Audio Research VT200 Mk.I  Review

by James Leahy

 

                                                                      Introduction

                                                                                

The huge Audio Research VT200 is the epitome of the VT amplifier series. The last of the largest stereo amplifiers Audio Research made. Producing a mammoth 200 watts per channel, I have found there to be no loudspeaker the VT200 could not drive to ear bleeding levels. If you are in the hunt for a true reference grade amplifier that you only need buy once in your life time, this may well and truly be it. The VT200 Mk.I is my current amplifier that I use in my reference system today and is a unique unit in more ways than one. I would class this as the best stereo amplifier Audio Research has ever made.

It uses sixteen 6550C output tubes with another ten 6922's for the input/driver circuit. The amplifier weighs in at a hefty 47kg's and I would advise having two people move this monster around when you have to transport it. This maybe the reason the amplifier is provided with two pairs of handles.

 

Most of the VT200's mass comes from it's huge power transformer. You had also better not be shy about paying your power bill with this baby hooked up as it consumes 680 watts at 'idle' and a scary 1200 watts at full tilt. I did noticed a considerable increased power draw with this in my system but I am not one to be concerned with such things. After all it is the sound that matters.

 

The circuit boards are mounted vertically in a pure dual mono design. There are 4, 8 and 16 ohm loudspeaker tapings on the back panel with both balanced and single ended inputs. The Mark 1 version in this review requires the installation of one shorting pin into each of the balanced inputs if the single ended inputs are used. I prefer to use the balanced inputs as I have noticed a cleaner image with better definition in this mode. If your pre-amplifier supports this connection type I would recommend you make use of it in this case.

This 26 tube behemoth is cooled via one 5" muffin fan located in the bottom centre of the unit. It has three variable speed settings that can be adjusted for maximum benefits relating to climate conditions as well as listener location.

 

 

The VT200 uses sixteen Nichicon capacitors in total for it's output storage capacity. The VT200 front and side panels are of considerably thicker construction than the VT100 series showing it's supreme build quality. Also probably to cope with it's considerably increased mass and to stop it's chassis from flexing. There is no +12VDC trigger on the rear panel of this model with the amplifier having to be switched on manually instead of getting it's heart jump started via a matching Audio Research pre-amplifier. However I do not miss this feature as I prefer to turn my components on separately anyway. There is also an anti-hot start relay circuit that prevents the amplifier from being turn off then on again until the tubes are completely cool. This obviously is to save undue stress on the vacuum tubes as they do not like to be heated and cooled down in rapid succession.

 

 

I would recommend that all owners of any large tube based power amplifier only use their amplifiers on a specially constructed amplifier stand that can provide sufficient air flow to the bottom of this amplifier and of course allowing for proper over head ventilation at the same time. The VT200 is a blast furnace of a powerhouse that requires sufficient cooling. You can feel the heat radiate off this unit as one would expect with sixteen 6550C output tubes on tap. I construct my own amplifier stands out of 3mm steel tubing which are then powder coated that allows for a hollow centre directly below the amplifier so the base of the stand is like a picture frame with open airflow to the muffin fan that is mounted to the bottom cover of the VT200/VT100 series. This helps tremendously with keeping the amplifiers at a substantially lower temperature especially in warmer climates.

Biasing the output tubes is done via four small holes (two on each side panel) which allow access to trim pots beneath the left and right circuit board covers. You do not have to remove the covers to access these adjustment pots. You do however have to remove the top cover to access the testing points with your multi-meter. You will require eight matched pairs of 6550C tubes for best results. This a simple affair and can be done with the minimum of electrical knowledge. Replacement of the input/driver tubes is a more involved procedure that is beyond the scope of this review to illustrate and should only be attempted by a trained technician.

The are eight Nichicon capacitors per channel that give the VT200 Mk.I it's explosive punch and dynamics and are ratted at a huge 674 Joules of energy storage. The most important single part in regards to sonic performance in a vacuum tube amplifier is it's transformer quality and the VT200's transformers are some of the best available.

 

Sonic Evaluations

After being used to the VT100 Mk.III in my system for 3 years how would this compare and what differences could be heard between the two. For a start the sonic differences between the VT200 Mk.I and the VT100 Mk.III were immediately apparent. The VT200 Mk.I appeared more warm in nature with a more laid back presentation rather then a more detailed one. The VT200 Mk.I uses all tubes in the critical input/driver stage where as the VT200 Mk.II version and VT100 Mk.III use JFETS. The full valve circuitry of the VT200 Mk.I seamed more to my tastes although if you like a more detailed and forward presentation the other versions listed above maybe more to your liking. Listening to the classic 'Infidels' album by Bob Dylan (CBS Records, 1983) the full magic of the VT200 Mk.I could be appreciated.

Natural timbre and tone can be heard in spades and the way the decay of little sonic cues fade to black is unique. The VT200 Mk.I has a soundstage of truly gigantic proportions that pushes you back in your listening chair with it's rock like control over every beat. This amplifier can master every loudspeaker I have used with it and displays it's grip and control in the most pleasing of ways. You are not left waiting for the soundstage to rebuild after a tough drum solo but are swept away with warmth and power combined into one hell of a sonic punch. It throws the music around like a rag doll in the jaws of a snarling Rottweiler, such is it command over every area of information.

The midrange was very well controlled and would suit listeners who prefer a multi-layered presentation without any harsh overtones or dryness. The high-end is at the same time very extended with a specified bandwidth reaching 200kHz it would want to be. Never even at extreme listening levels was the top-end of this amplifier brittle or shrill. It was not as detailed as the models that use JFETS in the signal path but in my system I can get much more enjoyment from this retro style of presentation rather than having everything in such crystal clear definition. I find that can be a little too detailed for my tastes. Do not get my description confused as the VT200 Mk.I is detailed and transparent in a different way compared to some. There is no grit or harshness that can sometimes be there if your loudspeakers are a little on the bright side or your listening room is not well dampened.

Having the shear overwhelming power of the VT200 Mk.I in your system is like being bathed in a divine beam of light shinning down from the Gods above. You are transported to another level of definition altogether when this baby comes on song. This is the amplifier that will separate men from boys and give your system the kick start it needs. More so you have to be sure the rest of your components are up to the level of definition of this amplifier. The most critical I found to be the pre-amplifier paired with this beast. I would recommend it is a must to use the balanced inputs and ideally be at least an Audio Research LS25 or better pre-amplifier to get the most from the VT200 MkI.

The bass extension has been the absolute best I have heard in my system, from any stereo amplifier. Not your typical weak soggy bass that some tube amplifiers are known for. The VT200 is the first valve amplifier that I feel could keep up with the likes of a Krell or Mark Levinson in the bass department but without the unflattering midrange or treble of these transistor amplifiers. I cannot listen to them for more then 5 minutes as they hurt my ears and cause undue listener fatigue and stress levels to rise dramatically.

The immense completeness in all areas that the VT200 Mk.I gives is pure bliss. Not in any area does it have any crippling weaknesses or flaws. The way it draws the listener into the performance is breathtaking and has to be heard in a good system to be fully appreciated.

 

 

 

Associated review Equipment

  • Line Stage:         Audio Research LS26

  • Phono Stage:      Audio Research PH5

  • Speakers:           ScanSpeak & Vifa Custom

  • Cables:              Neotech

  • Cartridge:           Ortofon MC Jubilee

  • Turntable:          Rega P7

  • Subwoofer:         Velodyne HGS-15

  • CP Player:          Sony SCD-XA777ES