Dynaco PAT-5 Preamplifier

Pat-5 Bi-FET from eBay auction #404977011

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Description:

Specifications:

Frequency Response:

High level inputs: ±1 dB from 10 Hz to 50 KHz.
Low level inputs: 0.5 dB of RIAA curve.

Distortion at 2 volts output into 10,000 ohms in parallel with 1000pF:

THD: 0.007% or less, 20 Hz to 20 KHz.
IM: 0.007% or less with any combination of frequencies.

Hum and Noise:

Magnetic Phono: 70 dB below a 10 mV input, at 1000 Hz.
High level: 90 dB below a 0.5 volt input.

Gain:

Magnetic Phono (LO) to Audio Out: 57 dB at 1 KHz.
Magnetic Phono (HI) to Audio Out: 63 dB at 1 KHz.
Magnetic Phono (LO) to Tape Out/E.P.L. Out: 37 dB at 1 KHz.
Magnetic Phono (HI) to Tape Out/E.P.L. Out: 43 dB at 1 KHz.
High Level to Audio Out: 20 dB.
High Level to Tape Out/E.P.L. Out: unity.

Phono Input Acceptance:

LO: Greater than 115 millivolts at 1 KHz.
HI: Greater 45 millivolts at 1 KHz.

Tone Controls:

Bass: ±16 dB at 50 Hz.
Treble: ±12 dB at 10 KHz.

Filters:

Low: -4 dB at 10 Hz; 6 dB per octave. (Conforms to newly revised RIAA phono playback curve)
High: -10 dB at 10 KHz; 15 dB per octave.

Voltage Output:

10 volts into 10,000 ohms or greater.
4.5 volts minimum into 1000 ohms.

Impedances:

Magnetic Phono: 47,000 ohms in parallel with 220 pF.
High level: 50,000 ohms
Tape Output:
From phono inputs, 15,000 ohms or greater may be connected.
From high level inputs, same as source.
Audio Output: less than 600 ohms

Separation at 2 volts output into 10,000 ohms; undriven input terminated in 5K:

20 Hz: 70 dB minimum.
2 KHz: 70 dB minimum.
20 KHz: 45 dB minimum.

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

Year Introduced:

1974

Price:

$239.00 kit
$399.00 assembled

Comments:

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.

Thanks to Rich Hollis for info regarding the LF357H.



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