Thumbnail for Original Dynaco-manufactured PAS-3X Epoxy-Glass Circuit boards - Two VERY rare birds! - These are original Epoxy-Glass circuit boards produced by Dynaco toward the end of PAS preamplifier production. MOST PAS preamps had phenolic circuit boards. These are MUCH more durable - (and need I say, RARE!) It is not known if these were produced by the original Dynaco folks in Philadelphia, or if they were manufactured by Stereo Cost Cutters/Sound Valves/Sound Values in Columbus, Ohio. *Probably* the latter. (They owned the Dynaco brand name before Panor.)
Thumbnail for Original Dynaco PAS preamplifier chassis and bottom cover - replated. - This is original Dynaco metalwork for the PAS preamplifier series. It has been re-plated with a silver cadmium finish. Notice a *tiny* bit of "staining" on the surface of the chassis. (Now you see why this plating company didn't get to do more than this preamplifier and the metalwork for an FM-3 tuner.) It's a minor "cosmetic" blemish, but it indicated a "less than completely clean plating bath." Cadmium is hard to get "perfect" but this could have been a *little* bit better.
Thumbnail for Original Dynaco PAS preamplifier rear and front panels - replated. - These are the other two pieces of original Dynaco metalwork for the PAS preamplifier series. These have also been re-plated in a silver cadmium finish. Notice the *tiny* blemish in the middle of the cooling vents on the back panel. Again, it's a "cosmetic blemish", but it too, could have been just a *little* bit nicer. Still, this will make a VERY good foundation for one LAST PAS-3X preamplifier. I call it "The Last of the Dinosaurs!"
Thumbnail for PAS-3X - NOS "Special" Bass Potentiometers - These *can't* be the LAST NOS "Special" Bass Potentiometers for a PAS-3X Or ARE they?
Thumbnail for PAS-3X - NOS AC Receptacles - Yep! These are NOS AC Receptacles installed in the back panel of our PAS-3X build.
Thumbnail for PAS-3X - Initial Mechanical Assembly - Rear Panel Convenience Outlets - NOS - Mechanical Assembly of the back panel of a PAS-3X begins with the mounting of NOS AC convenience outlets.
Thumbnail for PAS-3X - Initial Mechanical Assembly - Back of Front Panel - Switches and Lamp Holder - The Initial Mechanical Assembly of the PAS-3X Front Panel begins with the mounting of the four Slide Switches and the Lamp Holder. These Switches are as good as the originals AND they're available at the nearest Radio Shack! Yes, the Lamp Holder came from Radio Shack as well, but it is no longer available. (Are we going to be looking for NOS Radio Shack parts next?)
Thumbnail for PAS-3X - Initial Mechanical Assembly - Front of Front Panel - Switches - Well, this is where our journey begins. First, mount the Slide Switches in the proper locations. Take care to center them in the rectangular cutouts before tightening the screws completely. (I'll straighten the Tape Monitor Switch before wiring the panel.)
Thumbnail for PAS-3X - Phono Input Jack - Ground Clearance - Notice that the RCA Jacks are NOT grounded to the chassis. This is CRITICAL to avoid hum. There's not much clearance between the "shell" connection lug and the chassis. The right jack is the "Phono Input" jack and it is even MORE important to avoid grounding it to the chassis! There's a little "wiggle room" when installing the jacks. Use it wisely.
Thumbnail for PAS-3X - Initial Mechanical Assembly - Rear Panel RCA Jacks - You can see where Dynaco saved a LOT of money! If they spent more than 75 cents for these jacks, they were ROBBED! But, this was pretty common stuff back in the 60's. (Take a look at a Vintage Fisher or H. H. Scott, or a Heathkit, or EICO, etc.) Actually, a little De-oxit once a year and they do pretty well.
Thumbnail for PAS-3X - Initial Mechanical Assembly - Rear Panel - Complete - This is the completed Initial Mechanical Assembly of the Rear Panel to the PAS-3X preamplifier. Not designed to be fancy, but to simply get the job DONE! Two of the AC Convenience Outlets are switched with the Power Switch. Two are "hot" all the time.
Thumbnail for "Reclaimed" Blend Switch - After initial cleaning of the Wiper contacts. - This shows what a little time and a little de-oxit can do. While there is a small amount of wear, the contact surfaces really look pretty good. When we're finished, the Front section will look just as nice.
Thumbnail for "Reclaimed" Blend Switch - Before initial cleaning of the Wiper contacts. - Both audio channels have to travel through THIS? Not in its present state. Time to break out the de-oxit and see what's under that crud!
Thumbnail for PAS-3X - Initial Mechanical Assembly - Rear Panel RCA Outpu Jacks - Notice that the "Main Out" RCA Jack is directly connected to the chassis. It is the ONLY one that is so connected. The other jacks are isolated from the chassis ground. It is CRUCIAL to keep them that way!
Thumbnail for PAS-3X - Initial Mechanical Assembly - Front of Front Panel - *almost* complete - All done (except for one final potentiometer). The Selector Switch will be mounted later. It may not look too impressive now, but it's *beginning* to take shape.
Thumbnail for PAS-3X - Initial Mechanical Assembly - Back of Front Panel - *almost* complete - One final potentiometer remains to be mounted on the left side. Then we just have to WIRE it!
Thumbnail for PAS-3X - Initial Mechanical Assembly - Rear Panel - Complete - Inside Shot - These are the "Ins and Outs" of a PAS-3X preamplifier in all their radiant NOS glory! Nothing exotic here, but it gets the job done.
Thumbnail for PAS-3X - Selector switch - Cleaned and reassembled - Here is a picture of the cleaned and re-assembled "reclaimed" PAS-3X Selector Switch. The actual contact surfaces are in very good condition.
Thumbnail for PAS-3X - Selector switch - dis-assembled - In order to do a proper cleaning job, the "reclaimed" PAS-3X Selector Switch must be dis-assembled. It would be wise to mark the sections and the rotor positions so you can properly re-assemble the Switch once the cleaning is done.
Thumbnail for PAS-3X - Selector switch - Before cleaning - Typical crud! - Here is a look at the back of the front wafer before cleaning. This is actually pretty typical of the gunk and oxidation you will probably find on yours.
Thumbnail for PAS-3X - "Reclaimed" Selector switch - removed - Here is a "before" picture of our "reclaimed" Selector Switch. Since ALL of our audio must go through this switch, it is time to clean, clean and CLEAN!
Thumbnail for PAS-3X - "Reclaimed" Selector switch - before removal - Here is the rear wafer of a typical PAS Selector Switch as you are likely to find it installed in an existing preamplifier. Note the crud and oxidation on the actual contacts. There is much cleaning and de-oxidation that MUST be accomplished before we'll know whether this switch will be acceptable or not.
Thumbnail for PAS-3X - PC-5 and PC-6 - rebuilt - Here are the PAS-3X PC-5 and PC-6 circuit boards after rebuilding. Ready for another 40 years of operation!
Thumbnail for PAS-3X - Typical Selector Switch and Input Wiring - Here is the typical wiring of the input jacks and the selector switch. The green wires are for the Left channel and the Red wires are for the Right channel. Crosstalk anyone?
Thumbnail for PAS-3X - Selector switch - front wafer after first cleaning - Here is a look at the front wafer after its first cleaning. Notice that the heavy layer of oxidation and crud are now gone! Another round of cleaning will help clean the wafer itself.
Thumbnail for PAS-3X - Selector switch - front wafer before cleaning - Here's what we started with. This is the front wafer of the PAS-3X Selector Switch. Dirt, oxidation and who-knows WHAT else. Looks like another job for de-oxit!
Thumbnail for PAS-3X - Front Panel Assembled to Chassis - We have assembled the pre-wired Front Panel to the Main Chassis. It's beginning to look like a preamplifier!
Thumbnail for PAS-3X - Initial Mechanical Assembly - Main Chassis - Here is the Main Chassis of the PAS-3X preamplifier with the major components mounted. Next, we'll mate our pre-wired Front Panel and begin wiring them together.
Thumbnail for PAS-3X - Front Panel Shielded Wiring - closeup - Here you can get a good look at one of our "modifications" to the PAS-3X. We're using shielded wiring in order to reduce noise and crosstalk. Notice that the shields are only connected at one end. The shields for the wires that run from the Blend Switch to the Monitor Switch are grounded at the Blend Switch. The shields for the wires that run from the Volume Control to the PC-5 Line Stage circuit board are connected at the Volume Control.
Thumbnail for PAS-3X - Front Panel Shielded Wiring - Monitor Switch - If you look closely at the Monitor Switch, you'll see that the shields are NOT connected to anything at the Monitor Switch itself. They are grounded at the other end ONLY.
Thumbnail for PAS-3X - Back of Front Panel - Pre-wired and ready to mount on the Main Chassis. - Here is our pre-wired Front Panel. Notice the shielded wiring from the Blend Switch and the Volume Control. This is a "modification" of the original Dynaco wiring. Originally, all these wires would be unshielded. In a high impedance circuit like this, additional shielding is a GOOD idea!
Thumbnail for PAS-3X - Pre-wired Selector switch - Here is a PAS-3X Selector Switch pre-wired with shielded Input wiring.
Thumbnail for PAS-3X - Phono Input wiring - Here is the Phono Input of our PAS-3X preamplifier, Notice that we are using twisted wires, rather than totally shielded wiring.
Thumbnail for PAS-3X - pre-wired Chassis - Bottom View - Here is a picture of our PAS-3X preamplifier from underneath. Most of the chassis wiring is now complete.
Thumbnail for PAS-3X - Filament Supply - Here is a close-up of our new PAS-3X filament supply. The silicon diodes won't gradually weaken like the stock "old-school" selenium rectifier.
Thumbnail for PAS-3X - pre-wired Chassis - Top View - Here is our pre-wired PAS-3X preamplifier. All that remains is the Selector Switch installation and wiring of the Inputs and Outputs.
Thumbnail for PAS-3X - Output wiring - Here is a closer shot of the Output Wiring. Notice we have used shielded wiring here for lower hum and noise.
Thumbnail for PAS-3X - Selector switch - Shielded Wiring - Here is the completed wiring at the PAS-3X Selector Switch. That jumble of wires has gotten considerably neater.
Thumbnail for PAS-3X - Shielded Input wiring - Here is the completed wiring of the RCA jacks. Our shielded wiring now looks quite neat.
Thumbnail for PAS-3X - Chassis - Top View - Completed Wiring - Our PAS-3X is now Electrically complete. Here's an overall view of the top of the completed chassis.
Thumbnail for PAS-3X - Chassis - Bottom View - Completed Wiring - Here is a picture of our Completed PAS-3X wiring underneath the chassis.
Thumbnail for PAS-3X - Front of completed preamplifier - Here is a picture of the front of our completed PAS-3X preamplifier. While not absolutely PERFECT, I don't think anyone would be ashamed to display this unit in their "Vintage" collection. This is the so-called "new design" front panel made of extruded anodized aluminum. The finish is called "Champagne Gold" in Dynaco literature. Personally, I think it looks simply elegant, with a bit of a "European" flair.
Thumbnail for The Telefunken "Diamond" - Telefunken made it EASY to spot fakes. This is the "classic" Telefunken "Diamond" located on the bottom of every genuine Telefunken miniature tube.
Thumbnail for Original "Dynaco" branded 12AX7 tubes - Manufactured by Telefunken - The tubes EVERYBODY wants! These are "Dynaco" branded Telefunken-manufactured 12AX 7's. In a PAS-3X preamplifier, they truly make MAGIC!
Thumbnail for PAS preamplifier - Rear Panel Label - "Dynaco" version - This is a picture of a NOS Pas preamplifier label for the rear panel. There have been several versions over the years, but this was the final version Dynaco used. Notice the "Dynaco" logo, rather than block printing that read "Dyna Company"
Thumbnail for Rear Panel Label - PAS preamp - early version - Here is a scan of the rear panel of an existing PAS preamp label. This is an early version.
Thumbnail for PAS-3X - Chassis - Bottom Panel with Feet Installed - Here is the Bottom Panel of a PAS-3X preamplifier with feet installed.
Thumbnail for PAS-3X - Top Cover - Here is the top cover for our PAS-3X preamplifier.
Thumbnail for PAS-3X preamplifier - Rear Panel - With"Dynaco" version NOS label - Here is a picture of our completed PAS-3X Rear Panel with a NOS late-production label installed. Notice that this version of the label has the "Dynaco" logo
Thumbnail for PAS-3X Cover Screws - Cleaned and polished Dynaco PAS-3X Cover Screws
Thumbnail for PAS-3X - Rear of completed preamplifier - Here is a picture of the back of our completed preamplifier.
Thumbnail for PAS-3X - Front of completed preamplifier - with cover - Here is a picture of the Front of our completed PAS-3X preamplifier. This is as close to a new PAS-3X preamplifier as you are likely to get. As far as *I* know, this truly is "The LAST of the Dinosaurs!"