2002 Maz 38

“Hey Don, everything sounds great, I am super happy. Took it to rehearsal last night so I could finally play it at volume and it dialed in so easily. I’m sure you know this already but you all do wonderful work!”

Nick D.Owner of a 2006 Maz 38

“Got my amp back right on schedule, it’s fantastic. Very articulate, really brings out the individual characteristics of different guitars. It’s all I could ask for, thank you very much. I, and my friends who have come around to take a turn on it, are generating lots of positive buzz about the good folks at Dr. Z. My very best wishes to all of you.”

Joe O.Owner of a 2002 Maz 18

“Well my MAZ 18 chassis arrived unscathed and after popping it in my 2×10 cab it was singing like a bird – and I mean SINGING! Sounds like it has more gain as well. It also responds well to volume changes on the guitar, cleaning up nicely with reduced volume. Works well with both my Tele and 345 with minimal knob fiddling. Of course I always seem to end up playing louder practicing at home in a carpeted room, so I can’t wait to go live. Job well done!”

Jim SmailesOwner of a 2008 MAZ 18
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