The Dynaco PAS 2, for those who are unaware, is a pre amp kit introduced by Dynaco in 1960 to compliment the Stereo 70 (ST70) that came the year before (1959) and other various other power amplifiers in the company's lineup. The Dynaco PAS has developed a cult following, and there are an immense amount of boards being produced for those interested in restoring such archaic technology :) CurcioAudio, Tubes4HiFi, AudioRegenesis, ClassicValve and others have created drop-in boards to restore the PAS, whether you want to maintain the same circuit or drop in something completely different.
I chose to use reproductions of the original PAS 3 boards and rather than recreate the rudimentary selenium rectifier with standard capacitors, I chose to make use of the high-tech ClassicValve PAS Regulated Power Supply.
|ClassicValve Regulated Power Supply|
|A Stock PAS Switch|
|Stock PAS IO Board|
So... let's have a look at the splendid PAS 2 example that I was able to source:
|Original PAS Back|
|Original PAS Back Detail|
|Original PAS Insides|
|Original PAS Outside and Bottom|
The previous user left me with a lot more work that I would have had if I had a pristine PAS 2 / 3. There were a number of unusual mods, including plexiglass mounted RCAs, a 9 pin tube mounted in the middle, a non-descript transformer that was halfway mounted, some additional holes cut out of the back, and a powdercoated front panel that was rubbed with armor-all. No worries, one has to rise to the challenge.
The PAS was completely taken apart, a few parts were set aside, most were disposed of as they had been pillaged by mods. The chassis was sanded down and prepped for powder-coating.
The new boards were sourced and populated with my favorite parts, Kiwame and Takman resistors and Sonicraft caps.
|Old boards versus new boards|
Here's the final build:
|PAS guts from the right|
|PAS guts from the left|
|Outside with new gold front panel from ebay|
|Outside Photo 2|
|Rear, notice rear vent and Cardas output RCAs|
This little baby was an amazing amount of work, but it came out well and I'm really happy with it. Good luck to everyone out there restoring their PASs :)
Wondering where I got all my parts for this build? Check out a list of my favorite online vendors here.
The Fine Print:
Please remember that building circuits and performing circuit modifications can be dangerous to you and/or your surroundings and should only be performed by a certified technician. The owner of this blog and all associated parties can not / will not be held responsible if you attempt a build or modification posted above and cause physical harm to yourself or your surroundings. Many electronics contain high voltages that can kill, and mods, if performed improperly, can be a fire hazard. Please keep this in mind.