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Van Alstine Super PAS 3 preamp KIT

Rebuilding a vintage Dynaco preamp

Part I

[Italian version]

Product: Van Alstine Super PAS 3 rebuild KIT
Manufacturer: Audio By Van Alstine Inc.
2202 River Hills Drive
Burnsville, Minnesota 55337 USA
Phone: 612-890-3517
Approx. price: Super PAS 3 Rebuild Kit - $299.00
Optional Gold Plated Jack Set - $ 65.00
Optional Fiberglass Selector Switch - $ 55.00
Shipping and handling additional
Reviewer: Nels Ferré

[Van Alstine Super PAS 3]
The Super PAS 3 rebuild KIT


Dynaco was a big name in audio in the 1960's and 70's. At various times, they sold amplifiers, preamplifiers, tuners, speakers, and even a basic surround sound adapter.
They sold units utilizing vacuum tubes and later, transistors, and most units were available factory assembled, as well as in kit form at a substantial savings.
Dynaco was famous for value, and was an excellent alternative to the other two big brands of the time, Marantz and McIntosh. Dynaco was a popular brand, and many original and modified units are still in use today.

Frank Van Alstine of Audio by Van Alstine has been in the audio industry for many years. His company specializes in modifications of both Dynaco and Hafler equipment, and produces a line of equipment of their own design as well.
Like Dynaco (and early Hafler gear), Audio by Van Alstine makes much of their equipment available in both factory assembled and kit forms. And like Dynaco, AVA equipment is a fantastic value.

The Super PAS 3 Rebuild Kit

This kit is designed to totally rebuild any of the Dynaco tube preamplifiers. The newest of these is currently approximately 28 years old. As such, the individual parts can be wildly out of specification or beginning to fail.
The kit replaces the line and phono boards, along with the power supply. Additionally, the volume and balance controls are replaced with high quality Noble environmentally sealed devices.
The tone controls, as well as the switches for loudness and the high filter are not used as all, but rather left in the chassis for cosmetic reasons. Should either the power or tape monitor switches fail, they can be swapped with one of the other two now unused switches.
The only other original parts that are reused are the socket for the rectifier tube, and the power transformer. The original input/output jacks and the original selector switch will also be reused, unless the optional, very high quality replacements are ordered. The kit comes with all the parts that you will need including wire and solder. You will have to supply your own soldering iron, some basic hand tools, and a metal cutter, called a nibbler.

The unit that I rebuilt was the first stereo Dynaco preamplifier, the PAS 2. The PAS 2 was produced between 1964 and 1968. The unit I acquired for this review was originally built as a kit.
Upon receipt of the unit, I removed the top and inspected the wiring and the original circuit boards, as well as the tubes. It was amazing that the unit worked at all. The soldering was horrendous, and the wiring sloppy. None of the four 12AX7 tubes were the same brand. I consider this a compliment to the original designers that the unit did indeed work.

I then hooked it up into my system for a listen. I was appalled. The sound was lifeless and flat. There were no highs to speak of, and with the tone controls in their flat setting, not much bass either. There was no definition to the music.
It made my system sound like a very large clock radio. In fact, I could only listen to the preamp for an hour or so until I shut the system down, and hooked up my usual preamp. One thought has bothered me since: in finding a suitable "donor" preamp for this review, I came across many PAS preamps, usually through online auctions.
Demand for these are quite high and I have seen prices for a clean PAS 3 (cosmetically different but electrically the same) fetch more than $300. After listening, I just can't figure out why anyone would pay so much for something that sounds so bad.
A suitable preamp for this rebuild should cost around $100, although I paid less for mine.

I did have some difficulty building the unit. First, let me explain that I have never before built a kit. This kit requires that you first put all of the individual parts (resistors etc.) into the correct locations on the circuit boards.
That's where my troubles were. The parts all use manufacturers codes instead of color coding for identification. Unfortunately, I failed to realize that the packing list and parts list were different and put some resistors in the wrong places.
After a phone call to Frank, the confusion was unraveled, and Frank sent me some replacement resistors.

The kit assumes the builder knows the difference between a glass diode and a silicon diode (I didn't), and I had to secure another pair of silicon diodes from my local Radio Shack. Additionally, there were 2 parts shortages, a filter capacitor and a terminal strip. The capacitor was shipped promptly after a phone call to Frank. Rather than wait for the mailman to bring another terminal strip, I made another trip to the local Radio Shack.

After the "wrong resistor" fiasco, Frank asked me to send the completed circuit boards to him for inspection, which I did.
My work for the most part was good, although I did manage to put three capacitors in backwards. The mistakes were corrected, and the boards returned. Again, in my defense, I stress that I have never built a kit before.

The only other problem I had was that the person who originally built the kit wrapped the wires around the lugs on the Input Selector switch, which made disassembly difficult.
This finally required replacement of the origianal switch with AVA's optional fiberglass switch.

The rest of the project went pretty smoothly. I worked on the project only when I was in the mood to do so, and put it away if I felt myself becoming tired or irritated. Towards the end of the rebuild, I found myself enjoying it and actually was almost disappointed that the rebuild was to soon be finished.

Audio by Van Alstine does offer a free checkout of any kits that they sell. Minor problems are corrected free of charge, major problems on a case by case basis.
I do highly recommend sending the unit back for the free checkout. Do be aware that wiring mistakes can be dangerous or even lethal.

That being said, let me explain that I know from which I speak; I did not initially send the unit back for check out. I finished the kit at approximately 1 A.M., and excitement took over logic.
Looking back, this was not an intelligent decision. The unit did work properly, although the new LED power light was wired incorrectly. It blew immediately. I was lucky: far worse things could have happened, either to the preamplifier, or more importantly, to myself.
I did listen to the Super Pas 3 until the very wee hours and, after another conversation with Frank, sent it back for checkout the following morning.

How does the Super PAS 3 sound? See Part II

© Copyright 2000 Nels Ferré - http://www.tnt-audio.com

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