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Dynaco PAS-3 tube preamp mods and parts
our new, COMPLETE KIT - a modern PAS3 reproduction/clone
original circuit replacements
Z-mod
Tone Control Line Amp upgrade
PAS3 upgrade catalog - a newer version of this page
PAS3 upgrade catalog - a PDF download
HOLIDAY NOTE - due to the holiday season and rush of orders (they've already begun!)
most orders will ship in 2-4 days rather than our usual 2-4 hours!!
PAS3 preamp reproduction/clone
now offering a COMPLETE KIT of a modern updated version of the Dynaco PA3, this is a reproduction/clone using all new parts
Gone are the limitations of a small size chassis and a terribly underpowered power supply.The 4 tone controls (dual mono treble and bass) of the original are updated with dual stereo controls for treble and bass.
New reproduction/clone PCBs are used with the original circuit. New power transformers have 4X the current capability of the originals.
The filament supply is regulated at the optimum voltage for the tubes, to maximize performance, and to cut noise and hum to an absolute minimum.
KITS include ALL parts to build a complete preamp, including the tubes - chassis, two transformers, 3 PCBs, volume, balance, source selector,
treble and bass tone controls, power switch and LED indicator, front panel knobs, rear panel RCA jacks, AC cord, rubber feet, EVERYTHING for completion !
Delivery time is 2-3 weeks - priced starting at $499 !!
click here for more info and details
original circuit replacement PCBs
Dynaco PAS3 preamp rebuild
for those on a budget but wanting an updated/upgraded PAS3, we offer high-quality original circuit replacement PCBs with better than original parts.
new power supply board; $49 kit or $69 assembled
new PC6 phono PCB and new PC5 line amp PCBs - $120 for assembled PCBs
new input/output jacks; $59 kit or $79 assembled
recommended replacement of volume, balance, & selector for better quality
PAS3 upgrade catalog
VTA PAS3-Z modification
VTA PAS3-Z modification
Finally, a hi-end modification for the Dynaco PAS3 preamp. We haven't seen anything new in the past dozen years or so,and the only real alternatives are the Curcio kit for $662 and the VanAlstine kit for $449, now VacuumTubeAudio at www.tubes4hfi.com
offers an easy plug-in 3 piece circuit upgrade for the PAS3 that is identical to it's highly reviewed SP6 preamp kit.
This is for customers that want to KEEP their PAS3 chassis rather than building an all new preamp in a newer chassis.
Also, please NOTE this modification eliminates the tone controls, see our TCLA upgrade for a new ToneControlLineAmp.
The circuit has a hi-gain phono preamp using a 12AX7 gain stage followed by a highly accurate passive EQ,
followed by another 12AX7 gain stage, for a total gain of 45 db.
The line stage uses a 12AU7 in a cascode SRPP gain stage for high gain with excellent linearity and low output impedance, for a gain of 15 db.
The power supply makes use of the original 12X4 tube rectifier for soft-start, with 306uF of B+ power supply capacitance (compared to the original 80uF).
Printed Circuit Boards are mil-spec FR4 double-sided with plated-thru holes.
Easy installation takes about 1 hour. Full documentation included with the kit includes assembly manual, schematic, layout diagrams,
parts list, and installation instructions. Set of 3 bare PCBs $90 (includes all documentation and install instructions)
Set of 3 PCBs with all parts included except tubes $169.
Set of 3 PCBs assembled and ready to install (no tubes) $229
Set of 3 PCBs assembled and installed into your existing/working PAS3 preamp $350
*** please note, we recommend replacing the selector switch ($8 part, $30 labor) and the volume and balance controls ($50 parts, $30 labor) ***
*** additional note, this modification will disconnect all tone controls ***
Set of 2 new EH-12AX7 low noise phono tubes $40
Set of 2 new EH-12AU7 low noise line stage tubes $30
NOS 12X4 rectifier tube for power supply $10
PAS3 upgrade catalog
Finally, a hi-end modification for the Dynaco PAS3 preamp that INCLUDES TONE CONTROLS !!
This circuit uses four 12AX7 tubes for the extra required gain and tone control processing.New accurate tone controls are included that allow +/-12db of boost/cut for bass and treble frequencies.
Easy installation takes about 1 hour. Full documentation included with the kit includes assembly manual, schematic, layout diagrams,
parts list, and installation instructions.
This kit is for the line amp only, our Zmod power supply is recommended but not required (see above for $50)
Our Zmod phono stage is recommended to upgrade the original phono section.(see above for $75)
PCB kit with all parts except tubes $119
Assembled/tested PCB kit without tubes $179
set of four new 12AX7 tubes $50
*** please note, we recommend replacing the selector switch, and volume and balance controls ***
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PAS3 upgrade catalog
| 6 position selector switch - $10 including FREE shipping | ALPs volume and balance controls $50 | SPECIAL - volume, balance, and selector switch $55 |
| new input/output jacks on new one-piece PCB - $59 kit | new input/output jacks on new one-piece PCB - $79 assembled | . |
| new original style quad cap $40 20/20/20/20 µF @ 475 VDC  |
less expensive alternative quad cap and new clamp $22 40/20/20/20 µF @ 500 VDC  |
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PAS3 upgrade catalog
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send us email at: info@tubes4hifi.com
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