Dr. Z M12 FAQ

Lots of questions are being asked about the Dr. Z M12.  Good!

Since we've been answering lots of questions about the M12 through forums and email, we decided to share our responses on our website.  If you have any questions at all concerning the Dr. Z M12, please feel free to send them to info@humbuckermusic.com or post on the Dr. Z Forum located HERE in the M12 Amplifier Section.  For those not familiar with the Dr. Z Forum, you're truly missing out.  You'll find a well moderated group of mature, knowledgable guys which is hard to find in forums these days.

What exactly is the M12 and what purpose is it serving?

Essentially, it was created to be an ideal lower wattage pedal amplifier for the typical pedal board enthusist.  Since Dr. Z amps are well known in the higher-end amp community for being so pedal friendly, particularly his EF86 front-end amps (RT66, KT45, Z28, Stang Ray), who better to design and build this much needed amp?   After the first prototype was built, Dr. Z found something interesting.  The M12 sounded quite amazing with the guitar going directly into the amp.  More so than originally anticipated.  He describes the amp as "the perfect half powered offspring of the Z Wreck and Stang Ray.  You get the clarity of the Stang Ray with the sweetness and ease of the Z Wreck."  That's quite a statement!

Interesting that an amp designed to use with pedals would have an EF86 preamp section.  Aren't those tunes known for the way they break up?

The EF86 is indeed very high gain tube, but true gain is more of a indication of volume than overdrive. An EF86 can be used to send a very hot signal "downstream" in the circuit to create overdrive, *OR* it can be utilized in a way that makes use of it's tremendous headroom. As a rule of thumb, the more power an amp has, the more clean headroom. That's essentially the same principal with an EF86 tube. If you look into various uses of EF86's over the years, you'll find them in several audiophile home audio systems. As well, the EF86's headroom allows it to handle a wide variety of input voltages without losing the signal's integrity. That's why overdrive pedals work so well with Dr. Z's EF86 amps.

There's even more to the story of this amp... As mentioned above, Dr. Z is known for his use of the EF86 in his preamp stages. But what I want to mention is the power section of the M12. I see that some guys have speculated it's an EL84 version of the KT45, Route 66, and Z28. While those statements are entirely true, they leave out a crucial piece of information. The M12's power section is not a standard EL84 circuit. The voltage across the plates has been slightly reduced to decrease distortion and noise, allowing for greater input signal quality. Various "tweaks" were made until he ended up with an amp that was neutral enough to do the job, but still maintained it's character and attitude. Honestly, the result was exactly what I had hoped for.

I'm not sure a pristine clean EF86 preamp is the best choice for making OD pedals sound like they're part of the amp. I typically find you need to get a touch of amp OD going to get pedals to melt into the amp, but maybe there are other factor at play here in the M12.

I couldn't agree more. This is one reason a super clean amp like a Fender Twin isn't always the best choice. It's not just about it being too loud. Things that are totally clean tend to have a somewhat sterile quality to them.

However, your concern was intentionally factored into the design on the M12 from a couple angles. First and foremost, the Dr. Z preamp stage used here could be considered somewhat unorthodox. Essentially, the tone controls (Treble and Bass) are turned all the way up at noon on the dial. Anything past this increases the gain of that frequency range. You can actually dial in more drive for the treble, bass, or both as you increase past noon. The other factor is less present, but still a contributor, and that's the EL84 power section. By default, these tubes are still going to have some grit and harmonic distortion even at lower plate voltage. Of course, this level of harmonic distortion may not even be perceived by the listener, and nonetheless is pleasing to the ear.

Why would an amp made for pedalboards not have an effects loop?  I thought that would be a given.

Good question!  Typically, if you're using overdrive from your amp's preamp section, it is sometimes better (not always) to use an effects loop. However, when the preamp is sending a clean signal to the power section, it really doesn't benefit the signal to go through an effects loop.  Since the M12 (with it's high headroom, clean EF86 preamp circuit) produces a clean signal that's being sent to the power section, running pedals on the front end would be recommended.  The exception to this may be if you're using rack mount effects processors that run on "line level" signal.

Truth is, most pedal junkies that we know that have amps with FX loops don't ever use them. They just go straight in the front *even if* they are getting some of their overdrive from the amplifier's preamp stage.

If someone wanted, say, a half power Dr. Z Stang Ray would this put them in the ballpark?

Very close. Maybe even better.   I'll explain. I really dig the Stang Ray, but it's not the amp for me. It's a *real* players amp. I'm okay at goofing off and jamming around on guitar, but the Stang Ray is less forgiving than other Z amps. It's very dynamic and percussive. People with great control of their pick attack and left hand technique can really make that amp sing. In my hands it just pisses me off.

Well, the M12 is indeed like a half power Stang Ray, but it's more forgiving. Don't get me wrong, though. It still has plenty of dynamic and punch, but not as much as the Ray. I have to agree with Z on this one... It's got very similar headroom and clarity like a Stang Ray, but slightly smoother and more forgiving like a Z Wreck.

How would you say the headroom compares to a Maz 18 Jr ? Less headroom or more ??

Well, that's hard to answer in one sentence. Depends on perspective. Side by side, db level to db level, they're very similar. Comparing them on paper, however, and the M12 has a good bit more headroom.  I realize this sounds confusing, but let me clarify...  The M12 is less watts, but more clean headroom. When cranked to 85% of it's volume, it's still relatively clean. When the Maz is at 85%, it's already overdriven a good bit. Thus, the M12 has more headroom.

Now, where the M12 will shine is while it's still making clean tones, you're in it's "sweet spot". While the Maz is an excellent choice for a pedal amp, it likes to be cranked, and when it's cranked it starts to really color the signal. This coloration, while absolutely awesome (yes, the Maz is my favorite amp), it's not exactly going to deliver precisely what your pedal is giving it.

I like clean with headroom but with that bit of cookin' warmth. I also use pedals.  If this thing can hang in a gig situation - that is, mic'd for the FOH (front of house) but enough stage volume to be heard over drums, etc. - then this would be a perfect amp for small to medium clubs, right?

As far as hanging with the rest of the band in a mic'd situation, it really depends on the band, type of music, gear, sound guy, etc. You know how it is... One man's quiet is another man's loud. I have found that some bands understand being mic'd up, and they keep their stage volumes at reasonable levels. Other bands crank their stage levels regardless of being mic'd or not. I've seen metal bands with low stage volume, and gospel bands splitting eardrums.  But realistically, we are just talking about 12 watts. It's gonna be close. I'm just not familiar enough with your situation to even come close to making an educated guess.

Josh here at the store played it successfully live with his band, and I'd probably label call them Alt-Country. Andy here did the same at his church playing modern contemporary Christian music. Both felt it was loud enough for those settings.

I have a Maz38 Sr.   How does the clean AND overdriven tones differ sonically between it and the M12?

I didn't compare the two side by side, but from memory I'm going to say they are similar overall, but the Maz is a touch more percussive, and the M12 is a little thicker in its sweet spot.

Now, I want to talk about this "thicker" word I just used. When discussing amps of two radically different wattages (radical at least in the world of EL84's) we have to compare things relatively. When I say "thicker", that would be in a world where the Maz 38 made the same db levels as the M12. Remember that the M12 was designed to do its thing at lower volumes, so it'll never hang eye to eye with a cranked up Maz 38. I realize you know all of this, but I just don't want someone thinking the M12 turned up 90% will come across thicker than a Maz 38 at 90%. The higher wattage will push more air on the bass notes and be perceived as thicker, but it will be LOUD. We all know this, right? 

I need something with lower wattage to get that tonal sweet spot, but almost every amp I've tried (including the Carmen Ghia) thats really low wattage (12, 18 watts, etc) the tone just isn't as full and doesn't have a big enough bottom end for me. That's why I usually take the next jump up in wattage (30-ish). If it helps - I am the type of player that wants greats cleans and a little breakup that still works great as a pedal platform amp.

We see this all the time dealing with the lower watt amps. Unfortunately, since I'm not familiar with your specific situation I don't have a definitive answer for you, but in my experience I have found that it all depends on what volume *AND* bottom end the player needs out of the amp. What we all want is for the frequency range of our amps to be balanced. As we all know, when turning an amp up the first deficiency we notice is in the bottom end. The M12 has plenty of bottom end at a certain volume, but as any 12 watt amp will attest, they just can't reproduce the bass that a big amp can. There is a volume threshold where the frequency balance will start to shift away from the bottom end. The answer to your question lies in where your volume requirement meets your bass response requirement. Unfortunately, sound samples, video demos, and sales guys like me will not be able to answer that for you. The best thing is to get to a dealer and check it out.

With all that said (and in looking back at your question), I do want to add that if you have tried a Maz 18 and it didn't have the bottom end you were looking for, then my guess is the M12 will probably not either. As you increase the volume, it stays cleaner longer than a Maz 18, but it's output is similar to a clean toned Maz 18. Pretty close, anyway.

I notice for a 1x12 combo that the greenback is the stock speaker but that in some of the photos, there's a celestion blue as well. Is the greenback what you guys recommend as the stock speaker for a 1x12 combo? Does that showcase the amp best and represent it's sound best?

Well, when we were playing on the prototypes we played through a variety of 10's, and only two 12's. The Celestion G12H-30 and the Celestion Blue. It really wasn't until the past few weeks that we found out through Dr. Z that they decided the Greenback sounded best with the M12. I am only speculating here, but my assumption is this was done for a more neutral sounding tone as opposed to a speaker that would inject "character" into the tone. Of course, all speaker will inject a degree of character, but for what this amp is to accomplish, and at 12 watts, I can see why the greenback was chosen. We have a shipment of M12s that will be at the store on Tuesday, so we're eager to see how the Greenback does in the 12" combo.

I love celestion blues but will having one of those instead of the greenback impose too much of it's own sound? Considering the purpose of the amp is to be super pedal friendly and neutral, i'm wondering if a blue would be a bad idea. Then again, the amp seems to be pretty voxy on paper so i'm not sure if the blue would be better. With my experience, vox and voxy styled amps tend to be picky with overdrive/distortion/fuzz pedals and i want to avoid that problem.

Personally, I would choose the greenback if the purpose was a pedal platform. If you're looking for that "low powered Stang Ray" that is amp is capable of being, then the blue would be absolutely perfect. The Alnico Blue will certainly color the sound, so you'd have to want that out of a speaker. The blue sounds great in a voxy sounding amp, I agree! But for a neutral pedal amp... I don't think I'd do it.

How did the M12 come to be?

In 2011, we went to Dr. Z with an idea for him to consider.  We sell a huge amount of pedals and amps, and we are always discussing with customers how certain pedals react with certain amps.  Through listening to our customers, we realized a need for a high quality, hand-wired, low wattage amp designed specifically for all those pedal lovers out there.  

In short, we wanted an amp with the following features:

1) Lower wattage 
2) Clean headroom
3) Transparent and not "colored"
4) Basic tone controls
5) Right amount of dynamics, without too much
6) Hand Wired
7) All American!

No one was doing it, and we wondered why...

Well, one reason was apparent.  It's VERY hard to do it right.  In our opinion, to do the job properly the amp had to have a delicate balance of those qualities.  We say "delicate" because these qualities take away from each other if the balance isn't just right.  For instance, a good pedal amp needs to obviously be clean and transparent.  Clean headroom usually comes from higher wattage amps.  Problem is tube amps like to run with the volume knobs turned up in order to get those tube tones and dynamics we all love.  Creating a lower wattage amp with clean headroom in its "sweet spot" is usually a problem, if not impossible.  Another example is the matter of dynamic response.  Too much, and the pedals don't sound exactly the way they were designed.  Too little and the amp will be lifeless and without character.

As everyone knows, we are huge fans of Dr. Z.  Their amps are also known for being extremely pedal friendly (be careful as not all amps are). So, we called the good Dr. and presented him with our dilemma. We knew he was very busy, but to our surprise he took a great interest in the project.  We discussed it several times over the next few weeks before he told us what he wanted to do.  We (Humbucker Music) had initially imagined this as being a 6V6 based amp.  We have somewhat thought of the 6V6 as a hybrid of an EL84 and a 6L6.  Not too British, and not too American.  Clean, but still punchy and dynamic.  The only problem we saw was with the volumes associated with the 6V6 circuit.  We also love EL84s, but at full plate voltage they are not exactly transparent nor low volume.  As many of you know, a Dr. Z running at 18 watts is VERY LOUD!  Quite nice, but not exactly what we would want out of an amplifier made specifically for the pedal connoisseur.

Well, Dr. Z came up with a better idea and it was absolutely brilliant!  He figured an EF86 front end with an EL84 power section with slightly less plate voltage across the power tubes, by way of the 5Y3 rectifier.  It produced 12 watts, had headroom, was very transparent, but still retained the necessary amount of punch and dynamic, all while remaining uncolored.  Genius!  Dr. Z had found the cure!

He sent us a couple prototypes over the months to check out and troubleshoot.  Incredible results!  Every pedal we tried sounded better than through other amps.  When running several different overdrives, we noticed the differences between them all were greater than previously thought when running through other amps.  In other words, if you have two overdrive pedals that some people think sound the same, you may very well be able to tell the differences with this amp.   While beta testing, we also noticed something we didn't quite expect.  The M12 is VERY fun to play without pedals; just a guitar plugged right in to the input!  It's certainly quite dynamic and articulate, but not so much that it's not user friendly, as some amps are.  The dynamics were very easy to control.  It also seemed to exaggerate the subtle differences between very similar guitars.  Of course, that wasn't at all what it was doing, but it did seem that way since most amps don't have the clarity of this one, and even those that do are much higher wattage (and loud!) .  Even though we feel the M12 is the perfect pedal platform amp, we're certain it'll also find its place among those wanting a clean amp with plenty of punch and tone at a lower volume.  It's important to note that this is still a Dr. Z...  Even at 12 watts, it's a loud little dude.  No, it's not going to "keep up" with your bandmate's Twin Reverb cranked on high, but it'll probably surprise you how much umph it's got behind it.

Anyway, we were quite excited about the M12 and offered to commission Dr. Z to build us a large run of these amps, but in fairness to his other dealers, he respectfully declined.  We agreed with his feelings on the matter, but you can’t blame us for trying!  :)