CJ Solid State Amp Recommendations

[Timo62]

Hello,

I am considering a solid state amp for summer time use. My Classic 120 is like a little space heater and can be too much at times during the summer.

I am looking for something that runs cool , or just a little warm so not to add heat to my listening room. Also an amp that could be possibly comparable in sound to my Conrad Johnson Classic 120 amp. This would only be a back up amp for when the temperatures become excessive, so I can still listen to my music.

Is there anything in The Conrad Johnson vintage line up that might meet my requirements?

I really have no experience with CJ solid state amps and how warm they become during use. I have owned nothing but CJ tube amps over the years.


Thanks,

Tim

[Big Dog RJ]

G'day Timo,

That's a great solution to have, run a SS during summers and tubes during winters... either way works well in both applications and provides a high level of musicality that's the hallmark of CJ quality.

Although I've used several SS amplifiers from CJ and the few that I have very high regard for, such as Pass Labs, Momentums and Plinius, when it comes to CJ, I would very highly recommend the MF2550SE (no longer in production) sadly...

Once this beauty gets going, she really gets going! It takes a few hours to get upto speed, and sounds marvelous after around 3hrs. The beautiful thing is while this legend of an amp is tuning up, obviously you will enjoy the fines tunes along with the warm up time.

I've used this particular amplifier in my system on two separate occasions, while the monoblocks went upstate for mods/parts upgrade. Although I terribly missed the finesse and warmth of tubes, plus that expansive soundstage, I started getting used to the MF2550SE signature quality, and it is definitely a beautiful amplifier. Very easily handles reactive loads, such as full range stats. So no issues driving reactive and difficult loads, I actually prefer the MF2550SE over the Premier 350A.

Just my personal experience and one of my favorites, apart from the other brands I mentioned.
Cheers, hope all is well
RJ

[Timo62]

Hello RJ,

Thanks for your reply and information on the MF2550SE amplifier. Do you remember how warm/hot the amp would become while in use?

Tim

[Big Dog RJ]

Yes, in fact hardly hot at all.

It runs pretty warm but not hot to the touch. It has an effortless sense of drive, and on soft passages it's really soft! Play it at low levels and it sounds pretty flat... no life, not much dynamics and very mellow, unlike tubes which can be played at the lowest levels and yet you can still enjoy the realism. This was the biggest issue I had with both the MF2550SE and the Prem350A.

However, turn things up a few notches, and things really kick in, then increase those notches a few more and the acceleration in dynamics and speed, plus transient control is outstanding! This is where these SS amplifiers excell, they're not meant for the faint hearted or not suited for late night sessions, definitely not! Thus, is one of the reasons why I prefer tubes, simply because the late night sessions are so relaxing, I get lost in the performance, it transports me to the live event and before I know it, it's 5am!

The Prem350A is even more explosive than the MF2550SE, such that it's bullet like speed and propulsive bass is even more profound. I would say the Prem350A is more suited towards those huge Apogee ribbons or Maggies that were far more difficult to drive efficiently without strain. The Prem350A would also be another superb match with Infinity's of the Arnie Nudell era, such as the Betas and IRS Epsilon which I both owned, including the notorious Renaissance 90 and Kappa' s. In terms of those big monoblocks like Krells, Mark Levinsons, Jeff Rowland, Solution, CH precision, Boulder, Threshold... The Prem350A was one stereo amplifier that could pick a damn good fight with any of these. And matched with the ACT2, it was a formidable combination!

On a "slightly" lesser scale of wallop, slam and thunder, with an added sense of fine balance, more natural tonality, the warmth of tubes and that sense of musicality, rather than just pure brute force, the MF2550SE was that amplifier, it's a fine amplifier! One that I will eventually reach out to.

Of course if you try any of CJ's other MF series amplifiers or even the CA200 or CA150, they're all equally superb! It's just that sense of pristine power and finesse that the MF2550SE holds strong towards its inner core unlike no other.

The other comparisons I would closely relate this level of performance would be Pass Labs, Momentums and the Relentless monoblocks but the price tags are way different! It also goes to show how well designed the MF2550SE really is, especially holding well against these top tier contenders in terms of true amplification. These are not just ordinary amplifiers, they're exceptional in every way, and so is the MF2550SE.

I sincerely think not much recognition has been given towards the MF2550SE, probably due to the way things and terms are handled these days on popular media such as TAS & Stereophile. I can't believe some of the statements these reviewers make, when clearly some of the gear they have high regard for is clearly not the case, simply because I've heard it myself! Anyway, that's a different story, sorry to digress.

Cheers Timo, hope it all goes well.
Best, RJ

[mgttr]

I have a C-J Classic 60SE tube amp and a C-J MF2100 solid state amp. I had the same concerns regarding heat - the tube amp really heats up my small office! I got to wondering as well if the MF2100 would be a decent summer alternative. In addition, I saw a lot of postings on the Harbeth forums from Alan Shaw (head designer at Harbeth) regarding the perils of using a tube amp (inherently high distortion, and non-linear frequency response due to high output impedance). I decided I'd give the MF2100 a chance to see how it well it matched up with my Harbeth Compact 7ES-3 speakers, so I pulled it out of storage and swapped places with the Classic 60SE. I gave it some time to warm up and then sat down to listen.

Right away I heard a big difference in vocals. With the MF2100 vocals sounded thin and strident, and just downright non-natural. They lacked the warmth and harmonic richness that the Classic 60SE tube amp provided. Next I tried a jazz cornet player that I found recently (Kirk Knuffke). I was shocked when the cornet sounded just like a trumpet via the solid state amp! It was very brassy and had a sharp bite – didn’t have any of the mellow tone I had heard from the cornet via the tube amp. Next I tried some tracks with good bass – surely the solid state amp would prove superior there I thought. Nope, I preferred the bass through the tube amp as well! The bass might have had a bit more solidity and definition with the solid state amp, but it didn’t have the body it had with the tube amp – it sounded flat and two dimensional.

Now to be honest, this isn’t an entirely fair comparison. I think the MF2100 was only $1,500 new, and it is a lot older than the Classic 60SE, which sold for $5,000 new I believe. Just on the basis of price alone you’d expect the Classic 60SE to sound better. I think I'm just going to suffer with the heat from the tube amp. That and stay away from the rabid solid state fans on the Harbeth forums! Although, if I found a good deal on a MF2550SE, I might be tempted!

Jerry

[Timo62]

RJ ,

Thanks for your input. As always it is very insightful and very helpful.

I will take your advise in consideration. I do not play my music real loud , so that might be something to consider with MF2550SE. Especially considering it takes some volume to hear its true characteristics. It sounds from your description that is indeed a fine amp to consider.

[Timo62]

Jerry,

I am a Harbeth owner myself. I have a pair of M40.2 speakers and love running tubes with them. A lot of owners use tubes with Harbeth speakers. I know what you mean when you speak of Alan Shaw and other Harbeth owners recommending using only high power solid state amps. I am sure Alan has heard and enjoyed some really good tube amps driving his speakers though.

The Harbeth Compact 7ES-3 speakers are very nice sounding speakers!

Tim

[mgttr]

Tim,

Wow - Harbeth 40.2! You went straight for the pinnacle of the Harbeth line! My 7ES-3 come in at a much more modest price point, and yet I am delighted with them. I can think of no aspect of their performance that I am unhappy with. It's quite possible these may be my last set of speakers! In spite of what Alan Shaw thinks, I feel that tubes are a great match with these speakers. They seem to inject life into the music that I'm not hearing when I use a solid state amp with the Harbeths.

Jerry

[Big Dog RJ]

Yes that's pretty much spot on maties.

With Harbeths they do require some quality power to drive them efficiently and most high-end SS amplifiers do just that.

However, in terms of "quality" not always does SS power mean anything, in regards to power output. For example 100's of watts per channel doesn't mean anything, rather it's the current capabilities and power supplies of the amplifier that will ultimately determine how it drives and controls the speakers. Driving and controlling both in terms of handling its impedence swing plus the amount of drivers it has to drive across the speaker...two-way, three-way, four-way, multiple driver arrays, full range stats or ribbon panels etc.

These aspects all place a load on typical ordinary amplifiers and when asked to perform, sadly they run out of steam...
That's where tube amplifiers take over, and for that matter, you would hardly ever hear of a CJ tube amp running out of steam. They are so well built with extraordinary power supplies and high quality parts that comprise of the main power supplies. This is the corner stone in transformer design and applications that is used in every CJ tube amplifier. Therefore, they are rock solid! Extremely well built and made to last! With these tube amps, they can virtually drive anything. Their high current factors into the overall drive factor which in turn handles difficult loads, that's why all CJ tube amps are factory set to 4ohms. Basically nothing will stand in their way.

Now, considering SS amplifiers, CJ's SS devices are very musical sounding no doubt but not all of them can drive difficult loads. For example, I also had the MF2100 first hooked up to a PFR preamp driving a pair of Paradigm Studio 80 speakers. The overall sound was very nice, quite relaxing and pleasant to listen to, until I would need to crank up a few notches for that awesome dynamic demo or wanting a more powerful presentation from some fine fusion jazz groups... The MF2100 would run out of gas, it would start clipping and the LEDs on the front panel would light up. So obviously volume was turned down and things would settle again but soft to moderate is more suited.

Then we connected a MF2200, things improved vastly and finally we connected the MF2300, oh my! Now we're talking some serious power, great control and drive on the Paradigms to such an effortless affect. The Studio 80's and later on the Studio 100's were just singing beautifully!

After both these power amplifiers were sold, we took delivery of the Premier series, starting with the Prem11a, Prem 12"s and later on the Prem 8's ,which we kept as part of our own reference systems with the ART.

At one point while we were unpacking the Prem11a, we thought to ourselves what possibly could 70watts of tube power do better than a SS power amp having around 250w? As soon as I held it, I realized this is no ordinary tube amp just looking at the transformers and cap layout I could tell this is going to be interesting.

Connected it all up, powered it up and from the very first note- goodness gracious! And that's all she wrote!

The MF2550SE is a far margin of improvement from the MF2100 or any of CJ's previous MF series amplifiers put together. It's a marvelous thing when you get a chance to experience this in any high-end system. And it does so many things right but starts delivering an equally expansive soundstage similar to tubes only after a few hours of play. Until then it can sound flat and cold... once it gets going it's actually quite hard to simply shut off the system and go-to sleep. Every minute, every hour of play, it improves greatly and only then you will begin to appreciate what it can do.

Like I said, it's not just an ordinary amplifier.

CJ's tube amplifiers will always have that classic CJ sound, extended airy highs, superb transient control, top level of transparency in the midrange and that tuneful well balanced bass. Not too much of anything and just sounds right!
I guess this is why JF probably doesn't want to introduce anything for less, just stick with the best and something he's been doing since his very first time at CJ and that is building and designing fine tube amplifiers!

Cheers to that!
Enjoy the music, RJ

[mgttr]

RJ,

I know exactly what you mean - the first time I replaced the MF2100 with the Classic 60SE, I knew immediately that it was something special. The Classic 60SE had a certain magic to it that I had not heard with any other previous amp, whether tube or solid state. That's been my experience with high end audio: when you get a really good piece of gear, the improvements are immediately obvious, and are not something you have to listen carefully to for hours to appreciate. The Harbeths were like that too - I knew right away that they were going to be a huge improvement over my previous speakers.

Jerry

[AnotherJohnson]

For the OP - Premier 350 and MF2550SE are both capable of driving just about anything extremely well.

Compared to my Class A Krells (also solid state) they run very very cool. The heat sink on the MF2550SE, which I use nearly everyday, never gets too hot to touch.

[Timo62]

Another Johnson,

Thank you for you your reply and information on the Premier 350 , MF2550SE and operating temp on the MF2550SE.

[Timo62]

RJ,

Thanks for your input. I agree with what you have stated in regard to the importance of an amplifier's current capabilities and quality of power supplies.

[Timo62]

I normally play my music at low to moderate level volumes.

I am wondering if the Conrad Johnson MF 2275 might not be an option also considering that I would just be using the amp during hot days and not at high volume levels? I would imagine it would depend on how the amp sounds at low to moderated volume.

My Harbeth M40.2 speakers are fairly easy to drive at moderate levels. I also have a MV55 tube amp that sounds really good when driving my speakers. My Classic 120 does a much better job with my M40.2s, but the MV55 is still enjoyable.

[admin]

I don't own the MF2275 but I also listen at low/moderate levels so I don't find myself turning up the volume nob that high. I've never had an issue where an amp performed well at very high volume levels but poorly at low levels. As long as you have enough power, and more importantly, quality power, you should be fine.

[Big Dog RJ]

Yes, Admin is right and totally agree on the low to moderate levels of playback. Infact I think you hear more detail at low to moderate levels.

What I've found with most SS amps I've used in the past, owned, demoed and sold... they all kick in at fairly high levels. That is the level of realism takes form and creates a really good soundstage. The dynamics are more open and the frequency extremes/ transients have this sort of added bite to it, like razor sharp when things are turned up a bit...

Then again I could be wrong, simply because I haven't factored in the room and its parameters, such that it influences the overall shape and form of sound by a significant margin.

Otoh, when it comes to tubes I've noticed regardless of levels it's right there! The whole performance setting right in front of you, the soundstage depth and brilliance in frequency extension is all there. Plus the ability of CJ tube amplifiers to float an image between the speakers as if you could actually reach out and touch the performers, it's a marvelous thing!

The best thing is when tubes are cranked up, they soft clip or at least deliver a warmer tone. Whereas SS gear hard clips and that hard hitting clip is not pleasant! Then again the idea is not to force or overdrive your amplifier/ speakers into clipping plus distortion... that's where the added current capacity comes into play, with their solid design in power supplies and CJ's larger SS amplifiers do just that!

Timo, the MF2275 or the MF2250 are both outstanding amplifiers as well. It's just the MF2550SE and the Prem350A are in a different league. I would say both the MF2550SE & Prem350A are meant as main reference amplifiers not really for substitute gear during summers...
In which case, any of CJ's MF series should match very well with your Harbeths. They will be cruising along...

You could also try out the Evo2000, and the McCormack amplifiers, these were all made and designed in the same factory as CJ. The McCormack amplifiers are also very powerful amps, capable of handling difficult loads, no issues. They also have a good range, from moderate power to high power monoblocks. See what you can find out there and do let us know.

Cheers mate,
RJ

[Timo62]

Hello Admin,

Thanks for your input on low to moderate level playback.

[Timo62]

Hello RJ,

I will take into consideration your feed back on the MF2275 ,EVO2000 and McCormick amplifiers. Much appreciated!

[AnotherJohnson]

I think the amp section in the CA150 is similar to the MF2275.

I have one of them and I use it to run a pair of 86dB efficient Revel M126Be stand mounted speakers.

It does not get hot. And it sounds great at low volume.

Frankly, the Premier 350 and MF2550SE are not expensive ... if you can find them. The people who own them tend to hang on to them.

[Timo62]

Another Johnson,
Thanks for your input related to the pricing of the Premier 350 and MF2550SE and that the CA150 does not run hot.