- Vintage 1975 Dynaco PAT4 Solid State Stereo Preamplifier - Ultimate Rebuild - Sounds Stunning -
This preamp will readily compete with any preamp in the $3-5,000.00 price range.
Sporting its original chassis, faceplate and cover this PAT4 is deceptive because it looks bone stock. Turn it on and the magic shows up. Listeners will be amazed, doubters will be convinced and marvel at the sound quality of this Vintage Dynaco Preamp. Only if you show them the "under the hood" goodies making this unit a true "sleeper", will they understand.
The New Alps "Blue" sealed volume control is stepped, has a loudness tap and is simply a better, more accurate attenuator than the original.
A brand new balance control, reliable, accurate, clean & quiet operation
Original bass and treble pots were tested, cleaned, lubricated and treated with Deoxit and work beautifully
All original rocker switches were removed, cleaned, lubricated and treated with Deoxit.
The entire switch panel was reworked with new Panasonic film caps, Vishay and Takman 1% resistors and all new wiring.
A new original neon type "orange glow" bulb with a new resistor was installed in the original power switch, cleaned, lubricated and treated with Deoxit
The new selector switch is part of a comprehensive upgrade that includes relay controlled signal switching. The wires seen running from this selector carry only low voltage signals to control the relays. No audio signal is running all over the interior being subject to interference. Ultra quiet - no clicks, pops or thumps - looks nice and neat too - There's even 6 LED's to identify the active source selection.
The rear input panel upgrade has gold plated RCA jacks and now features 5 high level inputs for any high level source like a tape deck, CD player, tuner etc. There is a single low level phono input set up for moving magnet (MM) type cartridges / turntables - The ceramic and high level phono functions are intentionally eliminated in this design .
The tape loop / tape monitor functions are still active and work just like the original design.
The power transformer is a toroidal type and operates considerably quieter than the original did while also providing smoother more stable power.
The new flush mount fuse holder replaces the old "protruding" type which get broken so easily, the black power cord is original to the unit and is very nice
The multi section filter capacitor was replaced with a solid state regulated type that is light years ahead of the old design, it is much quieter, stable and more reliable
The high filter switch upgrade converts it to a single function now which turns the tone controls on or off, a great feature for the "purist" listener - In the OFF position, the tone controls are disabled. In the "15" position, tone controls maintain their normal function.
The circuit boards are new and feature high grade film capacitors and 1% metal film resistors. A low noise Darlington transistor is used at Q4 for a ten fold reduction in distortion compared to the standard bipolar transistor in the original design . These boards are incredibly accurate and make a super clean signal. This preamp is so quiet you'll think it's turned off between tracks. The stereo separation and detail is amazing. These circuit boards are superb and they're quite superior to the originals offering lower noise, lower distortion, a quieter, and a more accurate phono preamp set up only for a moving magnet (MM) cartridge. There's a much higher overload capability now in the phono preamp, with a built-in ultra-low frequency filter in the phono section, built in de-click resistors. These upgrade boards provide better linearity, lower noise, and more accurate channel-to-channel matching than ever possible before. Power-up/power-down transient suppression relays and time delays are built in to avoid noises commonly associated with power up/down. Each board also has an LED to indicate the board is powered and functioning.
The AC accessory sockets were eliminated to further reduce interference.
Four new rubber feet with steel bushings were installed on the bottom.
The chassis is very nice and this unit plays and sounds just incredible.
This preamp will work perfectly with the Dynaco Tube and Solid State Amplifiers like the ST-70, ST-35, ST-120, Stereo 400 & 410 MKII, MKIII, MKIV and MKVI - it will also work with most any brand like Hafler, Fisher, Marantz, Sansui, Yamaha, Pioneer, Kenwood, McIntosh and others.
About 40 hours went into building this PAT4 plus the cost of all the new parts and also the initial cost of the unit itself - was it worth it? You tell me....
A great addition to any vintage or modern stereo system or collection
Nothing else in the photos is included unless specifically stated. Sale is for the PAT4 preamplifier only.
As with all vintage electronics I sell, there is no warranty or guarantee
Guaranteed not to arrive damaged or DOA
Professionally packed / ships insured / signature required
No PO Box delivery, sorry.
Sale is final, no returns, unit will arrive as described, no warranty is offered or implied.
Shipped insured for full value with UPS - signature required*
Professionally packed and Promptly Shipped
No P.O. Box delivery
*All insured shipments require a signature at time of delivery.