MT15 after a few months...

BrianC

more toys than talent
Joined
Apr 26, 2012
Messages
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Location
Naperville IL
So I have had this amp for a few months now and I must say it was a smart buy. I have 4 amps and this one just keeps impressing me. Such a big band for the buck.

I switched the V2 tube today to a Mullard after also trying a TungSol. Each tube gives it a little different tone and voice in this position. It almost makes the amp a new experience. I am very happy with it.

Being a Marshall guy and going for a more souped up Classic Rock tone the amp is really almost there. The one thing I really want to try in the future is EL34's in the power section.
 
Sweet! Glad you're still digging it. I've been sitting on an NOS 5751 to try out in mine. Need to get on that, one of these days!
 
I've had mine about as long, and I'm having the same experience! Lots of amp in a little box, for a little money. I need to roll some preamp tubes apparently!
 
I have a new Mullard 12AX7 too, but I only tried it in V1. I thought it's made the tone a little too smooth and tame for my liking.
Maybe I should try it in another spot then.

I am liking the Tungsol I put in V1 though.

I'm sort of looking to brighten up the gain channel a bit so I think I need to remove either one or both of the darker sounding JJ's from V2 and V3. Maybe I'll pull an EH from one of my other amps...
 
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I'm sort of looking to brighten up the gain channel a bit so I think I need to remove either one or both of the darker sounding JJ's from V2 and V3. Maybe I'll pull an EH from one of my other amps...
good call, that's what you want to do if you want to brighten up the gain channel.
 
I just got done swapping some preamp tubes, and recording a riff with each combination, to see what I liked best. I have a couple spare current production Mullards, an EH, and a spare Tung Sol (and also already had a Tung Sol in V1) - Unfortunately wasn't able to replace all three slots that run the lead channel with the same kind of tube. But I found that the best combination was the Tung Sol in V1 and the Mullards in V2 and V3. In comparison to the JJ's in V2 and V3, the sound was more articulate, could be perceived as brighter, but really the low and low mid were cleaned up considerably. Looks like I need to order some more tubes, I'd like to try another Mullard in V1, as well as a trio of Tung Sols.

What I've found with cascading, high gain amps, is that usually all the gain stage tubes need to be changed to get the full desired effect. I swapped that single Tung Sol in all three slots (with the JJ's in the other two, respectively), and didn't notice a difference until I took the JJ's out.
 
So I have had this amp for a few months now and I must say it was a smart buy. I have 4 amps and this one just keeps impressing me. Such a big band for the buck.

I switched the V2 tube today to a Mullard after also trying a TungSol. Each tube gives it a little different tone and voice in this position. It almost makes the amp a new experience. I am very happy with it.

Being a Marshall guy and going for a more souped up Classic Rock tone the amp is really almost there. The one thing I really want to try in the future is EL34's in the power section.

I have a new Mullard 12AX7 too, but I only tried it in V1. I thought it's made the tone a little too smooth and tame for my liking.
Maybe I should try it in another spot then.

I am liking the Tungsol I put in V1 though.

I'm sort of looking to brighten up the gain channel a bit so I think I need to remove either one or both of the darker sounding JJ's from V2 and V3. Maybe I'll pull an EH from one of my other amps...

I just got done swapping some preamp tubes, and recording a riff with each combination, to see what I liked best. I have a couple spare current production Mullards, an EH, and a spare Tung Sol (and also already had a Tung Sol in V1) - Unfortunately wasn't able to replace all three slots that run the lead channel with the same kind of tube. But I found that the best combination was the Tung Sol in V1 and the Mullards in V2 and V3. In comparison to the JJ's in V2 and V3, the sound was more articulate, could be perceived as brighter, but really the low and low mid were cleaned up considerably. Looks like I need to order some more tubes, I'd like to try another Mullard in V1, as well as a trio of Tung Sols.

What I've found with cascading, high gain amps, is that usually all the gain stage tubes need to be changed to get the full desired effect. I swapped that single Tung Sol in all three slots (with the JJ's in the other two, respectively), and didn't notice a difference until I took the JJ's out.

For those of you that have rolled some tubes; got any recorded output? Would love to hear the differences.
 
For those of you that have rolled some tubes; got any recorded output? Would love to hear the differences.
Sorry, I can't capture the nuances on tape. A lot of it is feel variation too which I can't accurately explain in words, let alone capture on tape.
 
For those of you that have rolled some tubes; got any recorded output? Would love to hear the differences.

Here's mine - wasn't something I planned on putting out, so it's just a chord strummed a few times, but it worked for me to hear the difference. The first repetition is V1 Tungsol, V2 and V3 JJ, second rep is V1 and V2 Tungsol and V3 JJ, and third rep is V1 Tungsol, V2 and V3 Mullard. I think the last one is more clear sounding.

Signal chain is guitar into MT15, V30, SM57.

https://soundcloud.com/6stringthunder/tube-roll
 
Here's mine - wasn't something I planned on putting out, so it's just a chord strummed a few times, but it worked for me to hear the difference. The first repetition is V1 Tungsol, V2 and V3 JJ, second rep is V1 and V2 Tungsol and V3 JJ, and third rep is V1 Tungsol, V2 and V3 Mullard. I think the last one is more clear sounding.

Signal chain is guitar into MT15, V30, SM57.

https://soundcloud.com/6stringthunder/tube-roll

Thanks for posting that, Andy. Definitely a subtle difference. At least through my monitors. To me, the last one is clearer, too.
 
Thanks for posting that, Andy. Definitely a subtle difference. At least through my monitors. To me, the last one is clearer, too.

Yeah, I’m going to leave the Mullards in for now, and probably order some more of them and Tung Sols as well.

Certainly not bashing the JJ’s, as you said, the difference is subtle. I’ve been using JJ preamp tubes for a long time and will continue to have a stash of them on hand. Plus, how great is it that the MT15 ships with a full complement of nice glass - try finding an amp that price that comes loaded with anything like that! Another reason it’s the best deal out there!
 
Plus, how great is it that the MT15 ships with a full complement of nice glass - try finding an amp that price that comes loaded with anything like that! Another reason it’s the best deal out there!

My sentiments, exactly!
 
Nice clip Andy thanks, I don't have the means to capture the subtleties but I can hear them in your clip.
To me, the Mullard didn't smooth out the gain, I felt they tamed the gain voicing too much in my MT15. Not the gain level, just the aggressiveness.
I have days off upcoming, so I'm going to experimenting with EHs in both V2 & V3 to try and liven up the treble a bit.
I find JJ's are great in my Marshalls and Peaveys, but I don't think they work as well in darker voiced amps, which the MT15 sort of is IMO.
 
Well my theory worked. 2 x EH 12AX7s in V2 & V3 gave the gain channel a nice tight and bright kick in the teeth.
V1-Tungsol, V2-EH, V3-EH, V4-JJ, V5-JJ, V6-JJ
 
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So I have had this amp for a few months now and I must say it was a smart buy. I have 4 amps and this one just keeps impressing me. Such a big band for the buck.

I switched the V2 tube today to a Mullard after also trying a TungSol. Each tube gives it a little different tone and voice in this position. It almost makes the amp a new experience. I am very happy with it.

Being a Marshall guy and going for a more souped up Classic Rock tone the amp is really almost there. The one thing I really want to try in the future is EL34's in the power section.
You’re getting pretty close to the soul of most classic Marshalls. The Mullard 12ax7s need to be old, because there’s no comparison. Add the EL34s and I’ll bet you’ll love it! Even that combination in old Mesa/Boogie amps can coax Marshall personality.
 
You’re getting pretty close to the soul of most classic Marshalls. The Mullard 12ax7s need to be old, because there’s no comparison. Add the EL34s and I’ll bet you’ll love it! Even that combination in old Mesa/Boogie amps can coax Marshall personality.

Who makes the new Mullard tubes, how are the old ones different? I bought some, knowing full well they probably wouldn't be comparable to NOS, just wanted to try them since they're out there. So far I like them for what they are, and having never tried the old ones, I don't have to know what I'm missing out on!
 
Who makes the new Mullard tubes, how are the old ones different? I bought some, knowing full well they probably wouldn't be comparable to NOS, just wanted to try them since they're out there. So far I like them for what they are, and having never tried the old ones, I don't have to know what I'm missing out on!
"Mullard Ltd was a premier manufacturer of electronic components. Founded in 1920 in Southsfield, London, Mullard became known world wide for their reliable, high-quality components and vacuum tubes or "valves". The Blackburn factory in Lancashire was the source for Mullard's best sounding tubes. Vacuum tubes constructed in Blackburn are considered to be some of the most influential audio tubes ever made. The most famous of these include the EL34, EL84, ECC83 (12AX7), ECC81 (12AT7) and others. Today's new production Mullard tubes are constructed with the same commitment to quality and reliability. New production Mullard tubes are assembled by hand in the Reflektor factory in Saratov, Russia and their excellent performance closely mirror's that of vintage Blackburn construction."
 
I don't have to know what I'm missing out on!

Actually, you might want to know, because not all NOS is prohibitively expensive. Please read on.

New production Mullard tubes are assembled by hand in the Reflektor factory in Saratov, Russia and their excellent performance closely mirror's that of vintage Blackburn construction."

Unfortunately, that’s more marketing-speak than truth. Boogie’s right about this.

The new reproductions are superficially similar, but inside the tubes the internal parts quality and tolerances are not the same, and even how the plates, getters, and other subassemblies are put together isn’t the same. I’ve seen enlarged photos showing the differences, and it’s interesting to see how many corners are being cut in tube manufacture today.

Back in the day, folks had to depend on tubes for more than guitar amplifiers and retro audio gear. There was medical equipment, aircraft controls, military communications - hell, even car radios were tube. Everything electronic depended on tubes.

In other words, the product was infinitely more essential, and had to be rugged and reliable.

Tube manufacturing was a big, cutting-edge industry back in the day, and specialists with lots of technical experience making the best they could were in it. Today’s equivalent would be the semiconductor industry. Those generations of experienced tube technicians and engineers are no longer active.

The differences in manufacture also extend to the machines; the machinery used in Eastern Europe and the Far East was mainly bought from the West when the West stopped making tubes, by 1979 or so. Most machines were already pretty old at that point. The machine tools were also old.

Add all these factors up, and it’s little wonder that new and NOS tubes behave differently electronically and sound different.

I first became interested in NOS tubes around 15 years ago, when my first Two-Rock came with them. I had several conversations about them with the amp’s designers, and started trying NOS in other amps. Turned out it was indeed a pretty big deal.

Because these days preamp gain is more of a thing than output tube gain, the preamp tubes are the place to begin experimenting. Few players are driving output tubes very hard any more.

All three of my amps have NOS preamp tubes, and two have NOS output tubes. The output tubes in the third amp will be replaced in a few months with NOS. My experience is that the output tubes matter, but start with preamp tubes.

NOS tubes make a very good amp better, and a great amp that much more satisfying to play. Of course, this presupposes that the player groks the difference between very good and excellent tone. Some do, but most haven’t the listening experience at first. But take the NOS away after getting used to having them in an amp, and they’re missed, as in, “Where’d the tone go?”

My feeling is that while subtle at times, the biggest difference using NOS is being satisfied with my tone, long-term; by that I mean spending years with an amp and not feeling vaguely dissatisfied. Not casting about for some new ear candy all the time as I once did. Most of us have had that experience, that their amp for whatever reason isn’t cutting it any more, and surely there must be something cooler and more toneful to shop for! But at this point, if I buy a new amp it’s to add different types of sounds, not to find something that sounds better at the types of sounds my amps make.

In terms of dollars invested, even the rarest, and/or best sounding tubes are much, much cheaper investments in the long run than buying and selling amps in search of ever-elusive audio satisfaction. As for reliability, in 15 years I’ve had exactly one NOS preamp tube go microphonic, and one NOS output tube get a little noisy. The preamp tubes, of course, last for decades, while output tubes are more prone to wear, but NOS will still last substantially longer.

I’ve had many new-manufacture tubes go bad within a few days or weeks, and don’t even get me started on new power and rectifier tubes blowing like cheap lightbulbs.

For ultra-high gain players, though, NOS may be too smooth. They might prefer modern tubes that the circuits were designed to take advantage of. So as with everything tone-related, YMMV.
 
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Very well conveyed, Les! The only things I have to add are experiential: two situations left me slack-jawed and in awe of what I was hearing, and both involved NOS preamp tubes. Using my MkIII as a test base, the NOS Mullard 12ax7 in V1 made a tremendous impact compared to M/B labeled tubes in the same spot. In ch2, setting the amp as a single channel amp with master high and volume low (the exact opposite of how you typically set a Mesa amp) it simply sang with different harmonics as the stock tubes. The harshness was gone, the mids were very Marshall-like. With a mix of EL34s and 6L6s in the power stage, the amp was transformed into a totally different animal. Not like a Marshall, but a Boogie with Marshall influences...the good ones!

The other situation was using RFT 12ax7s in all 3 locations (V1, V2, and V3). Particularly in V3, it blurred the grind and darkened the amp in a way I didn’t think possible. I instantly understood why Diesel used these exclusively in several of their models. Almost like putting a choice fuzz in front, but not fuzzy or fizzy, but very very musical. Highly recommended.

I spend a lot of time Kempering these days, but when I pull out my amps, I cook the crap out of the power stage. There is no substitute for power stage overdrive and it was something I adopted late in my musical life. Mostly because I had a Mesa/Boogie amp that did not subscribe to this philosophy. So if you’re using a high gain amp that doesn’t lend itself to leveraging power stage distortion, then I implore you to find a friend that does and experience this phenomenon. It’s simply magical.

Btw, my NOS Mullard is currently sitting in V1 of my Super Dallas with also has an EL34 backend. It is glorious and noticeably different from where it was with the stock TAD 12ax7.
 
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