Good bottem end, strong midrange, smooth top end, great price.
good phono section.

Cheap and/or wrong tubes installed.

When I first received this PAS4 preamp I wasn't too happy with it.It was extremely harsh and shrill at the top end. I was just about ready to send it back to J&R audio
but decide to see what the guys at Arizona Tube Audio had to say about it. Dan at AZ Tube Audio recommended to retube first before sending it back. Opened it up and I was impressed with the build quality and the components used except with the tubes. They had some unknown and uncross referencable (6h23) Russian tubes in it. Dan recommended Ei 6dj8's and Sovtek 12ax7wxt+ Premium Selected tubes. What a difference, night and day, now warm and smooth on the top end, more so than the Hafler it replaced. Now I'm very happy with my PAS4 and wouldn't think to upgrade any time in the near future. The rest of my system is as follows:

Amp: Quicksilver GLA updated with KT88 power tubes
Interconnects: preamp to amp Nordost Black Knight
the rest are Monster Cable Reference II's
Phono: Sumiko Pro-ject 6.1 w/Grado Gold cartridge sitting on a Bright Star Audio Big Rock II w/ ceramic cone feet
CD: AMC CD9 w/AMC DAC8 and Wire World digital cable.
Speakers: Polk Audio RT1000P w/monster cables
My next upgrades will be Polk Audio RT2000P speakers and MIT MH-750 (tube termination) speaker cables which will be hopefully soon.

Similar Products Used:

Hafler 915 pure class A solid state preamp.

The Dynaco PAS-4 is turly one of the best kept secrets in the audio world. With reviewers spewing garbage like one cannot buy a decent line stage for under 2K, this product answers with a resounding Bulls**it! If you are considering a Conrad Johnson, Adcom, or somthing of that bend, buy one of these and save your money. The performance out of the box is very good, but a DRAMATIC increase in performance can be obtained by installing NOS tubes in place of the stock russian tubes. I installed NOS 7dj8's in the line stage (mullards), 6922's in the phono (amperex), and a pair of 50's vintage RAC black plates in the phono section. The results are stunning. There is a lot of overpriced crap out there that does not sound half this good. Get one while you can!

Great sounding full-function tube preamp. It really adds a touch of warmth to the solid-state power amp I have it paired with. The phono section is pretty good, but not enough gain for low output moving-coil cartridges. Not as quiet as the solid-state preamp it's replacing (tube hiss),but the trade off is worth it for the way it tames the upper end of my system. Build quality first rate, much better than you would expect for budget tube gear, though you wouldn't mistake it for an AR. After about a month of listening I put my Adcom preamp back in for comparison. What a difference! Out came the Adcom, back went the Dynaco. Highly recommended match for a lot of the decent solid-state power amps out there, makes them sound more like music and less like electronics.

The Dynaco PAS-4 has to rank as one of the best buys in audio, available from J & R Music World in New York City for $ 500.00! I got mine in April of 1997 when I retired my trusty Carver C-4000. The PAS-4 simply blew it away sonically. It upgraded the sound quality of my system so much I was kicking myself for not getting it sooner! Stone cold, out of the box and without break-in, it sounded terrific, after break-in, it was even better.The sound is smooth and natural, with only a bit of tube hiss audible when I put my ear close to my speaker's tweeter, it is completely inaudible under all listening conditions. While I can't vouch for the phono section's sound since I use an outboard phono pre-amp for my low output moving coil cartridge, this pre-amp sounds fine playing LPs, CDs, cassettes or FM. It also seems to be a great match for my solid state amplifier, an Acurus A100.
As the other PAS-4 owners who submitted reviews have said, build quality is very good for a pre-amp in the $ 1,000.00 or less category. While it doesn't sound quite as good as some of the great tube pre-amps from Audio Research, VTL and the like, it's amazing how much of that sound the PAS-4 has. This is one "budget" component that does not have to make any apologies!
Because of it's excellent sound per dollar value, I give it a solid 5 rating!

No remote

I wanted a vacuum tube preamplifier and after some research, decided that the Dynaco PAS4 provides the most bang-for-the-buck. This is truly an audiophile type preamp..no tone controls and no remote. Hoever, it does have 2 tape monitors, a phono stage, a 2nd set of outputs and a processor loop. It's solidly built and quiet. I may try replacing the tubes with better ones in the future. All in all, I'm extremely pleased with the performance. It's currently connected to a solid state Parasound amp.