Mixing and matching - ARC and CJ

[wspohn]

I make equipment changes slowly in my systems and have decided to make such a change in my second system, currently based on ARC SP-14, Classe DR3 VHC, Martin Logan CLS (original).

I wanted to try a tube power amp on the CLS as I had heard interesting/good things about that combination. I looked first at the possibility of an Audio Research power amp, but my SP-14 preamp is just before AR went to line stages plus phono stages and at about the same time switched to XLR balanced inputs/outputs. I decided that 1 - the SP-14 phono stage is actually pretty darned good, and therefor 2 - I wanted to stick with it but didn't want to mess around with cheater plugs to run normal cables into balanced inputs. For one things, they use different voltages and when you are playing with speakers that are only 85 db efficiency you can't stand to reduce input any further. Though tempted by the AR VT130, I decided against it for those reasons.

So for better or worse, I decided to go for another tube brand, Conrad Johnson, from the same vintage (mid 1990s), mentally gritting my teeth at the possibility of a mismatch in corporate sound style. I am using a CJ Premier 14 preamp with a big solid state amp in my main system and have been pretty happy with that, so figured that going the other way might be worth trying.

I picked up a CJ Premier 11a power amp which hopefully will drive the CLS to decent levels with only 70 w (the current solid state amp only has 45 w, but they are burly Class A watts). If things don't work out I can always sell the CJ on to another owner eventually.

I thought I'd solicit advice on choosing a tube amp for that system albeit after the fact as there are a bunch of people on this site that are long time hobbyists and may have experience with the gear in question. (My first thought had been to try a pair of old Quicksilver monos just to see if I was on the right track, but that deal fell through).

Any predictions or suggestions?

[Rob]

the premier 11a wont drive CLS's properly, I just sold my IIa and owned two pairs of CLS's until recently. in fact, the ARC ref110 I owned couldn't adequately drive the CLS and was worse on Acoustat 2+2s I have in house. IME you need 200 watts, the VTL 225s I've owned drove the CLS perfectly as well as the 2+2s. the CLS IIZ i sold went to a buyer w/ a JAdis Defy 7 and he sat in the near field and didn't play them loud, imo it was marginal.

[wspohn]

Thanks for the feedback, Rob.

Were you running original CLS with your 11a, or the later versions? The first iteration was rated for 20 watts up, though hard to see 20 watts driving them well.

The impedance on the CLS was reputed to be friendly for lower powered tube amps - Jack English in his Stereophile review said (emphasis is mine):

Though there is a $2520 "upgrade" available for the I, the CLS IIA is not an updated I. The only thing that isn't changed in the upgrade from a I is the wooden frame—everything else is replaced! The diaphragms, electronics, and transformers are all new. In short, the CLS IIA is an entirely different speaker and should be treated as such.

Considering it an upgraded version creates problems. For example, the CLS I could be effectively driven by a high-quality, low-powered tube amp. The impedance curve ran from 4 ohms at 20Hz through 32 ohms at 1kHz to 2.2/2.3 ohms at 18 to 20kHz. The impedance curve on the CLS IIA has less swing or variance over its range—it's nominally rated as a 4 ohm speaker—but it dips to a low of less than 1 ohm at 20kHz! With a low-powered tube amp this will result in a noticeably attenuated top end. Even higher-powered tube amps like the ARC Classic 120 will tend to attenuate the extreme upper frequencies........

Where low-powered tube amplifiers may have been ideal choices for the CLS I, solid-state amplifiers from companies like Krell and Classé may actually be a better match in a number of situations with the IIAs.

Guess I'll find out!

[mep]

Also, I'm surprised that you like the SP-14. It's really a SS preamp that has one tube in the phono stage. I owned it briefly and couldn't wait to unload it. To me, it was on the bright, white side of the audio spectrum. You certainly have some nice gear in your system and I think your system could benefit from a more modern preamp.

[wspohn]

I never liked the SP-9 in any iteration but like the 14 a lot more. I am not a tube guy and have always gravitated toward solid state gear and especially big Class A room heater power amps. I find the phono stage on the SP-14 quite acceptable and in fact think I prefer it to the more complex dual phono set up in my Classe DR7, a preamp that I doubt anyone here has experience with - never reviewed AFAIK, and few made. I know that I like the SP-14 better than the next rung down from Classe, the DR-6, as I auditioned that preamp back in the day.

I've dabbled in tubes, but only that - the odd Counterpoint and CJ (a PV5) but not on the power amp side.

The system we are talking about is intended as a heritage or period system with an emphasis on playing acoustic music, which I think suits the speakers, so I don't find the SP-14 out of place. Should an errant CAT SL1 cross my path, however, I might reappraise my priorities for that system (they would also be period in their early versions.

I'm not anxious to trade the SP-14 for what might well be a more current line stage, and then have to go looking for a decent sounding separate phono stage.

[Dr.Ears]

I doubt that you are going to like the way the 11a drives the CLS's. As MAP pointed out the SP-14 is really an SS amp with one tube in the phono section, so you are really listening to SS equipment. I would not waste much money on tube rolling with the 11a, there is simply no way, which I see them adequately driving the CLS's given it's tube compliment. I use an SET 211 amp, which adequately drives my 86db speakers, but it is completely custom and puts out more power than an off the shelf SET 211 amp.

[Rob]

Thanks for the feedback, Rob.

Were you running original CLS with your 11a, or the later versions? The first iteration was rated for 20 watts up, though hard to see 20 watts driving them well.

The impedance on the CLS was reputed to be friendly for lower powered tube amps - Jack English in his Stereophile review said (emphasis is mine):




Guess I'll find out!

I'm not putting myself out there as a CLS guru but I have owned and used the CLS Ib, CSL IIa and IIz. The IIz is the easiest of them all to drive and an ARC Ref110 huffed and puffed on them. I have a third pair of somewhat rare CLS Ib that are in my hi fi closet with bad panels, it is a vicious load dropping to 1 ohm in the highs. its no surprise that your DR3 loves them, it was the only amp (in bridged mode) that could adequately drive Scintillas, this was well before Dan D'Ag came out with KMA-200s. your DR3 VHCs are worth their weight in gold.

[mep]

I never liked the SP-9 in any iteration but like the 14 a lot more. I am not a tube guy and have always gravitated toward solid state gear and especially big Class A room heater power amps. I find the phono stage on the SP-14 quite acceptable and in fact think I prefer it to the more complex dual phono set up in my Classe DR7, a preamp that I doubt anyone here has experience with - never reviewed AFAIK, and few made. I know that I like the SP-14 better than the next rung down from Classe, the DR-6, as I auditioned that preamp back in the day.

I've dabbled in tubes, but only that - the odd Counterpoint and CJ (a PV5) but not on the power amp side.

The system we are talking about is intended as a heritage or period system with an emphasis on playing acoustic music, which I think suits the speakers, so I don't find the SP-14 out of place. Should an errant CAT SL1 cross my path, however, I might reappraise my priorities for that system (they would also be period in their early versions.

I'm not anxious to trade the SP-14 for what might well be a more current line stage, and then have to go looking for a decent sounding separate phono stage.

Sorry, I forget that you are juggling 3 systems. If you love the ARC SP-14, that's great.

[wspohn]

Sorry, I forget that you are juggling 3 systems. If you love the ARC SP-14, that's great.

I used the SP-14 for years solely as a line stage with the Vendetta phono stage, but before that had used it with phono stage as well (it took me some years to find a Vendetta for sale given the low numbers made - ~200). The AR phono stage is fine, but I prefer the CJ Premier 14 as a line stage, and of course the Vendetta is a superlative phono stage. I would ditch the AR, which I am certainly not in love with, but would then have to source a new preamp plus phono stage in what is, after all, my 2nd system (I actually have a 4th system, but didn't bother listing it - runs digital in the dining room using some Mission Cyrus speakers and an Audiolab 8000Q and a Bryston 2B, more trickle down from old set ups).

The idea of joining the CJ Premier 14 with the CJ Premier 11a is interesting as they were contemporary and would have been sold often together. Not sure the 11a would drive the Wilson Maxx better than the Roland 5, though. That weighty power amp was much too dark in other systems but seems to conjure some magic with those speakers. And then I have a Belles 'A' amp (ever heard of that model?) in the workshop I just can't seem to part with. I seem to go trhough a spate of mix and match and then settle down for a lengthy period of time..

And if the 11a won't play nicely with any of the other components, I'll just sell it on again.

Interesting that there are such a variety of contradictory reports on how the low to medium power tube amps run the first CLS.

[Rob]

...Interesting that there are such a variety of contradictory reports on how the low to medium power tube amps run the first CLS.

the 'net is rife with speculative posts and armchair quarterbacking, I'm speaking from direct experience. I recall a HFN&RR test of the early CLS and Quicksilver 8417 monos. I cant recall who, either Martin Colloms or KK that suggested it was a good paring. nothing could be further from to the truth! a local dealer at the time had them both and agreed it was a poor match, they demo'd with ARC M100s which they considered--at the time--the absolute minimum (tube power) for the CLS I. my Ref110 was sold to a guy replacing his ARC D-115, he was using CLSs too (small world indeed). I never got his feedback after the sale but he liked the D115 w/ his CLS, so there you go.

And we appreciate that direct experience. :-)

Still have a pair of 8417 Monos; they wouldn't drive Thiels or Maggies either. Probably need a refresh. I'm torn about getting them updated/retrofitted to the EL34 'cause I still have some unused GE 8417s.

[wspohn]

Well, they haven't made it into the CLS system, and may never do so. I stuck it in my main system with the Wilsons and the sound is beguiling - open and not as dark. The 11a may be staying there and the Roland 5 may be leaving!

[MylesBAstor]

You know cj doesn't upgrade or release new products every year and people kind of forgot about the brand. But when Lew and Bill release something, they've done their homework before hand. My ARTs are seven years old and still stand the test of time. That's not to say I wouldn't like to hear a KT150 based ART amplifier.

[MylesBAstor]

I'm not putting myself out there as a CLS guru but I have owned and used the CLS Ib, CSL IIa and IIz. The IIz is the easiest of them all to drive and an ARC Ref110 huffed and puffed on them. I have a third pair of somewhat rare CLS Ib that are in my hi fi closet with bad panels, it is a vicious load dropping to 1 ohm in the highs. its no surprise that your DR3 loves them, it was the only amp (in bridged mode) that could adequately drive Scintillas, this was well before Dan D'Ag came out with KMA-200s. your DR3 VHCs are worth their weight in gold.

Hmmm that wasn't my experience Rob? AFAIK the CLS Z was the most difficult of the CLSs to drive. Tube amps that could drive the earlier CLS model--and that was giving them the benefit of the doubt--just gave up the ghost on the Z-version. Chesky had the 300 wpc VTL on the earlier CLS and it wasn't bad; the VTL gave up the ghost on the Z-version. It was a horrible combo. (I'll never forget him phone call that night!) I just think the load rules out most amplifiers--not unlike the Apogees of the day. One of the worst combos I heard was with a now retired TAS reviewer who used ARC Classic 60s on the original CLS. There was absolutely zip, nada, zero, no low end and because of that the top end was merciless. I thought I saw paint chips falling off the ceiling.

I think one is just looking for eternal frustration trying to drive the CLSs with tubes. But yes, I totally agree with what you said about the Classe and Krell amplifiers.

[Rob]

Myles, the IIz was ML's answer as an easier to drive CLS and my experience has borne that out (lots of discussion on this at the MLO forum). I cant speak for David Chesky's experience using VTL 300's on CLSes, AFAIK his current reference speaker are Quad 57s - maybe his tastes and sonic priorities have changed

[bonzo75]

What about Jadis?

Also look at Berning Quadrazture Z if you get a good used price.

For preamps I would go with a Berning ZOTL Pre One. There is a very cheap one, 1.5k being made by linear tube audio, don't know how that compares to the Pre One, but Pre One is cheap used. It will give you the valve harmonics with a transparency and cleanliness that SS provides, but without the sterility as it has valves in, and the linearity and extension will be higher. I have owned AR Ref 3 before and AR Ref 110, and compared the Ref 10 to Koda K10, so know my ARs a fair bit. I owned Summits, have heard the CLS only with Edge, so if Myles says tubes are out, Berning Quadratures should be your first try. Will be easy to resale if you don't like them.

[bonzo75]

the premier 11a wont drive CLS's properly, I just sold my IIa and owned two pairs of CLS's until recently. in fact, the ARC ref110 I owned couldn't adequately drive the CLS and was worse on Acoustat 2+2s I have in house. IME you need 200 watts, the VTL 225s I've owned drove the CLS perfectly as well as the 2+2s. the CLS IIZ i sold went to a buyer w/ a JAdis Defy 7 and he sat in the near field and didn't play them loud, imo it was marginal.

How do you like Acoustats compared to the Logans? I love the Acoustats. Wish I could hear the bigger pairs

[Rob]

the 2+2s I have here need gobs of juice, an ARC Ref110 didn't have adequate power, VTL 225s were good on them. overall these Acoustats are too dark and polite sounding, dynamics at even moderate levels are castrated. I prefer the CLS to the 2+2 the quad 57 over both of those and Sound labs over everything - that would be my personal hierarchy for some of the 'stats i've owned.

[MylesBAstor]

Funny, never found an amplifier that really drove even the Acoustat 1+1s. The worst was maybe the Acoustat amplifier.

[bonzo75]

I heard the Spectras

[wspohn]

A couple more days of playing around with the new amp and I think that it may never make it up to the second system to see if it can run the CLS - it just sounds too good right where it is!

Have a friend that has had a number of tube amps and turned out to have a store of tubes from various units he'd owned (ironically he is currently using a new solid state Power Modules amp - David Belles - he bought after hearing me talk bout an old favourite of mine, a Belles A)

Turns out that using his Raytheon black plate windmill getter 5751s sounded decidedly better than the NOS GEs that came with it. Will have to do some more listening.

What is the experience from veteran tube rollers as to how much sound changes as tubes get some hours on them?

[wspohn]

Yes, 6FQ7/6CG7. Do they have as much effect on the sound? I have NOS GE in there now.

The 6FQ7/6CG7 do have a sonic influence - at least I could hear varietal differences on my Premier 12s. I'll second NOS Sylvanias in that position; still have a couple pairs 6CG7 from 1958. I ran RCA black plates for the 5751, very nice but canna remember the year.

I do wish the newer Wilsons were a bit easier to drive but I can't complain about their sound. Ever put yours on spikes?

[wspohn]

Thanks, I'll give the Sylvanias a try - inexpensive experiment.

I am still optimizing speaker location on the Wilsons, hence the casters. Plus I admit to procrastinating a bit - the black tape on the floor indicates the final positions pretty much, but the one thing missing from the 1100 pounds of boxes that hold the speakers was the special low rise jack that slides under them to raise them to allow the casters to be replaced with the spikes. Have to talk to the local dealer to see if they have one as the thought of trying to tip 400 lbs. while someone works under them isn't too attractive.

Thought of taking an old sneaker and placing it under one spike (assuming I manage to spike them in the end) so I'd have a story to tell about the helper the speaker attacked....