Roy Gregory: Preamps: VTL 7.5 Series III, ARC Ref 10 & CJ GAT Series 2

LL21

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Dec 26, 2010
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#1

XV-1

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May 24, 2010
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#2
thanks Lloyd

as you and I know. cj GAT Rules OK. :D

are you going series 2 anytime soon?
 

Harlequin

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Jul 30, 2013
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Of the three contenders I can only comment upon the REF10 in that replacing the ARC factory supplied Sovtek 6550's with NOS 1970's General Electric 6550A's takes its performance in all aspects to another level entirely, the former valve in comparison sounding sterile , 2 dimensional and lacking in harmonic texture, micro detailing, top end extension etc.etc.etc.

REF10 owners running stock regulators are, IMHO, most certainly not experiencing the full strata of performance this unit is capable of delivering. Should one be wealthy enough to also replace the stock 6h30's with NOS 80's production DR's these will impart further sonic enhancement.
 

LL21

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Dec 26, 2010
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#4
I have heard the Ref 3, Ref 5 and Ref SE and Anniversary Reference, since our local dealer uses their equipment a lot. I have heard the VTL but in a setup that was all-new to me. I could completely imagine system setup at this level with any of these 3 pieces of equipment could get you to wherever most mere mortals would want to go and possibly further. Certainly, the CJ in our system also benefits strongly from:
- NOS Tubes (I refer to Series 1)
- EAT Tube dampers
- HRS M3X isolation platform and HRS DPX dampers (4-5) on top
- I even happened to have 2 Finite Elemente Vibration Discs (i put one on top of each of the perspex tube guards)...teeny tiny benefit. Only did this since i happened to have these lying around.
- Grounding (Tripoint)
- Signal Grounding (Entreq)
- Purist Audio 25th Ann PC
- Entreq Wraps

The key i suppose is that the comparison of the 3 amps by Roy Gregory is 'like for like' with no such tweaks (of which he is a definite and public proponent). Having spent a lot of time with ARC preamps, i would really like to get to know the VTL better...and also many have recently discussed the CAT Legend which i have never heard and would also like to hear some day.
 

bonzo75

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Feb 26, 2014
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#5
Cat, like Lamm and Jadis, don't have a remote. I want to compare Nagra jazz and Ypsilon
 

Harlequin

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Lloyd....I entirely appreciate that all three units were evaluated from factory spec. In my previous post I merely sought to comment upon the areas of performance where Roy felt the REF10 to be slightly constrained, in particular, separation, transparency and tonal delicacy, in that all those points can be ameliorated and said aspects notably transported to another level with the substitution of a pair of GE 6550A's

The same applies to any later production ARC pre amplifier utilizing Sovtek 6550 power regulators including the 5se and 40 Anniversary.
 

LL21

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Dec 26, 2010
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#7
Lloyd....I entirely appreciate that all three units were evaluated from factory spec. In my previous post I merely sought to comment upon the areas of performance where Roy felt the REF10 to be slightly constrained, in particular, separation, transparency and tonal delicacy, in that all those points can be ameliorated and said aspects notably transported to another level with the substitution of a pair of GE 6550A's

The same applies to any later production ARC pre amplifier utilizing Sovtek 6550 power regulators including the 5se and 40 Anniversary.
Thanks, Harlequin...did not mean to come across as debating any of your points. If anything, was trying to add to them, which is that I agree...certainly it seems 2 out of the 3 seem to benefit from a lot of these refinements. I think to further add to your point, the benefits of the 'refinements' to CJ GAT set up would be:

- density, strength of signal
- less shimmer among individual notes, particularly on complex passages
- more propulsive, powerful presentation...but would not suggest this is a major change to the voice of the GAT...just perhaps 'much more of the same'
- improved bass in particular
 

LL21

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Dec 26, 2010
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#8
thanks Lloyd

as you and I know. cj GAT Rules OK. :D

are you going series 2 anytime soon?
Its not an inexpensive upgrade so while it is on the list, i suspect it is some time away. You?
 

LL21

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#9
May 30, 2010
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#10
Fortunately Roy Gregory is very clear:

"All I can report on is their relative virtues in this system; the degree of difference and even those differences themselves may well vary with different partnering equipment, just as they may appear different to a different set of ears -- and that’s the root of the problem. "

I have no significant experience with the recent VTLs, but I have long experience with the REF40 and REF tube amplifiers, including the REF750, and currently host GAT and LP257m's. I have owned the REF9 CD player for several years, and still have the same opinion - a great CD player, much better than price suggests, when matched with a balanced Audio Research preamplifier. IMHO the use of this CD player with the GAT introduced a strong bias in the review.

I have to say I failed to understand the part on the peak and average levels.

IMHO sound quality of top equipment evolved in a sense that does not allow the old mix and optimization game - each preamplifier will sound its best with the matching amplifier.

All in all, a very informative, interesting and thought provoking article, but that should be taken with many grains of salt, as stated by the author.
 

XV-1

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May 24, 2010
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#11
Its not an inexpensive upgrade so while it is on the list, i suspect it is some time away. You?

Like you, this upgrade outside of the USA is about double what it costs inside. Not planned anytime soon, especially when the GAT sounds so great on top of Stillpoint 5's and with Telefunken 6922 tubes.
 
May 30, 2010
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#12
Like you, this upgrade outside of the USA is about double what it costs inside. Not planned anytime soon, especially when the GAT sounds so great on top of Stillpoint 5's and with Telefunken 6922 tubes.
Unfortunately there is very little technical information available on this upgrade. Previous times I always knew pretty well what were the changes, but not this time.
 

LL21

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Dec 26, 2010
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#13
Unfortunately there is very little technical information available on this upgrade. Previous times I always knew pretty well what were the changes, but not this time.
Do you know anyone who has heard it in direct comparison with the Series 1? I can think of only Myles Astor and perhaps Big Dog RJ. i believe there might have been 1 or 2 members here who have since upgraded and who kindly provided comments about the upgrade differences in their own system.
 

XV-1

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May 24, 2010
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#14
Unfortunately there is very little technical information available on this upgrade. Previous times I always knew pretty well what were the changes, but not this time.
This update includes the introduction of an improved circuit in the regulator for the main audio power supply. The new regulator also features increased filter capacitance. the new circuit resides on a new master pc board. A great many very costly parts get moved to the new board. The update also includes boosted output coupling capacitance, again using more of the CJD Teflon capacitors. The tubes have also changed to NOS Phillips PC88s.
 

LL21

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Dec 26, 2010
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#15
Unfortunately there is very little technical information available on this upgrade. Previous times I always knew pretty well what were the changes, but not this time.
This update includes the introduction of an improved circuit in the regulator for the main audio power supply. The new regulator also features increased filter capacitance. the new circuit resides on a new master pc board. A great many very costly parts get moved to the new board. The update also includes boosted output coupling capacitance, again using more of the CJD Teflon capacitors. The tubes have also changed to NOS Phillips PC88s.
Gents,

thanks for this...what is the function of the 'regulator' of the main power supply? What does increased filter capacitance do?...is this like capacitance like in an amp where this is effectively stored energy giving the preamp its own internal source of energy for transients, peaks, speed of delivery, etc?

What is the function of output coupling and again what does increased capacitance do? Thanks!!!

just trying to understand the main thrust of what appears to be 2 power-related changes, including increases in capacitance.
 
May 30, 2010
14,115
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Portugal
#16
Gents,

thanks for this...what is the function of the 'regulator' of the main power supply? What does increased filter capacitance do?...is this like capacitance like in an amp where this is effectively stored energy giving the preamp its own internal source of energy for transients, peaks, speed of delivery, etc?

What is the function of output coupling and again what does increased capacitance do? Thanks!!!

just trying to understand the main thrust of what appears to be 2 power-related changes, including increases in capacitance.
The regulator is responsible for supplying a constant DC to the gain and buffer stages - typically uses a non feedback series regulator controlled by a string of zeners. More capacitance will reduce noise and impedance in the low frequencies.

The increased capacitance in the output capacitor will extend low frequency. However the subjective effects of these changes are sometimes much greater and in expected areas.

The ACT2 series 2 was essentially a simplification of the circuit reducing the number of parts in the power supply, re-allocating the teflon capacitors used in the pre-regulator to the unique regulator. But I can not see what can be done now - there was only one regulator stage left!
 

LL21

Active Member
Dec 26, 2010
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#17
The regulator is responsible for supplying a constant DC to the gain and buffer stages - typically uses a non feedback series regulator controlled by a string of zeners. More capacitance will reduce noise and impedance in the low frequencies.

The increased capacitance in the output capacitor will extend low frequency. However the subjective effects of these changes are sometimes much greater and in expected areas.

The ACT2 series 2 was essentially a simplification of the circuit reducing the number of parts in the power supply, re-allocating the teflon capacitors used in the pre-regulator to the unique regulator. But I can not see what can be done now - there was only one regulator stage left!
Thanks, Micro...certainly seems consistent with the listening notes i have read from those who've heard it. I think on the ACT 2 they felt that have two wells of capacitors/power supply, or however is the correct technical explanation was not as good as having one bigger well in terms of larger-transient peaks and response. Is that what you understand as well? I think they did 2 wells to lower noise floor, but in the end i think they went to 1 bigger well instead?
 

LL21

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Dec 26, 2010
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#18
Jul 9, 2011
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#19
I have to agree with Harlequin earlier in the thread. While already an excellent preamp, the ARC REF10 preamp jumps another level when you sub in the GE 6550A's. Great upgrade! Works for the REF10 Phono too.

The REF10 and Pass Xs preamp were close in my system with a slight nod going to the REF10. But after the GE 6550s were inserted, the REF10 was clearly the choice.
 
Feb 3, 2012
607
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Melbourne
#20
G'day mates.

As XV-1 confirmed the upgrades, I think that's about accurate as it gets, and also in the sunny land of Aus, this upgrade is like adding another component- somewhere around 10 grand just for a bloody upgrade! Probably even more after it has to travel to the US of A and back!

I have heard all three versions on my previous system when I had the Quads and Classic 60SE. The ACT2/S2, GATS1 & S2. Although I enjoyed my ACT2 very much, it started giving me some odd problems with the mute and left channel. This started happening around 2013, got it upgraded in 2014/15. All of a sudden during playback, approx. 2.5 to 3 hrs into play, the mute would automatically engage and paralyse the entire left channel or first the left channel would go quiet to soft and suddenly cut off, leaving all the LED's on the left side of the Act2. This was really annoying and I was later told that due to one of my Quads (the left speaker) being faulty, this is how and why the Act2 reacted. However, this same symptom occurred at my dealer mates place as well, when I took it in for an upgrade. After it was upgraded with additional tweaks done to the power supply & mains power cord internally, this problem stopped altogether but the Quads failed!

Then when I listened to the GAT, it delivered a very nice open, and expansive presentation compared to the ACT2-S2. The GAT allowed more music to flow with superb resolution and inner detail that comes out more prominently. The GAT also seemed to have better drive and control over the Classic 60SE, and really gave a thumping on those KT120's. It sort of made the Classic 60SE sound more like a 200 watter, and not so much a mere 60watts amplifier. The one major sonic factor of improvement in the GAT was its midrange, and through stats like the Quads, it was superb! A very musical, lush and palpable midrange that was only bettered through Lamm's in my opinion. Apart from this, there were other traits such as more depth, open soundstage, ambience and spacial cues were so well defined and it was just a marvellous presentation overall.

Then comes along the GATS2, and takes all what I just stated above to another level. And this is not just another level but quite a significant level of improvement, and most of all musicality. I have heard the ARC reference gear extensively (not on my system) but at the same dealer/distributor where I bought my Rega TT from, he uses only ARC gear in all of his high-end setups. The ARC ref gear is great sounding and gives you that typical sense of ARC authority and slam, plus plenty of headroom, smoothness and tube refinement at its best. BUT to me it does not have the musicality of CJ. There is something so darn musical about CJ, especially their preamps that presents music the way it should be heard.

There is no artificial "bump" or sonic bloom to it, nor any exaggerated thump to it, just pure musicality, and through recorded music, CJ heightens the enjoyment of this recorded music, of course provided it was recorded well! I am certainly not saying that ARC is not musical, in fact it is very musical, and equally powerful. Brings out all the sheer energy and greatness of a musical presentation. Having said that, there is still something it lacks compared to a CJ system. Even well regarded CJ poweramps such as the older premier series, the ART series, and LP series sound wonderful with a GAT or a GATS2 or even an ACT2 for that matter. The CJ synergy is something very hard to beat and extremely addictive.

Whereas ARC, I have noticed you simply cannot partner and mix pre-power and expect sublime performance. Infact when I was last over there, I did several comparisons with their new GS series power amps, and found that they need to be partnered either with a top of the line Ref pre, or at least a matching pre to sound their best. Just an ordinary ARC pre does not do the job quite as well, and all listening was on a Sonus Faber system with a Michel Gyrodec or Linn Sondek TT. Obviously on full range stats, this comparison would have been even more transparent and revealing.

To ARC owners, again don't get wrong, I absolutely love the ARC sound when matched and partnered properly. It's just that to me CJ does sound just right- this is obviously a personal preference. Would have been a real pleasure and treat to have experienced top of the line CJ gear, such as the ARTsa with a GATS2 driving a pair of Martin Logan CLX's! Oh! my gosh would that be the day maties!

Perhaps when the daughter is all settled & married, the wifey has lost her hearing- then I can go for an ART & GAT system! Excellent plan but then if the wifey has lost her hearing, I wonder where my ears would be... probably at the hardware store in need for a new pair! I always pictured the future someday this way, where we humans will be half/semi machinery. Our vital parts will be retro-fitted with machinery or bionic parts, so that when they go bad, such as our eyes, ears and other vital gadgets, we just hop to the hardware store for replacements! I wonder what type of high-end audio would exist...

Till then, to those who can afford the upgrade, as I mentioned before it's a definite recommendation to the series 2, it is probably the best preamp I have ever heard to date!
A full Lamm pre-power system is equally superb in performance, if at all a tad better and so are AN-Kondo amplifiers but this is drug money and only the top dogs in the cartel would have systems like these!
Cheers to the GAT S2! RJ
 

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