DYNACO PAS-2, PAS-3 VACUUM TUBE PREAMPLIFIER
Source Information for Updates and Modifications
The Dynaco PAS-2 and PAS-3 vintage vacuum tube preamplifiers can superbly deliver accurate and detailed sound quality, surpassing many high-end preamplifiers currently on the market. Many options are available to restore the original classic design, or upgrade and modify the original PAS to a brand new level of performance.
During the PAS production years, Dynaco sold over 100,000 PAS-2, PAS-3 and PAS-3X preamplifiers.
The difference between the PAS-2 and PAS-3 preamplifier is the PAS-2 has a flat brass faceplate with plastic knobs, and the PAS-3 has a silver anodized faceplate with metal knobs, otherwise both preamps are the same.
The PAS-3X preamp has a revised tone control circuit which takes the tone controls out of circuit when set to the flat position.
The information printed below is for a quick reference. Please follow the links for up to date information on pricing, specifications, descriptions and the availability of services offered from the various web sites.
Unofficial Dynaco Home Page
The Unofficial Dynaco Home Page created and maintained by Greg Dunn. Copyright © 2000-2002 Greg Dunn. ... Dynaco is a registered trademark of Panor Corporation.
Dynaco PAS-2/2X Vacuum Tube Preamplifier Designed by: Ed Laurent, Year Introduced: 1960 - Tubes: 4 12AX7 (ECC-83); 1 12X4
Dynaco PAS-3X Vacuum Tube Preamplifier Designed by: Ed Laurent, Introduced: 1966 - Tubes: 4 12AX7 (ECC-83); 1 12X41966 review of the PAS-3X in Stereo Reviewmagazine 1966 review of the PAS-3X in High Fidelitymagazine.
Audio by Van Alstine
AVA is well known for their Dynaco modifications. Their PAS modification spent several years on Stereophile's Recommended Components list. They're at 2202 River Hills Dr, Burnsville MN 55337, Ph 612 890 3517. They also sell custom selector switches and gold jack sets for PAS preamps, which are very high quality and useful to any PAS modifier
Dyna PAS Rebuild: Super Pas ThreeSuper Pas Three Rebuild for the Dyna Pas-2, 3, and 3X Price: Factory Rebuild (includes jack set and new tubes) $799 Kit $399 Circuits: Super Pas Three Chassis: Your Dyna PAS-3, 3, or 3X Options: Jack set kit $79; fiberglass selector switch $59
Curcio Audio Engineering
High Resolution Vacuum Tube Audio Systems1686 Hyacinth Lane San Jose, CA 95124 Phone: 408-269-4273 (PST) FAX: 603-584-6573
DYNACO PAS PREAMP UPGRADES & MODIFICATIONS
PDF FILES AT CURCIO'S WEB PAGE:PAS 2/3 Owners Manual (full) Removing the PAS Tone Controls Replacing the PAS Selector Switch Replacing the PAS Filament (Selenium) Rectifier
Power Supply Supplement Module - Resolves the weakest part of your PAS - its power supply. It totally eliminates all hum. The 7A module contains a high speed low "Z" HV regulator and a complete high current regulated filament supply (with transformer). Bass impact is dramatically improved & dynamic contrasts are extended across the entire frequency spectrum.Blank Board (P/N PWB-7A) @ $55 Blank Board w/ parts (P/N KIT-7A) @ $178 Assembled & Tested Board (P/N ASM-7A) @ $198
Basic Line Stage (PC-5) Module Upgrade - Dramatically improves every aspect of the line stage - the heart of your preamp. An audiophile's line stage that will transform your PAS into a world class preamp. Removes veiling and extends imaging while retaining the musicality of the original. Lowers output impedance (finally) so that any power amplifier (or crossover) can safely be driven. A "drop in" board replacement for the original Dynaco PC-5 that's a snap to install.Blank Board (P/N PWB-5AH) @ $55 Blank Board w/ parts (Includes Tubes) (P/N KIT-5AH) @ $178 Assembled & Tested Board (Includes Tubes) (P/N ASM-5AH) @ $198
Basic Phono Stage (PC-6) Module Upgrade - A high resolution replacement for the original Dynaco PC-6 phono PC board that incorporates high transconducance low noise triodes with a perfectly executed RIAA topology that thrills vinyl enthusiasts.Blank Board (P/N PWB-6A) @ $55 Blank Board w/ parts (Includes Tubes) (P/N KIT-6A) @ $162 Assembled & Tested Board (Includes Tubes) (P/N ASM-6A) @ $180
PAS 2/3 Replacement Hardware Items - Common PAS 2/3 AilmentsSelector Switch Replacement Kit (P/N SSW-PAS) @ $36/ea Selector Switch Upgrade w/ Download Instructions (P/N RSW-2P) @ $11/ea Teflon Rewire Kit (4X 10ft Red, Black, Wht, Grn) (P/N TWK) @ $20/set Stereo Volume Control Replacement - (P/N PAS-VC) @ $16/ea Dual RCA Input / Output Connector Kit, Nickel (P/N P3-RCA-N) - $36/ea Dual RCA Input / Output Connector Kit, Gold (P/N P3-RCA-G) - $50/ea Replacement Power Transformer (P/N P3-XFMR) @ TBD Anodized Aluminum Replacement Faceplate & Knob Set (P/N P3-FP) @ TBD
A cheap fix for the Dynaco PAS Preamplifier
SDS Labs - Vintage Audio Equipment Refurbishing
Dyna PAS Modifications
Dyna PAS Power Supply Replacement Board
Dyna PAS Filament Supply Rebuild Instructions
Dyna PAS Input Connector Board
Installing the SDS Labs Dynaco PAS Capacitor Board
Installing the SDS Labs Dynaco PAS Capacitor Board - A description on how to install a Sheldon Stokes Capacitor Board in a Dynaco PAS pre-amplifier.
VACUUM TUBE VALLEY
P.O. Box 1499, Lakeport, CA 95453 USA Telephone: (707) 263-5881 FAX: (707) 263-7648
Dynaco PAS-2 and PAS-3 Tube Preamp Rebuilding Kit.
A very easy upgrade to do and the performance difference will be amazing.
$65 (Please specify PAS-2 or PAS-3)
Comes with all required parts including:- eight metal-oxide low-noise carbon film plate resistors - 22 high-quality 630V rating film capacitors - two-high-capacity electrolytics for the filament supply - two-1N4007 silicon diodes for the DC filament supply - schematic of the preamp indicating replacement parts
Vintage Electron Inc.
(Vintage Electron has acquired the remaining parts inventory of the former Dynaco National Service Center.)
Dynaco PAS upgrades:$23.00 Dynaco PAS (2, 2X, 3, 3X) re-tube set (Save $3.64 off individual prices):(4) Sovtek 12AX7WA/7025's (1) NOS 12X4 (Our choice of brand)$75.00 PREMIUM Dynaco PAS (2, 2X, 3, 3X) re-tube set (Save $7.00 off individual prices:(4) NOS Lewis and Kaufman 1960's 12AX7WA/7025's (1) NOS Tung-Sol black plate 1960's 12X4 silkscreened "DYNACO"
Circuit Board Upgrades: Definite improvements you can hear; designed with new layout, circuit board material, and improved components in these new production circuit boards.
Dynaco PAS 2, 2X, 3, 3X Circuit Board Refits:We are pleased to announce the introduction of our new PC-5A and PC-6A circuit board re-fit kits for the PAS 2, 2X, 3, and 3X preamplifiers. These boards are newly manufactured from FR4 fiberglass board material, use plated through holes, as well as solder re-flow on all the traces. The refit boards offer components of much better quality and stability over the original parts. High quality ceramic tube sockets are standard. The boards utilize the original 12AX7 circuits and are a complete drop-in replacement solution to your restoration and re-building needs. Simply unsolder the wires from your existing boards, unbolt the boards from the chassis, and drop in our new re-fit boards. Boards come completely assembled with all components and include (2) new Sovtek 12AX7WA/7025 tubes (shown) for each board. JJ 12AX7/ECC83 tubes are also available (bulk factory direct non-silkscreened), please request at order time. INTRODUCTORY SPECIAL PRICING:PC-5A PAS assembled re-fit board & (2) Sovtek 12AX7WA/7025 tubes: $75.00 PC-6A PAS assembled re-fit board & (2) Sovtek 12AX7WA/7025 tubes: $75.00
Triode Electronics Online
PA211 Power Transformer
Power Transformer upgrade and replacement for the Dynaco PAS2, PAS3 and PAS3X preamplifiers.
Norman L. Koren
SPICE and the art of preamplifier design
Part 2: New preamplifier designs
by Norman L. Koren
Dynaco PAS preamplfier circuit and performance modifications.
Arthur Salvatore and High-End Audio LTD.
MODIFICATIONS - TUBE PREAMPLIFIERS By ARTHUR SALVATORE AND HIGH-END AUDIO LTD.
Dynaco parts and modifications sources
Richard Sherman - 'The Music Room' Richard's Personal Collection of Vintage Tube equipment.
Dynaco PAS-3 Stereo Preamplifier
Roger W. Stevens
Rebuilding the Dynaco PAS Preamp
Rebuilding Basics - Test Equipment for Tube Gear
Vintage Dynaco Pictures and Descriptions
IMAGES - VACUUM TUBE PREAMPLIFIERS - PAM-1, PAS-2, PAS-3
IMAGES - SOLID STATE PREAMPLIFIERS - PAT-4, PAT-5