tubes 4 hifi
 "the path of least resistance is through a vacuum"

PAS3 preamp upgrades, modifications, replacement parts


our partner TubeNirvana is now the official distributor
of ALL of our PAS3 parts, upgrades, and modifications.
go to webpage here


POWER SUPPLY
this replaces the original filament supply circuit (selenium rectifier and two large capacitors),
and also replaces the 4 section hi-voltage "quad-cap" with modern capacitors,
raising the total B+ storage capacity from 80uF to 266uF, and adds a fuse
REGULATED POWER SUPPLY v13
This option is for the customer who wants the ultimate and final piece of a total PAS3 upgrade.
This replaces the original or upgraded power supply, with a supply that provides regulated
280v B+ voltage for the line amp and an additional 220-280v B+ for the original or Zmod phono amp.
This option also includes two new power transformers with higher current
to replace the original underpowered PA211 transformer.
This will require drilling two small additional mounting holes
this power supply is for running 4 tubes plus the rectifier tube
HD REGULATED POWER SUPPLY v14
This is the same power supply as above but with a larger filament transformer
to run 6 tubes plus the rectifier tube, for use with the TCLA or AIKIDO boards and a phono stage.
This will require drilling two small additional mounting holes
21 step VOLUME control 100K
replace the old worn carbon volume pot with new high quality
21 step attenuator
VOLUME control 100K
an original style volume control with LOUDNESS if you're on a budget
VOLUME control 250K
replace the old worn carbon volume pot with new high quality
ALPS RK27 "blue velvet" VOLUME control with LOUDNESS function
OUT OF STOCK UNTIL MAY
BALANCE control
the ALPS RK27 "blue velvet" BALANCE control 250K
NOTE: you'll need to replace the orignal knobs with item #8
OUT OF STOCK UNTIL MAY
BALANCE control
budget Bourns balance control 500K
NOTE: you'll need to replace the orignal knobs with item #8
SELECTOR SWITCH
this replaces the huge old fashioned "rats nest" selector switch which has fragile contacts
and is usually noisy and worn out with a much smaller new modern style input selector switch

TONE CONTROLS
we recommending disconnecting the old tone controls for better fidelity
but for those that want upgraded replacements we offer them here as a set of 2 bass and 2 treble controls
this kit also INCLUDES 6 new replacement capacitors that are directly wired to the tone controls
NOTE: you'll need to replace the orignal knobs with item #8
for much higher quality tone circuits see also
our modern replacement TCLA (tone control line amp) listed below

new style RCA jack I-O PCB
this replaces the 4 old terminal strips with SEVEN wider spaced RCA pairs
one PCB with 7 pairs of wider spaced and higher quality gold plated RCA pairs
new solid aluminum knobs for new controls
after replacing the balance and/or tone controls, you'll need modern type knobs with a set screw, as the old originals were designed for "knurled shafts" >br> this includes two large knobs and six small knobs, they look similar to originals but NOT identical
new ORIGINAL STYLE replacement circuit boards
after replacing the power supply and some other parts above,
now you can finish upgrading with these original design PCBs
that are made with mil-spec FR4 material,
huge improvement over the old phenolic PCBs, and these come with modern higher quality parts
such as low-noise metal film resistors and polyproplyene capacitors
the PCBs are exact drop-in replacements with the same hookup markings as the originals
this set includes the PC6 phono amp and the PC5 line amp PCBs and parts,
tubes not included
new design "Z-mod" upgraded circuit replacements
if you are going to spend a couple hundred $$ upgrading your PAS3,
why not make a HUGE IMPROVEMENT in the sound quality by replacing
those 50 year old mid-fi circuit designs with modern Hi-Fi plug in replacements?
Our VTA "Z-mod" circuits are identical to those used in our highly reviewed
and respected SP8 premium preamp design and are exact "drop-in"
replacements for an easy upgrade.
This item includes the "Z-mod" PC6 phono amp (uses 2 12AX7 tubes)
and the "Z-mod" PC5 line amp without tone controls (uses 2 12AU7 tubes)

and we definitely recommend that you combine this with item #1 above, the upgraded power supply
NOTE - the Z-mod PC5 line amp does NOT have tone controls, so if you want
a high quality, modern tone control line amp
see the next circuit design below - our "TCLA" upgrade
upgraded Zmod PC6 phono amp only
as described above
upgraded Zmod PC5 line amp only
as described above
new "TCLA" modern hi-quality tone control line amp
This option is for the customer who wants tone controls AND
a totally modern Hi-Fi design for very MUCH improved sound fidelity.
This is a 4 tube (all 12AX7) line amp only, it includes new linear tone controls, and can be used
with either the upgraded Z-mod phono PCB or with the original phono board, or alone by itself without phono.
Our #1 item or #2b upgraded power supply is recommended but not required.
NOTE: if you are also going to use a phono board AND the TCLA board, you will need the HDv14 power supply (item #2b above) NOTE: you'll need to replace the orignal knobs
brand new "PAS3-Aikido" (SP12 circuit)
This is our highest quality circuit and has been specially designed to fit into the PAS3. Identical circuit to our hi-end SP12 on a smaller PCB, and using PAS power supply. Our regulated power supply v14 is highly recommended for this
brand new PH10 phono circuit
This is our highest quality circuit specially designed to fit into the PAS3. Identical circuit to our hi-end PH10 phono circuit and using PAS power supply. An upgraded power supply (#1, #2a, or #2b) is recommended but not required.
set of new tubes for original design PCBs
this includes 4 JJ 12AX7 tubes and 1 NOS 12X4 tube
set of new tubes for Zmod upgrade PCBs
this includes 2 low-noise EH 12AX7 tubes, 2 JJ 12AU7 tubes, and 1 NOS 12X4 tube
set of new tubes for TCLA tone control line amp
this includes 4 JJ 12AX7 tubes
set of new tubes for AIKIDO line amp
this includes 4 JJ 12AU7 tubes
set of new tubes for PH10 phono amp
this includes 2 EH 12AY7 low-noise tested tubes
original type DPDT slide switches set of 4
new LED replaces old style pilot light
saves 140ma of filament current!



our partner TubeNirvana is now the official distributor
of ALL of our PAS3 parts, upgrades, and modifications.
go to webpage here



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return to VTA home page

send us email at: sales@tubenirvana.net


 tubes 4 hifi
 "the path of least resistance is through a vacuum"