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

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

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.

inexpensive,utilitarian simplicity.sounds great. will add musicality to solid state "rockbox" amplifiers.

no balanced outputs. Mundane appearance to
bells and whistle lovers.

while most people are running around trying
to figure out how many speakers dolby wants
them to have in their "theatre" A few of us
got one of these gems at rummage sale prices
from gotham's big outfit. Pull out the mystery tubes and take the advice that Arizona Tube gave one of us lucky reviewers;
ei's in the line section or phillips and
sovtek 12ax7lps's in the phono section. Wow
Hello analog Andy goodbye digital Dan. Great
sound period. I don't need to say anything.
this preamp got a 4.83 for a VERY good reason. If you can find one you will love it
just like almost any valve amp or pre-amp.
Tube it properly and you cannot lose.

Similar Products Used:

sunfire classic vaccuum tube preamp and onkyo p304 integra preamp.

Excellent parts/materials selection, Wonderful product build quality, 4xRCA Connections for an external Processor Loop (dBx, Equalizer, etc.)Dual Outputs for Sub-Woofer of Biamp. A truly refreshing 'un-commercial' product. Vacuum Tubes are alive and well, thanks to product like these.

No Headphone Jack.

I understand that this PAS-4 model went out of production along with the ST-80 and ST-160 in late 1999. My new PAS-4 arrived safely, the packing was very good and the Owners Manual even has the schematic, plus lots of very helful and subtle hints concerning several unexpected features. How a simple turn of a switch overcomes impedance loading issues from connecting Low-Impedance Tape Decks of less than 2000 Ohms (quite rare indeed.) Coming from a long dynasty of previous classic designs, the PAS-4 is no sleeper. The unit powers up nicely with a red LED indicating that the unit is warming-up and the tubes are stabilizing. After the PAS-4 properly warms-up the Vacuum Tubes, it's ready to play by automatically turning the LED to Green. The Line Stage is very, very quiet and appears to sound quite linear and neutral. My Denon CD DCM-370 HDCD player sounded clear and un-colored, when using HDCD encoded disks, it gave some outstanding sound through the PAS-4 and my Stereo 2A3 amplifier, Lowther PM6C Speakers. The Phono stage is very neutral, tested with Linn LP-12/Akito/K18-II cartridge. The total abscence of tone controls makes this the ideal unit for checking the quality of source material, not to mention it's true mission as a "first-rate" Tape Recording line stage and CD ripping pure analog audio source. This in not a preamp for the masses, but I can definetly say that anyone can enjoy the sound quality of this wonderful component for under $500 dollars right now until all remaining units are sold out. All controls work very smoothly. The preamplifier has lots of voltage gain which accomodates most amplifiers with input impedances of more than 50K with little loss of signal. Overall I would rate this the best single component acquisition that I have made in the last 20 years. And judging from the quality of manufacture, this is the preamplifier that can serve as the centerpiece for a very musical system. Highly recommended but not for the average tone control maximizer, it conveniently has none, you get to hear what your system is really doing as a whole. It speaks the musical truth about what your sources are doing and how your room acoustics are interacting. The unit has a very low noise floor and the dynamics are absolutely impressive. I would buy another one next week just to keep it in NIB for a future Ebay posting several years from now. This is a real thoroughbred Dynaco, the latest creation from a long Dynaco heritage of great sound at truly reasonable prices. Get a PAS-4 while they are still available on ebay or various Internet Audio Web Stores. I understand that there are no current plans for a PAS-5.

Similar Products Used:

Harman Kardon Citation 1, McIntosh C-28, McIntosh C-20, Dynaco PAS-2/PAS-3, ADCOM GTP-400.

price, sound, budget, quality, tubes,
looks, name, warmth, softness, has two outputs: great for sub-woofers

lacks tone controls and headphone jack

I have a Series II Pas 4 pre-amp, which is the new Panor Corp. version of the old Dynaco classic. It is black with white letters proclaiming it a vacuum tube pre-amplifier; which is nice because it does not look old. I bought it five years ago for $500 to soften out the my Cds and Klipsch Cornwalls. It is matched to a 60 pound monster, Class A Pioneer M-22, 30 watts per side, dual mono amp with THD .005% at 1 watt into 8 ohms.

The pre-amp soften the mid-range, reduced the ring and shatter of the CDs and warmed up female vocals. I don't use any of the features, except to switch it from video to CD input. The volume knob is a type B potentomter, which means that is closes reflects the amount of power that your amplifier is actually using. This means that at 7:00 on the dial, I get almost no sound, but at 8:00 on the dial, I have too much sound. I rarely (when the wife is out of house) play Sting, Springstein or even Billy Idol above 10 or 11:00 on the dial.

The sound does seem to warm up after 1/2 to an hour, but the old tubes start to crackle a bit after several hours of use.

I switched from a NAD 1020 pre-amp. I had tubed pre-amp before - if the sounds wasn't so scratchy back then (15 years ago) I never would have switched.

The popularity of powerful solid state sub woofers to fill in the bottom end of music frees up the mid and high range for warm and wonderful sounding speaker and amplifier combinations.

I have no complaints at all from this solid little performer. In fact, it will be several major upgrades on my all the other parts of my dream system before this unit - with only two obvious flaws is replaced. There are no tone controls - it would be nice to turn down the treble on older analogue CDs and there is no headphone jack. And even then I will have to be a whole lot richer. My next move is to try tubes amps again for the speaker power…

Similar Products Used:

NAD 1020, tubed recievers 20 years ago

Great build quality; nice looking; deep soundstage; excellent dynamics. This pre-amp will actually 'open-up' a system.

The Sovtek replacement tubes for the Chinese are a bit edgy.
My unit has the chrome knob and the chrome is a bit thin.

I auditioned this guy with my Edge Audio speakers, DH Labs silver streak wire and a cheap, AIWA portable CD player. The result was astonishing. The speakers melted away and the sound just blossomed forth. I was really shocked that the pre-amp could make a system really shine. I do audition with Mapleshade recordings so I can rely on a particulary, decent source.

I did swap the 12AX7as with NOS, mil-spec NOS and Mullards and liked the increase in 'smoothnes' that they provided. I finally went with the Mullards as my final choice.

I then hooked it into my 'better' system (good, better, best):

Madisound Odin Speakers
Thorens TD-145C TT with Ortofon cart.
Kimber 4TC speaker cable
Acoustech Phono pre-amp
ATI 1502 Amp
AKAI GD252 Cassette
ZuCable Oxyfuel and XLO Reference ICs

The result: the bass was actually earth-shattering. The FSV of the Madisounds is 22Hz, but I've never heard it delivered in such a forceful manner. I actually jumped when the cartridge hit a scratch that had contained, low frequency sounds. Pretty amazing stuff.

I've tried many pre-amps in the past five years and this one ranks with the best of them. I would have to rate is as
'system enhancing' a unit as the AI Mod 3a, a step above the others I've listed and none of those are slouches, trust me.


In summary, if you see this product, which is no longer in production, give it serious consideration. It may just be the product you stick with.

Similar Products Used:

Dynaco PAS-3, Dynaco PAT-5, Sonic Frontiers SFL-1, Audible Illusions Mod 3A

Build quality - clarity - definition - very natural sound

no tone controls - not really needed

Very natural sounding - upgraded tubes important as mentioned in other reviews - perfect for my Klipschorns - My Outlaw 1050 receiver is very very good but feeding signal through this preamp is slightly but significantly better. Particularily noticable in violins which sound more natural and warmer than the slightly "metalic" transistor sound. Adds an etherial quality that makes you feel that, especially in the dark, that you are at a live performance. Between this addition and the Perceptual Technologies DAC, upsampling, jitter correction and bit conversion (from 16 to 24 bits) devices, I feel I have all the advantages of an LP sound with all the advantages of CDs and with none of the disadvantages of either! Now all I need is the PTech software for speaker and room frequecy/impedance correction and high definition video. Through purchase of internet only companies, ebay auctions, net price searches and help from sites like this, I have been able to put together a breath-taking system at a reasonable cost (under $10,000.)

Dynaco PAS-4 Tube Pre-amp
Outlaw 1050 6.1 Receiver
Klipschorns with new upgraded ALK crosssovers for music
4 Klipsch LaScalas for center, surround and rear
2 Klipsch LF-10 subs for movie LFEs
Klipsch KSW-15 for LFE "punch"
MSB DDS6000 Digital Director (switching and added jitter reduction)
3 SONY CX 400 CD changers
Nivis Slink-e computer interface (programs and controls changers thru computer connected to internet for cd content and album cover downloads)
Perpetual Technologies P1A Correction Engine
Perpetual Technologies P3A DAC
SONY 798 HF VCR
SONY S530D DVD player
SONY XA1ES CD player
Panasonic Monitor (for component DVD output & CD covers from computer)
Phillips Pronto Programable remote
Radio Shack wireless remote control extender (components in seperate room)

Beautiful, sonorous, and solid tube pre-amp at discount-store price.

Some of the usual tube issues.

I purchased the Pas-4 to replace an Onkyo pre-amp that had developed a switch problem. I nearly went with a feature laden "surround-sound" device, but as a musician, I decided that sound accurracy was more important to me, and that if I wanted to go the cutting edge high-tech route I would build a separate, dedicated muti-media system. Out of the box I was blown away by the Pas-4's performance immediately! In back-to-back comparisons with the Onkyo, the Pas-4's performance opened a door to a sonic clarity that I had heard only in high-end showroom displays or at CES. With the Onkyo I had to use the tone controls to make it "sound good." Now the Pas-4 now allows my system to reproduce sound very accurately and naturally. I love it. The quality of the board and the components is first class, almost unbelievable at the price.
I reccommend this product to anyone concerned with audiophile quality and sound at a reasonable price. There are no "bells and whistles," but that is the sound I'm after.
I plan to upgrade the original tubes soon, as they tend to "sing" if not warmed up properly. I can't reccommend this component enough. I am using it with a Crest Audio FA-800 400wpc amp, Polk SDA 2 speakers (which are great with the nasty "holographic sound" Interconnect Cable DIS-connected), a Sony CD player, a Technic SL-10 turntable, and Monster Cable 400 MK II's all-around.

Similar Products Used:

Vacuum-tube guitar and bass amps ('59 Fender Bassman).

The Dynaco Pas 4 preamplifier is a full function tubed unit whichincludes a phono stage. The construction quality of the Pas 4 is
certainly superior to that of other budget tube products from Van
Alstine, Lazarus, and Sound Valves. The sound is less euphonic and
more accurate than my old Lazarus Classic. The Dynaco is able to
offer the detail of solid state without the treble hardness associated
with most budget gear. The "fit and finish" of the Pas 4 is stunning
for the price. The price? The Pas 4 is a bargin at $995, at the
current selling price of under $500, it deserves more than 5 stars!!
You would have to spend $995 for the Musical Design SP2b (without Phono)
to find a better sounding preamplifier.

What a great preamp for $500.00 , it blew away my Carver PSC-50 ! It has a nice smooth uncolored sound and built like a tank . I like the two preamp outputs which comes in handy for using a subwoofer. I use it with my old Carver TFM-35 power amp a pair of JBL 4312`S and a Rega Planet C.D. player.