My gut tells me trying to use any tube amp with mbl is the proverbial square peg in a round hole, but I could be wrong.
Maybe there is some tube amp that can do it, but at that point, why bother with tubes at all unless one enjoys having to babysit a very complex and expensive rig just to keep it going?
To each his own I suppose if that is the case....
Or I would say, if tubes are your thing, look toward other good speakers that are designed to be tube friendly, not mbl.
I'm sure some tube amp vendors are willing to step up to the challenge, as long as they do not have to pay for the service costs. |
Looking for MBL 101C or earlier 101B or A models
Any help appreciated |
First, I doubt speaker dude has personally measured the current output of the VTL, CAT, and VTL side by side.
If he hasn't he should be more accurate in giving advice:
"My listening leads me to believe that..." would be fine.
If he has, I would love to see his results (measurements)posted.
That said, having owned the TRL 400s, VTL 750s, and CAT JL1
LEs (and MBL 101 a and d versions)-CAT JL3s are probably far and away the best amp to use. The MBLs need very tight bass to make the mid bass football driver to blend with a slightly warm(ported)
conventional cone. |
Open reply from Convergent Audio Technology:
I've had some direct inquiries, some slightly hostile, about my comment made above concerning JL3s driving MBL 101s.
First, the "man" I referred to who reviewed the JL1 with MBL 101s was Michael Gindi. This review was published in the very first issue of FI magazine. That system was the toast of New York - a veritable Mecca for audio reviewers and upper crust dilettantes. I bought my MBL 101s after hearing this system with my prototype JL1s.
Second, I made NO disparaging remarks about any other amplifier company in my previous post. I mention two amplifiers only as 500 watt and 700 watt tube amps. My point being that power, as in raw wattage, is not the key to driving a difficult speaker such as the MBL 101. To decide that I must have meant some particular company and then take umbrage is not reasonable.
Third, a couple of people have asked me what makes the JL3 (and older JL1) capable of driving difficult loudspeakers when more "powerful" amplifiers cannot:
- Huge output transformer -- at 55 lb. bigger than any other amps output transformer (and much bigger than the 10-12 LB transformers typical of 150 watt tube amps). This means that this transformer runs at a fraction of its capability even at bass frequencies and even at full power for much better magnetic linearity.
- high turns ratio in transformer - the transformer could be driven by 2 pairs of output tubes to achieve the same power rating, but we use eight pairs (four in the JL1&JL2) to achieve the same power. This means that the load impedance - and variations of same - are reduced by a factor of four times versus similar triode amps from other companies. Obviously this makes the load less difficult for the output stage tubes.
- High energy storage/watt -- at over 1000 joules for a 150 watt amp (7 joules/watt) this is possibly the highest ratio in any production amplifier. This means the power supply is much stiffer at any given output level and therefore the sound will be more stable and authoritative at all levels.
- very wide high frequency bandwidth output transformer - gives high stability into capacitive loads. We actually test each amplifier with the 8ohm/2uf "IHF load". The resulting ringing is minimal - about 5 percent. Most tube amps will ring violently or even damage themselves when faced with such a load. Stereophile gave up testing tube amps on the IHF load several years ago. I have talked with one tube amp manufacturer who considered this load "unfair" to tube amps. We don't consider it "unfair" at all -- and I point to the CAT amps success at driving all sorts of difficult loads as proof that designing such abilities into an amp is a good thing. Electrostatic speakers tend to look highly capacitive. (Soundlabs for example, look a bit like a 4uf capacitor in parallel with a 30 ohm resistor -- most amps get hard at modest volume levels when driving Soundlabs. I've talked with some people who incorrectly blame the Soundlab for this hardness because it happened with all amps that they tried on the speaker. This won't happen with any CAT amps.)
Lastly, I would like to thank all of the people who posted such kind remarks about our amplifiers. Its gratifying to hear such high praise in an anonymous forum such as Audiogon. |
From my perspective your room size is moderate. How the speaker will perform from an ultimate spl level is very much dependent on how the room is decorated, what's on the walls and floors, etc. If your room is fairly lively and you're not a headbanger you are unlikely to hit the threshold of speaker metallicism. If, conversely, your room is on the dead side and you like to rock out, the mbl and/or its associated amplifier could be taxed beyond their respective limits. |
Speakerdude, What is your definition of a large room? My room is 15x20x10. Where does this fit in? |
"If you are not trying to go over 95 db average SPL I can whole heartedly recommend the JL-3's (they may play louder but i can't vouch for their efficacy)on the 101 e's"
My experience with the 101d's is that an average 95db or so is the upper limit of the loudspeaker itself in a large room. In a smaller room, of course, you can reach into the low 100's before a speaker-derived metallic edge creeps in. |
Speakerdude- Why not share your experiences with the other amps, I am really quite curious. You seem to feel that I am trying to cause turmoil when I am in fact VERY curious about this. I know the CAT's are great amps, and if you, along with others feel they drive the 101's with aplomb- great! So instead of making condescending remarks about me, please share your experiences with these amps and these speakers(also let me know what other associated equipment we are using). This is a forum after all and we can all stand to learn something from time to time. |
"Do you or don't you have experience with MBL 101(c,d or e's) paired with VTL, tube research labs and CAT?"
Yes. Do you? I didn't think so. You seem to depend on specs which are fine for newbies. For you "more watts" are "better" which demonstrates a fundamental lack of understanding regarding the nature of electrical power.
"I am wondering if I might be better off thinking about using ss amps instead of the tube approach."
No. Although it's pretty hard to argue against mbl's own ss amps which are wonderful with mbl speakers and are second only on these speakers to the CAT amps in my experience. |
I am wondering if I might be better off thinking about using ss amps instead of the tube approach. Specifically, I was entertaining the thought of using a Rowland 302 on top and a pair of 501's on the bottom. Any thoughts would be appreciated. |
Speakerdude- Since you may no realize my questions were aimed at you, let me try again. Do you or don't you have experience with MBL 101(c,d or e's) paired with VTL, tube research labs and CAT?
P.S. I was going to let this one go, but since I am getting private hate email from it I figured I should continue ;) |
... One more thing, which was not fully clear from my post.
It is only the truly great tube amps like the CAT's that have output transformers of such quality that they can really nail the conversion of tube voltage into current. I cannot speak for Mr. Stevens or Speakerdude, but I believe that this is what they are saying. |
My salesman at a well-known NYC store was adament that the VTL 750's, which he sells, could not drive the big PipeDreams, and even more adament that the VAC 70/70 (65 watts/channel) could drive the big Pipes with ease.
If a tube amp doesn't have first-class power supplies and first-class output transformers, it won't drive current-hungry speakers, regardless of ostensible watts. I have VAC 140 monos on my Revel Salons in my main system, not an easy speaker to drive, and have powerful, clean, highly refined sound.
And I have heard the CAT JL1 limited editions on my best hi-fi friend's Salons. Extraordinary.
Hope this helps. |
"...but its really hard to grasp that an amp capable of delivering 1250 watts can't handle a 83db speaker even if its only delivering 10 amps of current-"
I do not find it difficult to grasp at all. |
I own a pair of 101E's and use the CAT JL-3s with them. The combination is very good and the JL-3's drive the speaker to reasonable volume in my 14x20 room with authority and finesse. The 101's still have some discontinuity between the MR and lower drivers however.
Its important to understand that I listen at average volume levels of about 85-90 db with peaks in the upper 90's. That is all my room can handle before the room itself becomes a major factor(yes I have treated the room acoustically, but remember the sepaker radiates 360 degrees).
the sound of the CAT amps is not typically tube; it has the subtle finess of SET's but is clear and fast with a very good low end (better than most solid states in having both bass defintion and nuance)It is an amp that blends the best attributes of both tube anbd solid state with out the drawbacks. Having had a pair of Wavac 833 monos as well as Atmas-phere mA-2's i can say that the JL-3's betters both of those amps by significant margins
If you are not trying to go over 95 db average SPL I can whole heartedly recommend the JL-3's (they may play louder but i can't vouch for their efficacy)on the 101 e's |
Yes I agree, I have met Ken and while he is a very nice guy and we did get along, he is, how should I put it, eccentric. He may also have a some what bias-no pun intendid :o) opinion |
The development of the CAT JL1s was mainly done using the older MBL101B, which at 78db, is even lower efficiency than the current model. Not only is the 101 very inefficient, it also has an impedance curve which can only be described as highly unusual -- actually bizarre would be a better description. It is EXTREMELY difficult to drive.
One man in NYC had 500 watt tube amps on his MBL101Bs. The MBL designer, Jurgen, visited and told him that those amps did not have enough power. The next time they visited the man had switched to the CAT JL1s. Jurgen was adamant that the man had gotten the 100 watt power rating wrong. He thought that they must have a 1000 watt rating. So they called me to confirm the rating.
This same man wrote the first US review for the JL1 for FI magazine, based upon his evaluation on the MBL101B - and he bought the amps.
The JL3s are even more linear than the JL1. They have much more energy storage and twice as many tubes driving, basically, the same output transformer. Although I haven't heard the combination I have at least two customers who own it and swear by it. I will see if the US owner is interested in posting his reaction.
Playing brute force games with "more powerful" amplifiers will not work. Not only will these amplifiers not sound as powerful and strain free as the JL3 - they will not have the level of transparency and refinement that the MBL needs. This is, after all, the most transparent speaker in the world. Many times it gets blamed for a harsh grainy sound because it is revealing the grain in the preceding system. Recently I had a conversation with an audiophile who described it as "soft, polite and fudgy." Clearly his 750 watt tube amp was not up to driving the speaker.
Ken Stevens
President
Convergent Audio Technology, Inc. |
If you are interested in talking with comeone who has heard the MBLs paired with the CAT amps, call Ken Stevens. Based on my conversation with him earlier this week, I gather that he has heard this combination extensively. I would caution you against bringing up the topic of synergy, however, as the mere word is likely to set him off. (He does not believe in "synergy" per se.) |
Do you personally have experience with the 101's and all of these amps or are you just assuming? I do not have experience with mating any of those amps to those speakers and I don't know anyone who has used tube amps with 101's(c, d or e's) I acknowledge that all amps mentioned are highly regarded and I have heard them in various systems over the years and have been impressed in one way or another by something they have done. I find it VERY hard to believe that the huge VTL's would fall short on an 83dB current hungry speaker- I have an 84dB current hungry speaker and if I was in the market for a tube amp they would be at the top of my list.
I agree that an amplifier of the proper power is needed to mate well with the speakers, however, saying synergy doesn't matter is plain foolish. I don't think ANYONE can do more then surmise as to the outcome of this situation. Unless of course you do have 101's and have heard them mated with all 3 amps listed. If you have then I stand corrected, but its really hard to grasp that an amp capable of delivering 1250 watts can't handle a 83db speaker even if its only delivering 10 amps of current- that being said I've been wrong in the past. |
"but at this some what insane price range its all about synergy and personal preference."
I couldn't disagree with this statement any more strongly. Price level has nothing to do with the issue which is, quite simply, the ability of a tube amplifier to drive a highly insensitive (read current and voltage hungry) load.
That's the issue. Synergy has nothing to do with it.
You can try and try and try to synergize the wrong amplifier to a speaker by changing flavors of cables and flavors of sources and flavors of tubes but synergists are doomed to play synergy games which are all about flavors and taste and nothing to do with the accurate replication of the input signal. If the amplifiers don't have the appropriate linear power (read current and voltage) delivery capability, all the synergy and personal preference in the world ain't gonna make the system sound good. If you start with an amplifier that can drive the load, and easily drive it, you won't be left with playing a synergy game you can't win.
Hey I like VTL amps too. I kind of like Tube Research amps too though I don't believe they offer a terrific performance/value ratio. But just try a VTL amp, any VTL amp, on the mbl speakers and you'll hear that what I'm saying isn't bold, it's accurate. The CAT, on the other hand, drives this speaker with ease and that is what the original poster asked about. |
That's kind of a bold statement, any specs. or way to back your statements? I am not a "fan" of VTL amps like Mejames is, but I do appreciate what they are capable of. The same goes for Tube Research labs and CAT(I had a very long listening session with a prototype JL-2 a few years ago and left VERY impressed). I am not trying to stir the pot but I find it VERY hard to believe that the Tube research labs and VTL's would be inferior to the CAT's- perhaps a different flavor but at this some what insane price range its all about synergy and personal preference. |
There's only one tube amp on the planet that can drive the mbl 101's. CAT JL3's. Yes the JL1's can drive them too but I'm talking about current production amps. What everybody here is missing is the linear power delivery and current capability. No matter how many "watts" an amplifier has if its transfer function is non linear by nature the amplifier will crap out after the first few watts whether or not there are 500 more watts on hand. The CAT amplifier delivers clean, linear power that makes it effectively more powerful than amplifiers rated at five times its power. As far as current delivery is concerned, the other amps mentioned here including the giant Tube Research Labs amps fall far short of the mark set by CAT. So technically the CAT is the superior amplifier and what do you know, when you listen to it the damn thing sounds better than either the VTL or Tube Research or any other tube stuff that I ever heard that sounds veiled and bloated compared to the CAT. |
I spoke with Ken Stevens yesterday, and he mentioned that the CAT amps pair very well with the MBLs. I own the CAT JL-1 Limited Edition monoblocks, and I can tell you that they are exceptionally powerful. While I have not heard the JL-3 monoblocks, I would expect that they would be a good match. |
Why not try the VTL Siegfried. |
Tireguy, I heard the 800 GTR's with Nova Utopias..nothing small about those guys. Each chasis covers 8 square feet of floor space, times that by four and you still need another 8 feet for their reference pre, took up half the living room floor! Larry from Hi end has a pair, got a spare 80K? |
The Giant tube research amps or the VTL 1250 and they still may not synergize well with those speakers. I know its very difficult to get them mated with complimentary equipment and even harder to get setup properly, but when you get there, its suppose to be something really special. |
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Ask Albert Porter here on Audiogon about his VTL MB 750's, they are listed with pics. Heard them in Miami last week with the new Wilson Maxx, dont know if they will match with your 101's but Im sure Albert will know. Good luck |
