Dynaco PAT-5 Stereo Preamplifier (1974 MSRP  $239 Kit, $399 Built)

Dyna's replacement for the venerable PAT-4, adding such niceties as a high-power switchable outlet, speaker selector and terminals, dual tape monitors, an external "processor loop" intended for EQs or other signal modifiers, and an op-amp high-level stage. The BI-FET term is a trademark of National Semiconductor for the JFET LF357H IC used in the PAT-5 BI-FET version. This replaced the NS LM301 opamp in the PAT-5 preamp in 1977, opening the door for numerous audiophile mods including the highly acclaimed Frank Van Alstine and Walt Jung upgrades.

Semiconductor complement: 13 transistors; 2 integrated circuits; 3 zener diodes; 4 diodes.

Dimensions: 13-1/2" x 4-1/4" by 11-3/4".

Power Consumption: 12 watts, 120V or 240V, 50/60 Hz AC.

Shipping Weight: 13 lbs. (5.9 kilos)

Designed by:

Wade Burns

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Image Credit: Starsky on eBay

McIntosh C-20 Stereo Compensator / Preamplifier (1959-1963)

Retail price $269.00 in 1959.

"Simplicity, flexibility, and beauty have been integrated by careful engineering and design in the McIntosh C-20 Stereo Compensator. The greatest listening pleasure in stereo or monophonic reproduction is assured as a result of over a year of careful and diligent research in hte requirements of a new preamplifier designed for stereo. Full stereo flexibility has been provided plus built in protection for your investment in monophonic records. McIntosh has designed in the C-20 Stereo Compensator the necessary features required to give the finest monophonic reproduction the keenest listener may require. Complete satisfaction is yours in monophonic and stereophonic with the McIntosh C-20 Stereo Compensator."

For Sale:   This Mcintosh C-20 is currently for sale on eBay via seller Starsky. Get your bids in now, auction ends April 23, 2014.

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All images Credit: eBay Seller "Starsky10"

Mcintosh C28 Preamplifier  (1970-1978)

The McIntosh C28 is a high quality stereo pre-amplifier made in from the early to late 1970's  Each channel of the C28 consists of four parts, a low level amplifier, high level amplifier, active filters and headphone amplifier.

Specs:

Response 20-20kHz (+0 -0.5dB). Distortion 0.1%. Noise and hum -90dB aux, -78dB phono

Size 5-7/16"H, 16"W and 13"D behind panel. Weight 25 lb. Sold from 1970-1978. Last retail price $649.00

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All images Credit: eBay Seller "Starsky10"

 Dynaco / Dyna-Kit PAS 3X Tube Preamplifier

Designed by Ed Laurent and introduced by Dynaco in 1966, the PAS series of stereo amplifiers are renowned by audio enthusiasts the world over.

As with many Dyanco produts, the preamplifier was sold under the Dyna-Kit name for $69.95 as a build it yourself kit.  There was also an option to buy it fully assembled for $89.95.

Check the back panel of your PAS preamplifier - if the speaker binding posts and RCA jacks are attached with screws, then it was originally built as a kit.  If there are rivets, you have a factory wired unit.

More specs and pictures after the break.

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Mcintosh C26 Preamplifier (1967, $449 original MSRP)

In 1967, I began design of the C26 preamp. It replaced the C24. This was the first preamplifier to have an all glass front panel, which matched the new MC 2505 power amplifier. It was assigned a project number of P 216. The requirements had already been determined by Gordon Gow, based on his marketing research.  Some of the circuitry was already being used in the MAC 1700 receiver, but I revised several features and added several new ones.

Response: +0 -0.5 dB 20 to 20,000Hz
Distortion: less than 0.1%
Input sensitivity: 2.0mV phono. 0.25V aux, tape and tuner

Panloc mounting
Front panel: glass, gold/teal, illuminated
Size: 5-7/16” high, 16” wide and 13” deep
Weight: 18 lb.
Sold from 1968 to 1977
Last retail price: $449.00

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Harman Kardon Citation I Preamplifier

The Harman Kardon Citation 1 preamplifier does not adhere to conventional circuitry and incorporate many advanced engineering innovations normally available only in the highest quality studio equipment. The unit consists of a group of circuit blocks called active and passive networks. Active network are those which incorporate vacuum tubes and furnish amplification. Passive networks consist of resistors and condensers exclusively and do not amplify. An effort was made to carefully seperate thes circuit blocks in this preamplifier

Specifications :
Frequency Response at 1W...............(+0dB, –3dB) : 5Hz - 80kHz
Distortion (Stereo).............................<.05% at 2 volts
Hum and Noise.................................High Level Input: 85dB below rated output /
..................................Low Level Input: less than 1.5 microvolts referred to input terminals
Output Level.....................................Main Outputs: 2 volts / Tape Outputs: 0.3 volts
Input Sensitivity Line (high)................0.2 volts
Input Sensitivity Line (low)..................Phono RIAA: 2.5mV / Tape: 2mV / Ceramic Phono: 0.1 volts
Filter................................................Low Frequency: FLAT; 15Hz subsonic filter; 75Hz rumble filter
Finish..............................................Charcoal Brown and Gold
Cabinet Finish..................................Hansome Walnut Enclosure
Dimensions(w x d x h)......................41.5 x 32.5 x 20 cm
Weight............................................15 kg

Download the original owners manual here:

Harman Kardon Citation I Owner's Manual.

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[Image Credit:  eBay Seller 'Starsky'. Visit Starsky's eBay Store to see his current vintage audio auctions]

Fairchild 245 Mono tube preamplifier (1955-1959)

In 1955 the Fairchild 245 mono preamp was released and remained in production until 1959. It was the most advanced, expensive, and sonically accurate preamplifier available during the pinnacle of the golden era of audio.

The circuit of the 245 has several distinguishing features which lend to its tremendous performance. The high-level inputs go through the first half of the dual volume control and the tone controls without any amplifying circuit intervening. The main portion of the preamp is a two-stage amplifier with overall negative feedback to provide a low output impedance and low distortion. One half of the dual volume control is at the input to this amplifier, and the other half is in the feedback loop. As a result, it is impossible to overload the preamplifier with strong signals; and, in fact, the increased negative feedback at low gain settings, as compared to maximum gain settings, slightly reduces distortion.

Typical Tube compliment:

Two ECC83/12ax7 (2x Mullard, 2x Amperex) Tubes Four Amperex Ef86/6267 Tubes Two 6x4 (1x Mullard, 1x Tung-Sol)

image credit: Chris Fuller

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Dynaco PAS Series Tube Preamplifier (PAS / PAS2 / PAS3 / PAS3x

The Dyanco PAS-3X stereo preamplifier is a two channel control center which permits either monophonic or stereophonic reproduction from any program source, with any modern amplifier.

This preamplifier design is most renowned for it's low noise and distortion, and it provides striking simplicity of operation while retaining full flexibility for the enthusiasts subtle adjustments.

Specifications

Inputs: 3 stereo low level, RIAA phono, NAB tape head, special, 4 stereo high level

Distortion: less than 0.05%

Frequency response: 10Hz to 40kHz

Gain: 60dB (phono, tape), 20dB (line)

Tubes: 12AX7 (ECC-83), 12X4

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Marantz 3200 Preamplifier (1973-1976  $219.95 RRP)

Controls:

Selector: Phono 2, Phono 1, Tuner, Aux, Tape 1, Tape 2.
Tone Mode: Out, In, 250Hz, 4kHz, 250Hz/4kHzclassicaudio.com
Bass: (Slider)
Mid: (Slider)
Treble:(Slider)classicaudio.com
Mode: Left, Right, Stereo, Reverse, Mono L+R
Volume
Balance: Slider

Switches:

Hi Filter
Monitor: 1/2classicaudio.com
Monitor: Source/Tape
Loudness
Spkr Mainclassicaudio.com
Spkr Remote
Power

Shipping Weight 25 lbs.

 

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