Audible Illusions Modulus L1- Am I missing something?

[piece-it pete]

Howdy folks!

Well I got a chance to audition one of the above, probably the highest quality piece ever in my system.

Clarity. Noise floor. It should be GREAT! It has a very nice sound BUT - it seems like it, as my audio challenged SO put it!, "runs out of steam". It gets louder but never seems to have the sparkley presence I expect.

I had it checked by a knowledgable tech and it passed all tests with flying colors. I have outside confirmation of this issue, on a much better system than mine, but all reviews I find just sing praises.

Any ideas?

Pete

[dean_martin]

Hey Pete!

I'm guessing this is the tube linestage preamplifier from AI? What amp were you running with it? Perhaps it doesn't mate well with some SS amps? I don't really have a response for you, but I've considered putting together a system with a tube preamp and a solid state amp and have read that you have to be careful of matching ohms or input and output loads or something. I don't fully understand what to look for as far as specs go yet. Maybe you have some advice?

[piece-it pete]

Hello Dean!

Yep, it's a tube pre, running my super-high-end Marantz 1152dc .

It sounds like you might know more than me on this subject already, although I suspected originally ( and told the tech so) that it wasn't putting out as much whetever as it should, but he said yes it is.

The outside confirmation was a very experienced tube guy running a very very nice Yamamoto A-08 45 SET "flea power" (2 wpc!) tube amp pushing hi-e speakers with edgarhorn tops ( I like the edgarhorns A LOT - very realistic reproduction imo) and eminence woofers. We did not say what was wrong, heck that there was even a problem, and both had the same impression, on these two very different systems.

What I'd really like to do is try it in a more "normal" ss system, defined as moderate efficiency speaks (vs my very low e DQ-10s) and a better amp. Nothing I can do about the speakers, but will be trying out a couple of ss amps, don't know which ones yet, only that they'll be quite good (yay!), within the next month or so, hopefully I'll still have the L1 & try it out, I'll post.

This is getting fun! When I look back at the system I had when I signed up here (cheap Sony HT, old junk Marantz towers) I can't believe how far I've come. I also can't believe how much farther there is to go!

Pete

[dean_martin]

Hello Dean!

Yep, it's a tube pre, running my super-high-end Marantz 1152dc .

It sounds like you might know more than me on this subject already, although I suspected originally ( and told the tech so) that it wasn't putting out as much whetever as it should, but he said yes it is.

The outside confirmation was a very experienced tube guy running a very very nice Yamamoto A-08 45 SET "flea power" (2 wpc!) tube amp pushing hi-e speakers with edgarhorn tops ( I like the edgarhorns A LOT - very realistic reproduction imo) and eminence woofers. We did not say what was wrong, heck that there was even a problem, and both had the same impression, on these two very different systems.

What I'd really like to do is try it in a more "normal" ss system, defined as moderate efficiency speaks (vs my very low e DQ-10s) and a better amp. Nothing I can do about the speakers, but will be trying out a couple of ss amps, don't know which ones yet, only that they'll be quite good (yay!), within the next month or so, hopefully I'll still have the L1 & try it out, I'll post.

This is getting fun! When I look back at the system I had when I signed up here (cheap Sony HT, old junk Marantz towers) I can't believe how far I've come. I also can't believe how much farther there is to go!

Pete

There's something about the output of some tube preamps being lower than an average ss preamp and the input rating of tube amps being higher (or lower) than an average ss amp. I think these are measured in ohms and the ss amp's and tube preamp's specs will tell you whether they are a good match functionally (whether they sound good together is of course a whole other ball of wax). Anyhow, I don't know what to look for in the specs but I picked up on this while reading a review of an ARC preamp and amp in Stereophile. The reviewer said that this new model of the preamp had a different output rating from earlier models so that it would work better with ss amps. Just another confusing factor that makes this hobby so intriguing.

BTW, your friend with the SET and horns has gone pretty far!

[Justlisten2]

I have a tube preamp mated with a solid state amp. Yes, as dean_martin stated, it could be an impedence mismatch between preamp/amp. Another thing it could be is your long time listening bias. Tube equipment tends to sound smoother and richer in the midrange then solid state equipment. Solid state usually has more punch at the frequency extremes. SS will sound more 'sparkley' on highs, as you describe it. That's why folks who like tubes, like tubes. Because much of this treble information is falsely attenuated up during the mastering process, many prefer equipment which will de-emphasis this issue. No, people don't buy tube equipment for 'sparkley' high's. They buy tube equipment for the rich, enveloping midrange, which is where the music lives. Once your ears adjust to the 'natural' sound of music, you may realize that you prefer it more than the 'electronic' sound.

I find the litmus test is listening fatigue. I find that I can listen MUCH longer with tubes and vinyl than I can with digital and solid state. I have a tube cd player, phono preamp and preamp (18 tubes in all), mated with a solid state monoblocks (Class A biased).

So it could be an impedence mismatch, or it could be that you're just so used to the 'artificial' sound of music, that the 'natural' sound sounds bland. That is why recording/mastering engineers feel the need to add more 'sizzle' during recording process, for the special effects lovers. This is not meant to be derogatory. If you enjoy that whiz-bang effect, stick with what you like. Whatever better enables you to enjoy the music. That's what it's all about really, you pays your moneys, you makes your choices.

Cheers,
John

BTW, SS does have a lower noise floor, but with a good tube design, noise really isn't an issue. I find the more natural decay of musical notes more than makes up for a slightly higher noise floor. I can only hear my system noise if my ear is within two feet of the speakers and there is no music playing. What is the point of sitting that close to the speaker and not playing music though?

[dean_martin]

OK, I went back and tried to figure out what's important in matching amps and preamps and though I don't completely understand what to look for I think I found some clues. I had read some reviews of the Pass Labs Aleph 3 amp and its successor the Aleph 30. Due to the Aleph 3's "low voltage gain", it was not a good match for passive preamps (a preamp without active output). The Aleph 30's design included an increase in the voltage gain so it could be matched with not only passive preamps/controllers, but also with some low output TUBE preamps. I also discovered that some tube preamps like the Audio Research SP16L have low output levels presumably to lower the noise floor or to lessen audible "tube rush".

So, I think if you were going to match a tube preamp with a solid state (including single-ended like the Pass Labs) amp, you would need to check the amp's voltage gain and the preamp's output level. The remaining question is what are the threshhold values in amplifier voltage gain and preamplifier output level for a satisfactory match?

I'm not sure but I think I've found some clues. In the review for Audio Research's VS110 power amp and SP16L preamp (which you can find at stereophile.com in the archives), the reviewer tried the two components together and then substituted each one seperately into his system. The SP16L's output level (which the reviewer categorized as "gain") is 11.5dB. The "gain" rating for his reference preamp was 26dB. That appears to be quite a difference. When he put the SP16L in his system, he had some of the same volume problems that Pete noticed. No juice.

On the other hand, the VS110 amp from ARC had a gain of 28dB which the reviewer said was slightly higher than average, but he didn't say what average is. Therefore, the SP16L performed much better with the VS110. The preamp's lower gain was apparently for the purpose of lowering the noise floor, and its lack of juice was compensated for by the slightly higher than average gain from the VS110. So, I think you can conclude that if you were going to get the SP16L preamp for your existing amp, you should check your amp's voltage gain and make sure it's at least 28dB (or, slightly higher than average, whatever average is - maybe 26dB?)

Once again, I owe Petey thanks for providing me an oppurtunity to work through and overcome my issues.

[piece-it pete]

John, Dean,

Thanks a mil. I've spent a great deal of time with the pre this weekend.

This has been a real learning experience for me, I think I have it figured out - both of your impressions/instincts are at least partly on target, imo, I think, maybe :

The biggest part of the problem is (drum roll please): My amp is underpowered for my watt-devouring speakers. I have been regularly overdriving my amp!

What I find so irritating about the sound (the litmus test is very bad on this one, John) is that I think I'm pushing the amp too hard, and that it sounds worse with the AI pre than the ss Hafler, for some reason the ss sounds better while overpushing the amp than the AI. I'm 95% sure of this, and think this is the #1 reason. An impedance mismatch would further exaggerate the problem.

At lower levels it sounds much much better than the Hafler. John, I should have been more clear, this tuber has a *very* low noise floor with GREAT clarity. I'm aware of the "used-to-it" issue, the 1st 1/2 hour with my old maggies a couple of years ago was almost - confusing? to my ears, though far better than the speaks I was using. Nonetheless, the highs are more rolled off with the AI (where perhaps they're a bit too hard with the hafler?). Still, the AI has a MUCH more natural sound than the Hafler (at low levels, in my system!).

Conclusion? It's a good piece, probably a great piece, it appears almost certainly the problems I had were caused by MY SYSTEM. I can't demo it properly, therefore, the AIs' perfect record stands.

I hope to be able to hold onto it until I get a chance to use it with a bigger amp, if I do I will certainly post.

Regardless, I'd better get a bigger amp, I must not be getting the best sound out of the DQs' (which I've been told by probably 20 people, but as usual had to prove it to myself ). Hmmm, I wonder what my next upgrade will be ?

Pete

BTW Dean, are you kidding?! I'd say you worked through MY issues!!

[Justlisten2]

John, Dean,

Thanks a mil. I've spent a great deal of time with the pre this weekend.

This has been a real learning experience for me, I think I have it figured out - both of your impressions/instincts are at least partly on target, imo, I think, maybe :

The biggest part of the problem is (drum roll please): My amp is underpowered for my watt-devouring speakers. I have been regularly overdriving my amp!

What I find so irritating about the sound (the litmus test is very bad on this one, John) is that I think I'm pushing the amp too hard, and that it sounds worse with the AI pre than the ss Hafler, for some reason the ss sounds better while overpushing the amp than the AI. I'm 95% sure of this, and think this is the #1 reason. An impedance mismatch would further exaggerate the problem.

At lower levels it sounds much much better than the Hafler. John, I should have been more clear, this tuber has a *very* low noise floor with GREAT clarity. I'm aware of the "used-to-it" issue, the 1st 1/2 hour with my old maggies a couple of years ago was almost - confusing? to my ears, though far better than the speaks I was using. Nonetheless, the highs are more rolled off with the AI (where perhaps they're a bit too hard with the hafler?). Still, the AI has a MUCH more natural sound than the Hafler (at low levels, in my system!).

Conclusion? It's a good piece, probably a great piece, it appears almost certainly the problems I had were caused by MY SYSTEM. I can't demo it properly, therefore, the AIs' perfect record stands.

I hope to be able to hold onto it until I get a chance to use it with a bigger amp, if I do I will certainly post.

Regardless, I'd better get a bigger amp, I must not be getting the best sound out of the DQs' (which I've been told by probably 20 people, but as usual had to prove it to myself ). Hmmm, I wonder what my next upgrade will be ?

Pete

BTW Dean, are you kidding?! I'd say you worked through MY issues!!

It's difficult for me to beleive it's the amp's output power, as this should remain constant regardless of which preamp feeds it. I do know the AI's output voltage is VERY high, but I would think that would simply mean that you listen with the volume knob at a lower position for the same power output, (Eg., maybe the AI's 9 o'clock setting plays at the same SPL output level as the Hafler's 12 o'clock setting). It has very high gain, by comparison, my BAT VK-31SE has 17 db of gain vs. 30 db of gain for the AI L2 (nothing about the L1 on the AI website, but probably similar). So you may drive the amp to clipping sooner if you're trying to match positions of the volume knob.

One more thing you could try if interested is tube rolling. I'm sure you probably have the stock Sovtek tubes inside. Try a pair of NOS Amperex/Siemens/Mullards, etc. Yes they are quite expensive, but worth it in my opinion. You'd only need one pair, I need five pair for my phono preamp alone! That's when it can get really expensive.

Hope this helps,
John

[piece-it pete]

John,

I'm no expert but I think I've been overdriving my amp all along, the 1152 puts out 76wpc and the DQ-10s' are about 82db efficent (I've been told by a reliable source).

So what I'm thinking is that the ss pre overdrives the amp in a nicer way? Is that possible?

There is no doubt that overall it's a MUCH better unit than the Hafler. Right now it's running Slovak tubes but the original AI branded tubes are in the box, I'll try them tonight. I have no way of knowing if they are "good".

If I started tube rolling wouldn't that make me an audiophileious nutticous? I'm not sure if I'm ready lol.

Could it be the (gasp) interconnect?

Pete

BTW, your equipment sounds fantastic!

[dean_martin]

Regardless, I'd better get a bigger amp, I must not be getting the best sound out of the DQs' (which I've been told by probably 20 people, but as usual had to prove it to myself ). Hmmm, I wonder what my next upgrade will be ?

Pete,

Some of the solid state amps I've been considering for my modest/attainable-in-the-not-so-distant-future dream system are from Belles, McCormack and Pass Labs. Belles and McCormack have models with very high power ratings and I've read that they mate well with most tube pres. The Pass Labs has a lower power rating but is pure class A and ultra-transparent.

Some of the tube pres I've been looking at are from AI (the modulus 3A), Cary and Conrad-Johnson. I would like to find one with a good phono stage (and a headphone jack would be a welcomed bonus).

So, in pursuit of this dream, everyone on my Christmas list is getting a homemade gift this year!

Merry Christmas!

[Justlisten2]

John,

I'm no expert but I think I've been overdriving my amp all along, the 1152 puts out 76wpc and the DQ-10s' are about 82db efficent (I've been told by a reliable source).

WOW! That would be severly under powered, unless it's in a very small room. I would think you'd need at least 200wpc, or more efficient speakers.

So what I'm thinking is that the ss pre overdrives the amp in a nicer way? Is that possible?

Possible, but hard to beleive. Tubes are known for 'soft' clipping. Some SS designers like NAD try to incorporate a soft clipping circuit, but tubes seem to do this naturally. From the description of your speakers/amps above though it does sound like your problem would probably be 'clipping', which is what happens when you overdrive an amp. Careful, I've blown out tweeters this way! You can damage your speakers by overdriving your amplifier.

If I started tube rolling wouldn't that make me an audiophileious nutticous? I'm not sure if I'm ready lol.

Probably, but I think even the cable nazis will acknowledge that tubes sound differently. Just be glad that the L1 only has 2 tubes, as I've said before I have 18 tubes in my system!

Could it be the (gasp) interconnect?

Probably not.

BTW, your equipment sounds fantastic!

You can hear it in Ohio??? I'd better turn the volume down!



Thanks. My system is special to me. It helps releive me from a stressful world.

It consists of:

Speakers: Vienna Acoustics Strauss

Amplifier: Clayton Audio M100 monoblocks (100 wpc Class A biased (HOT!!)) (SS)

Preamplifier: BAT VK-31SE (tube)

CD Player: BAT VK-D5SE (tube)

Phono Preamp: BAT VK-D5 (modified by Great Northern Sound Co.) (tube)

Analog: VPI HW-19 mk IV w/ SAMA and SDS, VPI 10.5 tonearm and Lyra Helikon cartridge.

I also have a Sony 9000ES DVD/SACD player, but to be honest I don't listen to many SACD's.

Most of the equipment was bought second hand on AudiogoN. I couldn't afford to build a system like this first hand. AudiogoN is great for folks with champagne tastes and beer budgets. Overall, I would say it cost about half of list. You couldn't tell any of it was used by looking at it though. You should take a look. I see all sorts of 200 wpc amps for under $500 (Hafler/Acurus/NAD/Rotel/etc), good stuff!

Cheers,

John

[Justlisten2]

Pete,

Some of the solid state amps I've been considering for my modest/attainable-in-the-not-so-distant-future dream system are from Belles, McCormack and Pass Labs. Belles and McCormack have models with very high power ratings and I've read that they mate well with most tube pres. The Pass Labs has a lower power rating but is pure class A and ultra-transparent.

Some of the tube pres I've been looking at are from AI (the modulus 3A), Cary and Conrad-Johnson. I would like to find one with a good phono stage (and a headphone jack would be a welcomed bonus).

So, in pursuit of this dream, everyone on my Christmas list is getting a homemade gift this year!

Merry Christmas!

Ho! Ho! Ho! That's the way to go .

Sounds like some quality gear there. Of the ones you mention, I think a AI M3A would sound great with a McCormack DNA-1 Deluxe. I beleive only the older Aleph series from Pass is Class A biased. The X-series is Class A/B. The AI doesn't have a headphone jack, but has the best phono stage. Another preamp you may want to take a look at is the Rogue 99 Magnum, it also has a very good phono stage.

Cheers,

John

[piece-it pete]

Howdy guys!

I hope you all had a great holiday season. Mine? Well pretty darn good.

I've been "just listening 2" the AI now for some time, and plugged the ol' Hafler back in a couple of days ago, so I think I'm ready to add my final thoughts of this very nice piece.

My final answer: I just don't think it's a good match to my admittedly somewhat flawed (underpowered) system.

I would LOVE to hold onto it long enough to try it with a bigger amp, I think I would probably want to keep it, but it's just not in the cards, according to my astrologist (aren't I the yukster today).

But there is NO DOUBT it is a quality piece. I will miss the quiet and clarity at low
volumes, particularly late at night listening to good classical vinyl. And I really like the seperate level controls for the right and left channels, so much better than a balance control. This feature is because of tube variences, correct? Add a large number of inputs and two outputs, that is a great thing.

So that's that. I sure learned a lot about my system. # 1 thing? I need to spend more money lol.

John, that 200 wpc + figure is exactly what the 20 folks told me! It may be a moot point now, as it looks like I'm moving into a new home, with no "extra" room for the a/v.

Moot 'cause I don't think I'll be able to keep the huge DQ-10s, She Who Must Be Obeyed (occassionally ) won't like them in the living room. I honestly don't blame her, the rooms' not that big. I might even get modern with something nice looking like Audes Blues or the multiple driver Rockets, heck I don't even know at this point, who am I kidding, all cash to house now .

Cable nazis lol.

I'd like to try the tube thing sometime, the best sounding amp I've ever owned was a little Fisher 30A monoblock. I think I'm going to sell both my Marantz (which is really too bad, I think it looks very nice, and it's built like a tank) and my speakers and start over.

Dean,

How did your homemade presents go over lol.

I've been told the L1 IS the 3A, with a headphone jack instead of a phono preamp. I'd think with your proclivity to research you'll end up with a GREAT system.

Another day, another piece of stereo equipment .

Pete

[piece-it pete]

Hey, after doing even more reading I've become convinced that John had it right, it's the tubes. Many many have said the solvaks qc has gone down the tubes, even AI mentions it. I sure wish I could try tube rolling. Oh well, easy come, easy go!

Pete

[GlenNewdick]

Hay I'd like to give my two bits too. first if your trying to drive them DQ's with 70w/ch then you are in need of a more powerful amp ( or a tube one). I Own a Cary SLP 94 and have driven many SS Amps ( Bryston, Sim moon, Levenson) with very good results. but I don't know the Imput impedance to your amp's so that could be a problem also old tubes will clip earlier then new ones will so new tubes could change the whole deal. don't give up on a tube preamp thats a very good one.