A U D I O... P A P E R


 DEC 2003
by Steve Deckert

It's easy to see why our Zen Triode Select is so popular when compared to our signature monoblocks.  It's a stereo amp and cost $695.00  When you acclimate yourself to the Decware web site the price of our signature monos seems high.  If you first came across our signature amplifiers in a hi-end stereo salon the price would probably seem too low. That said, there are many who own our little Select who have spent many times it's price improving the remainder of their systems. In fact the amp has almost a cult following.

Many eventually stepped up to the signature monos because they wanted a bit more power.  Some who had high efficiency speakers and were more than happy with the power of their Select, stepped up to the monos in hopes of reaching a seemingly impossible higher level of fidelity.  After all, for the difference in price they have to sound better right?  These people experienced the all to rude reality that hi-fi is a delicate balance of compromise.  They discovered that our Select amp with a single output tube per channel had an edge over the signature monos when it came to resolving inner detail. The mono's on the other hand had more weight and control with better dynamics.  

This was no accident.  The most popular speaker efficiency in use when a customer buys an amplifier from us is 90dB.  Consequently, this is the speaker they start out with when they get their first Zen Triode amp.  A speaker in this range of efficiency has to be unusually good to resolve the potential for inner detail that I mentioned.  If a customer finds themselves wishing for more power after a period of time it is certain their loudspeakers were not an ideal match and could not reach the potential of the amplifier.

This was all taking place in 1997 when the selection of affordable and good sounding high efficiency speakers was small.  The reality was people were going to use these amps with whatever speakers they owned.  We had to make sure when they hooked a Zen Triode amp up to their speakers that enough magic came out to inspire them to choose the amp over the speakers.  Of course not having to choose was the ideal goal hence the quest for more power.  Our goal was to keep the same sound we had with our original amplifier but just get more of it.

The monoblocks had 3 output tubes per channel vs. a single tube and because we used more expensive coupling caps and resistors the monoblocks exceeded our goal actually sounding better then our SE84C.  Years later I decided to incorporate these better parts into our original amp so people who could not afford the signature amps could still enjoy the same fidelity at a slightly lower power level.  The result of this was our SE84C-S nick-named the "Select".  

With high resolution speakers the Select actually could do some things better then our signature monos.  With conventional speakers it was just the opposite.  Today, many years later, the shortage of affordable high resolution/high efficiency speakers is over. It's getting easy to hear how good a Select really is, and the majority of people who buy the Signature amps do so wondering if the sound can really get any better.  

My response the changes in our market niche was to re-design the Signature amps and frankly make damn sure they DO actually sound better then a Select when compared on speakers that a Select could drive to adequate levels.

My first paper on the redesigned signature amps focused on the similarities between the them and the popular Select amp.  In short, the signatures could now be run in either of two configurations.  Single tube per channel - exactly duplicating a select, or Dual tube per channel - similar to it's original sound when it used three tubes per channel.

In the months of testing my new signatures on different speakers I could hear merit in both the single tube mode as well as the dual tube mode.  I can't say one categorically sounded better then the other because it really depended on what speakers were being used with what source and personal taste.

I was disappointed to find out after selling several pairs that people were not even trying the amp in dual tube mode.  In fact I've also found out many people have not tried or use the bias switch on the top of the original monoblocks or Selects.  Now, if you've ever taken the opportunity to listen to these amps in both settings, you will prefer one setting over the other.  My question is this - wouldn't it be silly if you were listening to the wrong setting all this time?  Many customers are.  I've also got people calling me asking me to make the signatures cost a bit less and only put one output tube in them.

It is clear to me that my original paper that focused on single tube mode for the new amps was more of a disservice then it was a help.  People are missing the boat here because the new signature amplifiers are actually configurable as 3 completely different amps with 3 completely different sets of strengths and weaknesses. Now, I can't help those who don't want to explore the different sounds. The more amps you have at your disposal the better the odds are of finding one that is truly serendipitous with the rest of your system!


Here are the present configurations possible with the SV83S Signature monoblocks.

A) Front switch positioned towards the tubes - duplicates a Select amplifier using the same 9800 ohm output transformer.  1/2 of the dual triode input tube is used to drive a single output tube per channel.  In this configuration only the center output tube is active. You may even remove the two outside tubes if you want. Comfortable with impedances between 1 and 4 ohms.

B) Front switch positioned away from the tubes - changes the amplifier to use the two outside tubes in parallel driving a 3300 ohm transformer. The inside tube becomes inactive and could even be removed. 1/2 of the dual triode input tube biased to have a lower output impedance to properly drive both output tubes. Comfortable with impedances between 4 and 8 ohms.

C) Front switch in the same position (away from the tubes) just like above but with one of the two outside tubes removed.  This is a completely fresh combination not found in any of our other amplifiers.  In this configuration you have a single output tube coupled with the 3300 ohm output transformer and biased twice as hard into class A.  The output tube runs on the edge of death where the sweetest tone hides and will probably last no more than a year, 6 months with hard use.  But a single tube that costs under $10.00 shouldn't break the bank.  This configuration doubles the RMS power of the output tube when compared to configuration A as long as the loudspeaker impedance is no lower than 6 ohms.  8 and even 16 ohm speakers become very serendipitous with the amp in this mode.

When using 8 ohm speakers and comparing mode A with mode C, you'll find the presentation of A to feature detail and ambience with almost the same focus as vocals and instruments. With configuration C you don't loose any detail or ambience, you just gain a wonderful and welcome weight and presence in the midrange with this incredible unbelievably good tone.  It feels like easily twice the power but it melts you with seductively real sounding playback.  In all my years of doing this, the tone and timbre of everything is more "right" then I've ever heard it.  So good that it makes listening to CD far less traumatic for a vinyl guy like myself.

Of course there have been many listening sessions when popping the second tube in changed the presentation to favor more accurately what it probably sounded like on the recording.  Better control, slightly more forward sounding, letting you push the amp a bit harder to reach those higher SPL when the mood hits you.




Decware is a trademark of High Fidelity Engineering Co.
Copyright 1996 1997 1998 1999 2000 2001 2002 2003 2004  2005 2006 2007 2008 by Steve Deckert