Audio Research VS55 Stereo Tube Amp with new SED KT88 Tubes

Price reduced $200!!! There is still room to negotiate so make an offer!

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This VS55 stereo amp was used to power my main speakers for 4.5 years up until early January this year, when I had to purchase a solid state amp that my family needed for convenience. I used the VS55 with the 6550C tubes, but just for this sale I replaced them with KT88 tubes as they are more reliable and superior in the midrange. The KT88's were delivered from Upscale Audio in April 1 this year and the receipt will be provided to the purchaser for warranty purposes. Also purchased a 5th spare tube that will be delivered to the purchaser. I operated the KT88 equipped amp long enough (approx 15 hours) to bias and compare its sound to the other VS55 I'm selling in Audiogon (see separate entry) that has the 6550C tubes. The KT88 equipped amp does sound noticeably better particularly in the midrange, but not by much. These SED KT88 Winged "C" (formerly Svetlana) tubes are very high quality Russian tubes costing nearly $70 each (with tax & shipping). Their life expectancy is significantly higher than that of the 6550C.

In addition to the 4 power output tubes, the amp contains three 6N1P input/driver tubes that are still the original ones because they normally last for at least 5000 hours, and I would estimate them at approximately 2300 hours currently. On average the amp was used 10 hours per week.

This amp produces noticeably sweeter high-end than most, along with very detailed sound, as well as wide and deep soundstage with warmth that brings to life musical instruments with astonishing realism. You'll also be amazed at how much bass this 50 watts per channel amp can produce if your speakers can deliver. A famous reviewer wrote that this amp is the most vivid way of demonstrating tubes versus transistors, and he was so right.

The amp is in excellent visual and operation condition but just to be safe I'll say 8 out of 10 in case you'll find any minor flaw that I couldn't find. The amp will be delivered in its original box and packaging materials. The original power cord, manual, fuses, and plastic screwdriver used for biasing will be included. Each tube will be marked so that you'll know to which socket to plug it, because the biasing is done individually for each tube. (Try not to leave fingerprints on the tubes as this shortens their life). Always give the amp a minimum warm-up time of 20 minutes to sound best and/or check bias. You should have a good DVM (digital voltmeter) so that you can verify the bias of of 55mv (representing 55ma) on each tube (give or take 5mv, but not more than 5mv apart from the other tube within the same channel). Ignore the manual recommendation of 65ma bias as Audio Research changed this recommendation early on to 55ma when they switched to Svetlana tubes in place of the initially supplied Electro Harmonix tubes that were troublesome. The amp is very stable so you will not need to verify bias often. Once every 3-4 months is what I used to do and found that the bias usually stayed within the desired range. But because the included power tubes are new, I recommend to check and adjust the bias more often for the first 50 hours of operation (35 hours more).