Converting MV60 to Triode

[rmac587]

Hi Folks,
I’m relatively new to CJ, and I must say I now have all the fanaticism of a recent convert. I was lucky to acquire a MV60 a couple of days ago and I’m enjoying it immensely (I also have a PV10 on hand and a PV5 on the way).

I’d like to wire the 60 for triode, however. I’m fairly handy with a soldering iron, although not a wizard, and I don’t relish the idea of packing this beast all the way across the continent to do a simple conversion if I can do it on my own bench by moving a couple of jumpers and addressing a couple of capacitors, etc.

I’m sure the information is out there, but for some reason I’m not finding it. Can anyone offer me straight forward instructions on this?
Much Obliged, Rmac587

[roberto]

Hola rmac587,

The newer models, the technical info is not available for the users. Why? There are a lot of counterfeit in the past..so for the newer models this info is not available.

You could address your questions direct to service@conradjohnson.com but with much respect, the MV-60 is a jewel as it is. The wide stage presentation, the timbre, the right dynamics, the transparency, the easy listening for any kind of music is marvellous.

To do that conversion, is going to cost an arm and a leg.

Happy listening!

[Big Dog RJ]

Hey Robbo mate,
Hope you're keeping well and enjoying those fine tunes!

Just came across this post: I've owned both versions of the MV60/SE, my understanding is that the MV60 comes standard as triode mode, operating the output stage with EL34's.
If the owner wants to upgrade towards the SE version, which uses 6550C's, that's where the cost of conversion goes up... (Teflons, metal foil resistors & 6550's or KT120's)

However, in this case, the owner wants to go Triode mode, which is already in triode mode, since he has the MV60, not the SE version.

Am I missing something here?

Unless his MV60 is actually the SE version, and now prefers to go triode. This means resetting few things, resistors and only minor adjustments. I don't think this would cost too much though. Plus EL34's are much cheaper than 6550's or KT120's.

What do you reckon mate?
Cheers, RJ

[roberto]

Hola RJ, my dear friend,

Thanks for pointing out it. My mistake was thinking the MV60 as SE model. You are right my friend RJ...now the customer knows that his model is already a class A power amp.
Thank you for the clarification!

Happy listening!

[AnotherJohnson]

It would be a costly mistake to change an SE model back to a non SE model.

It’s the owner’s money to spend as desired, but that’s a guaranteed money loser, and a sonic loser too.

[Big Dog RJ]

That's only if the owner actually has the SE version or not... haven't heard from him as yet...

When I came across the post, and it said wanted to wire for triode, I automatically put together that this must then be the SE version itself. Whereas the standard version of mv60 is already in triode mode using EL34's.

I was just wondering if there's any other triode version that CJ offers but they don't. CJ never went into SET amplifiers either, always push-pull in ultra linear or linear pentode design. Pretty much the same has remained with ARC and VTL for many decades isn't it? Manley Labs does the occasional 300B version but no longer I think.

Anyway, hope all goes well at that end of the triode woods.
Cheers, RJ

[rmac587]

Cheers Roberto, Big Dog, and Another,
Thanks for chiming in! I contacted CJ and the answer was, of course, “you have to send it to us.” I get that they want to maintain control of intellectual property and not have their amp schematics being used to build knock-offs somewhere, but if the amp is years out of warranty and production, why not make it easier for customers who don’t live on the Eastern seaboard? I’d much rather someone local (or me) resolder four pins and possibly four resistors than pay $200-230 US shipping (about $300 AUD) before they even touch it.

I find it surprising they cannot see their way to establishing a single authorized service rep among, and for, the 142,000,000 people who live west of the Mississippi. McIntosh, HQed our east, has EIGHT service reps just in Southern California and Arizona. Manley is local, and frankly, as much as I am now a CJ fanatic, the ability to get service without huge shipping costs will likely play a role in future amp decisions.

Now, am I happy with the MV60? Oh man, CJ gear has been a revelation! I was fortunate to develop a great friendship with a local CJ owner. Hearing his Mv60se and Thalmann modded PV-10 was my gateway to audio heroin. Now, the plan is to compare my 60 and his 60SE, and alternate his modded PV 10, my unmodded PV10, and a PV5 I “accidentally” acquired with a relatively modest “buy-it-now” offer that I didn’t expect to be accepted. That way we can compare the various sound signatures, i.e. modded vs not, KT88 vs EL34, PV5 vs variants of the 10. It should serve as the basis of a separate thread.

RJ, the way I read the manual, it suggests the amp comes wired ultra-linear as it notes “optionally, the MV60 may be reconnected for triode operation at the output stage....” Subtle, but a bit ambiguous. At any rate, I thought it would be worth a comparison if it were a simple process. I did see a post where this was done on a MV55, with instructions, but they ended up preferring ultra-linear. As it stands, I’m just not sure how it’s wired! There are some pictures of the MV55 that should give me enough information, but in terms of doing it on the 60, I can’t be sure it wouldn’t also require a resistor change. On the 55 it is simply moving a jumper over a couple of pins.

The listening session, however, may show the SE version so superior that I end up sending it anyway.
Thanks All!

[Big Dog RJ]

Yes, that sounds about right rmac.
In fact, many of the CJ owners manuals are not too clear... either they address certain areas pretty well, such as specs, tube compliment, fuses to use etc., but other areas such as further technical know how is a miss. I guess they have their reasons. I remember many of our former customers used to say the exact same thing, even though we had plenty of tech support throughout the Sth East Asian region, the majority didn't want to send their gear all the way to VA.

As for which model you have, it will be noted on the serial number plate at the back of the amplifier. My understanding is the standard mv60 uses EL34's wired in ultra linear mode. If you wanted to go triode mode, EL34's can still be used but the mod is required internally, and also the output power drops to about half the rated power on UL mode, if I'm correct?

It's been a while since I've come across these different versions but I think in triode mode, the mv60 would drop to around 30w nothing more. In ultra linear it's around 50w and the SE version delivers around 60w.

Regardless of which version you choose, the mv60 is a marvellous amplifier! It replaced the legendary Premier 11A and MV55, it uses the top grade Transpectral trannys that are only used in the Premier line of amplifiers. I used both versions for many years, primarily a MV60SE partnered with the ACT2 driving Quads and Maggie's, it was outstanding!

I really enjoyed those years of ownership and there's really no better version than the other... it's all about personal preference and you never know, you may actually prefer the EL34's in triode mode. I even once had the ARTsa in triode mode using EL34's driving the very same Quads ESL 2905's, it was mighty fine!

By all means try it out rmac, and decide which type of sound you prefer. Once you hear it, you'll know straight away, and that my mate only your ears can decide .

Cheers, and enjoy those fine tunes!
RJ

[JoshT289]

This is a great forum! I really enjoy reading the back and forth.

FWIW, I loved the sound of the original EL34 MV60 when I heard it at Spearit Sound in Boston upon its release. In my opinion, it's unfortunate that the MV60SE became its de facto replacement instead of a truly parallel offering. I know they were both available, but the MV60 disappeared from the dealers' shelves and the attention of reviewers as soon as the SE version came out. It became a special order product with no marketing. (Actually, that seems to happen to all of the so-called "entry level" CJ gear whenever SE versions are released, which is a shame.)

By the time I heard the original MV60, I already had a Premier 17LS paired with an MF2250 and I didn't feel like I could justify swapping the lovely and "all purpose" MF2250 for the lovely but "limited purpose" tube MV60. And by the time I decided to give it another listen, the MV60SE had replaced it and Ralph and everyone else at Spearit Sound were singing its praises. But to me, the SE sounded dry and etched when I home auditioned it with my 17LS. And it sounded that way to me compared to both the original EL34 version as well as to a used Premier 11 I had home auditioned earlier.

Over the years when I've retold this story, I've been assured by most who respond that there must have been some issue with the unit I auditioned, especially when I point out that I enjoyed (and now own and love) the Premier 11A, which the MV60SE supposedly replaced. I dunno. We all hear things differently, but to me the MV60SE was soulless. My wife really hated it and now praises the sound of the 11A even though she initially didn't want me to buy it (or any other additional amp for that matter, lol).

Long story short, I would opt to leave your MV60 as is in ultralinear because it sounds so good that way. I have not heard the MV55, but the original MV60 sounded to me the way people describe the MV55 as sounding. In fact, I liked it so much that I considered asking CJ to reset my Premier 11A for EL34 tubes but without putting it into triode mode. But I'm not going do that for the same reason that I would leave yours as-is -- I am enjoying the Premier 11A with 6550s too much as is.

P.S. And I'm not against triode mode. To me the venerable Cary SLi 80 only sounded good in triode mode, and very good indeed. It sounded wrong in UL when I home auditioned one years ago.

[AnotherJohnson]

FWIW, Ralph Spear is said (by high muckity mucks at CJ) to have had significant influence on production of some models.

I was once told that the CA150 was Ralph’s brainchild, and that virtually the whole production went to him.

About 10% of them were SE models.

I think one reason that the SE models seemed to supplant the regular versions wasn’t by design, but was because of CJ’s batch build strategy. The regular versions, which were always less expensive, sold out, and remaining inventory was limited to the SEs.

The SE models used the very best parts available. The regular versions used excellent parts, but not the very best.

Many, perhaps most, would not fork over the extra $1500 to $2500 for the promise that after 300 hours, the SE would blow the regular version away. I was the same, until I broke down and tried SE versions. Since that time, I’ve been an SE advocate.

[Joe Appierto]

NT

[JoshT289]

FWIW, Ralph Spear is said (by high muckity mucks at CJ) to have had significant influence on production of some models.

I was once told that the CA150 was Ralph’s brainchild, and that virtually the whole production went to him.

About 10% of them were SE models.

I think one reason that the SE models seemed to supplant the regular versions wasn’t by design, but was because of CJ’s batch build strategy. The regular versions, which were always less expensive, sold out, and remaining inventory was limited to the SEs.

The SE models used the very best parts available. The regular versions used excellent parts, but not the very best.

Many, perhaps most, would not fork over the extra $1500 to $2500 for the promise that after 300 hours, the SE would blow the regular version away. I was the same, until I broke down and tried SE versions. Since that time, I’ve been an SE advocate.

Thanks, that's interesting, and sounds right to me. Ralph's employees told me he was behind a number of CJ's products, including the SE version of the MV60. Ralph told me in a discussion that he liked clean and transparent sound and was not a big fan of tube power amps generally, especially those with EL34 tubes. He preferred the linearity and bass of the CJ 6550 tube amps or pairing CJ tube preamps with their solid state power amps. He also was a huge fan of the CA200, which I recall being released prior to the CA150, so maybe he was the brainchild behind it too.

When I had operational issues with my Premier 17LS, he encouraged me to trade it in towards a CA200, which I did. I think he was convinced the problems were in my head because he couldn't replicated them and neither could CJ, lol, but that's OK. He was quite generous with the trade in / exchange offer even though it was two years after purchase and I didn't even ask him for a resolution. I was fairly happy with that CA200. The treble was extended but sweet and the bass was strong. But it was a bit lean in the midrange for my tastes, so I ended up selling it a few years later.

Ralph was also a huge Krell dealer. He sold me a KAV300i before the CJ stuff, which I pretty much hated. I remember thinking later that the CA200 was essentially a very good sounding version of that nasty little Krell, lol.

I really like Ralph. I understand he's enjoying retirement. I looked at his current NOS and used inventory online before deciding to buy a used Premier 11A.