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Audio by Van Alstine Ultravalve Vacuum Tube Amplifier - Gorgeous - Must
See!!!! [Expired]

no longer for sale

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Research Pricing

Item Description

Audio by Van Alstine Ultravalve Vacuum Tube Amplifier
The amp
retails for $1,999 with a basic tube set consisting of two National 6GH8 tubes
(made in China), a quad of Electro Harmonix 6CA7 tubes (made in Russia) and a
5AR4 rectifier tube (made in China).

I have significantly
upgraded the tube set to include two NOS RCA 6GH8 tubes, a brand new matched
quad of Svetlana SED "Winged C" power tubes and a NOS big bottle Sylvania 5AR4
rectifier tube.  The SED factory has closed for good and hence the
wonderful sounding "Winged C" tubes have become very pricey as of late.

The amp is in excellent cosmetic and operating condition.
The polished stainless steel finish is gorgeous, but it does have some
small polishing marks.  This is a very musical amplifier and it is rock
solid from the standpoint of reliability.  The middle and high end is
detailed and the low end has lots of bass slam.  Frank Van Alstine's
support of this and all of his products is second to none.

Checking  and setting the bias voltage on this amp is very easy using the
pin jacks on each side of the top plate.

I do have the
original box and cocoon packing as well as a copy of the owner's manual.

Other Particulars

The amp will be double boxed, packed with extreme care, fully insured and
require a
signature upon delivery.  It will absolutely arrive to
the new owner in the condition shown. No add on charges for PayPal, packing
or otherwise.

Buy with absolute confidence. Check my superb feedback here and on E-Bay
under the same user name.

All reasonable offers considered.

Thanks for looking!

Here is a description from the Audio by Van Alstine
website.

The amplifier that was rated "best bargain at the recent Rocky Mountain Audio
Fest" by the senior editor of The Absolute Sound.

The Ultravalve is our
lovely looking and playing pure vacuum tube amplifier with a polished stainless
steel chassis and a gold anodized faceplate with black graphics and text.

The great grandmother of the Ultravalve amplifier is the original Dyna ST-70,
no big surprise.We started taking a close engineering look at the ST-70 in the
1970s and were able to identify several design weaknesses that could be fixed at
a rational cost. These included getting the bandwidths of the power supply,
audio circuits, and input acceptance into the right set of ratios so that no
input signal short of output clipping could drive the unit into gross distortion
at any frequency. This made the feedback loop job much easier and the whole amp
cleaned up a lot all the time.We also added a solid reference to the screen grid
resistor and achieved even better stability.

We sold this upgrade as a complete do it yourself kit, our original Super
Seventy amplifier, for many years. The kit also resolved the issue of aging and
non-available basic power supply capacitors, and the value drift of so many of
the original carbon comp resistors.

Next, we introduced the Super 70i when the supply of 7199 tubes dried up and
we replaced them with 6GH8A tubes (identical performance, different pin-out).
The Super 70i is really the grandmother of the Ultravalve amplifier.

After several more successful years with the Super 70i, it was time to
re-evaluate the design again. By this time, we had come up with some unique
successful power supply design ideas, some of which were applied to our highly
regarded Transcendence Eight preamplifier.

We were able to incorporate these design ideas, namely a separate high
voltage regulated power supply for each plate of each tube, into a brand new
board design for the Dyna ST-70, our Ultimate 70 amplifier rebuild kit. However,
by this time the supply of decent remaining Dyna ST-70 chassis were drying up,
as were the number of audio users who dare still try a do it yourself kit.

It was time to rethink things again thoroughly.

What needed to change to produce a thoroughly modern and rationally priced
vacuum tube amplifier?

First, we needed a complete new modern chassis. We worked with Dynakitparts
to produce the chassis for us from our design in lovely polished stainless
steel. Adding a gold double anodized bead blast finished faceplate from our
local vendor finishes off the elegant looks of the Ultravalve.

The Ultravalve has a lighted power switch on the front. The back has premium
input jacks, 5-way binding post output jacks on 3/4" centers for 4 ohm, 8 ohm,
and 16 Ohm taps, a line fuse, and a captive 16 gauge polarized AC line cord. The
chassis top has small pin jacks for bias adjusting and the bias adjust
controls.

The basic internal wiring layout was just fine, providing low noise and
stable operation, and working on the "no surprises" mode we mostly replicated
the Super 70i chassis wiring layout because simply it works very well.

The audio circuits are built on a ground plane shielded double sided PC card.
We improved the grounding to make sure the amplifier is very quiet, and we
located the board inside of the chassis to protect the user from exposed high
voltages, and to keep the circuits from being exposed to the heat of the output
tubes.

With room for a better power supply yet, we were able to widen the power
bandwidth to 3 dB down at 50K Hz and 5 Hz and still maintain our goal of no
feedback related overload under any condition of use. More engineering math
provided us with better solutions for the bandwidths of the feedback and
coupling circuits. Our tube choice has kept up with all the new audio circuit
engineering even better than expected.

The Ultravalve uses a 5AR4 rectifier tube, two 6GH8A small signal tubes, and
four output tubes. We supply it with matched quad sets of EH 6CA7 output tubes,
but EL34 or KT77 tubes can be used too.Power is 35 watts per channel, but you
can use it where you would normally use a 100 watt solid state amplifier. It
does a great job of driving our 85 dB efficient Salk HT3 speakers full range to
reasonable levels. This is one amazingly wide band, dynamic, transparent and
utterly musical amplifier. It just does not have typical vacuum tube power
amplifier limitations.

The whole thing, except for some active and passive electronic parts, is made
in the U.S.A.

Rated "best bargain at the recent Rocky Mountain Audio Fest" by the
senior editor of The Absolute Sound, the Ultravalve is ready to markedly improve
your home audio system too. The price is $1999 factory wired, plus $45
shipping in its custom protective "cocoon" packaging. It is ready to play out of
the carton, no initial adjustments, burn-in, or set up necessary at all. We
think you will love it.

Dimensions 13" wide, x 7" high, x 10" deep. Weight 31 pounds

Seller Information

mcurtis846

Last 12 months

63

100.0%

All-time

534

100.0%

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