A Rediscovery Article
THETA Tube Preamp:
One of the best values you can find
A Rediscovery Article
THETA Tube Preamp:
One of the best values you can find
THETA
is best known today for its digital to analog converters, an enviable
niche that it has carved out for itself since the very early days of the digital
audio age. There is an interesting fact however about Theta's history that not too many people are aware of. The company used to produce tube components - a preamp and power amp!
The former is the subject of this inquiry.
It is a sad and sometimes disconcerting fact that most new products fail, and they fail for a plethora of reasons. It could be because of poor management, lack of capital, inferior design, over design, incorrect pricing, competition, market saturation, etc. In my opinion, in order to achieve success, the product must achieve momemtum. With established names in the constellation such as Audio Research and Conrad-Johnson, a start-up like Theta would really have a hard time acquiring a large market share of the tube audio market. It would however have a much better prospect of making a name in the nascent digital audio market.
Packaging
For your information, Audio Shopper acquired two Theta preamps - the first one from its original owner, a medical doctor in Dallas, and another from a gentleman in Florida who had had the unit updated by its designer. The preamp came in two packages - aluminum and black. Consistent with its straightforward electronic design, the styling is utilitarian and spartan. The metal work is solid, and looks like it would last a lifetime. The preamp's slim look reminds me of a hybrid between the Great American Sound Thaedra preamp with its sliding volume controls and the Hafler DH101 preamp with its push button access to inputs. The Theta preamp measures 9"Wx17"Lx3"D (add 1" per side for the rack mountable faceplate). For the aluminum model, the lettering is in sky blue; in contrast the black model uses white.
An all tube design, the Theta preamp was supposedly one of, if not, the first preamp to harness the 6DJ8 tube. It uses six 6DJ8's by the way and, lo and behold, polypropylene capacitors, supposedly the progenitor of the Wonder Caps. Production quality while high is not at parity with today's standard of excellence exemplified by Audio Research, Conrad-Johnson, Audible Illusions or Sonic Frontiers. The unit offers the following facilities: phono, tuner, auxiliary 1, auxiliary 2, tape monitor, stereo reverse, mono, and mute.
Listening Experience
I have had both Theta units for about four months . During that time I have had the opportunity to listen to each unit using different setups. Most of the time, however, I used the VTL Stereo 120/50 amp, Quicksilver KT88 monos, and ARC Model D-76 amps, the JVC XL-Z1050 cd player, Pink Triangle turntable with MMT arm and Promethean cartridge, Promethean Bandpass interconnects, Inouye power conditioner, and Kimber 8TC speaker cables hooked up to either Castle Isis, Linn Index, Rogers LS3/5A, or Sound Lab A-2X Electrostatic speakers with Hsu Research 10V subwoofer system.
I compared the Theta with my in-house reference, the Audible Illusion Modulus 3 tube preamp.
It's in the details
It is often a wonder why we discard the old for the new without much forethought or due diligence. The Theta is a valid case in point.
If there is one aspect that distinguishes the Theta preamp, it is its superlative extractive ability. This is its hallmark. It is this ability to surprise that makes it so endearing.
Lately, I have been collecting records of bands from the 1970's. One of my favorites is History/America's Greatest Hits (Warner Brothers BSK 3110). In the Tin Man for example, you'll hear more disrinctly the soft shimmer of the cymbals, the tinkling of the triangle, layered accompaniment, echo, and voices. It's like peering from a newly cleaned pair of glasses.
The Theta's bass delivery is also exemplary. It is not only solid but articulate. In fact, it slighlty exceeds the Audible Illusion Modulus 3 in this regard. I found this out while listening to several cuts within Pink Floyd The Wall (Columbia 36183).
An ability to extract and articulate may in some cases be disastrous. Not so with the Theta. What makes this execution successful to my mind is balance - or the capability to scale in proportion. Let me explain. If one turned up the treble, one will hear more high frequency energy and likely more detail in that range. But because of its disproportion, the end result will be cloying. It is too much. It becomes bothersome.
The Audible Illusion Modulus 3 has been my preamp of choice for many years. It captures much of my musical preference. It is a bit dark and romantic like a good tube component should be. The Theta is less so. It has less body and roundness.
The Theta's presentation is upfront. By this I mean, it is in front of the speakers rather than behind. The Audible Illusion Modulus 3 takes a less forward approach - a better one at that. Thus, there appears to be more depth and spatial dimension.
Caveat
Like a well honed racing car designed solely for a singular purpose, the Theta is not for the faint of heart. Its designer eschewed downstream protection in favor of performance. If you are not careful, it will fry your amp, and take out your speakers in the process. I've seen it happen. Because I use mostly tube amps, which limit the signal at the bottom, and because I am cautious, i.e., mute the preamp before powering on and off, I have been able to evade any misfortune. Knock on wood.
Conclusion
The Theta preamp is really a surprise. It does not have the drop dead georgeous look of modern preamps. It does not present a clever technology or engineering wizardry. It does not even command the voguish loyalty and appeal of the stellar brands. It requires care in powering on or off. Beneath its mundane metal work however is tube preamplification that is extraordinary. I can honestly say that the Theta preamp presents one of the best values you can find in the used high end audio marketplace. We bought our units at around $400-$500. This is a four clefs component at a two clefs' price. I consider this a huge bargain.
by Rome Castellanes
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