Fully rebuilt and restored 1967 Dynaco PAS Tube Preamplifier
Here's a fantastic vintage tube preamp all ready for reliable and enjoyable daily use again.
The original unit was taken apart to the bare chassis for cleaning, polishing and the full rebuild / restoration.
New reproduction circuit boards loaded with premium components like Multicap and Mundorf capacitors along with some Panasonics and Nichicon Icell (Italy).
All the resistors are 1% metal films and carbon films by Dale, Takman, PRP, TE Connectivity and Vishay.
The line stage tubes tubes are (2) Raytheon 1950's black plate 12AX7A labeled for Baldwin Organ and Piano. These both tested balanced and nearly new, they sound great.
The phono board has two NEC 12AD7 tubes both testing at NOS levels and very balanced, these sound ridiculously good.
The new tube sockets are high grade ceramic type.
The rectifier tube is a NOS 12X4 by RCA, it is a black plate tube and sits in a NOS cinch socket.
The original style bias supply has two NOS CDE 2000uF 75 volt electrolytic caps and uses two diodes, these replacing the outdated selenium rectifier.
The power transformer is the original 1967 Dynaco PA-211 with cloth leads and works perfectly.
The multi section filter capacitor is a brand new Dynakit 20/20/20/20uF rated for 475 volts.
The original selector switch was bad so it has been replaced with a modern Alpha 6 position switch. This also facilitated installing a new input/output rear panel which eliminates the old ceramic phono and special jacks. The unit now has 5 line level inputs and a standard phono input for moving magnet type cartridges. The front panel is original so it is still labeled for the old original positions. The way it works now is as follows: starting at the full left position on the front selector labeled special, this is now phono, the with each click going clockwise the selector follows the logical order of the inputs on the rear of the unit. I have a simple diagram prepared and this will be included to help you get used to the new way the selector works. See the last photo in this listing also for clarity. A nice brass phono grounding post has been added to the rear of the chassis. New wiring to and from the rear panel, all new resistors installed there also.
Since the new selector is a non shorting type you should only have one active source at a time at the inputs. You don't need to disconnect anything, just don't input more than one signal at a time to prevent crosstalk.
There is now no tape monitor / tape loop feature on this preamp.
All of the remaining original bass, treble and blend controls were also tested, cleaned, serviced and reinstalled with all new wiring.
All capacitors and resistors for the original controls are new and the switches are all brand new by Alpha.
The entire preamp has all new wiring.
The AC accessory sockets were reduced to a single outlet to help minimize stray electrical fields.
The empty holes are blocked off with a phenolic board to keep debris from getting in the lower chassis.
A brand new polarized power cord and Heyco retainer are installed.
Obviously the front panel is original and is missing some lettering at the volume control position and the power switch.
The power indicator lamp is an adjustable amber LED behind the original amber pilot jewel.
The knobs are original and in great condition.
New rubber feet with steel bushings are installed on the bottom plate.
This PAS is dead quiet and simply fantastic sounding, why wouldn't it be? All of the dated and out of spec parts are replaced with super high grade modern components.
All of the original functions are intact and work. When you have a great design like this and bring it back to a like new condition it is a very satisfying experience.
I love the sound of a healthy and proper working PAS. You will too.