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Vacuum State Electronics JLTi mk2 integrated hybrid amplifier

Just Listen To it (again)...

[Italian version]

Manufacturer: Vacuum State Electronics - Australia
Price: 1500 Euro approx
Reviewer: Geoff Husband - TNT France
Reviewed: June, 2005

[JLTi mk2 Front]


Now for another update to a review done only 6 months ago. Why? Because though from a sonic point of view the JLTi was an excellent amp its cosmetics left a lot to be desired. So OK I just write two lines and post the picture... But there have been other changes, and the second chance of playing with the design gave me the opportunity to have a closer look at one part of it...


Well first you have to go back to the original review because I'm not going to type that lot out again... Then look at the 'before' and 'after' pictures... 'Before' = DIY, 'after' = professionally produced amp. The new casework is neat, understated and businesslike. It's not going to worry B+O or even look as good as the old Musical Fidelity A1 (my old fave integrated) but then what does. The most important thing is that now people can buy the amp for its sound without being put off by the appearance - that alone is significant because it immediately increases the potential market for the amp. The thing is surprisingly heavy as well which will satisfy those that buy amps by the kilo.

At the same time as the improved casework a few other things were changed, enough to justify a 'second-look' on their own. For those I'll hand you over to designer Joe Rasmussen

"The all new JLTi Mark 2 has - new metalwork, cryo'ed tubes and new internal signal cabling, and (let the trumpets sound) T-Network technology. The latter is a major development that reduces the effects of back-EMF from speakers by a theoretical 100:1 ratio. Every little peak in the amplitude response of a speaker causes back EMF. The results are gratifying - this a truly a major advance and a first in any commercial amp design we know off. Franz Gysi from Switzerland collaborated on it (I owe it to mention his name). The other change being an upping of the size of the toroidal transformers and thus a small increase in peak current."

[JLTi mk2 rear]

Sound quality

I hope no-one minds because here I'm just going to lift verbatim what I wrote about the ESE Niribu phono stage update...

" a manufacturer gets a good review, goes away and tweeks and screws it up. The difference between wonderful and ordinary seems to be tiny and the magic easily lost... Manufactures never seem to have heard the phrase "if it 'aint bust don't fix it..."

Sorry Joe, but it's always a worry, it seems much easier to screw up a good product than improve it... So again to an old quote, this time from the original JLTi review...

" The lovely natural ability hinted at before remained, this is an amp you could listen to all day - I don't mean it's 'rolled off' or anything like that because that irritates after 5 minutes. No it's even handed and consistent, it doesn't jar you as it picks out certain aspects of a piece, neither does it leave you trying to pick out the words of a song you know you should be able to hear. "

That was driving my Loth-x Horns which cost about 6 times the JLTi... I feared this ability to match with the very best, and fussiest speakers would be gone, but I needn't have worried. With a gap of 6 months it's always hard to judge what's going on between a Mk1 and a Mk2, but my notes for the earlier model could equally apply to the Mk2. Certainly the new amp was as accomplished as the old, better? Quite possibly, I suspect it was even closer to my Audionote pairing (13 x the cost) but I'd be lying if I said I could spot it for sure.

So there you go, the Mk2 looks better and plays at least as well as the Mk1 and yes it's a safe recommendation all round if you have speakers of decent efficiency and not too difficult a load. But...

Now with another slot of time what am I going to do with the JLTi? Well as you'll read from the original review one interesting feature is that the valve pre section has a pre-out and so the amp can be used purely as a pre-amp.

Out came the Audionote M3 (5 times the JLTi's cost) to be replaced by the JLTi's pre-amp section driving the Audionote Quest Silvers. Once again it was a downgrade - the M3 sounds impossibly 'big' and powerful - no pre-amp section of a 1500 euro integrated is going to match it - but once again the result was extremely listenable. Detail was close as was speed and attack, the dynamics and scale a little muted but if I were comparing an 1500 Euro pre-amp with the M3 I'd have considered it an extremely impressive effort. One way of looking at the JLTi would be as a good value, full-function valve pre with a power amp thrown in for free :-)

And because of one very important development this ability is extremely significant. The Sonic-Impact T-amp has turned the world of sub $2000 power amps on its head. Now for $30 you can get a 6 watt power amp with a volume control that will do things that few amps will do at any price, not least of which being detail and sound stage. I said when Lucio contacted me to write a paragraph about it in his T-amp review that I considered that any integrated amp coming to my system (with its 104 dB efficient speakers that need 1 watt) would be in for a very, very hard time. Then of course poor Joe sent in the JLTi Mk2 like a lamb to the slaughter...

THIS was why what should have been a short, superficial update developed into a careful examination of the pre and power sections of the JLTi.

OK for those with speakers of less than 94 dB efficiency you can skip this bit because the JLTi will trample the T-amp simply because it will happily drive speakers of 90dB efficiency and the T-amp won't. For the rest of us (and that's a growing number) the JLTi has several possible ways of justifying its existence in a post T-amp world.

Firstly the T-amp isn't perfect. In my experience it's weaknesses are a tendency to a certain hardness or thinness to the sound. This is something the JLTi as an integrated has no problems with. The JLTi doesn't have such a wide soundstage but has more depth and texture, a more natural presentation if you like. I'd give detail to the T-amp by a small margin, but here remember the T-amp is frighteningly good. So in overall sound quality the JLTi isn't going to be a pushover for the T-amp by any means. Of course the JLTi is also a full integrated with switching - few people are going to to use the T-amp with just one source so they need something that switches.

Here we get to the second reason for buying a JLTi... As a pre-amp alone it represents good value. So I tried plugging the JLTi into the T-amp :-) Nice...

The JLTi managed to fill out the T-amp and add some much needed warmth. That hardness reduced. In fact the combination was one I'd quite happily live with driving my horns... To my surprise I found that I still preferred the JLTi alone to the T-amp + JLTi but it was close and the T-amp retained the advantage in stage width and detail.

Now the good bit :-)

So you have speakers of say 90 dB efficiency... Bi-wireable? Well the JLTi is going to get a strong recommendation, but you must have $30 left over? You've had the JLTi a couple of months, you're very happy (you will be I think), but hey it's time for a new hi-fi fix. New cartridge? Arm? Cd player? But you only have $30 left over because obviously you've blown the rest on new records to try your shiny new amp out with. Hmmm. Geoff and Lucio say the T-amp is something everyone must try but not with those speakers... Hmmmm... But 6 watts would drive that tweeter OK wouldn't it?

So - just plug the JLTi into the bass driver and then bi-amp (we're getting very high-end here...) using the JLTi to drive the T-amp into the tweeters alone. You even get to alter the relative levels using the T-amp volume control. He he hee...

I tried it... My IPL S3's are only 87 dB efficient so not ideal (but an easy load) and even driving just the tweeter the T-amp was limited, but it hinted at 'good things'.

The JLTi allows you to do this because it's flexible and both sections are first rate, you can play. I've only given one example of how you can use it for bi-wiring (because it's the most intriguing) but that pre-out could drive subs or any other amp either in a bi-wiring (or with a splitter - tri-wiring) configuration. This isn't new, the old NAD 3020 could also be split, but no-one would pretend that its pre-amp section was up to driving a multi-thousand dollar valve power amp, but the JLT'i is.


In a post T-amp world the idea of 'value-for-money' has been turned on its head. But even in this world the JLTi is a fine piece of kit. I'll be sorry to see it go because it gave me a lot of pleasure and allowed me to play swaps - it'll do the same for you...

systems used

© Copyright 2005 Geoff Husband - www.tnt-audio.com

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