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The SV83SE by Jeffery Larson Commissioned by Herbert |
| This amp was a commissioned act brought about by an owner of two of my previous amplifiers, and is my best design and implementation to date. Loosely based on the original ZEN concept by Steve Deckert of Decware, this amp strives to offer the same or better sonic reality. The all original design employs James output transformers. And except for the vintage RCA power transformer removed from a stereo 6V6 SE amp, all the parts are NOS or new new stock (NNS).
 A brass on silver theme was chosen to match the brass on silver of the James trannys.
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As all my amps, this one is also designed from the ground up. I borrowed a few "features" from the original Zen in so much as I use a split power supply to feed the input tube, and a switch to alter the input tube's bias point. This amp uses either the 6N1P or any tube from the 6DJ8/6922 family. The bias is optimized for the 6N1P in one position, and the 6DJ8 (and family) in the other. However, either tube can be run in either switch position.
In addition, I took advantage of the James tranny and incorporated a UL mode for the SV83 outputs. So there is a switch to change the output mode as well. This combination of BIAS and UL/Triode modes in conjunction with a wide range of input suitable tubes allows the listener 4 different sonic experiences with each input tube. This is omitting the fact that the output tubes could also be changed.
I tried many pairs of 6BQ5 variations in this amplifier. All had their good points. The final pair was chosen as the Svetlana SV-83. After a short break-in, this tube has a lush smooth sound that got my vote for best of the lot. The Mullards were fine also but too muted sounding. Perhaps they were too old. The no-name Japanese ones sounded the best (if a tad bright). Just try to convince anyone to try them. In the final analysis all the tubes worked fine and sounded great.
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This chassis represents the best of my newer 2" design. All my anodized aluminum chassis are made by hand and contain flaws either hidden at the time by the protective covering, or created by working the metal. This chassis came out nearly flawless, and my workmanship is improving even to the end panels which have a new degree of cleanness and integration. My only complaint is that the paint coating on the James' is too soft and/or not deep enough. It just takes a passing fly to scratch them. I was alerted to this issue by feedback from another buyer. I cushioned them on soft cloth during the entire process, but still picked up a few marks.
Silver wire input connections, silvered solder used throughout, PIO coupling caps, all NNS Metal Film front end and NOS Carbon Comp resistors everywhere else. Vintage ceramic resistor in the power supply. |
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Gosh I hate writing this section. Sound is in the ear of the beholder, in the acoustics of the room, in the type and placement of the speakers, mood of the moment, time of day and prevailing winds. We've been playing this amp on and off for nearly a month, first in the prototype stage and later as a partially and finished chassis. We like everything we toss at it. We even learned a few of our favorite CD's actually don't sound that great, and our great CD's sound ... well, GREAT! That's why it got built! Sweet!
The amp received a few updates. Thanks for looking.
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