Preamps... nothing is perfect.

[JackD201]

Hi Ian,

Congrats! If you ever get the chance it would be really cool if you could compare XLR vs BNC from P1 to the Dart

Why do I see a 468 on Ian's future? Hehehehe!

 

[Al M.]

Al, what I mean is that if the Top of the line CAT preamp sounds veiled or otherwise faulty when paired with the matching CAT amps, then something is wrong in the chain somewhere. Remember, Ken Stevens, the CAT designer, most surely designed his gear to be completely synergistic. If a preamp, and particularly a ss preamp can actually sound better in that pairing, this would indicate to me that there is something going on that is interfering with this synergy.
Having heard all of the CAT preamps, I can absolutely state that to my ears they are totally revealing (unless there is something faulty with the particular unit?)...and certainly not in any way less transparent than the best ss. ( yes, I have heard the Dart on Sevaral occasions). Since Peter A seemed to hear a loss of transparency with the prior CAT Legend, and since the OP has decided to go away from this preamp, ( yet likes the amps, which are actually in almost all other CAT users hierarchy, less capable than the preamp) -this leads me to my conclusion.

Davey, I still fail to see the logic in your conclusion, also in light of the excellent sound quality that I hear from Ian's system. There is nothing 'wrong' anywhere in the chain. I heard the same thing as Peter A did, a loss of transparency with the CAT legend, and if that preamp is as good as you claim, then the simplest and most straightforward conclusion would be that there was something wrong with Ian's particular unit of the CAT Legend (you allude to that possibility as a further alternative). But there is now no way to test it, it's ancient history, and irrelevant in the sense that Ian has now found a suitable preamp that he likes.

 

[PeterA]

Al, what I mean is that if the Top of the line CAT preamp sounds veiled or otherwise faulty when paired with the matching CAT amps, then something is wrong in the chain somewhere. Remember, Ken Stevens, the CAT designer, most surely designed his gear to be completely synergistic. If a preamp, and particularly a ss preamp can actually sound better in that pairing, this would indicate to me that there is something going on that is interfering with this synergy.
Having heard all of the CAT preamps, I can absolutely state that to my ears they are totally revealing (unless there is something faulty with the particular unit?)...and certainly not in any way less transparent than the best ss. ( yes, I have heard the Dart on Sevaral occasions). Since Peter A seemed to hear a loss of transparency with the prior CAT Legend, and since the OP has decided to go away from this preamp, ( yet likes the amps, which are actually in almost all other CAT users hierarchy, less capable than the preamp) -this leads me to my conclusion.

Davey, Mine is only one opinion. The problem may simply be the way I hear things. For instance, I thought Ian's system sounded great with the all Pass XS electronics - amps, pre, and phono. And I still have very fond memories of that sound in Ian's system. Ken Stevens apparently does not like Pass gear. Could it simply be a matter of taste? I would love to have heard Ian's new AirTight Opus cartridge in his all Pass XS system.

In the end, Ian now seems to have the dynamics and drive that he had with his active preamps, plus the transparency of the passive preamp. He has resolved the question in the thread's OP.

 

[PeterA]

Which passive preamp was it?

I don't recall. Perhaps Ian will answer this one.

 

[KeithR]

I don't recall. Perhaps Ian will answer this one.

Pass Labs B1 buffer

To be fair, the Magicos aren't particularly efficient which may limit the value of that kind of preamp in his system.

 

[caesar]

Respectfully disagree on both counts. The VTL 7.5 III is unmistakenly a tube preamp as the majority of the gain is from the tubes. (By the way, I wish that when folks refer to the sonics of a tube preamp, they would specificy the tubes being used since the character of sound changes dramatically with the choice of tube. Long plate Mullards sound very different than NOS Telefunkens, both of which are very different from the stock Ciftie's that come with the unit).

Both the CJ GAT and the VTL use a MOSFET output driver whose benefits, among many, provide a low output impedance with the concomitant balls to drive anything with aplomb. It is the low output impedance of the VTL that has allowed me to use it successfully with the Spectral DMA 400's as there are only a few preamps with a low output impedance that make this possibility feasible (BAT and CJ are two others). The VTL in particular has dynamics and drive that hardly takes a back seat to the Spectral DMC 30 SV. The choice there will have far more to do with one's sonic preferences than dynamics/drive.

I have heard the latest CJ GAT at Myles Astor's recently and it is a superb preamp. If you are comfortable with it's attributes (single ended only), it would be a mistake to dismiss it from consideration, especially since it is a relative bargain compared to many other units out there.

Marty,
Thanks for clarifying on the SS device - the MOSFET. A lot of orthodox tube guys, with great ears, are able to sniff that out in a cinch, like sending your kid with a cheeseburger instead of a grilled cheese sandwich to the shul camp. But my thinking was that for someone like MadFloyd, who is sensitive to the euphonic characters of tubes, may be happy with a more neutral sounding VTL.

 

[caesar]

Hi MadFloyd,

Congrats! Are you all set, or are you entertaining the other suitors, still?

Also, just noticed in your signature you no longer have the dCS Vivaldi, but the Schiit Yggdrasil DAC. What are the sonic attributes of each? Isn't the Schiit Yggdrasil a ladder DAC, with a different sound than the dCS? Or is the Schiit Yggdrasil better?

Thanks

All the Best!

 

[microstrip]

Al, what I mean is that if the Top of the line CAT preamp sounds veiled or otherwise faulty when paired with the matching CAT amps, then something is wrong in the chain somewhere. Remember, Ken Stevens, the CAT designer, most surely designed his gear to be completely synergistic. If a preamp, and particularly a ss preamp can actually sound better in that pairing, this would indicate to me that there is something going on that is interfering with this synergy.
(...)

I feel tempted to agree with you - if a complementary pairing does not sound good in my system I do not insist. If we do not appreciate in full the sound characteristics that the designer wanted us to listen, I move away, particularly in simple systems - this means without subs of crossovers. In my experience with many brands - Krell, cj, ARC, Lamm, Dartzeel, Jadis, Cello... - unless I was replacing the original with one of much higher price/rank I never got better long term results than with the matching preamplifier.

 

[microstrip]

Respectfully disagree on both counts. The VTL 7.5 III is unmistakenly a tube preamp as the majority of the gain is from the tubes. (By the way, I wish that when folks refer to the sonics of a tube preamp, they would specificy the tubes being used since the character of sound changes dramatically with the choice of tube. Long plate Mullards sound very different than NOS Telefunkens, both of which are very different from the stock Ciftie's that come with the unit) (...).

Marty,
Thanks for clarifying on the SS device - the MOSFET. A lot of orthodox tube guys, with great ears, are able to sniff that out in a cinch, like sending your kid with a cheeseburger instead of a grilled cheese sandwich to the shul camp. But my thinking was that for someone like MadFloyd, who is sensitive to the euphonic characters of tubes, may be happy with a more neutral sounding VTL.

The VTL 7.5 III uses the tube as a no feedback element for gain - a change from previous designs - it should be as euphonic as many other tube designs, as confirmed by Marty findings that it changes its sound when we change the tube brand. And it does not use MOSFETs, but special power JFETs that according to Luke Manley sound more "tube like" - a trend in his more recent designs, as he explained several times.

I think that the old traditional binomial relation (euphonic tubes, neutral or harsh solid state) is something of the past since many years ago. Going on superficially analyzing equipments and systems along these lines, ignoring the designers technical aspects and intentions, is highly misleading.

And I do pretend to know what would make Ian happy. I sometimes even am not sure what technicalities makes me happy! In the end it is the implementation and our matching abilities that matter most.

All IMHO, YMMV.

 

[bazelio]

Pass Labs B1 buffer

To be fair, the Magicos aren't particularly efficient which may limit the value of that kind of preamp in his system.

Ah yeah, the B1 is going to suffer in the area of dynamics, so that explains it. And yeah, if there's not enough gain in the system then actives can have a place despite doing inevitable damage to the signal.

 

[Al M.]

Ah yeah, the B1 is going to suffer in the area of dynamics, so that explains it.

In a system like Ian's, yes, when you need extra gain. In mine dynamics are intact with the Pass B1 in the chain.

(I have a newer version with no caps in the signal pathway, but I don't think that matters much in this respect).

And yeah, if there's not enough gain in the system then actives can have a place despite doing inevitable damage to the signal.

I have just heard today in Ian's system a comparison of the DartZeel with the passive B1, and I am impressed by the resolution, neutral sound and authority of the DartZeel. It's a great buy, congrats again, Ian!

 

[bazelio]

In a system like Ian's, yes, when you need extra gain. In mine dynamics are intact with the Pass B1 in the chain.

(I have a newer version with no caps in the signal pathway, but I don't think that matters much in this respect).



I have just heard today in Ian's system a comparison of the DartZeel with the passive B1, and I am impressed by the resolution, neutral sound and authority of the DartZeel. It's a great buy, congrats again, Ian!

I don't know why you and PeterA are referring to the B1 as a "passive" device. It isn't. The Pass B1 is an active device that doesn't do gain. It utilizes JFET buffers to solve potential system impedance mismatches. Big difference there. Good passives, such as those utilizing AVC, won't introduce impedance mismatch issues in systems with sufficient gain as their load impedance doubles (in value) for each 3 dB of attenuation. For example, in my chain I'm at about 93-95 dBA in the room depending on the record with the AVC knob at about -30dB. So the amp input impedance is essentially irrelevant at even the loudest of volumes I care to use, and I could easily be using a less efficient amplifier or less efficient speakers and still have more than enough volume and headroom. And dynamics up the wazoo!

 

[Al M.]

I don't know why you and PeterA are referring to the B1 as a "passive" device. It isn't.

Nelson Pass himself does:

https://www.passdiy.com/project/preamplifiers/b1-buffer-preamp

Quote:
"Figure 1 shows the full schematic of the B1 buffered passive preamp."

The Pass B1 is an active device that doesn't do gain. It utilizes JFET buffers to solve potential system impedance mismatches. Big difference there.

But yes, you have a point, the B1 is an active device.

Ian seems to need the extra gain over the B1 in his system, I don't. You apparently don't need extra gain either.

 

[bazelio]

Nelson Pass himself does:

https://www.passdiy.com/project/preamplifiers/b1-buffer-preamp

"Figure 1 shows the full schematic of the B1 buffered passive preamp."



But yes, you have a point, the B1 is an active device.

Ian apparently needs the extra gain over the B1 in his system, I don't.

Nelson does not really refer to it as a passive preamp there; in fact, he starts the article by describing what the classic DIY "passive preamp" contains: just an input selector and a volume control. Yes, *that* is a passive preamp. So his B1 has the "passive preamp" stage (so to speak) but then it is also buffered by active devices. And incidentally, I feel this is a poor approach. If you don't need gain, then you certainly don't need (and should avoid) an extra power supply in the signal path. But I digress. I felt the nomenclature was worth correcting because I've seen at least two misconceptions on WBF regarding passive preamps: (1) That all passive preamps are essentially the same, sharing the same shortcomings; and (2) that "zero gain" and "passive" are somehow interchangeable.

 

[Al M.]

Nelson does not really refer to it as a passive preamp there;

Well, he does, as quoted. But he also says his buffer has an active circuit, so you are right to call it an active device.

So his B1 has the "passive preamp" stage (so to speak) but then it is also buffered by active devices. And incidentally, I feel this is a poor approach. If you don't need gain, then you certainly don't need (and should avoid) an extra power supply in the signal path. But I digress.

Sometimes you do need impedance matching. I cannot run my subwoofers with just a passive device, without a buffered preamp. I tried.

I felt the nomenclature was worth correcting because I've seen at least two misconceptions on WBF regarding passive preamps: (1) That all passive preamps are essentially the same, sharing the same shortcomings; and (2) that "zero gain" and "passive" are somehow interchangeable.

Again, you made good points.

 

[microstrip]

Ah yeah, the B1 is going to suffer in the area of dynamics, so that explains it. And yeah, if there's not enough gain in the system then actives can have a place despite doing inevitable damage to the signal.

Damage or improvement?

Does anyone know what is the gain of Ian's CAT amplfiers?

 

[MadFloyd]

Damage or improvement?

Does anyone know what is the gain of Ian's CAT amplfiers?

If I recall, it is listed as 17db, but I’m not sure it’s accurate as the Pass Labs XS amps I had when I bought the CAT were listed the same and they were much louder.

EDIT: My memory failed me (wouldn't be the first time, certainly won't be the last!); the number should have been 27db.

 

[PeterA]

If I recall, it is listed as 17db, but I’m not sure it’s accurate as the Pass Labs XS amps I had when I bought the CAT were listed the same and they were much louder.

My Pass XA160.5 are 26dB. The Pass website lists the Pass XS 150 amps as 26dB gain also.

 

[bazelio]

If I recall, it is listed as 17db, but I’m not sure it’s accurate as the Pass Labs XS amps I had when I bought the CAT were listed the same and they were much louder.

The CAT JL7 gain is 27dB (8 ohms), or 24dB (4 ohms). It's a fairly efficient amp. It also has input impedance of 100K. M-Project speakers have 91dB/W/m sensitivity. Unless your phono gain is unusually low, I don't suspect the issue in your system was gain. It seems more likely to have been the B1 itself. The Dart is likely just a much better device. By the way, have you posted impressions of the CAT vs the XS somewhere I could read? Perhaps I'll pick your brain via PM.

Anyhow, in my case, my speakers are 90dB/W/m, amp has around 26-28dB gain, phono has 66dB gain (adjustable), and when my passive AVC is at -26 to -30 dB, the listening volume is loud at the listening position, 3m away. Too loud for extended listening. Dynamics and articulation are superb, even at low volume. Clearly no reason to have additional gain as I'd just need to attenuate it away.

 

[ack]

I avoided writing earlier, but I believe I was the one who first let PeterA and Al M know that Ian's CAT preamp was highly veiled and colored. I don't think they believed me at first, but apparently they eventually did. The system's sonic signature became quite obvious to me very quickly, and Ian and I took the preamp out within half an hour or less. Basically, it presented the music in a euphonic and veiled way - "fake news" if you will - and all the information came back in a more realistic way when we took it out. However, digital was somewhat thin, and I attribute that to DACs just not being able to drive amps directly. Analog was much better - after gain there was adjusted much higher - but in the end, that also left me wanting more, and for example, I liked Steve Williams' ZYX set-up over Ian's; I am also no longer a fan of unstabilized pivot arms, and I think Ian's is one of them. I believe he'd be better served with a different (and better) arm. But the sheer fact that we had to increase phono gain significantly (12dB?!?) tells me those amps just can't be properly driven directly from sources.

FWIW, I get the same detailed but thin sound from my digital driving my Spectrals - and all Spectrals I've ever had - direct, because simply put, the 1mA DAC output is just not enough.

At the end of the day, I can see why Ian is still looking for a truly transparent preamp that can drive his CAT amps, though I have not heard the DartZeel. Bottom line for me: I just could not stand the coloration and masking of detail of his CAT preamp, and just to give an example, I pointed to specific information missing, like triangle hits, and I believe I had also pointed to solo piano being all over the place. Perhaps the tubes were bad, but I can only judge what I heard. But I can attest to the CAT amps being really good, and I suspect they sound better now.

PS: I HATE Ken's writing style, and I base this on many emails I have seen over the years with others.