Dynaco Pas 4 Preamplifiers

Dynaco Pas 4 Preamplifiers 

DESCRIPTION

Modern tube preamplifier

USER REVIEWS

Showing 1-10 of 23  
[Apr 30, 2018]
model 28


Strength:

I recently purchased a used pas 4 after doing a lot of research and reading the reviews. I auditioned it and thought it sounded good but not great. After I read about the mods others recommended I decided to do the same. There are only 2 tubes for the preamp line stage and the other 4 are for phono. I opted for a pair of national 7dj8 from upscale audio and also upgraded the output caps with Mundorf silver and oil. Wow! A whole different amp. The soundstage huge, depth and dynamics incredible. Very engaging. I'm really impressed with this preamp and it's a keeper for sure. I'm sure this will keep up with preamps in the thousands. Build quality is exellent and not a lot of them made. No bass and treble controls and believe me you don't need them. Music as it were meant to be heard. If you get a chance to buy one do not hesitate. They come up from time to time and prices keep climbing.

Weakness:

No remote control

Purchased:
New  
OVERALL
RATING
5
[Jul 23, 2018]
Rick277


Strength:

Clear, bright, huge sound stage, tube preamp. I purchased this amp about 20 years ago and have it mated with a fully restored Harman Kardon Citation II tube amp built by the master Jim McShane. It feeds a pair of Martin Logan SL3 Electrostats and a dual voice coil 12” hand built subwoofer. I primarily feed the phono stage of the pre-amp from a RPM 9.2 table with the Sumaco Blue Point EVO III cartridge. The ML Electrostats are extremely revealing speakers and the HK Citation II has a tremendously detailed soundstage which allows great component comparisons. I re-tubed the PAS-4 right away because the Chineese tubes were not good. I’ve got a significant tube collection and have tried most everything, settling on mostly U.S. JAN (joint army navy) military tubes. They are built like a tank and sound great. Changing between these and Phillips, RCA, Mullard, and others truly reveals different sonic platforms that are audible and its fun to test and tune. This PAS-4 pre-amp has just what I wanted, separate tubes for each section, NO TONE CONTROLS (I’m an old audiophile and have learned that all that tone control stuff adds wires, sound path complexity, and just lessens the sound quality), simple build philosophy, and great build quality. For comparison, I have a class A Creek Audio 5350 Special Edition amp that is a Stereophile recommended component with a factory Phono pre-amp section. The Creek being a SS amp does sound different. But I would put the tube equipment up against this SS or any SS system any day of the week. Very detailed, fast, quite, articulate, deep and wide soundstage that is “live”. You can pick the pieces out of the virtual stage. For the original purchase price the Dynaco PAS-4 is an absolute steal and you will not be dissapointed in its performance regardless of price if you can still find one on e-bay. This version of the Dynaco Tube preamp was built by the Panor Dyna company versus the earlier original Dynaco tube amps and in my opinion sound much better. They are hard to find now however. Post scrip message: I recently tweaked the PAS-4 by installing a pair of Mundorf Supreme EVO Silver,gold,oil caps in the final section of the audio path. I then installed a few “bypass capacitors” which are very low .01uF 160 Volt Vishay’s. This had as much impact at the high end Mundorf and are just over a $1 each. Very tiny black caps that dramatically improve the soundstage especially in the mid/highs. They ar

Weakness:

A lot of people list not having tone controls as a negative. I never buy equipment with tone controls. It lessens the sound quality by introducing more complex electronics that in my opinion degrades the sound stage and detail accuracy. Simpler, shorter path = better audiophile level quality.

Purchased:
Used  
OVERALL
RATING
5
[Jul 10, 2015]
Robert C.
AudioPhile

I've been using PAS-4 for about 18 years. Never failed me.
As far as sound quality is concerned this pre is a champ. But few things have to be done:
1. Replace cheap power cord with a good one. I did that and little hum it had was almost gone.
2. Replace stock vacuum tubes with good quality tubes. It's an investment of about $130.00 but it's worth all the money.
After light modification this preamp will reward you with airy mids, good micro/macro dynamics, good treble extension, springy bass, decent sound stage and imaging. This what mine did to me after tubes and cord replacement.
With good recording (CD or LP) PAS-4 shows a good deal of "being there" impression. CDs definitely sound better. I stress it again, replacing stock tubes is really important if you want to have a good sound. It has some shortcomings but comparing it to my ARAGON AURUM pre amp ($1900 when new) left me scratching my head which one to choose. It's that good. It's definitely more airy than AURUM.
If you can find used one in a good condition do not hesitate to buy it.
Who knows, buying PAS-4 might be the beginning of the addiction to tubes and tube sound.
No, I'm not going to sell mine. Phono stage is too good.

Associated equipment:
ARAGON 8008ST - amp
VPI Scout Jr - turn table
Denon 1650 - cdp
PS Audio DAC III - digital to analog converter
Legacy Classic HD - speakers
AudioQuest, Nordost, Alpha-Core (Goertz) - cables

OVERALL
RATING
5
VALUE
RATING
5
[Mar 16, 2012]
Ralph Perrini
AudioPhile

I urchased this PAS-4 new from J & R Music World back in March 1997 for $ 500.00 exactly 15 years ago. The unit has been making beautiful music in my system since then. The fit and finish is very good, and the innards are neat and well made. One of my very best audio purchases ever!

Replacing the original 6922 tubes in the linestage with 6N1Ps made a big improvement, as did replacing the stock power cord. The 6N1Ps are not only quieter, with their slightly lower gain they give the volume control a much greater useful range, with the 6922 things got very loud with the volume control at 9 o'clock. I don't use the phono stage since I have an outboard phono stage for my low output MC cartridge. However I had to leave the phono tubes in because removing them produced an infernal howl.

The combination of this pre-amp with my solid state Acurus A100, also purchased 15 years ago produces a very detailed, smooth sound that holds up well against far more expensive set ups. And having served reliably in my system for 15 years and counting I can vouch for it's quality and reliably. If you can get your hands on one I highly recommend it.

OVERALL
RATING
5
VALUE
RATING
5
[Jan 25, 2005]
rgf343
AudioPhile

Strength:

Low price, very good quality build and design. Outstanding sonic capability with very minor alterations. Tighter low frequency than most S.S. and more transparent mids/highs than most tube preamps. Overall, an excellent preamplifier.

Weakness:

Factory tube recommendations do not distinquish this preamp. and upgraded power cable required to improve performance.

Have tried quite a few preamps., both S.S. and tube, e.g. Audio Research and B.A.T.. The PAS-4 is a well designed and built preamp. that sounds great as is. However, get rid of the 6922s in the line section, replace with a matched pair of Russian 6N1Ps, Cyro treated, from Tubeman, and, if you don't use LPs, take the phono tubes (12ax7s & 6922s) out of the low level section (unit will run cooler). Most preamps. won't allow use of 6N1Ps to replace 6922s because of increased filament current needed, however the PAS4s regulated power supply handles this without difficulty. Upgrade the power cable to 16 ga., polish the chassis (so it will go faster and look impressive), let unit warm up for a couple of hours and you will experience a preamp. that will definately blow your hair back, assuming you have good equipment to utilize with it. Sound is extremely clear, distortion is reduced, low frequency transients and ability to access frequencies in the bottom octave with absolute authority, along with smooth, extended high frequency output is nothing short of phenominal. Dynamic range is outstanding. In my opinion it would take a class of preamps. costing several thousands just to match what this is capable of with these minor changes, don't forget to polish the chassis for reduced wind resistance. If you can locate one my advice is grab it when you can, hopefully you will be as pleased as I am. rgflato3@hotmail.com

Similar Products Used:

Audio Research, Sony, B.A.T., P.S. Audio, Adcom, etc.

OVERALL
RATING
5
VALUE
RATING
5
[Apr 06, 2003]
JohnJE
AudioPhile

Strength:

Seemingly well made, rack width, simple/handsome design, built-in phono, IEC jack (yes, upgrade the power cable and you'll be rewarded), lots of facilities, subwoofer output,thick PC board, minimal wiring within (very point-to-point). I'd love to know who developed this pre - they really know their stuff for the price.

Weakness:

No headphone jack, cheap RCA jacks (corners had to be cut somewhere!), no remote, ss and some tube amps quieter, nothing special switches and potentiometers, not quite as dynamic as many solid state, not quite as transparent as many hi-$$ ss and tube pre's. Price considering - nothing damning for me.

Had a Superphon pre for 14 years - wondered what I was missing in tube pre's. Bought a vintage PAS-3 - tho lacking alot, the midrange was alluring. Not wanting to spend much $$, I found the great reviews here at AudioReview to be convincing. Found SoundBug1 on ebay, bought a retubed B stock PAS-4 for $599.00 (Tel 12ax7's in phono and chrome knobs). Tell ya' what..I've heard many other tube units in past year or so and the PAS-4 is good enough to stand on its own against any I've heard. The Russian Sovvies are good..I upgraded to Russian Military Rocket 6H23. Clearer, smoother - a little less dynamic. The Sovtek 12ax7LPS are as good as any - save your money on pricey NOS tubes. Hook the rig up to good filtering (mine thru PS Audio PP300 and Ultimate Outlet)and upgraded cord (real benefits)and distance with megabuck units becomes quite small. Tho it's called a Tube preamp, buffering makes it more dynamic and less euphonic than all tube units. In reality, it's a hybrid unit rather than all tube. Makes it better to my ears. Put it on good stand/isolation, sorbothane or akin equipment points, give it air to breathe and your a happy dude with the music.

Similar Products Used:

Superphon Dual Mono (upgraded by Stan Warren), Conrad Johnson Sonographe SC22, Hafler Series 915, NAD 3020, Dynaco PAS-3. Can't not give it 5 for Value and 5 Overall.

OVERALL
RATING
5
VALUE
RATING
5
[Sep 19, 2002]
Vincent Chen
AudioPhile

Strength:

Affordable tube performance,Phono Stage included,dual direction tape dubbing.

Weakness:

Yes, no Headphone stage, but I have other gear that handles that hurdle, maybe I will get a tube Headphone amp too.Not the last word in refinement, but what do you want for a bargain pre anyway?!

Smoothness,finess, and good detail are what I like about this used Preamp I bought. I haven't changed tubes yet but soon to be done. Well currently I am using a Sony XA7ES CD player for the front end, Sonic Frontiers SFM-75 Tube Mono Blocks with KEF C80 speakers. I listen to a wide mix of music, except "RAP". This preamp even made my Rotel RMB-1095 sound more fluid without that hard edgy Transistor sound. My main focus was to build a Tube based system for less than $2000.00. Sure the Dyna is not perfect, I like the C.J. preamps better for detail, refined harmonics etc. but have you checked new C.J. prices lately? The Dyna Pas 4 then is a terrific bargain. I love it on female vocals, and Solo Acoustic Jazz Instruments best. I always wanted a Dyna kit to build, but missed out on that, so I guess this is the next best thing. I almost bought a Bottlehead Preamp kit. I hear they are great, but the lazy person in me made the Pas 4 the only choice. Musically satisfying, and affordable, and terrific way to take the edge off CD and Solid State. Try one out and see if it is right for you. It was for me. Highly Recommended BARGAIN.

Similar Products Used:

NAD,LUXMAN,Rotel,Harman Kardon,Sony ES

OVERALL
RATING
5
VALUE
RATING
4
[Apr 29, 2002]
cyclonicman
Audio Enthusiast

Strength:

Durable construction, quality components. very transparent, neutral, and dynamic. Value is well above price!!

Weakness:

No headphone jack and Standard power cable.

I purchased the Dynaco Pas4 because I wanted to approach analog sound with primarily a CD system. The Pas4 took a couple of days to break in. The sound was fantastic. It was clean, transparent, uncolored and neutral. It definitely softened the sound of my CDs as only tubes can. After about a year, I retubed it with Mullard 6dj8''''''''''''''''s and Telefunken 12ax7''''''''''''''''s. I would have to purchase a preamp in the 2,000 - 3,000 range to get the sound that I am now getting from the Pas4. The soundstage is huge. Its a shame that Panacor is no longer engineering Dynaco equipment. If you can get your hands on a Pas4, do it, you won''''''''''''''''t be sorry. The value is excellent for the money.

Similar Products Used:

Yamaha c1 preamp, Soundcraftman preamp

OVERALL
RATING
5
VALUE
RATING
5
[Feb 08, 2002]
Jondahl Davis
Casual Listener

Strength:

Imaging, soundstage is wide and deep, appearance, price, works well with cheaper Russian tubes (in my system) so you don''t have to pay $25 each for slightly used Telefunkens

Weakness:

Prone to hum pickup, crosstalk between tuner and CD inputs, runs very hot, case has a lot of screws that make tube rolling difficult unless you leave it off all the time

This preamp made a huge difference in my system and in my wallet. I plugged it into the power amp section of my NAD 3140 and immediately noticed a big upgrade in the soundstage. It seemed bot wider and deeper. It was so amazing, that I knew I''d have to upgrade the rest of my 20-year-old system. I had always wanted Dynaco equipment, but they folded just about the time I was putting together a system. It was good to see the Dyna logo again. I did have a lot of hum problems. I had to do a lot of cable swapping and moving. It seems prone to hum pickup. There is also crosstalk between the Tuner and CD inputs on my system. I have to turn off the satellite system when playing CDs. I swapped out the Chinese 12AX7''s from China with vintage three mica GE 5751''s. I may switch them back, because the GE tubes seem to roll off and soften the high end too much. I think that it was designed for Russian tubes and it sounds best in my system with a tube producing a brighter sound. The former Dynaco technician I bought it from says that the 6N1P tube is the best to replace the 6922, but I haven''t tried it. Those pull more current, and this unit runs very hot. The transformer gets hot enough to use as a hotplate. They used high quality components, but I''m hoping the heat doesn''t roast them. You could probably find a quieter preamp, but this has an excellent soundstage and a smooth sound. My 3140 preamp must have slowly deterorated over the years. I swear the imaging wasn''t that bad in the early days. This preamp deserves an audition if you''re looking for a tube unit. It''s about the cheapest way to get into good tube sound unless you go with the Antique Sound Lab equipment. This is a very modern design with an excellent appearance. It looks like the expensive units I couldn''t afford in the old days, much better than the old Dynas. My system: FR MC-201 moving coil NAD 533 turntable Dynaco PAS-4 ODL HT-2 amplifier Nakamichi CR-1A cassette deck Pioneer CLD-D604 laserdisc player (also plays CD''s) Infinity IL-40 speakers This system now sound so good that all I need is another CD source and I''m set until I''m too old to hear

Similar Products Used:

NAD 3140 Integrated Amp

OVERALL
RATING
4
VALUE
RATING
5
[Feb 06, 2000]
Robert Cudny
Audiophile

I removed PAS-4 from my system and let CD-player (Denon 1650) drove my amp (ARAGON 8008ST). Reprocuced sound was without a thin veil, more detailed. I could see deeper into the soundstage. I think, it is a good pre-amp for less demandig listeners. Recently, I've had a problem with the source selector knob. Customer service dept. was really helpful, and sent me replacement free of charge.

OVERALL
RATING
4
VALUE
RATING
4
Showing 1-10 of 23  

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