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Original Message

REVIEW: Threshold Corp. S/500 A-A/B Stasis E Amplifier (SS) Review by Horn at Audio Asylum

Posted by Horn on December 18, 1999 at 09:07:03:

Portions of this are from Michael A. Murphy – murph@maine.bitnet

Product Review: Threshold S/500 Stereo Power Amplifier
Manufacturer's Specifications:
Rated Output Power : 250 watts per channel. Both channels driven at no more than 0.1% distortion into 8 Ohms resistive or reactive impedance.
Bandwidth Response : Halfpower (-3 dB) points at 7 Hz and 100 kHz.
Slew Rate : 50 volts per microsecond
Output Transistors : 20 transistors per channel. Transistors are ultra-high speed 200 volt 20 ampere rated power devices.
Output Current : 12 amperes continuous, 100 peak amperes per channel. All continuous ratings are fuse governed.
Power Supply : 1,000 watt toroidal transformer, 120,000 microFarads storage capacitance.
Input Impedance : 75,000 Ohms.
Output Impedance : Less than 0.1 Ohm 20 Hz through 20 kHz
Gain Factor : +26.6 dB
Noise : No greater than -100 Db, unweighted, referenced to
rated output.
Permissible Load : Operation is allowed into any load within limits
imposed by power supply and rail fusing and/or
thermal protection.
Dimensions : 17 1/8" deep, 8 3/4" high, 19" wide.
Weight : 78 1/2 pounds.
Suggested Retail New : $3995.00 USED $1,300-$1,700
Just what you're getting for your $3995 [new] $1,300 used bucks:
The input connectors are gold plated with a multiple contact point inner conductor. This is supported in a machined teflon insulator. The construction quality of the circuit boards is superb! All the circuit boards are military-grade, glass-epoxy with gold over copper over nickel plated traces. This is an amp that you really have to see to believe. The power transformer is huge as are the storage caps. The quality of the wiring and soldering is very impressive. There are a number of high end products that just are not built as well, or sound as good as I found out.
According to Threshold, all products were given a three day testing period at the factory. This consists of each amplifier being required to pass a dead short power test both before and after the three days of power "burn-in" consisting of self-oscillation into a two Ohm load. That was a SERIOUS burn in.
Where I was surprised was in the vast difference I heard in comparing the sound of the Threshold to that of my Adcom GFA-555. The VMPS are happiest when there is a lot of power in reserve but it certainly can't be denied that the Adcom, is more that adequate from a pure power standpoint. Up to the point where I had substituted the Threshold into the system I would have considered them difficult to surpass the Adcom. To put it mildly, the Threshold simply blew it away!
I have never heard such deep bass and impact ever before on the VMPS.
No doubt that this is the most neutral SS amplifier I have yet had the pleasure of listening to. I can say that it holds it’s ground today, easily surpassing some Krell amps, Bryston 4b [as my friend calls them “Brightstons”], Aragon 8008’s and the Sunfire stereo amp.
I listened to Linda Ronstats “For sentimental reasons” for female vocals. I was awash in detail that was never apparent from those other amps. There was a tube-like warmth and low grain to the sound that was just effortless and magnificent. It is NOT totally tube warm, but it’s warmth is away from the dry, sterile or bright that SS can deliver. In fact, the Adcom sounded blurry and hazy by compare.
The raw horsepower is evident in Wagner’s “Die Walkrie” as the bass attack, and depth. The slam is just amazing. The Adcom sounded slow and soft by a/b. The S/500 has extraordinary detail on every recording I listened to. It certainly helped in extracting a great deal of the room information and ambience that is typically missing with lesser designs like the Adcom.
The S/500 adds a great wealth of detail to the music that I have realized was missing. There are subtle clues on a number of albums which hint at the room dimensions but which through my current system have always been a little blurred.
The high frequencies were also more extended than I am usually accustomed, but they were also smooth, not edgy. This amp produces a far perspective unlike a tube amp that supplies a closer perspective. This is what I mean by the role an amp plays in the SOUNDSTAGE. This is only on SOME recordings that are well done- a small percent of what I have.
If you believe you should hear everything contained on a recording, be it vinyl or compact disc, this amp is probably for you. . If however you are more interested in reproducing a musical experience in your listening room with the majority of recordings available you may wish to listen to alternatives like tube amps. This is not to say you couldn't tailor a system around this amp, you could quite easily. When you start getting into the true high end components great care must be taken when putting together a system. It is imperative that you be allowed to "try before you buy" in order to make sure you can get the sound you are searching for. After listening to the S/500 I have reached the conclusion that there are things it does (or doesn't do) to the music that I wish tube amps around it’s price did. A tube amp for my application would have to be incredibly powerful, and I am sure there is no way that I could afford such a beast. Since I cannot afford a tube amp that will do everything this amp does- I am willing to stay with the tradeoff. I feel that despite it’s age, the Threshold is an incredible amp that is still now a high end treat, and a relief from some of the harsh SS out there. If you find one of the babies in mint condition like I did- try it out. The only thing you will lose is respect for some of today’s new SS up to $3,995.