Zen SE84C Revie


Reviewed by: Richard , Audio Enthusiast, from San Bernardino

Product Model Year:
2000

Summary:
I have owned several tube amplifiers, and listened to many more. I have always enjoyed the 'warmer' sound of tubes, but they have always been far from perfect. Transistor amps have great, clean bass with sharp, harsh highs and mildly unpleasant mids (remember, we are talking affordable amps - I am NOT saying that top of the line transistor amps sound bad, just that ones I can afford sound harsh and unpleasant).

For instance, while a Dynaco ST70 has very clean mid-range and decent high frequency sound, the bass has always sounded bloated and imprecise. The Mk IIIs, have a much cleaner bass, but the tubes are incredibly expensive. My solution in the past has been to bi-amp ST70 systems so the tube amp carried mid and upper end frequencies while a nice, clean transistor amp took care of the bass.

This form of bi-amping, however, has created more problems than it solved. While all frequencies are delivered to the speakers more 'cleanly' than with one amp, I found that I was dissatisfied with the overall sound; the sounds were there but they didn't sound very musical.

So, I decided to try single-ended amplifiers. I started by looking at prices and was astonished to find that 8 watts of single-ended, stereo power started at $1,600 and went up from there. In addition, many used tubes that made the KT88s from the Mk IIIs seem cheap by comparison.

Then, I stumbled across a little single-ended amp made by Asusa, the K2003. This is a 4 watt per channel amp that uses three tubes, and all are inexpensive. When I hooked up the K2003, I was soon struck by several impressions:
* it didn't sound like 'only' 4 watts;
* it had stronger and better bass then my ST70, at only 1/10 the power;
* the mids and highs were so sweet and musical that I was truly amazed.
* at $550 list, it was a bargain.

I was sold. THEN, I stumbled across Steve Deckart's website at www.decware.com and started reading his papers about amplifier design. Rechecking the K2003, I found that it used negative feedback and transistor rectification - both big problems according to Steve.

So, I decided to make my own comparison. I ordered a Zen Triode from Steve.

After doing extensive, back-to-back comparisons, I can say that he is right; his Zen amp is almost as far above the K2003 as the K2003 is above an old Dynaco. It is simply amazing. Sounds that have always been there, but muddied, or somehow masked so they weren't noticeable, suddenly stood out and grabbed my attention. A perfect example is a recording that has extensive use of a steel guitar. It sounded great on K2003, but on the Zen, all the odd sounds of a steel guitar were rendered so clearly that it sounded as though it was in the same room with me.

Vocals, especially female vocals, had a new richness and timbre that I didn't think was possible in a mid-priced stereo system such as mine. Acoustical instruments often sounded as though they were live, not recorded.

My only objection is that the power output is so low, that my system now has difficulty reproducing orchestral music. My speakers, at 90db, are simply not efficient enough to do the music justice. This amp should have speaker efficiency of at least 93db to really function well.

My solution: I am going to sell the K2003 and my last ST70, purchase a second Zen Triode, and use one per speaker as monoblocs. Wired this way, they will have more than enough power to deliver any music I want to play.

As an aside, my source is a Rotel RCD-955AX cd-player used as a transport, a California Audio Sigma tube DAC, a Conrad-Johnson PV-2a preamplifier, and my speakers are B&W DM602s.

I give my heartiest recommendation to this amp; it compromises only power, but it delivers fabulous sound at a bargain-basement price, list $550, same as the K2003, and uses tubes that are in current manufacture and are very cheap (the power tubes are only about $7 each, compared to $15 dollars each for ST70 tubes, $65 each for MkIII tubes, and $150 each for 300B tubes used in all the 'best' single-ended amps you can buy.

Have a small budget but want the best sound for your dollar? If you have the speakers for it, this is the amp.

Strengths:
Musical reproduction, sound stage

Weaknesses:
Power.

Similar Products Used:
Asusa K2003, Dynaco ST70, Eico ST70, Dynaco Mk III

 

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