Phase Linear 4000 Series Autocorrelation Preamplifier - Restored

Description

WHO WE ARE
SkyFi Audio is a small startup business specializing in the purchase, reconditioning, and reselling of high end audio equipment. We only buy equipment that we admire and are passionate about. No mid-fi, no gimmicks, no junk.
Each piece of equipment is cosmetically restored and fully tested in our well-equipped lab by an engineer with 30+ years of experience in the HiFi world. If it does not meet or exceed the original manufactures specifications, it will not be sold. We are very selective about the equipment we purchase, focusing on mostly analog, high-build quality, American, and European built units.
Through our sister company, which is an authorized dealer for McIntosh, Audio Research, Sonus Faber, ClearAudio, Project, and Sony ES, we have access to OEM parts, service, and support.
----------
Stunningly beautiful preamp from Phase Linear, and a great match to our that's also listed for sale.
The 4000 Autocorrelation Preamplifier was a collaboration design by Bob Carver and Bill Skinner. It was designed to expand or decompress the sonics of recorded material. In audio parlance, it's called dynamic headroom. In the midst of all the knobs and toggles was the four channel balance joystick.
The 4000 had the capability of controlling up to six components: a tuner, two tape decks, two turntables and an auxiliary input. It had three switched and three unswitched AC plugs. The 4000 was manufactured from 1973 to 1977. It retailed for 0 but the price rose 10 % in 1977. It's still highly sought after today.
This example is in near perfect condition, with no signs of use or abuse. Working perfectly and there are also signs that this unit was previously and correctly restored. Such as Cardas RCA Jacks on all rear connections and select electrolytic capacitors replaced with Nichicon.
Our Testing Process for Preamplifiers at SkyFi:
We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage. Special attention is paid to the power supply which is the most common source of failure for preamps. We then power up the unit and run a simple 1k sine wave while monitoring the low voltage output on an oscilloscope for signs of distortion or noise to get a baseline.
At this point we will lubricate and clean all switches and potentiometers (that are not sealed) with a high quality contact cleaner, and then re-test all functions for any signs of noise or scratching.
Final testing involves putting actual music through the preamplifier We have learned over time that some issues are only noticeable to a trained ear while listening to a familiar source material. Our test bench has reference vintage Kef speakers that we are super familiar with which will quickly reveal any discrepancies. Some preamps will then move into the listening room where they will be tested with our in-house reference system.
Please
for detailed specifics regarding our specialized packing process that separates us from the rest.
Item
Included
Original Box
No
Manual
No
Remote
No
Cables
Yes - Power
Physical Condition
8
Working Condition
9
Slight channel level imbalance but easily compensated with center panel joystick. Some light scratchiness in some toggle switches.
----------
PURCHASING FROM SKYFI:
This item will be professionally packaged and insured for safe transit to your home unless you opt for local pickup from our shop. Please note that all local pickup items are only wrapped with industrial strength clear cling stretch wrap if the original manufacturer packaging is unavailable.
Local pickup is available in Glen Rock, NJ, just a half hour drive from Midtown Manhattan, with convenient parking near our building.
If we don’t have the original manufacture’s packaging, we use heavy duty double-ply corrugated boxes with custom made to your item Instapak expanding foam custom inserts. In many cases this has proven to be better than the original packaging! We also use high quality fiber reinforced tape to seal our packages. Lightweight items will be bubble wrapped and shipped in a high-quality box.
----------
PURCHASING GUIDELINES:
We do not accept or review any offers that do not go through the official eBay system. We have too many items for sale and it’s nearly impossible to keep track of offers outside of the official system. Please don’t message, email, or text any offers.
TRADE IN POLICY:
We accept trade-ins of equal or lesser value under certain conditions. Please visit our website to submit your gear for full consideration. We will only consider high-end equipment from mainstream manufacturers such as McIntosh, Mark Levinson, Audio Research, Krell, etc. and will typically pass on displays, projectors, receivers, dated surround processors, and mid-fi equipment of any type. We will offer a fair value for your equipment, but keep in mind we’re running a business and will need to be able to resell the equipment at a profit after investing a great deal of time and resources in testing, certifying, repairing, cleaning, and packaging the incoming equipment. If you’re looking for top dollar, we suggest selling direct on your own.
SELL US YOUR GEAR (Working or Broken):
We’ll also purchase your used or broken gear and arrange pickup if you’re in our local market. Simply visit our website to submit your gear for full consideration.
SCHEDULING AN APPOINTMENT:
We are currently operating from our shop inside our dedicated building in Glen Rock, NJ. You’re welcome to make an appointment if there’s a piece of equipment you’d like to see in operation before or after purchase. We have several well-equipped and dedicated listening areas, plus a dedicated listening studio with tons of equipment of all makes and models. We’re not a store, so please don’t make an appointment if you’re just curious as to how a speaker or piece of equipment sounds. In essence - no tire kickers please.
You can message us here on eBay with any questions or to schedule an appointment. We can also arrange to install, calibrate, and tune your newly purchased gear in your listening room if you’re local to our area. This is super useful when purchasing large speakers or heavy amplifiers. It’s also great for ensuring your new turntable is setup correctly in its final resting place.
eBay v1.2