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Amp/Preamp Asylum: REVIEW: Balanced Audio Technology (BAT) 42 SE Preamplifier (SS) by Ferrstein

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REVIEW: Balanced Audio Technology (BAT) 42 SE Preamplifier (SS)

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Model: 42 SE
Category: Preamplifier (SS)
Suggested Retail Price: $6,5000
Description: BAT solid state pre released in 2006
Manufacturer URL: Balanced Audio Technology (BAT)
Model Picture: View

Review by Ferrstein on January 22, 2010 at 05:38:00
IP Address: 71.158.98.130
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for the 42 SE


Okay, I’ve listened to my VK-42se for quite a while now, and I wanted to post my long-term impressions. The following several paragraphs of text are more of a recap of an audio journey for the perfect linestage rather than a review of the ‘42se. If you want me to cut to the chase, I’ll say this: The BAT VK-42se is one of the very best linestages I’ve had the pleasure to own or listen to. This one is staying put… it’s mine, keep your hands off! Without discussing tubes, solid-state, or passive topology, all I can say is this is just one hell of a product. If you want me to cut even more to the chase, skip the next four paragraphs you’ll see that I finally start talking about the ‘42se.

First, I want to explain my setup and take you through a bunch of listening comparisons. During this listening period, components other than my linestage remained constant. The system is a bit unconventional and requires just a bit of explaining. I listen to a fully modded LP12 turntable, equipped with a Kloneparts SC (reproduction aluminum billet subchassis), Ekos Tonearm, Cirkus bearing, Lyra Dorian cartridge, and Lingo power supply. From there I feed into an Ayre P-5xe phono stage via a custom tonearm cable made by Moon Audio. This cable connects to the Ayre in such a way that a balanced signal is pulled from the cartridge (see http://www.tubecad.com/july99/page9.html for more information). The Ayre phono stage has a heavily modified power supply and many upgraded signal parts, and is the best phono stage I have heard in my system. From there, I run a balanced signal into the linestage (provided the preamp has a balanced input). From the linestage I go into a rather strange balanced amplifier application. I run two Acoustat direct-drive servo amps per channel (four total) into a pair of Acoustat Monitor 4 speakers. I have changed the function of the amplifiers to produce an identical signal on both outputs (stock configuration is a + and – output to run both the front and rear stators). The first monoblock amp is fed the + signal from the balanced linestage and drives the front stator of that speaker. The second monoblock amp is fed the – signal from the balanced linestage and drives the rear stator. This creates what I call MCMNR or Mechanical Common-Mode Noise Reduction. Any common-mode noise that is picked up along the chain shows up at my electrostatic stators and pulls the diaphragm in equal-and-opposite directions and is thus dropped from the music signal. Fun stuff, and the reason why I wanted to put components in place to allow a balanced signal from my phono cartridge all the way to my speaker stators.

I also want to note that the Vk-42se is currently sitting in place of my long-time reference preamp, a heavily modified Counterpoint SA5000. I had Mike at Alta Vista Audio apply a bunch of magic to this unit. It is a sweet instrument in every sense of the word and has battled out and won against many a linestage. Alas, it does not have a balanced input, and through no fault of the SA5000, the Ayre phono stage simply sounds better when it’s balanced outputs are used. I discovered this when I borrowed my local audiophile friend’s Aria WV5 preamp. This is very similar to my modded SA5000 (albeit much improved), and it has balanced inputs. In an A/B comparison it took no time to discover that the balanced signal coming from the Ayre simply sounded better. It was bigger, more dynamic, and more refined all at the same time. Details seemed more accurate and real compared to the single-ended outputs. Because of this, I started a long search for a linestage with a balanced input that could sound as good as my beloved Counterpoint’s linestage. As much as I lusted after the Aria, it simply wasn’t in my price range at the time, and they almost never come up used. Anyway, on with my quest…

My journey started with a passive volume setup. I accomplished this with a component I found via a rare score on Audiogon – a balanced Placette RCV. Most all of the Placette units are single-ended, so I jumped at the opportunity to grab a balanced unit. It is a beautiful piece, using switched Vishay resistors in the signal path. I tried this setup because the output of the Ayre phono stage is quite robust and I figured it could drive my quartet of Servo amps just fine. Having said that, I wasn’t too surprised to find that this just didn’t live up to the musicality and enjoyment of the Counterpoint or Aria. Not even close. So, I looked into the impedance numbers, and found that the Placette has a lowish input impedance. Maybe the Ayre was having trouble driving everything. There was a fix for that in my growing lot of used equipment - I had a couple SCE HRS systems laying around. These are impedance matching devices with a 100k input impedance and a 150 ohm output impedance. I modded them to work with balanced signals (I just stacked two stereo units and added XLRs to them, running the + and – phases of each channel through it’s own circuit path within the HRS chassis), and put them in front of the Placette. Now we’re talkin’! Very good sound, dynamic, lifelike, and detailed. Way better than I thought a passive preamp could sound. Of course with the HRS units in place, we weren’t really passive anymore. I liked the sound of this setup quite a bit. Still, when compared to the Counterpoint, it wasn’t even close. The SA5000 still sounded a whole lot better, even with the penalty of having to run from the single-ended output of the Ayre. With the Counterpoint there was simply more of everything.

Next up was a BAT VK-30. This is the unit that uses a sextet of 6922 tubes, the same tubes that the Counterpoint uses. Out of the (10 year old) box, this unit had a bunch of promise. It was detailed and threw out a huge soundstage. Beautiful sound for a reasonably priced product. Again, I greatly preferred it to the Placette/HRS system. In fact, we were starting to get into the territory of the Counterpoint. Mind you, the VK30 had an advantage right off the bat that the Counterpoint didn’t – it could make use of the superior sounding balanced outputs of the Ayre. My issue with the ‘30 was that it was a little sluggish. Even with a sextet of early Siemens tubes, which I usually find very linear and fast, the VK-30 still sounded bloated and slow. I decided to try to upgrade the stock output caps (this unit did not have the sixpak option). I placed some 4uf Dynamicaps in place of the 1uf Jensens. While I was in there, I also applied some felt damping beneath the circuit board. I have written more about these mods in my last paragraph below. With these changes in conjunction with the use of the Ayre balanced outputs, I felt that I had harnessed much of the sound I was getting with the SA5000. In fact, the ’30 had a giant sounstage that bettered the ‘5000. The sheer enormity of it simply blew away every barrier in my listening room. Ceiling, walls, hell – even the floor! There was an unbelievable scope of positions from which sound was emerging. It was truly one of the biggest soudnstages I’ve heard. Still, the ‘5000 bettered it in overall realness, delivering vocals and instruments in such a way that I could no longer use the phrase “the musicians are in the room with me”. Rather, it was more as if I had stumbled upon a room full of musicians. I was in the room with them. This preamp has an authority and confidence to it’s sound that the lightly-modded VK30 simply wasn’t matching. In comparison, the ’30 sounded lacking in detail and realness, with an almost veiled presentation.

Next up was an Aesthetix Calypso that I picked up for a great price. This unit uses a 12AX7 tube in the linestage, followed by a 6922 buffer to reduce the output impedance. I installed this unit and did some tube juggling right off the bat. I ended up with Telefunken 12AX7 tubes and Amperex 6922s. The Amperexes were the orange label variant – not usually my preference, but for some reason they sounded incredible with the Calypso. This unit compared well to the VK-30 and the Counterpoint in some arenas. It had a wide and deep soundstage, excellent dynamics, palpable vocals, and great mid-bass. It was a very exciting linestage to listen to, and I enjoyed it immensely. For me, though, there was a very big problem – the high frequencies were recessed and cut off to my ear. No tube rolling could fix this, and I began to think I was simply hearing the limitation of the 12AX7 tube. Since my system is already somewhat dark sounding, this unit was simply not the answer for me. I would guess this linestage may be a great unit in the right system, and the signature version with it’s Dynamicap output caps would possibly do better in this area.

My next move was a departure from my love of tubed preamps. A BAT VK-42se came up on Audiogon at a price I couldn’t turn down. I decided to give it a shot. After all, 10 years is a long time between the original VK-30 design and the new VK-42se. I figure a company such as BAT must’ve learned something along the way. Since I very much liked the sound of the VK30, I figured I’d give this one a listen. The ‘42se has the upgraded power supply, mosfet gain stages, and the upgraded sixpak output capacitors. The specs on this unit are incredible – a 100k input impedance, and a 200 ohm output impedance. How cool is that? As a diehard tube guy, I never see specs this good. Before I sold the Aesthetix (I had to - at this point I was running out of cash!), I did a quick listening comparison. In my system, the ‘42se just stomped on the Calypso. Again, this is likely a system dependant issue, but to my ears and with my rather sluggish speakers, the ‘42se was a revelation. It had the extension and air that I was missing with the Calypso, and it had all of the enormous soundstage that the VK-30 had. In fact, I could definitely hear a BAT house sound, but it clearly bested the ‘30. This thing through a huge soundstage that was easily defined, coherent, and rock solid – very similar to what I heard with the ‘30. Instruments that appeared 5-feet in front of my speakers were as sure-footed as images right on the speaker’s surface. Detail was kicked up a great deal, and dynamics were much better. This thing was a winner right out of the gate. Simply jaw-dropping sound. The coolest thing about this unit is that it images with the best I’ve heard – and I’ve sat behind some serious preamps! I won’t list them here – the systems are different, settings are different, etc… but I my experience I always prefer tube preamps. They just seem to image better. Instruments float into the room in a way that I hadn’t heard a solid-state unit duplicate – until now. This thing has all of the realism, presence, and dimensionality of the best preamps I’ve listened to. Soundstaging is as good as I’ve heard. I had the opportunity to listen to BAT’s own REX preamplifier driving a system very similar to mine… Acoustats with balanced mono amps. However, this system is in a much larger room, and the speakers themselves are much larger, with 10 panels playing per side as opposed to my four panels. That system, with the REX in place, was a revelation to me, and I thought I’d never get that kind of soundstage in a room as small as mine. To my surprise, the ‘42se does many of the things I heard in that larger system. It seems scaled down a bit to be sure, but in an accurate way. It’s hard to explain, but the sound I’m getting with the ‘42se in play is just huge in every way while still sounding suited to my room. And here is where the ‘42se excels over anything in my experience - bass reproduction is simply world-class. Lightning fast, extended, detailed, and accurate. No comparison to anything I’ve heard, period. This is one area that the ‘42se simply smokes everything I’ve ever heard. The authority to which it belts out the lowest octaves is simply unparalleled. This is my replacement preamp, there are no caveats.

But are there really no caveats?

No, there aren’t.

Or are there?

Here are my gripes. That freakin’ Counterpoint, with it’s lack of balanced inputs, was still creating this presence, liveliness, and realism that’s hard to define. That stock ‘42se wasn’t doing it, even with it’s balanced input advantage. Listening to the stock ‘42se compared to the ‘5000, I still felt it was missing some detail, and the vocals didn’t have the presence I wanted them to have. This was a somewhat minor complaint, but it was easy to hear in direct comparison. When listening to music on the ‘42se, there were simply less instances of surprise and awe from a specific soundstage event as there were when listening to the Counterpoint. Time to tube roll the ‘42se! Oh, wait… that isn’t gonna happen. But I can play around with the output caps. Even though this thing has the sixpak option, I think it’s time to change them out. Although I had my eye on some Teflon V-caps, I decided to stick to what was used in the ‘5000 and what worked in the ’30. Dynamicaps it is! Plus the V-caps are, um, expensive.

So… here’s what I did. I had already tested these mods on my VK-30, and the improvement in sound was good on a fundamental level, so I decided to repeat the process for the VK42se. For the output capacitors, I replaced the factory-upgraded sixpak units with the venerable 4uf Dynamicaps. The factory sixpak mod consists of three 1uf oil capacitors in series per phase per channel, making a total of six capacitors per channel (thus the name). Total capacitance is 3uf per phase per channel. This is the famous BAT upgrade from the stock output cap configuration, which consists of one 1uf oil capacitor per phase per channel. Hand on heart, I simply can’t get accustomed to the sound of the oil caps in my system. Don’t get me wrong, they are beautiful sounding. Gorgeous, even. The issue for me is that in my system they are simply too laid back. As I mentioned above, my system consists of very large electrostatic speakers (Acoustat Monitor 4s) in a fairly small room. Translation: my system ain’t normal. Those speakers are very laid back in their own right, so it isn’t unusual for me to need to tailor the sound of my components to suit my listening tastes. So, I decided to focus on the output capacitors of the VK-42se. My long-term reference preamp, the aforementioned Counterpoint SA5000, was the first component I had listened to with Dynamicaps in the signal path. Mike at Alta Vista uses these capacitors throughout his pieces. They are outstanding. Very dynamic (as their name suggests), exciting, detailed, and with PRaT (Pace, Rhythm, and Timing) out the wazoo. Just a great sounding cap, and just what my system needs to not sound too laid back. I figured these would give my ‘42se just the kick in the pants it needs. Another thing I did at the same time I replaced the caps was to apply some circuit board damping. This is another trick that I learned from the modifications that were performed on my SA5000. I basically I placed a piece of felt between the bottom of the chassis and the circuit board. This felt is as thick as the circuit board standoffs, and it compresses slightly when the circuit board is bolted into position. I did this while I had the unit apart installing the Dynamicap output capacitors. Thus, the results of both the felt damping and the output caps are combined. Yes, this is not scientific process. My bad… it’s just that time is limited and I figured I would apply the damping while the unit was apart. I had heard the damping mod alone on my SA5000, and it was a very worthwhile improvement to the sound of that unit. Image location and precision was improved, and at the same time the authority of the tone quality was transformed. Images just sounded more present and fully fleshed out. My tests did not isolate this modification for the VK-42se, which admittedly has more attachment points on the circuit board when compared to the Counterpoint. The board itself is also very thick. Still, I figured the install of this damping material couldn’t hurt, and probably helped. Perhaps one day I will remove it and see if I hear anything different. The bottom line is that these mods made the VK-42se a perfect match for my system. Where the speakers are lacking in punch and attack transients, this preamp simply takes over and fixes the deficit. The synergy between this preamp, these mods, and my system creates a sound that is better than anything I could have imagined. This one is a keeper, at least until I figure out how to get a balanced input on the Counterpoint. It is a balanced design, there just aren’t any provisions for switching, volume control, etc. I’m looking into tackling these road blocks as we speak. For now, the BAT is the hot ticket for my system, and I will be happy if it is the last preamp I own.

Post write-up: Okay, I know what you’re thinking… what’s with making a big deal about the balanced cable run between your phono preamp and linestage? If you like that frickin’ Counterpoint so well, why don’t you just marry it? At the end of the day, I’m not sure I have a good answer for that. From a technical standpoint, that really is all that is missing in the balanced chain from my stylus to my stators. Once I heard the difference between the balanced and single-ended outputs of the Ayre phono stage, I had to pick up that improvement in my system. Plus I had that cool MCMNR thing going on at the speakers as mentioned above, and I was also running balanced off my MC cartridge and into my phono preamp – something that most people don’t do. At the end of the day, after implementing those cool balanced ideas on either end of my system, it just seemed silly to go single-ended in the middle of it all. So, this quest ended in sound that is really similar to what I started with. It is better to be sure, but only slightly so (save for that bass slam), and I wonder if getting a balanced signal into my Counterpoint would swing the favor back to the ‘5000. I dunno. I think the next step for me is to get the Aria preamp back over here to listen to it. Even though it is newer and better than the heavily-modded SA5000, it is a Mike Elliott design that is one of the best I’ve heard. The next step is to compare the VK-42se linestage to the linestage of the Aria. I will do that comparison soon and report back soon. That’s right… I have more typing to do!


Product Weakness: In my system the stock output caps were a bit soft sounding. I replaced them with Dynamicaps for better system synergy.
Product Strengths: Enormous Soundstage, incredible detail, and the best bass reproduction I have ever heard, period.


Associated Equipment for this Review:

Amplifier: Acoustat Servo x4
Preamplifier (or None if Integrated): N/A
Sources (CDP/Turntable): Linn LP12 with Kloneparts SC
Speakers: Acoustat Monitor 4
Cables/Interconnects: Moon Audio and AR Master Series
Music Used (Genre/Selections): Rock and roll
Room Size (LxWxH): 17 x 11 x 7.5
Room Comments/Treatments: OC 705FRK bass traps
Time Period/Length of Audition: 8 months
Other (Power Conditioner etc.): Audience chords and conditioners
Type of Audition/Review: Product Owner
Your System (if other than home audition): N/A




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Topic - REVIEW: Balanced Audio Technology (BAT) 42 SE Preamplifier (SS) - Ferrstein 05:38:00 01/22/10 ( 5)