Recommended Tube Amp for CLS I model

MartinLogan Audio Owners Forum

Help Support MartinLogan Audio Owners Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
F

fdriver

Member
Joined
Nov 18, 2009
Messages
16
Reaction score
1
Location
Charlotte, NC (USA)
Happy holidays!

I've just acquired a pair of CLS I speakers with recent panel upgrade. I know this speaker is supposed to be tube friendly and the easiest to drive of the CLS range. I am very familiar with the IIz model, but that has very different characteristics from what I understand.

I'm looking to pair a good tube amp with these speakers, to be driven by a Tact 2.2 Mini digital preamp that will be configured to send lower frequency signal to a REL sub and a time-aligned mid / upper signal to the CLS via a Tube amp. (I used a similar setup with an Accuphase DF-35 Digital dividing network and CLS IIz and REL - the Tact is a cheaper option if you just need to 2-way xover division). The digital discussion can take place in another thread.

For now, I am looking for a good tube amp to drive the CLS I model. Since the digitally split signal will be sans deep bass, low frequency performance is not a high priority. So far, I'm looking at ARC VT130SE and VT150 monos (both nice, but a lot of negative feedback used), Rogue Zeus (triode mode), ARC VT100, ARC VS115, etc.

Any recommendations from those familiar with the original CLS?

TIA!
 
Last edited:
What did you use with your previous setup (CLS IIz) that you didn't like, which wants you to make a switch, or just looking for the tube 'mid range euphoria' ?
 
twich54 said:
What did you use with your previous setup (CLS IIz) that you didn't like, which wants you to make a switch, or just looking for the tube 'mid range euphoria' ?
Click to expand...
There was nothing wrong with the IIz setup I had; but, as a card-carrying audiophile, I must conform to the "curse" that requires me to look for even better sound, real or imagined.

I had sold the IIz and, along with audiophile friends, did a major restoration on a pair of rare Apogee Full Ranges (300 lbs each - took 3 people just to stand them up). Amazing speakers with the rare amps that could drive them, but they were way too big for space I had.

Since most ML enthusiast seem to believe the original CLS I has the best sound potential of the series, I wanted to hear for myself and, hence, build a system around the CLS I model that I just acquired. The CLS I and IIz appear to be very different in terms of what you need, amplifier-wise, to drive them.
 
Last edited:
You still didn't answer my question....??? what were you previously using ???
 
twich54 said:
You still didn't answer my question....??? what were you previously using ???
Click to expand...
I'm not quite sure what relevance your questions has, since I'm asking about the CLS I - not IIz. Perhaps you misread my original post. If you are interested in an amp for the IIz model, then you should post that in a separate thread - I would be happy to respond to it, as would others familiar with that particular model.

The CLS I has a very high impedance range above 100hz (etc) that make it a good match for tube amps. The II series is a very different animal with very low impedance ranges suited mainly for SS amps, imo.
 
fdriver said:
I'm not quite sure what relevance your questions has,.
Click to expand...

duh...........by your very explanation you imply that your CLS's have different 'needs' than your CLS IIz's, therefore......AGAIN......I wonder what you were using that apparnetly wouldn't sufice with the IIz's.......So........in recomending a tube amp we wouldn't go down that possible path.

FYI, when asking for recomendations, help, etc don't be afraid to give us the details afterall I merely asked what amp you were using not anything to personal is it ??????????
 
HMMM OK......... Honey and Vinegar comes to mind ............


Im not sure of your facts as the CLS and the CLS1 series are extremely hard to drive and dip much lower into the curve than a CLS II series. That was the main reason ML changed the crossover and changed the voltage biasing to make them much more amplifier friendly. The Bass on the CLS1 or CLS1A in my opinion is much better but you need tons of current to bully them around. They are not a friend of low current amps. Will the play? YES, will they sound their best NO! I have heard many a tube amp and liked a few but Audio Research has always been ear friendly. There are many SS amps that get a bad rap because many never have heard them set up well and integrated into a system properly. Your ears are the boss.

There are a few members here who use tubes with the CLS . We used to have a old member who swore by the MAC 275. Its how the amp speaker and room play together is the real key.
 
twich54 said:
duh...........by your very explanation you imply that your CLS's have different 'needs' than your CLS IIz's, therefore......AGAIN......I wonder what you were using that apparnetly wouldn't sufice with the IIz's.......So........in recomending a tube amp we wouldn't go down that possible path.

FYI, when asking for recomendations, help, etc don't be afraid to give us the details afterall I merely asked what amp you were using not anything to personal is it ??????????
Click to expand...
With the IIz, I used several amps, actually. My favorites were the battery-powered Rowland Research Model 6 amps (super quiet and clean, but not very dynamic) and Inner Sound Monos (nice compromise). The Gryphon amps also sounded good too and very dynamic. I also managed to get an Atma-Sphere MA-1 (with Speltz autoformers helping) to work - not perfect, but a very magical sound indeed when the source was not too challenging.
 
C.A.P said:
HMMM OK......... Honey and Vinegar comes to mind ............


Im not sure of your facts as the CLS and the CLS1 series are extremely hard to drive and dip much lower into the curve than a CLS II series. That was the main reason ML changed the crossover and changed the voltage biasing to make them much more amplifier friendly. The Bass on the CLS1 or CLS1A in my opinion is much better but you need tons of current to bully them around. They are not a friend of low current amps. Will the play? YES, will they sound their best NO! I have heard many a tube amp and liked a few but Audio Research has always been ear friendly. There are many SS amps that get a bad rap because many never have heard them set up well and integrated into a system properly. Your ears are the boss.

There are a few members here who use tubes with the CLS . We used to have a old member who swore by the MAC 275. Its how the amp speaker and room play together is the real key.
Click to expand...
According to my info, the were 4 models - CLS I, II, IIA, and IIz. In addition, I believe the very first batch of the CLS I models had a unique screen design that is no longer available.

Regardless, are you sure not confusing the I and II series? The IIa had impedances almost as low as an Apogee and only a few super low current amps (such as grizzled Krells, etc) could drive them.

Here is a simple explanation of the differences from Stereophile:
http://www.stereophile.com/content/martinlogan-cls-loudspeaker-jack-english-cls-iiz-june-1994

The evolution of the design has resembled the swings of a pendulum. The original CLS worked well with lower-powered tube amps that could handle very high impedance loads. That was good (moderate power demands). In response to criticism, M-L redesigned the speaker and gave us the CLS II, whose impedance load didn't stretch so far into double-digit ohms (good), but dipped so low that it was below a single digit (bad).

In fixing one problem, another popped up: The II required greater amplifier power (bad). One of the original's captivating strengths was its sense of immediacy (good). But in tackling the load, the II somehow lost a great deal of immediacy (bad). The speaker was taken back to the drawing board, and eventually the IIA was born. It recaptured some of the I's immediacy (good), but its impedance load dropped so low that it drove many amplifiers nuts (bad). Relative to the original—see JA's review in Vol.9 No.7 and my review in Vol.14 No.12—the IIA had significantly improved deep-bass extension, better midbass articulation, a more extended treble, and a minimized upper-midrange glare.

MartinLogan then released the fourth version of the CLS: the IIZ, which featured a new crossover board and power supply, and a reconfiguration of the transformers. While the IIZ purportedly maintains the immediacy of the I and IIA, it more than doubles the lowest impedance load, effectively ameliorating the major complaints people had with the II and IIA.
Click to expand...
 
According to that article (and to most of what I have heard from CLS owners), the IIZ model is both easier to drive and a sonic improvement over earlier models. So I can't understand why you would want to go from owning a IIZ back to a CLS1. :confused:


The net improvements of the Z-mod (in terms of both sonic improvements and relaxed amplification requirements) have been obvious in the many consistently positive reviews MartinLogan has received for the updated/new Aerius and Quest hybrids. While the IIZ continues to suffer from deep-bass limitations, it has taken yet another step forward in terms of both sonics and practicality. I found the Z version, as advertised, easier to drive with a broader array of amplifiers. These ranged from the low-powered, inexpensive AMC CVT-3030 to the monstrous, wondrous Conrad-Johnson Premier Eight. While the speakers perform better with better amps, the IIZ can now be used in more systems.

Of course, all would have been for naught had the sonic performance taken a step backward. Fear not. As usual, the overall performance was remarkably coherent, with every nuance cut from the same cloth. The visually transparent panels continued to be remarkably coherent sonically, allowing the IIZs to retain the magic immediacy that has captivated so many CLS owners.
Click to expand...

Regardless, I would expect you would want a pretty high quality and powerful tube amp to power these speakers. I can recommend the Conrad Johnson Premier 140 as a great tube amp that I have used with Ascents and it performed wonderfully. Great dynamics and beautiful midrange.
 
Rich said:
According to that article (and to most of what I have heard from CLS owners), the IIZ model is both easier to drive and a sonic improvement over earlier models. So I can't understand why you would want to go from owning a IIZ back to a CLS1. :confused:




Regardless, I would expect you would want a pretty high quality and powerful tube amp to power these speakers. I can recommend the Conrad Johnson Premier 140 as a great tube amp that I have used with Ascents and it performed wonderfully. Great dynamics and beautiful midrange.
Click to expand...

Thanks, Rich.

"Easier to drive" in terms of the CLS I vs IIz probably has to do with SS amp owners who don't like the high impedance nature of the original that favors tubes. Just like those who do not like the IIa, because only brute force SS amps could handle the load impedances of that model. To each his own, I guess.

There is a very substantial population of CLS owners who still believe the overall traits of the "original" CLS are the best. I'm not saying they are entirely correct; but, there is enough of them that wets my interest to find out for myself.

Check-out this interesting discussion I found on Audiogon, about driving the different CLS speakers:
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1281205415&openfrom&2&4#2
 
Last edited:
I have a pair of the original CLS 1 speakers that have panels that were replaced about 3 years ago. They are of the newer design and I have also ordered a backup set just this month after ML notified us of discontinuing support for the CLS1.
Originally i powered them with a Krell KSA250 and KBL preamp with balanced MIT cables The Krell electronics previously powered the Quests which I sold and replaced them with CLS speakers. The Krells worked great for the Quests but didnt match well with the CLS's.
I sold the Krell gear and replaced them with a Mcintosh C2200 tube preamp and a McIntosh MC275. I also am running a ML Descent. The tubes made a huge difference. I lost a bit of dynamics with the tubes but the midrange smoothness is magical.
Hope this helps.
 
Ok.....the real expert CLS owners will continue to 'hop in' but I was wondering given your past liking of Inner Sound if Rodger's latest monoblock creations would be capable of the imp issues that exist ? Rich uses them I'm pretty sure ........

As far as tube, you mentioned Rogue, of which I am a fan (American made, local for me,moderatly priced) and feel they perform and sound damn good. You mentioned the Zeus.......how about the Apollo Monoblocks or for that matter the M-150/180's ?

Prima Luna has a very good following lately in the moderatly priced tube world with various monoblock supporting multiple imp taps.........

I know you seemed concerned relative the apparent large amounts of neg feedback employed with ARC amps you mentioned but I for one trully love their faithfullness to neutrality. I think BAT follows closely behind them. If added warmth is what your after than CJ (s Rich expressed) is stellar and Cary Audio takes a step further.
 
mosttoysrk said:
I have a pair of the original CLS 1 speakers that have panels that were replaced about 3 years ago. They are of the newer design and I have also ordered a backup set just this month after ML notified us of discontinuing support for the CLS1.
Originally i powered them with a Krell KSA250 and KBL preamp with balanced MIT cables The Krell electronics previously powered the Quests which I sold and replaced them with CLS speakers. The Krells worked great for the Quests but didnt match well with the CLS's.
I sold the Krell gear and replaced them with a Mcintosh C2200 tube preamp and a McIntosh MC275. I also am running a ML Descent. The tubes made a huge difference. I lost a bit of dynamics with the tubes but the midrange smoothness is magical.
Hope this helps.
Click to expand...
Wow - thanks for alerting us to the fact that ML is discontinuing support for the CLS I. That is disappointing.
 
twich54 said:
Ok.....the real expert CLS owners will continue to 'hop in' but I was wondering given your past liking of Inner Sound if Rodger's latest monoblock creations would be capable of the imp issues that exist ? Rich uses them I'm pretty sure ........

As far as tube, you mentioned Rogue, of which I am a fan (American made, local for me,moderatly priced) and feel they perform and sound damn good. You mentioned the Zeus.......how about the Apollo Monoblocks or for that matter the M-150/180's ?

Prima Luna has a very good following lately in the moderatly priced tube world with various monoblock supporting multiple imp taps.........

I know you seemed concerned relative the apparent large amounts of neg feedback employed with ARC amps you mentioned but I for one trully love their faithfullness to neutrality. I think BAT follows closely behind them. If added warmth is what your after than CJ (s Rich expressed) is stellar and Cary Audio takes a step further.
Click to expand...

Thanks, Dave. Appreciate the comments and definitely agree with the CJ warmth note, as I have also experienced that with their products.
 
II panels will fit I

"discontinuing" support for CLS1 seems like it would only affect the electronics. The panels are the same or interchangable between II and I variants, from what I have read.

I have CLS 1, and power them with 845 SET amps sometimes. It works out fine, they have maybe 20w of power if that, and fill up a medium sized room fine. I also run them off a Stax solid state amp, and Sony TA-E1 sometimes too, both of which do fine.

So, any nice tube amp with 15+wpc should be fine. SET sounds better to me, but push-pull can be nice too.

-Ed
 
Not true anymore. ML has recently stated (3 days ago) that they will continue to service all legacy products. See the thread started by Justin of ML for further info. I assume that means panels and other innards. However, one has no idea what that service may cost.

Seems to me to be some misinformation on this thread.

I had the IIA's. All newer iterations from the original CLS were meant, in part, to make the speaker more amplifier friendly.

Good luck with your search.

GG
 
Last edited:
CLS Valve Amp Choice

I heard a EAR driving one of my sets of CLS the other day. VERY good amp amp and superb bass control with these fussy speakers. Not huge power, but drove the speakers to louder than I would generally listen to without any problem.
If I didn't have the Halcro I would have that amp in a heartbeat for the CLS.
Only other valve amp I heard on them in the last two years or so was the ARC D70....not even in the ball park, compared to the EAR.
 
Why Valves???

GDSA said:
I heard a EAR driving one of my sets of CLS the other day. VERY good amp amp and superb bass control with these fussy speakers. Not huge power, but drove the speakers to louder than I would generally listen to without any problem.
If I didn't have the Halcro I would have that amp in a heartbeat for the CLS.
Only other valve amp I heard on them in the last two years or so was the ARC D70....not even in the ball park, compared to the EAR.
Click to expand...

In my experience with the CLS IIz and many hybrids before that, "loudness" really is not the issue. I have heard many tube amplifiers on the CLS's from VTL, BAT, ARC, CJ, and ASL. They all exhibited some amount of stress in dynamic passages. IMHO, at the end of the day the only way to truly hear the CLS at full capability is to drive them with an amplifier with massive amounts of current as well as an amplifier that remains linear in response and completely stable at the impedances of 1 ohm and up.

Pairing up a set of VTL vintage Wotans or 450's or Siegfrieds would do the trick, but otherwise I would look seriously at a highly stable solid state amplifier with tremendous power reserves and linearity such as a Pass X350.5 (or larger) or perhaps a Sanders (although I only have anecdotal evidence that this amplifier has what it takes to drive the CLS).

In the end, the choice of an amplifier is also a subjective matter. There are "pleasant" distortions in using an under-powered tube amplifier, but if you are looking for maximum performance across the freqency spectrum regardless of volume levels, then I would certainly go solid state.

My $.02.

Cheers,
 
You must log in or register to reply here.

Similar threads

G
CLS-II ... some crazy mod ideas
Replies
18
Views
3K
john65b
J
F
Expression 13A, Source, Motion series Atmos tops and sides
5 6 7
Replies
134
Views
13K
Fidji99
F
R
Anthem STR Integrated Amplifier.
Replies
9
Views
5K
wink
wink
H
CLS Buyer's Guide - What Should I Look For?
Replies
4
Views
1K
Rehan Azim Hashmi
R
R
Mcintosh MA7900 - Integrated Amplifier
Replies
3
Views
19K
Cvo_man
C

Latest posts

Back
Top