Something Old...

fiddlefye

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.... is much better than new again. Yes, I am talking about my dear old CJ MV-45. We've been together a long time now - three and a half decades - and it was love at first listen and ever since. I bought it (for $400) when it was still a five-year-old puppy. Until recently the only work I had done (apart from changing tubes) was to have the electrolytic power supply caps changed when they started to slump. Not too bad for a forty-year old. Recently the original RCAs started to get iffy and I figured that the time had come to do the whole restoration/upgrade if it was all coming apart anyway. It apparently isn't the easiest amp to work on, but it didn't take that much convincing to get my tech, Dennis to do the job.

The MV-45 is a pretty straightforward amp - PP EL-34 (I've been running Gold Lion KT-77s for some years now), one 5751 and two 12AT7s. I usually get a year and a half to two years out of a set of outputs and a decade out of the signal-level tubes. As is typical with CJ, biasing is an easy job involving a screwdriver and some LEDs. It runs the output tubes pretty hard and some tubes don't stand up very well to the treatment - Sovteks were never good for more than a half year (and sounded grainy in the bargain). The GLs seem to hold up really well, as good as the NOS Mullards I've run a couple times in distant past when they were more affordable.

There was a lot replaced - all-new high end wiring, new op-amps for the biasing circuit, RCAs, all carbon resistors gone, all new caps. There were some particular Mundorffs he really wanted to use and because they wouldn't fit on the board he made up a couple of "daughter" boards for them. The PS now has silicon carbide diodes in the rectifier bridge. The ground arrangement was completely re-thought as well. We considered installing an IEC-type power cord and some modern binding posts, but the compact nature of the box just didn't allow for such niceties. As it turned out there had been some horrors happen to the amp before I got it - a resistor had apparently exploded and burned, scorching the bottom of the top plate and a bit of the board. To add insult to injury it had been replaced with something of quite inferior specification. All water under the bridge now, but...

Testing revealed the following results - 40 w/ch - 20Hz - 20 kHz (rather than the more usual tube amp standard from 30Hz - 15 kHz), top end dead flat to beyond 20 kHz.

I got the usual box of rejected bits to bring home. There were a few.
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The MV-45 is not one of the "blingier" amps in history. To me it just has a certain utilitarian elegance that I like just fine.
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Time for bed. Listening impressions tomorrow...
 

billfort

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A long-term love story, very cool!

I too was very happy with an old CJ piece (MV-75A1) and had it for years before diving into the low-power SET world. Some blew off CJ from that era (caramel colored presentation, too tubey, blah, blah) but I loved that amp - it just made music like nothing else I tried at that power level or above.
 

fiddlefye

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A long-term love story, very cool!

I too was very happy with an old CJ piece (MV-75A1) and had it for years before diving into the low-power SET world. Some blew off CJ from that era (caramel colored presentation, too tubey, blah, blah) but I loved that amp - it just made music like nothing else I tried at that power level or above.
No one who heard my MV-45 at any point over the years I've owned it could accuse it of "caramel coloured presentation" or being "too tubey" etc. - like many things in audio those have over the decadess become truisms. Yes, the early CJ amps are often spoken of in somewhat derisive terms. Some of the next generation or two after mine that I've heard did sound a bit "darker" than average perhaps? My MV-45 is remarkably neutral and (especially now) extended beautifully out to the extremes of range. What it does is produce some really delightful harmonic complexity through the middle range that creates a really seductive engagement. Strings (for example) are reproduced with a glow of reality that other amps I've had through simply don't manage.

Dennis and I (and for a time another chap who dropped in) listened to the amp before I brought it home and had a long chat about what the "secret sauce" is that CJ put into the recipe for the amp. Dennis had recently done a no-holds-barred restoration/upgrade (all of the same stuff as my amp, plus total cosmetic job) of a pair of MC-30 monoblocks which had not been picked up yet. His opinion is that (much to his surprise) the renovated MV-45 is at least as good, just with slightly different presentation. What he decided makes it all work is that there is that added bit of seeming "lushness" through the mids that then blends seamlessly into the extended top end. All is so subtle it doesn't appear when doing measurements where it all looks about as flat as any good SS amp. So it is not "mid-range bloat" from a measurement standpoint.

So, what exactly did they do to create that bit of magic? Jury's still out on that. All I can tell you is that Dennis has decided to get one for himself to get the same treatment as his personal amp. Fortunately there is one floating around town. When I bought mine from local audio "legend" John Kornafel (sadly RIP, he was a dear buddy) all those years ago he had two of them (along with hundreds of other pieces - he was a bit of a hoarder). John tried for years to talk me into buying the second one and doing them up mono, but I've never required that much power in my system and twice as many tubes seems to me unlikely to sound twice as good. So after John passed his sons sold off his stash and the other amp reappeared in rather miserable non-functional state with blown cap and the cage missing. Dennis did a quick repair so it worked again and someone else bought it and apparently stuck it on a shelf without even plugging it in and listening to it. So Dennis is embarking on a patient quest to pry it out of those hands eventually. He said he'll do some interesting powder coat on the chassis and give it the same treatment as mine.
 
I have a Conrad Johnson amplifier here- a solid state one. Conrad Johnson makes interesting choices, from aesthetics to parts choices and everything in between. I loosely categorize them as the eccentric movie scientists, much like Van Alstine. And that’s not a bad thing by any means- while sometimes the product seems so straightforward as to almost seem simplistic, at the same time it may hide an innovative or creative secret to the circuit, or may use unique parts specified in the layout to direct the end result. And they both have a bit of a cottage industry feel to them. I hope this isn’t misinterpreted wrongly- what I’m saying above are positive things. There’s creativity, or innovation, or both happening in many of their products. I like that.

I attempted to grab some tube Conrad Johnson product in the past but unfortunately the stars weren’t aligned in my favor. I like the tube amps like yours through the MV-60 series and some of the more straightforward preamplifiers with a more neutral presentation than the magnified lushness some have been labeled with.

As for looks- I dig it. It looks older than it is- almost resembles an upscale looking Dynaco ST70 in many ways.

I’m thrilled to hear how this turned out for you. Congratulations!
 

fiddlefye

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Having already pretty much shot my bolt in terms of "listening impression" I'll just describe the moment - listening to Leonard Cohen's 'You Want It Darker'. The amp now has more resolution than anything I've had here before so I'm hearing details in the mix I'd missed previously. Apart from that - the bass has much more depth, variation in colour and is far more articulate than previous experience. Heck, there is much more variety and clarity in timbre in everything as a whole. Same output transformers (obviously), but somehow the soundstage has grown a whole lot in every direction and solidified (is that the word?). Before the work it was already the nicest of any amp I'd owned. Overall the music just has a flow to it and coherence that I really love. The sensibility of the music is somehow clarified - if that makes sense?
 

fiddlefye

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I have a Conrad Johnson amplifier here- a solid state one. Conrad Johnson makes interesting choices, from aesthetics to parts choices and everything in between. I loosely categorize them as the eccentric movie scientists, much like Van Alstine. And that’s not a bad thing by any means- while sometimes the product seems so straightforward as to almost seem simplistic, at the same time it may hide an innovative or creative secret to the circuit, or may use unique parts specified in the layout to direct the end result. And they both have a bit of a cottage industry feel to them. I hope this isn’t misinterpreted wrongly- what I’m saying above are positive things. There’s creativity, or innovation, or both happening in many of their products. I like that.

I attempted to grab some tube Conrad Johnson product in the past but unfortunately the stars weren’t aligned in my favor. I like the tube amps like yours through the MV-60 series and some of the more straightforward preamplifiers with a more neutral presentation than the magnified lushness some have been labeled with.

As for looks- I dig it. It looks older than it is- almost resembles an upscale looking Dynaco ST70 in many ways.

I’m thrilled to hear how this turned out for you. Congratulations!
Your experience in acquiring CJ gear has been the exact opposite of mine. I've tried to make a move on more than one CJ SS amp in past and it has never managed to come to fruition. I'd kinda like that to happen sometime yet, though.

I have a CJ tube pre, a PV-12 and it really is quite marvellous and anything but over-lush. I alternated it with the Anthem Pre-1 for a few years, both being quite neutral pieces. Since I got the TVC they've both been residing in the closet which is really quite a shame, though I'm not sure I'm ready to part with either of them as yet.

As to cosmetics - of the CJ amps only the MV-45 had this sort of design that harkened back to earlier times. Even the MV-75 of the same time period had a look more like what came later. I like it too and the chassis is really compact.at 9.5" x 14". My tech might argue that in terms of working on it things are just a bit too compact...
 
Your experience in acquiring CJ gear has been the exact opposite of mine. I've tried to make a move on more than one CJ SS amp in past and it has never managed to come to fruition. I'd kinda like that to happen sometime yet, though.

I have a CJ tube pre, a PV-12 and it really is quite marvellous and anything but over-lush. I alternated it with the Anthem Pre-1 for a few years, both being quite neutral pieces. Since I got the TVC they've both been residing in the closet which is really quite a shame, though I'm not sure I'm ready to part with either of them as yet.

As to cosmetics - of the CJ amps only the MV-45 had this sort of design that harkened back to earlier times. Even the MV-75 of the same time period had a look more like what came later. I like it too and the chassis is really compact.at 9.5" x 14". My tech might argue that in terms of working on it things are just a bit too compact...
The PV-11 and PV-12 were the two tube pres I had the most interest in. I believe they inverted the signal (phase)- I know it’s for purity of sound but that was the only thing I didn’t like. Otherwise, a solid well executed piece of gear, without the need for fistfuls of tubes to sound great.

I still window shop for them.
 

fiddlefye

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The PV-11 and PV-12 were the two tube pres I had the most interest in. I believe they inverted the signal (phase)- I know it’s for purity of sound but that was the only thing I didn’t like. Otherwise, a solid well executed piece of gear, without the need for fistfuls of tubes to sound great.

I still window shop for them.
A couple of simple upgrades really up the game with a PV-12 - Schottky diodes in PS and upgraded wiring. I count keeping the number of tubes down to manageable levels as a major plus. As I recall the phase inversion keyed into the matching power amps of the era, though I never found it to be problematic.
 

fiddlefye

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Last evening the restoration work on the amp brought out some of the unfortunate aspects of online audio discussion, sadly. The forum and correspondent shall remain nameless, but continued the standard CJ bashing trend (basically over-rated, overpriced junk). I should have binned the amp and bought a Dynaco Stereo 70... The argument presented was that the MV-45 output transformers apparently are shy on laminations compared to the "vastly superior" Stereo 70 type which "have a bandwidth to at least 100kHz". Apparently the "cheap" and "inferior" transformers foisted on the public by CJ will "over-saturate" long before the potential of an EL-34 is realized. Now, I've no idea what the specs on the transformers in the MV-45 might be, but it seems to me that like the RR specs of a bygone era they are "adequate". Wondering where all of this "information" and opinion stemmed from (coming from someone who has clearly never heard the amp) I did a little search and found a few ancient threads with references that almost duplicated the comments, word for word. Such are the repeated notions in our audio echo-chamber reinforced.

Now don't get me wrong - I like the Stereo 70 (when one is really up to snuff) and had really good one stay with me a few weeks some years ago. Not so different in many respects, if a bit less lively in the mid-range and with a considerably leaner and less articulate bottom end. I did suggest that if the gent wanted to come and visit for a listen he was welcome and I'd even supply libations...
 
At the end of the day, as frustrating it is when someone takes joy in deflating your birthday balloon, and it’s certainly a souring experience, when you flip that switch and get that bliss…. That cannot be taken away from you unless you allow it.

I’m always game to read opinions and even learn a few things if presented with some good information, but a big part of my long hiatus from forums was the lack of tact, decorum and civility as well as constructive positive interaction. Bad behavior is bad behavior- if it took place face to face I’d excuse myself from the conversation or at least minimize my interaction with the individual or individuals.

I’d jump at the chance to listen to that amp, and I’d enjoy discussing what was done to that unit to achieve the end results. Having the tech there, plus the addition of libations would make it one heck of an enjoyable afternoon.
 

fiddlefye

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At the end of the day, as frustrating it is when someone takes joy in deflating your birthday balloon, and it’s certainly a souring experience, when you flip that switch and get that bliss…. That cannot be taken away from you unless you allow it.

I’m always game to read opinions and even learn a few things if presented with some good information, but a big part of my long hiatus from forums was the lack of tact, decorum and civility as well as constructive positive interaction. Bad behavior is bad behavior- if it took place face to face I’d excuse myself from the conversation or at least minimize my interaction with the individual or individuals.

I’d jump at the chance to listen to that amp, and I’d enjoy discussing what was done to that unit to achieve the end results. Having the tech there, plus the addition of libations would make it one heck of an enjoyable afternoon.
I would be delighted to have your company in the listening, for certain! I have to say that nothing in the "discussion" last night has done anything to affect my enjoyment, believe me. The exchange (with someone supposedly extremely experienced) just reinforced my belief that there are many roads to Rome. I'm enjoying the scenery on mine...
 
I would be delighted to have your company in the listening, for certain! I have to say that nothing in the "discussion" last night has done anything to affect my enjoyment, believe me. The exchange (with someone supposedly extremely experienced) just reinforced my belief that there are many roads to Rome. I'm enjoying the scenery on mine...
I frequently am told my Dynacos are junk. And before I heard one that was properly working, I may have been inclined to have believed them.

Oh- and folk can get ornery about the front end topology and changes to it. Some are insistent that the original circuit is best. I prefer both the Van Alstine modified circuit and my VTA board although the restored one isn’t a bad sounding unit. It has all the Dave Gillespie mods.

One of the two VTAs runs KT66s. I really like it this way- although that ruffles some feathers too. I understand- the transformers are designed to operate best with EL34s.

I keep that in mind while grooving to the ‘66 bottles.
 

fiddlefye

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I frequently am told my Dynacos are junk. And before I heard one that was properly working, I may have been inclined to have believed them.

Oh- and folk can get ornery about the front end topology and changes to it. Some are insistent that the original circuit is best. I prefer both the Van Alstine modified circuit and my VTA board although the restored one isn’t a bad sounding unit. It has all the Dave Gillespie mods.

One of the two VTAs runs KT66s. I really like it this way- although that ruffles some feathers too. I understand- the transformers are designed to operate best with EL34s.

I keep that in mind while grooving to the ‘66 bottles.
Listening to Glenn playing the Goldbergs as I type (second version) and he's never sounded so good. I never mind the "singing" along the way. I love the flow this amp gives to the music - almost makes it feel like the tempo is quicker, as if that makes any sense!

I am very curious about the KT66s. They're a sort of hotrod version of the 6L6(GC), right? If/when I get my father's old Williamson rebuilt it would be fun to do it so it can run them perhaps? Mono set-up that would be.

I've heard a couple of Stereo 70s that were abysmal and a few that were truly lovely. The one I had here for a few weeks was one my tech did up and it was with a more "modern" small tube set, whichever board that is he would have used (or maybe he did his own, that would be typical). For a while a few years back he seemed to always have one under restoration, but he seems to have stopped. It was a really fine amp.
 

paul_b

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Those output transformers look to be a smaller stack of laminations, yes, but the actual lamination size looks to be one or two sizes larger than what's on an ST-70, so I think I would call that a wash.
 

fiddlefye

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Those output transformers look to be a smaller stack of laminations, yes, but the actual lamination size looks to be one or two sizes larger than what's on an ST-70, so I think I would call that a wash.
Thanks - I wouldn't know how to compare them (especially not having ST-70 transformers to hand) and I don't have huge experience working with varieties of transformers, but they seem to get the job done just fine. I haven't kept the amp as long as I have for sentimental reasons or for lack of having good things come through to compare it to, but it has always been with a little feeling of happy relief that I've put it back in the system. For a couple of decades I've tried periodically to find something I like better and it hasn't happened. Hence the restoration work and just being happy I think. Not that I'm ever against trying new things (like maybe something SET sometime..).
 

Ingenieur

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Nice work. I love the lab instrument 'look'.
The barrier terminal strips are cool to.
She'll be around another 40 years.
 

fiddlefye

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One last mod for the MV-45. As designed it really does run the output tubes quite hot when biased using the inboard LED system so we (as in my tech and I) decided to set things up with some probe sockets so I can do the job with a multimeter and know what I'm doing when trying a few different bias settings. Dennis did a lovely job, as always. The plan is to work out what is the best combination of sound and tube life. Sounds gorgeous backed off a bit. With this last change I think we're done...
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