552 in domestic environment

Posted by: M. Brandstetter on 27 June 2002

Dear all,

yesterday evening i got the chance to hear the new
552 at U.Hohn's place.

First, thanks to Stefan Gellrich, owner of SG-Akustik in Karlsruhe (Germany) bringing the
pre. Also to Ruediger Jankowski (sp), who accompanied Stefan.

And last not least to Ulrich, calling me and
fixing the date, so i got the chance to hear
the pre.
The travel was filled with disappointment at
the beginning, cause i had some problems at
the highway with workplaces (???) and traffic jams.
But arriving it was nice to be welcommed by
Ulrich, his wife and son.

It was a nice evening, Mrs. Hohn prepared a lovely
cake for inbetween the listening sessions.
When Stefan and Ruediger arrived they had
packed up the car with to (new design)
naim audio shipping boxes. Weighting each a ton.
(Not realy that much, but i expected one to be
lighter then the other, later more on this topic)
So we stuffed these into the Ulrich's musci room,
and first had a listen to his normal gear.

Main interest, like you all know was the
turntable and what would happen using the
552 in this setup.

First DJ-Ulrich played a collection of
five music peaces, to have a zero level
of knowledge what his gear is able to do.
This alone was jawdropping.

After the first session, Stefan and Ruediger
build up the 552 with PSU and connected it
to the ensemble of naim boxes.
Here the new XXX-Cap was the easiset part ;-).
The new pre and his spring based subchassis
are a hell. We had to lose (sp) 4 screws and
take care of the angle we hold the amp. So
no subchassis could jump out of the holding.
( I would like to have a look inside this
box, maybe naim could be so kind to release
som picutres to that??? )
Nevertheless, ruediger managed this hard part
easily.

After installation we had the first break
to give it a few minutes with a radio signal.
(And well, eating the cake... thanks again baebel.)

Here we discussed a bit about turntables, stands
and other stuff.

Returning to the listening room the first
im pression was, wow. Nice radio station (mono, but very impressiv).

Stefan connected the prefix directly to the
552, so we had the chance to first have
an impression on the 552 alone, but we planed
to try the scap also.

First the entrance plop, putting the neadle onto
the record has changed. It was more soft and
not that noisy, here also notable was an absence
of the record surface noise, this we had before
with prefix, scap, 52.
Well and then the first tunes float out of
the speakers. AMAZING, the music was more fluid
and comprehensible.
The room behind the musicians was no longer
black. Here it was the wall of a studio, or
the musician behind the other.

A peace with cello (form debussy) was very
amazing. Here we heard things we former even
didn't recognized they where on the disc.

OK, you'll say that we must be stupid, but
the 552 clearly wins against a 52 :-(((
I wouldn't believe it just reading a magazin or
a post on the forum ;-), but experiencing this
was far more then i expected.

Here i thought that a jump form 72 to 52 was
big. Forgett it! 552 is further away...

Yep, it's a pitty. The naim engineers delivered
a more then adaequat new preamp.
Even more bad, what i thought would be impossible,
they bettered the 52 :-(

First glimpse i had on the 552 in the AV-Setting
was well: nice (but no comparison with 52 was made).
In direct AB it more then wins.

Maybe you remember i wrote a few lines ago
that we planed to try the scapped prefix.
Herefore the S-Cap was not unplugged.
So good condition, you would say for the test.

We reangered the wiring and ruediger had to
reprogramm the 552 so that an input reachable
with the S-Cap signal wire could be used.
Thanks Thomas vdV for the telefon support.
This is a non trivial thing ;-)
To say a few words against the 552..., it's something like windows (tongue in the cheek).
You have to press a button on the remote, press
mono (or nearby) then looking at the back for
the LED's, pressing mono for a few times...

Maybe naim will relaese the manual soon on
the web.
Nevertheless it was amazing.

After reconfiguring one input we plugged
the S-Capped prefix in, and Ulrich lowered
the neadle into the record groove.
First impression was, oops more background noise
again.
The first tunes where played and obviously a curtain was layed over the musicians.
Gosh, i didn't believed it in the
first moment.
The prefix driven over 552 with this new power-supply betters an expencive supercap...

I wonder when naim make this XXX-Caps available
as a domestic upgrade PSU (like Supercap) for
a migration route to the new top of the class
systems.
And whats inside? A better trafo, different
voltage regulators...just a bunch of parts
thrown together with a better understnading
what's going on.
Man they evolved a lot since the old S-Cap times.

For that it was clear, the direct driven
prefix was better then the other way.

Finally it was a more then win win situation
for the 552.
In a domestic environment and in a stereo
installation it's capable of more then
stunning music presentations.

Here i remember posts blaming nerds that they
would say that a 52 sounds liveless, flavourless,
dull, uninvolving after listening to a 552.
YUP, they where right.

The 552 is better. But also the price tag is
more then high. So after a bankrobbery or
a big lottery win, i know what to buy
before the house, the porsche, the boat, the
aeroplane....

Only pitty, there are no phonoboards available.
At ulrich's place this was not a real problem,
but i remember there are turntables out (like mine) where there is no place for a prefix.
Stageline doesn't do the job.

So please naim, maybe you find a solution
for us non lp12 owners.

Hope you have fun doing hifi-diet (water and
maybe every second day a slice of bread with
a few grain of salt...).

Gratulations to all possible 552 owners.
You'll made a right decision buying this
PRE. Acompanied by 500 amazing. Maybe
there is a chance to listen to it in a
weaker system then ulrich's.
But i think that there would be ever
the PRO for the better PRE ;-)

Have fun listening to music. (I'll start with diet for the next 10years... :-( )

Regards
mathias

PS: Thanks to musicline germany who made this
session possible.

PPS: The night was bad, wallowing in bed,
proceeding the experience.
Hearing a 552 and not beeing able to
afford it is pain.
(The old word roules: Don't listen
to unaffordable Naim gear :-( )
Posted on: 27 June 2002 by M. Brandstetter
One thing i forgot to mention was
revealing the secret about the two
haevy parcels...

The 552 is a truck!
It weights a lot. Stefan told that
there is a heavy plate inbuild.

I lifted it during packing after the
transportsrews where fitted again.
It's more like a S-Cap then a 52 ;-)

Maybe the 52 owners should try to tweak
the 52 by putting a lead plate into it...
anybody tried???

Regards
-mb
Posted on: 27 June 2002 by David Antonelli
Hi,

First of all... the title is a reference Cliff Patterson's historic thread of two years back when he first bought the 500...the reason? I was drinking a beer with him on the Thames a few days after he bought it and before he posted discussing when I should buy mine. (BTW, I don't know why I remember the title of his thread! Just stuck in my head like a MacDonald's jingle)

Well, two years later i finally took the leap. She's in my system. Had to trade in my beloved 250, hicap. headline, and senn hd 600 to bring the price down, but the eagle has had about 6 hours of play so far. Mathias would have to ruin it by posting on the 552 (!).

I'm using CDS2/52/ and ACT 2 on Wilson Benesch Triptych/Aside. So far it is much like an XPS onto a CDX. More detail, more weight, more oomph. Still somewhat tight and ragged around the edges, but there is an amzing sense that, like Mathias saw with the 552, you can experience the whole listening room and not just the black background. On Dylan's time out of mind this is particularly noticeable. Also, more groove, more impact. The ACT 2 are big on impact and subtlety, and the 500 seems to bring it all out.

But I have heard it takes a long while to break in...I am expecting a lot more, because an XPS is about 6K CAD, a 500 now 31 K.

dave
Posted on: 27 June 2002 by M. Brandstetter
hi dave.

gratulations to your 500, yep it's fabolous.
i don't know what the outcome of yesterdays
session would be if ulrich doesn't already
own a 500...

maybe a tip for breaking it, ulrich recognied
that his one didn't get warm driving his sbl
(they don't need that much current).
therefore he let is dealer burn them over a
weekend feeding nbl at mx vol over
a weekend and cd on replay (not for home use ;-)
and neigbors...)

Hm, selling headline... i remember the old days
and your posting about 52 and buying the headline,
hopefully you will not miss it to much.

sorry for copying the title of another thread,
i did not realize that. so i thought hard about
a title sounding serious and not hinting to the enjoment we had.

The 500 will come to live soon ;-), please
be prepared for a jump like 250 after 5 days
playing.

At least a warning, don't AB 52/552, it's a shock.
Listening to a 552 is amazing like 52, good luck
memory fades very fast. But A/Bing is deep
impacting.

Best
mathias
Posted on: 27 June 2002 by David Antonelli
Mathias,

I'm sure the 552 is amazing. But as ever, I am always one step behind. When I bought my CDS 2 it had been out for a few years already and the 500 had just been released. Now that I have a 500 there's a new pre. Oh well, I think I won't be upgrading for a long time. My system with a 250 was about 80% of where I wanted it to be, so I think the 500 should hit smack on the target. Gotta buy a car and be a responsible adult (gag) at some point!

The 500 is sounding more eloquent now. For the first while it was a tad scrappy and thuggish - a mixture of wooly bass and sharp highs. This has disappeared, but now I notice it has trouble with complex passages and transients. In other areas (such as ambient detail) it is really startling. I'm sure by 5 days time it'll start rocking (but I'll give it six weeks to really show its mettle). It is already a bit warm to the touch, at moderate volumes, so I guess the ACT 2s are tougher to drive than the SBLs.

dave

PS: I miss the old days on the forum. WHo got the last Snappy?y
Posted on: 28 June 2002 by M. Brandstetter
Sorry the snappy i don't know.
But the 5days where ment to the 250.
The 250 tooks at least 5 days to start
singing.

what should i say. i'm way behind the
wind. so cds2, 52 and 500 is a bloody
good setup.

best
mathias
Posted on: 28 June 2002 by Dev B
I wish I could be there - it sounded like you had a really good time. In particular, I would love to hear Ulrich's system. It is very interesting to note that the new 552PS is so quiet, it is better than a Prefix/Supercap.

Maybe one day I'll visit Ulrich - if that's okay?

regards

Dev
Posted on: 28 June 2002 by M. Brandstetter
:-(

hifi diet is a bad thing, hunger occurs
and i think i'll quit it for today ;-)....
having lunch....

(obelix words: maybe i'll eat a kracker with
a tiny bit on top, a pork)

Cliff, you're right. You'll lick your fingers
after the 552 once a/b tested to 52.
If you don't compare you also stay happy with the
"old" 52.
For shure the S-Cap seams to limit it all.
The prefix lost so much driven by it. Here
it comes up to my mind whether OLD 52 owners
are out using the original 52ps before the
s-cap was available.
Maybe with such a setup the gap is from
the musical side not that big?
(Here i assume that the old psu was more
sophisticated then the s-cap. If i remember
correclty 2 transformers where inbuild.)

You still have the nbl's?

Please report your experiences with the 552.

***

Mark, 500 hot and fans comming up to work?
WOW, i don't know how powerconsuming bricks
are but that sounds after a heavy turn
on the volume knob.
Do you have a real tall room, or was it during
a party?

Regards
-mb
Posted on: 28 June 2002 by M. Brandstetter
Dear Dev,
yes the absence of any noise was
marvelous. Without listening i would
not believe it.

Strange here is, that with 52 you
better the quality with buying a
s-cap for the prefix.
But now this puzzles me.

Here the same effect is true, with pre/s-cap
you also gain a lower noise floor.

I'll stop thinking about, it's better
for my health.

Hope you all enjoy the music and
have fun.

Regards
-mb
Posted on: 28 June 2002 by Ulrich Hohn
Hi Mathias,
I read your report with pleasures. Owing to also from my side at Stephan Gellrich. The best dealer, whom I had ever!

We developed our own technical language, in order to describe the sound from hifi gear to. With a life chamber concert it would never come me into the sense to use these terms.

I was now at the home demonstration likewise. My present plant (see profiles) can show nearly realistically piano music. With the string quartet it sounds well however still clear as hifi.
With the 552 also this cliff is mastered. Hifi is moved complete with the Nac552/Nap500 into the background - Paul S. wrote some days ago that its own gear sounded only after 3 days like life. There is thus still possible for increase!

And there was a second surprise this demo: I have some years ago some weeks with the table for my record player employed. Now I heard for the first time, how well that had obviously succeeded to me.

"Maybe one day I'll visit Ulrich - if that's okay?"
Dev, yes.

Regards
Ulrich
Posted on: 28 June 2002 by David Antonelli
Mark,

The 500 is slowly coming awake now. It's been playing about twenty hours. It still seems more shut in than the 250 was, but the detail and scale and drama is all coming out now. As it opens up and takes charge it really should be something else.

My question is whether distortion from one component to the next one downstream is:

a) additive

b) multiplicative (ie distortion equals net distortion of component a multiplied by net distortion of componet b.

c) some other function. For example, in an FT data file the signal to noise ratio increases as the square root of the number of aquisitions.

If distortion is multiplicative there would be many cases in which the very best speakers with a great, but not the best, preamp (52), will show less of an improvemnt with the addition of the best preamp (552) than in the same system with good, but not great speakers (albions, perhaps). And I'm sure this could hold with all components in the chain.

Do less than optimal speakers "add" to the distortion, or do they "multiply" whatever disortion is coming from the source components and amplifiers?

dave
Posted on: 28 June 2002 by JeremyB
So the big question I have is, given a mid range (250/180/102 or whatever) which is the first recommended upgrade - 552 or 500?

That is, of course, if you could only afford one of them.

Jeremy
Posted on: 29 June 2002 by Martin Payne
Someone from Naim recently posted that 52->552 is a far bigger jump than 250->500.

Until someone posts an opposing view, that's your answer (and that's from a 52).

cheers, Martin
Posted on: 29 June 2002 by Tuan
David

I can see that you will be heading for the 552 soon (beside all the crying and hurting from the bank balance). You just need sometime to recover from the spending shock (laughs). How long did you have the 52 and 250 combo? and what is the main reason for going to the 500 model? your speakers?? I am thinking of a pair WB ARC and perharps I have to go for those 135s as well to drive them. Please give us your analysis on the WB speaker and the NAP250. BTW congrats on the new toy. I hope it will give you lot of pleasures rather than new upgrade problems.
Posted on: 29 June 2002 by David Antonelli
Tuan,

I have never heard the WB ARC but it probably sounds like the ACT 2 with less scale. The Discover series is said to have a slightly better tweeter than the super revelator and a slightly more inert cabinet, having disposed of the wood used in the ACT series. When the ACT 2s play loud the slanted wooden top vibrates noticeably more than the carbon side panles, which are almost vibration free.

I lived with the CDS2/52/250/ACT 2 for a year, after upgrading from a CDS2/52/250/Royd Albions. I switched from the ALbions because at the end of the day they had a hard time with dynamics and transients, sounding either soggy and muffled or bright. They ACT 2, although I was warned the 250 would not be enough, was and still is the biggest upograde of my life. But I just have played my 500 for about 30 h now so, this might change. The ACT 2 is such a special speaker in that it is pretty close to full bandwidth, has ball bruiser dynamics, yet is as delicate as a feather when it comes to subtlty and nuance. I have never heard such fast, detailed, tuneful, and cohesive speakers with such "round earth" attributes thrown in the mix. However, the 250 lost control of them at higher volumes, the music not becoming shouty, just louder and not as tuneful. So I upgraded to a 500. I also thought running such speakers from a 250 may not have been doing them justice, all do respect to the mighty 250!

The 500 today is sounding very snappy and alive. Yesterday it was overly rich and velvety and slow, today it is dramatic and detailed but a bit fatiguing. The usual naim burn in melodrama! What strikes me is the amazing 3-d sense and how sounds seem to occupy real space like 3 dimensional objects receding into the speaker. It is not yet as nimble and cohesive as the 250. But the 250 was on constantly for almost three years!

So, I believe a 250 will be enough for the arcs, but I think you will no doubt get added refinement as you go up the power amp ladder.


Dave
Posted on: 29 June 2002 by Tuan
Thank you David

I know that you will always lead the Canadian Naim users here as far as the upgrade is concerned as I see your upgrading history. Once again congrats on the new amp that provides you so much pleasure now. What you are experiencing now is the so called sound-stage effect that only from powerful amps (and if they are made correctly). I remember to feel the same with Mark Levinson system demo at Brack Electronics in Toronto with a pair of B&W N802 (part of their permanent system in store). Yes the sense of music all around you and the room is filled with crystal notes .... Of course it was a 50,000 dollars system (like yours now). So who says that Americans do not know how to make super amps???
Posted on: 30 June 2002 by David Antonelli
Tuan,

I have only heard a full blown levinson system once, it was paired with their top of the line CD player and JM Lab Mezzo Utopias. It was sublime and spacious and natural on jazz and folk and really filled the room with "crystal notes" as you say, as though they were all around you. I wasn't sure I liked the set up so much on rock, though. I had a remastered rolling stones disk "Only Rock and Roll" and it sounded a bit flat and scrappy. But this could be anything from the CD player to the speakers or two-inch thick cable or even the room.

The bass is getting a bit smoother now. The trebble is wonderful, free of any glare and totally resolving, dark, and velvety. The deepest bass is still droping like stones though and isn't so fast and tuneful yet. My burned in 250 was a lot more tuneful than the 500 at this stage. How long does it take to fully burn this monster in?

Dave
Posted on: 01 July 2002 by M. Brandstetter
Richard you are absolutly right ;-)

(just one thing, i loved the old
apearance more then the new design...

also a 552/500 costs lot more then
52/250)

Nevertheless it would be very intersting
to hear somebodies findings in an A/B
demo between 552 and other similar priced
stuff.

Frank A. isn't that 552 price tag comparable to
chord?

Keep the music in mind and follow the
notes to heaven.

Regards
-mb
Posted on: 01 July 2002 by Frank Abela
Mattias,

The top Chord stereo preamp is similar in price to the 52. Their new surround sound processor is in 552 territory. Chord's power amps go well beyond the purchase price of the 500.

As I've said so often before, Chord amps sound different to Naim amps. Some would say it's more hifi. Unkind people I know say it sounds like posh Pioneer! In many ways, it's not as engaging as Naim is to listen to.

I have heard a pre-production version of the 552. It's certainly a step up the ladder. I'm sure some lucky (probably deaf) reviewer like Ken Kessler will get to play with the 552/500 and put Apogee Scintillas on it (0.9ohms and outside the performance envelope of the Naim) and complain that it can't drive them as well as his Audio Research from hell amp. He'll have the Naim on the silver kimber cable mains ring instead of his copper ring and he'll insist on using some weird impedance speaker cable with a totally unsuited cd player.

Reviewers - if context was a word in their vocabulary, they'd have to revise all their work (navel gazing?) so far! smile

Regards,
Frank.
All opinions are my own and do not reflect the opinion of any organisations I work for, except where this is stated explicitly.
Posted on: 01 July 2002 by David Antonelli
Mark,

Thanks for your comments. Last night, on its 4th day, the 500 finally started to take off. After a couple of days of wooly base, obnoxiously loud bass, a shut-in sound, interspersed with moments of "wow I didn't know that was on that recording"
I woke up and turned on the radio. It didn't sound so great, so I put on a DMX CD at moderate volume and left the house for the day. When I came back I flicked it to the rdio and made dinner. After dinner everything suddenly was different. The sound was deeper, more controlled, and much more cohesive. It was making sounds the first few days, suddenly it was making music. What really struck me was how well it could make notes out of the deepest bass in the worst Drum and Bass recordings. The Mix mag LTJ Bukem CD I have (with Source Direct's Exit 9) was suddenly listenable, if not utterly profound. It sounds OK on a boom box, but when you put it on a top flight system it can sound thin, dry, and distorted. Suddenly everything was in place. Those bass booms are actually notes! Much better! It is starting to sound like I had imagined it, maybe even better. I heard a 500 in Chicago with Wilson Sofia's but the Sofias are just not in the same league as the ACT 2, and I had to admit I liked my own 250 based system better. But now...!


As for distortion, imagine this (if multiplicative), all values hypothetical:

Component Distortion (In milliVuks)
52 1.6
552 1.0
500 1.0
Royd Albion 2.9
ACT 2 0.9

Total distortion of a 52/500/Albion = 4.64
52/500/ACT 2 = 1.44
552/500/ACT 2 = 0.9
552/500/Albion = 2.9

The shocking result here is that changing from a 52 to a 552 in the albion system makes a bigger difference (4.64 - 2.9 = 1.74) than it does in the ACT 2 based system (0.54), although the ACT 2 system is better. This defies what we all take for granted, ie that a better speaker will allow us to hear an up stream upgrade more. But, if distorion was additive, then a mediocre source should sound great through an excellent pre/power/speaker combo if the distortions of the downstream components are low enough to offset the higher distortion of the source to give a whole whose sum of distortions is quite low.

So, neither of these scenarios make much common sense and how distortion of one component effects that of another is obviously more complicated. It is my feeling that distortion is not additive and that mediocre downstream components exagerate rather than cover up the deficiencies of mediocre source components.

Does anybody at naim have an answer to this? It must be common knowledge to an electrical engineer.

dave
Posted on: 01 July 2002 by NigelP
I too have heard that the 552 is an amazing feat of audio engineering. That's why I am refusing to listen to one! Someone posted a reply to my comments on the CD12 regarding the CDS-II not being the ultimate in CD playback yet. They said:
quote:

first the NBL, then the 500 and now the 552 - the CD player will be next
As a 500/NBL owner I am desperate to know what the combination is capable of with an improved preamp. If the preamp had come out first I would have certainly done this before the 500 knowing that I would get more for my money in terms of music. What Naim have done can be for one of two reasons:
  • The guys wanted to produce improved equipment further downstream so that they could master the source
  • Or (more cynically) they knew that 500/NBL owners would be watering at the mouth to get their hands on a 552 and eventually a CDS-II replacement
Whatever their strategy Naim are starting to show the rest of the hifi industry the new benchmarks and, for a small independent manufacturer, I think that's excellent! Keep it up lads and look forward to seeing a CD12 beater!!
Posted on: 01 July 2002 by JeremyB
Thanks, Nigel for clearing this up, it makes sense. Of course Naim couldn't go source first in development - how could they/we hear the whole improvement if they did! Same as you need test equipment accurate enough for whatever you're trying to measure. Lucky for us that Naim already had good enough test equipment (ears).
Posted on: 02 July 2002 by JeremyD
NigelP: What Naim have done can be for one of two reasons:
  • The guys wanted to produce improved equipment further downstream so that they could master the source
  • Or (more cynically) they knew that 500/NBL owners would be watering at the mouth to get their hands on a 552 and eventually a CDS-II replacement.

Surely, anyone who bought a new 500 would have taken it for granted that Naim would eventually launch a better pre-amplifier? The 52 is a ten year old design, I think.

My own theory (in the absence of a shred of factual information) is that practical considerations are the dominant factor in Naim's decisions to launch products: they didn't decide to launch one before the other - it's just the way it worked out.

JD
Posted on: 02 July 2002 by Tuan
Not too long ago the concept of having separate power supply from the pre-amp to have claer sond (less interference). I noticed that Mark levinson pre-amp (380S) has internal power supply (in the same box) and so is the naim model 552. What do they say now (the designers)? Why do they lead us to a different belief?
Posted on: 02 July 2002 by David Antonelli
Cliff,

I guess I was thinking in terms of %distortion or distortion units instead of %signal or Musical units. But your % system necessitates a multiplicative relationship. ie if a 52 gives 90 % of the music and 135s give 90% of the music, the combo will give only 81% of the music and not 80% [(100-90) + (100-90)].

After sleeping on it, I think it is more like applying filters in photoshop, because distortion can hide things (gaussian blur filter) or it can give the illusion of more detail (sharpen mask). When you get a poor quality original scanned in you can apply all sorts of filters to make it look better, but you are ultimately just casting a web of illusion over the original.

Mike Frongillo, the mighty electron microscopist at MIT, always used to say "if your girl friend is ugly no matter how good a photographer I am I can't do much to make her look good." It was a bit of a callous remark, but he was always mad at people who came in with lousy samples for electron microscopy that would blame him if the images came out bad.

I think audio and photoshop are similar. A combination of a blurr filter and a sharpening filter can obscure mistakes while making the whole look a bit shrper than if you had just applied the blurr, hence the sharpening filter masks the blurr filter which masks shortcomings of the original. A perfectly clear window would be no filters and no distortion and would necessitate the use of only the best originals scanned in at the highest resolution from photos taken with the fastest shutter speed and highest f-stop possible for that level of light/film speed used.

The dealer in chicago claimed he could "hear the 52" through a 500/Sofias, although he had not yet heard a 552. How did he know it was the 52 he was "hearing"? What specific character does a 52 impart to the music, that the 552 eliminates?

In other words, what does a 52 "sound like"?

Dave
Posted on: 02 July 2002 by Martin Payne
quote:
Originally posted by David Antonelli:
The dealer in chicago claimed he could "hear the 52" through a 500/Sofias, although he had not yet heard a 552. How did he know it was the 52 he was "hearing"? What specific character does a 52 impart to the music, that the 552 eliminates?



Dave,

perhaps he'd tried it with a Krell preamp as a reference?

cheers, Martin