CJ Integrated and Klipschorn

[Conductor]

Just bought a used Conrad Johnson CAV50 integrated amp to drive my Klipschorns. Has anyone here used or heard this combination?

[mobile homeless]

Ahhhhhhhhh..... So this is what you bought. Well, I have to say you are probably going to be very happy. Although I have not heard the CAV50 with any of the Klipsch vintage speakers, I have heard the amp in several systems and actually thought of getting it at one time.

The amp is really based on the MV-55, a sweet little EL-34 amp that was just replaced with the MV-60, an amp I have not heard. I have listened to both the MV-55 and CAV50 and thought the CJ integrated really had a nice tone and was very musical. If you enjoy combo jazz and classical, as well as jazz vocals, it will serve you well. I can only imagine good things with the Klipschorn. It is also one of the few amps that looks as good as it sounds, surely better looking than the Wright Sound 3.5, if not quite the equal in sound in all ways. Make sure you ditch the ulgy cage and let the tubes and chassis be more visable.

Of course, the push pull CJ CAV50 will not sound as open and unfettered as a good SET such as the Wright 3.5. One thing you can do is have this amp wired in either triode or pentode mode, just like they could do with the MV55. While you will be cutting the watts down in the 20s, wiring in triode mode would bring about a more liquid and relaxed sound and will be MORE than enough to get the volume up via your 104dB Klipschorns.

Others were talking about Audio Research amps recently and I think the Conrad Johnson seem so much more musical, at least the products based on the EL-34 tube and not the 6550.

In fact, there is a CJ CAV50 right now on Ebay for a very good price still...that is, before some dremel runs the bid up.

Let me know how you like it. Hope you have a good source to go along with it. You still need a good SET amp to try with your Klipschorns as you wont believe it... You might never go back.

kh

s y s t e m

Linn LP-12/Linn Basic Plus/Sumiko Blue Point

Rega Planet

Cary Audio SLP-70 w/Phono Modified

Creek OBH-12 Passive Preamp

Welborne Labs 2A3 Moondog Monoblocks

DIYCable Wire - Various

1977 Klipsch Cornwall I

Alternate Components:

EICO HF-81 - btw, perfect Cornwall match

ASUSA A-4 EL-34 UL

ProAc Mini-Towers

EICO HFT-90 Tube FM Tuner

Sumo Aurora Tuner

Nakamichi CR-7af>s>

This message has been edited by mobile homeless on 12-05-2001 at 04:27 PM

[arco]

Good buy!

I also owned an MV-55 (before I acquired KH's, though...) and I have been quite amazed with the sound of the amp, especially after a comparison with the big transistor CJ MF-2300...

The real reason for my post is that I wanted to stress out the fact that, if you connect your EL34 pentodes in "pseudo triode" mode, you get - as MH says - even better results. Please note that the mod is CJ approved and very easy to perform, either with the help of a dealer, or by asking CJ for the relevant schematic.

Aristidis

www.aca.gr/pop_coumpas.htm

This message has been edited by arco on 12-10-2001 at 03:00 AM

[leok]

Conductor, mobile, & arco:

This is not easy to resolve; too many variables. I think I see pentode, triode, push-pull, and ultra-linear.

I use 2 Heath W5Ms, which use triodes for initial gain, phase inversion, and driver, and then KT66 (beam tetrode) as output, with g2 connected for ultra-linear operation.

Two of the 4 Sovtek KT66 output tubes I was using lost their ways and I settled for 4 Chinese "Valve Art" devices. The Valve Art tubes seemed to suffer from excessive Miller capacitance so the W5Ms sounded cutoff at 10KHz or so.

Now to the triode pentode stuff: I rewired the Valve Art KT66s with g2 tied to a convenient 400V dc, so that it would perform its original function as a Miller capacitance block. This was successful and upper harmonics have returned. But now I really wonder:

If Conductor wires his EL34s in triode mode, will he lose high frequency capability because the EL34s that he has have too much Miller capacitance? Are there EL34s that will be better suited to the triode connection.

The CAV50 is wired ultra-linear, I think .. not pentode. Is ultra-linear (which looks very much like triode except that the g2 "feedback" and Miller capacitance is reduced) not a compromise to minimize the odd harmonic distortion of the pentode and also the even harmonic distortion of the triode.

Note: mobile, I think your HF-81 is an ultra-linear configuration of the EL84. If that is perfect, what is the difference between it and the Moondogs. Or, are the Moondogs really more perfect.

I have heard the EL34 in ultra-linear mode in a revised Eico ST-70 and that was impressive. Is that similar to the CAV50 "sound?"

Eventually these questions work back to the speakers. While mobile listens to Cornwalls, I use Forte IIs and RF-7s (both modified), and Conductor listens to something. Of what we are hearing, how much is amp? how much is speaker? And, how much is source or room?

Thanks to mobile, Conductor and many others at the Klipsch Forum for informative and enjoyable discussions. By the way, Thanks to everyone also including Gregorius, Colin, and others, for the most entertaining, but much too fast-moving for me, thread: "DecWare Amps."

[arco]

leok,

In the CJ MV55-CAV50 the only thing you have to do (to wire for triode mode...) is to move - by resoldering - two jumpers and remove two small capacitors. After this simple operation, the amplifier works a treat, without any problems whatsoever...

Aristidis

www.aca.gr/pop_coumpas.htm

[leok]

arco,

Hmmmm, I wonder what that cap does.

But mostly, what is the difference in the sound. The circuit difference here, and please correct me if this is wrong, is between a Williamson circuit (the one with the triode connection), and an ultra-linear circuit. I would have expected lower distortion with the ultra-linear connection, but maybe not, or maybe there are other tradeoffs. So, can you describe some difference in the sound?

thanks.

[mobile homeless]

Hmmm... Lordy. A lot of questions...

I'll see if I can sift through some of them. First of all, when I refer to these tubes being pentode, I am just referring to the tubes themselves. You are correct in saying that the CAV50 and MV55 are indeed wired in "ultralinear" mode as stock from the factory. Ultralinear is supposed to give you the benefit of some of the triode sound except with pentode type power handling. It is a suitable compromise in some instances and many amps are wired in this mode. Cary is one of the manufacturers that made it possible to switch in and out of triode mode via a switch mounted on top of the amp. Given all things being equal, especially high sensitivity speakers, I would tend to prefer the EL-34 (pentode tube) wired in pseudo-Triode. The EL-34 wired in triode sounds pretty damn musical, all things considering. I would think he would get any rolloff in the highs, just sweeter mids and a more relaxed, natural sound. The entire spectrum would be slightly less strident. On the other hand, one might lose a bit of the punch of the more powerful Ultralinear mode. Still, given his speakers, I think Triode wired is the best option by far. Actually, CJ does not advertise the conversion to triode in the CAV50 (like they do in the old MV55) but I am quite sure it can be done. I would recommend it with something like the Klipschorn and any speaker that is not a hard load. I just am a fan of triode sound.

As for the little EICO HF-81, it is not wired in Ultralinear mode; it is actually a Williamson circuit and is a very classic design with an all triode front end. I thought it easily beat out the Jolida 302b wired in Ultralinear or the ASUSA A-4 (another EL-34 amp) in Ultralinear also. I think this has more to do with the great circuit and the excellent output transformers, something that REALLY makes an astounding difference in tube amplifiers. The little EICO also has tube rectification, something I have always preferred over solid state rectified amps. Tube rectification sounds more natural and relaxed sounding and seems more linear to me as well. The power supply has such an important roll and it is VERY audible even though some consider it out of the signal path so less important. A good PS can make or break an amp. None of the above EL-34 amps happen to be tube rectified except the early Cary SLA-70, EL-34 amps.

As for the difference between my 2A3 Moondogs, they are actually in another league. They use the 2A3 tube which is actually a TRUE triode tube unlike the amps above which use pentode tubes wired in triode. A pentode is a five element tube while the triode is a much more simple valve with only three elements. The 2A3 Moondog Monoblocks are Directly Heated Triode(DHT) SET amp, the simplest amplification device there is. A single-ended triode amp amplifies the entire signal as a whole, not splitting it letting another tube handle the negative half. Hence the SET amp does not induce distortions from splitting the waveform like a push pull amp. As said, it is the simplest amplification device and does VERY little to corrupt the signal. There is no crossover distortion which is evident in PP amps.

And finally, most SET amps use ZERO NEGATIVE FEEDBACK... Negative Feedback tends to improve specs and dampening ability but CORRUPTS the actual sound and decreases the amp's actual performance letting the musicality factor suffer.

What the SET amplifier offers is the most magical first few watts of any amplifier made! The realness, naturalness, musical nature, with utter open and clear sound is just something else and not equaled by ANY solid state device I have heard.

Obviously, if one is running super sensitive horns in the 104dB range, the first few watts is what really count as that is all it will take to drive speakers of this nature to realistic output levels.

The Klipsch vintage horns are REALLY made to take advantage of the wonders of SET amplification. Most of the negative comments by those within this forum come from people with no experience with SET amplifiers or with the wrong associated components. Obviously, a good SET amp is really demanding of all things upstream, very much like the Klipsch vintage horns.

As for the sound, it is the most immediate, life like, open, natural, unfettered, alive sound you will experience, making most other amplifiers sound pedestrian. The midrange is so magical, it is almost impossible to describe. And if properly designed with good output transformers, the SET amp is ANYTHING but rolled off, extending in both directions with amazing clarity and detail. And this is MUSICAL DETAIL, not overly etched and hyped detail many are used to with solid state amps and even PP tubes with solid state rectification.

Hope this answers a few of your questions. It might raise many more...

kh

This message has been edited by mobile homeless on 12-12-2001 at 03:11 AM

[arco]

I think MH said it all...

And, yes, you can do the mod on a CAV-50 which is nothing else than a passive version of the PV10A preamp, combined with the MV-55, in the same chassis. To be exact, you get 45W/ch and 22W/ch in pentode and triode modes, respectively (CJ specs.).

Cheers,

Aristidis

www.aca.gr/pop_coumpas.htm

[leok]

mobile, arco, Conductor

Based on the above discussions, I tried a few experiments with my 2 Heath W5Ms.

The amp is normally configured as ultra-linear with KT66s biased dissipating just over 20 Watts each, at idle. One of my Sovteks died so I had only a set of Valve Art tubes which seemed to lack high frequency capability.

I had re-wired the g2 directly to 400V dc to operate in tetrode mode, which is designed to reduce Miller capacitance and improve high freq. response. This worked, but there was clearly some distortion at the high end.

Mobile strongly recommended the triode configuration, so I tried it; connecting g2 to the anode. I had expected high frequencies to vanish, but they didn't. Much of the high end distortion also vanished. What was left was some swirly sounding stuff on the "S"s.

Mobile even more strongly recommended single-ended triode so I disconnected the signal input to one of the KT66s (leaving it in to balance the bias into the output transformer). This was very good. In fact, this was much better than I would have thought. The sound was cleaner, more articulate, and the swirly stuff was gone. At this point, what I had was very much like a big operational amplifier, with a voltage gain of 10, and a single-ended output. This is a really cool thing and one would do well to stop there.

But Mobile also mentioned that single-ended triode with no global feedback is worth a try, and there are plenty of reviews that agree. Also, there is plenty of engineering that agrees. So I removed the first gain stage and phase splitter (which wasn't helping anyway). The results were very remarkable except that the KT66 had absolutely no local feedback and was scrambling the high end again. So I re-connected the ultra-linear connection to give it some negative feedback (why the triode connection doesn't do this is a mystery to me). This is a tradeoff between high end distortion and upper mid. detail. I'm sure this is the starting point for a real single ended triode amp. The point for me is I have never heard anything that comes close to this. I am completely sold: SET is the way to go. This setup has better frequency response, and greater dynamic response than any amp I've heard, and a soundstage that is alive.

The RF-7s performed well throughout this excercise, as I'm sure most Klipsch speakers would. What impresses me was if I can get the amp right, the speaker is ready to do it justice. More than ever I believe if you don't like what your Klipsch speakers are doing, it's probably what your feeding them. Conductor, as for your CAV50, If you can check out triode mode, do it. You can always change it back, and you might get a big surprise.

[mobile homeless]

Very interesting and very rare within this forum for someone to pertake in such experiments; Great work...and it was obviously a very educational experience and unusual in that you get to hear one amplifier perform with so many different parameters. Granted, through some of those, you may (as you realize) not have been achieving near the full results of the true circuit designed for the application, but at least you were getting a taste of what was to be had.

You sound like a good candidate to actually construct a quality SET amp with good parts and circuit, thus saving much money and quite possibly getting a far, far better product than any commercially available amplifier as commercial products, even those at great expense, or more often than not designed at a price point with compromises made throughout the device.

There are many excellent SET kits around as well as proven circuits that will bring you World Class sonics with only labor and a wise selection of parts such as quality iron and passive components. I am serious in that there is potential to get top class performance here.

Let me know if you are interested in this route as I might have some recs that you might be interested in. That being said, SET amplification is not for everyone but it does offer one of the intimate glimpses into the heart of the music, much like what a good horn can give you in comparison with a regular dynamic speaker.

kh

This message has been edited by mobile homeless on 12-17-2001 at 09:03 AM

[leok]

That's an offer I can't pass up. Let me see .. I could spend the next seven or so years trying to figure this out by myself, or check a few recommended references. I choose the second. I'm real interested in any references you care to share.

Meanwhile, the modified W5Ms provide great listening with the RF-7s or Fortes.

Also, best wishes for the Holidays.

leok

[arco]

leok,

May I suggest those 300B/2A3 monoblocs? I have built a pair myself, just to discover that they work wonders with Klipsch speakers, as they combine a hefty power supply (slam) with a simple Loftin-White circuit (utter refinement). Finally, they are low gain (a rarity nowadays...) and - as a result - completely noise free...

You can have a look at those by visiting: www.diyparadiso.com

Merry Christmas,

Aristidis

www.aca.gr/pop_coumpas.htm

[BBZink]

On 2001-12-11 at 2:37 AM, arco said:

leok,

In the CJ MV55-CAV50 the only thing you have to do (to wire for triode mode...) is to move - by resoldering - two jumpers and remove two small capacitors. After this simple operation, the amplifier works a treat, without any problems whatsoever...

Aristidis

www.aca.gr/pop_coumpas.htm

Hi

Link don't work on how to transfert pentode to triode for a CAV50?

 

anyone have a pic?

regards

[richieb]

In case you didn't notice this thread nears 16 year ago --

[Audio Flynn]

Very cool blast from the past. Mobile always has good points. I bought a chip amp from leok he built from scratch. Sold it back to him. Good folks!

CJ rocks.