Audio Amplifier Review: PSS 600 Yuri Gutsatz Realisation

This new thread will be dedicated to a review of the PSS 600 audio amplifier.

The product is distributed in Australia by NET and is manufactured in France.

When the amplifier arrived, my first impression was this amp is heavy and opening the carton revealed a well packaged product.(15 kg)

The amplifier is supplied with a quality printed manual detailing the main specifications and product features.

This model, the PSS 600 has a gain of 31 db with an input sensitivity of 1 volt, input impedance of 20k ohms, damping factor of >250 (8 ohms), distortion @1000 hz less than 0.009% and is rated at 300 watts @4 ohms, and 150 watts @8 ohms.

The chassis has a solid feel, its made of powder coated pressed steel, the front panel is designed for rack mounting and has handles to assist installation.

On the front panel is a large power switch, independent level attenuators for each channel and a row of LED's indicators ,4 red, 2 yellow, 2 blue to show the status of the amplifier.

The rear panel is populated with professional Neutrik XLR balanced inputs and Speakon output sockets.

The ventilation system is unique.

Central within the chassis is a fan which draws air in from the front and rear of the amplifier over a special aluminium extrusion containing the MJ15024 Bipolar T03 output devices.

The fan does make some background noise but this is unlikely to be a concern in a professional environment.

Taking off the top cover shows this amplifier is all about quality and precision.

The components and the manner of assembly are of a very high standard not normally found in domestic HiFi equipment. The twin power transformers are very large and the power supply has ample supply filtration.

These images give some indication of the PSS 600.

My impression is this amplifier has evolved over a long period and shows great attention to detail in its design and construction. The PSS600 solidly made and has a unique quality that can only be found in products made in Europe.

Ian Mackenzie

Its 9.30am in the morning here and I've had the amp warming up for about 2 hours. I am not a morning person so it will really take something to impress me.

Probably the most powerful thing I can say at is point about the PSS600 is that is will make many JBL owners re appraise their much loved, and in some instances much hated speakers.

By this I mean it will show your JBL's for what they really are.

For a long time I held the belief that for what ever reason JBL's sounded often overly bright, fatiguing for long term listening or were just too in your face until I came to the realisation that most mass market amps are crap. They really are. This became a fact when I started using a well known hi end amplifier and realised there is absolutely nothing wrong with JBL speakers at all, and at that point I discarded the thought of ever using a mass produced amp again.

Well the PSS600 defies the odds and is a standout in the crowd on its sonic virtues.

Playing a familiar DVD (DTS), Eric Claptons "One More Car One More Rider" Track 4 Tears in Heaven, the vocals are absolutely pure, the rhythm and pace of the guitar and drums toe tapping.

Track 5 Bell Bottom Blues, the space of individual instruments is clear and pure, and the snare sounds just as it should, like a snare. The PSS600 is the ideal partner for your home digital mastering Lab.

Do I see any reason for disconnecting the PSS600, absolutely not.

Well done Yuri.

Ian Mackenzie

If anyone would like to ask any questions or make comment please post.

I am happy to answer even theoretical questions or issues related to the review.

Ian

Quote:

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Originally Posted by Ian Mackenzie

If anyone would like to ask any questions or make comment please post.

I am happy to answer even theoretical questions or issues related to the review.

Ian

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Well, hopefully the flames have died down from my earlier questions about how to hook this amp up to consumer gear (sheesh..what a thread). I've had adequate opportunity to audition this amp now and I'm ready to offer some of my views and opinions.

Some things to keep in mind as you read this which might prevent another outbreak of insanity:

1) I am a home user, not a music production studio. I had to buy some adapters (with my own money I might add) to give this amp a listen. Whether or not you believe they might affect the sound is up to you...

2) You cannot A/B two amps without having to spend a few minutes moving the connections between the two. It makes direct comparisons (like between CD and LP) very difficult.

3) The fan is NOISY in the home environment. I'll say this in the nicest way I can - I've been making custom PC's for about 10 years now and why this supposed wonder of European engineering and craftsmanship doesn't have a $2 thermo controlled fan (that's QUIET at idle) is way beyond me. I have to imagine that not every pro studio is going to love this extra noise either.

4) Still on the subject of cooling, shouldn't all rack-mounted devices get fresh air from the front panel and exhale is it through the rear ? This top input would be mostly blocked in a full rack and seriously impede cooling I would say.

5) It was bad enough coming from Yuri, but you too Ian ?


I quote "The PSS600 solidly made and has a unique quality that can only be found in products made in Europe. "

Does that unique quality extend to the flimsy and unsubstantial level pots on the front panel ? Or the half-baked cooling setup ? My :bs: meter is pegged....


So, how does it sound, compared to a 20-year old Yamaha pro amp through some L250's ? Very good in fact. It has great reserves of power and is very good at revealing the details of the source material. It doesn't impart any unique sound of it's own and it never misbehaved.

In other words, it's a quality transistor amp that - to me at least - does nothing special to differentiate it from the Yamaha I already have. I wanted to get into the loop on this amp eval to see if I could hear any difference between this highly regarded, state of the art studio amp, and the $200 ebay bargain I've had for years. I have to say that there wasn't much of a difference - which is good. I should be fair and say that the Yamaha was $3k in its day and is twice the amp physically that the PSS is. That the PSS compared as well as it did (being less powerful - and I drove them both hard) says a lot about Yuri's design. I'm sure he hasn't 1/1000 the resources of a large corporation
like Yamaha.

In conclusion, I'd have to say that - for me - amps are not "as signifigant as you might think" to quote Yuri. The other new addition to my system last week was a beautiful Yamaha PX-2 turntable, also from the early 80's. This $1200 (in 1981) 45lb cast aluminum wonder made a GIANT difference in sound over the Luxman PD-264 I was using (which wasn't exactly a piece of junk). I've been spinning nothing but vinyl since I got it and it may be some time before I listen to digital again. It's that good and the difference was immediate and obvious.

I do have one question for you Ian - I love that Clapton DVD too and I'm wondering how you were able to listen to a 5.1 channel DTS disc with this 2-channel amp ? Were you just listening to the PCM stereo track on the DVD ? Were you only powering the mains of your HT setup with the PSS? I'm just curious what the actual setup was....

So - who's next on the USA tour of this white wonder ? I would prefer an East Coast shipment if possible to minimize shipping costs.



jblnut

Well you appear to have used this as an opportunity to post your own review of the amp you (which is not identical to this one) have . Would it be more appropriate to do that in another thread?

Regards 5) It was bad enough coming from Yuri, but you too Ian ?
I will refer this to an engineer with 25 years installation experience.

About the DVD I mixed the 5.1 down to 2 channels used the DVD's setup.

I have found similar pots in $10,000 mixing consoles, a firm or heavy torque is no indication of electrical quality imho.

The amp meets CE standards which is not easy to obtain. However perhaps your question on the cooling would better to referred to the manufacturer.


Ian

Quote:

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Originally Posted by Alex Lancaster

:) JBLnut:


Most proamps exhaust to the front.:bs: .

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The only amp I've ever owned the has a similar cooling system is a Crown Macrotech 1200. It will intake air from the front and vent to the sides. It's a great amp. It's been "giggin'" for over 16 years. I have had problems with the fan shaking loose from its housing. Make a real ugly noise and takes about a half-hour to tear apart and fix.

This message comes from JBL Dog :dj-party:

I have studied the amp and the air flow.

Examination of the air flow and the brochure confirms review feedback comments from the manufacturer.

"Shape of the front panel: because air is pulled from the top, the amp has such a shape; hot air is exhausted on the front, rear, and sides. Exhausting some even hot air on the sides cools down the transformer in heavy duty and or maintains it and the power caps to a better temp that enhances the sound quality (a hot transformer and hot power caps sounds better hot than cold)."

Yuri advises he has tested both cooling the cans and the base of the T03 and got almost the same results.

"I took some TO3 and removed the cans and made tested my cooling on them: result was almost the same!"

Noisy fan: "This is a PA amp; it is not the studio one. That is why there is no thermal switch on the fan."

Ian

The amp Ian has and the one jblnut has are two different amps! Ian has the PSS600 while jblnut has the 1200!

Fans, well for me fans in bass amps are a must, and not heard over the music or ambient noise level in my enviroment!

What I can say of Yuris cooling system, drawing the air in through the top right down over the ouput transistors, is that it does work! So, regardless of whether one cares for its sonic virtues aside, the PSS1200 ran rock solid in my place for 14 hours a day, being pushed at high volumes! Amp never complained one iota!

Conversely, I have had other " famous " brand amps, that have crapped out under demanding use, and didnt live up to their lore! So, although the fan may be noisy, its neccesary for someone like me! And the PSS cooling topology does keep the amp working perfectly under demanding use!

Jus sumthin from the peanut gallery! :)

I will do some more evaluation over the weekend.

Perhaps it would be better to Pm me of you need other information to avoid irrelevant posting.

Ian

The plan to allow the amp to stand for a week and play it continuously.

This will allow me to un train my ears and make some meaningful observations.

Once owning and using an amp for a while, you get to like it anyway after a time. That does not mean to say its right or the best...the mind plays tricks on you. The same applys to speakers and particularly those like to design, test, evaluate and build their own.

Its takes a while to size up the impact of a new peice of equipment in your system. Given I know very well the properties of the rest of the signal chain it should be interesting.

No, you can't really direct A/B amps and unless one is highly distorted its pointless. The trained ear is far more adapt at discerning change over a period of time. Particulary when focus is on a variety of criteria and these differences are often even more disolved.

I then plan to cut back the my control reference amplifier and revisit the much longer term appreciation of the system.

When I'm done I will take up Yuri's offer and modify the amp to the Studio B specifications and post details of the comparisons. The parts are being supplied by Yuri.

This is a wonderful opportunity, to be able to work with the manufacturer and appreciate the subtle variations on a design and the impact they have of the subjective performance of the amp.

Ian

Well I've had the amp for a bit now and I continue to like it.

The final analysis:

To be critical, while the central imaging has a sense of holographic focus, there is a lack of spead and the depth some what planar.

The mid range is fleshy, and even fruity and has emphasis, and this is where the voicing comes from. Its easy on the ear but but not necessarily real.

My analogy is the 4430 to the 4315 or 4345, there imaging and there's imaging. The sound should not always appear central focused, if is does your being fooled.

However the amp is most unfatiguing and works very very well.

Ian

On with the program and at this point Yuri and I have arranged some modifications to bring the PSS600 up the Studio Breference specs with the exception of the 1600 va transformer.

Yuri was kind enough to mail me all the parts and provided detailed instructions.

I turned it on........wow, what a difference.

Hard to put into words, but my instincts suggest the amp is more at ease.

There are more nuances and more spacial images which now have body in space, the sound stage is bigger and more open.

The presentation much less planar then before, the instruments and voices have soul. The highs shimmer beautifully, the bass firm but tactile and not clamped like before.

What do I put this down to?

Well the exact modifications are IP of Yuri but changes to the open loop gain (and closed loop gain) and removal of the output stage Vi limiters in part has something to do with it.

Expressed another way, an audio amplifier is termed a Linear amplifier by design.

However nothing is perfectly linear and engineers use mechanisms like feedback ( in a variety of forms) to make amplifiers measure very well on paper. In their pursuit of a perfect design on paper many small refinements are made and the design becomes increasingly complex. In addition other mechanisms are very often used to protect the amplifier. But the end result or action of these mchanisms is to add or subtract information from the signal path.

Unfortunately and more often than not, as the design evolves insufficient subjective evaluation is performed from the outset to determine what key parameters are important to musical audio performance.The design process of true audiophile amplifiers involves a lot more careful listening, experimentation in design and thinking outside the square.

This process is time consuming and expensive and is therefore seldom found in large multinationals that are driven by overheads, market share and shareholder dividends.

Why aren't all amplifiers designed the same? Mostly they are!

To illustrate this more, just imagine a business completely run by accountants. They are more concerned about profit, costs and capital outlay than who the customer is or what he likes. The same applies to marketing where an attempt to appeal to the target audience is based on technical numbers in literature, rather than MR and R & D involving the customer. The consequence to this is that competitors are also often copy cats and the market becomes conditioned to consuming rubbish instead of the real thing.

Just try gowing your own vegies and having your own chook pen, its all in the taste test! They are also better for you and you might live longer...you are what you eat after all.


back to the PSS amp .........

Yes its less electronic sounding and more musical.

The gap has closed considerably with (these modifications) against the reference amplifier. At this point the amp is in the realms of the ML, Boulder and other big hi end Class A/B amps.

In other words more of less well done is better.

There are some other updates that have come to hand recently and I will advise of these shortly.



regards

Ian

Yes I realise this has been a bit of a rant, but sometimes a rant is necessary to illustrate a point.

STUDIO B REVIEW

I have just made one more amendment to the P600..now the Studio B .

This is just Amazing, just amazing ...a discovery (to steal a line from the opening sequence of The Fifth Element...Aziz ).

Meaning I would never have thought taking out one part would make such a transformation in realism.

To assess the subtle and not so subtle variations I have been playing James Taylor's performance "Live at the Beacon Theatre". This DVD (mixed down to 2 channels) is probably the best technical and artist capture of a live recording on DVD that I have heard, and the tight visual direction provides conclusive evidence of what your hearing.

There is now a surreal clarity about it to the point that the speakers have literally disappeared. I find that uncanny because the speakers have not been touched.

This clarity, or perhaps better termed transparency is vividly displayed with every specific action of the performers. I put this down to not just a lack if colouration, but the cohesive and natural manner in which the timbre, pace and harmonic overtones are conveyed.

To describe this I refer to the striking of cymbals, where the fundamental, that being tonality of the metal is distinct, while energy is released like hot vapour from the decay of multiple harmonic overtones from the metal itself.

This is a beautiful sound, and an absolute test for even the finest audiophile equipment.

Similar jaw dropping discoveries can be described about other aspects of this recording but that is best left to new owners of the Studio Series.

I recommend to PSS Studio Series to any serious music lover.

Ian Mackenzie

Copyright

The above review have been written and prepared expressly for members and visitors to make a well informed accessment of the PSS amplifier.

I am in no way commerically affiliated with PSS and this review has been assessed purely on the audio performance of the product sample I recieved (including modifications under the direction of the manufacturer).

The above reviews are Copy Right of the author.

While not everyone may agree with Yuri's unorthodox approach to the marketing, he has produced a most remarkable audio amplifier and this needs to be respected regardless of your race, nationality, brand loyalty or personal attitude or beliefs.

A great review Ian, sure makes me curious about this line of amplifiers.

Ken

Ken,

Its like so many things in our world, its having the courage to try something new that makes the difference.


regards

Ian