to be perfectly honest I’m very happy with my system but I‘ve decided to put my trusty pre amp up for sale and scour the options out there.
It’s no spring chicken, first on sale early 1990’s, but it can easily hold its own against the new tin machines with their DACs, streamers and headphone sockets. It’s a versatile pre amp with enough inputs to be the hub of any system. My own concerns about an amp of this age would be capacitors but… CJ used plastic film capacitors and not the electrolytic capacitors which are prone to drying out. Most Conrad-Johnson amps are tube based and for a solid state amp it has a definite tube like warm/musical sound.
I’m told the phono stage is better than average but I tend to use low output MC cartridges and an external phono stage. I expect with a high output MM or MC, it should be fine. It has tape-out for a headphone amp. The balance adjustment knob has been bypassed because such things are sinful in the ears of the Lord.
Basically as a pre amp it disappears… no colouration to the sound but the soundstage has a bit more air, instruments more space but it really imposes nothing. If you feed it a poor digital source, DAC or CD, it will give that back to you unpolished but… if you give it quality it will match it to reveal detail and warmth.
Condition seems to be near 10/10 with no visible scratches, a service label on the top which can be easily removed but… when I take it out of its shelf I may see something but certainly nothing obvious on a rack. This is literally in everyday use and will be used again tomorrow!
The unit was bought from Cloney Audio, is silver and has a captive mains lead.
I’d be looking for offers near €750 - based on an average of internet prices.
“The PF1 was the first solid state preamp bearing the Conrad-Johnson name. More than one decade of research and development led to the introduction of PF1. The circuit design featured a unique distortion cancelling circuit that resulted in excellent linearity without resorting to global negative feedback. Independent discrete dc power supply regulators are used for each gain stage for absolute insolation between stages. Parts quality are to Conrad-Johnson’s usual high standards. All capacitors, including power supply, are polypropylene and cjd polystyrene. There are no electrolytic capacitors in the PF1. All resistors are 1% metal-oxide deposited on glass construction resulting in very low noise. The PF1 nicely combined the lucidity and harmonic balance of CJ vacuum tube preamps with the superb definition and detail of transistor designs.”
https://www.stereophile.com/content/con ... eamplifier
Inputs/Outputs
•phono
•tuner
•auxiliary
•monitor and recording facilities for two tape decks with dubbing from Tape 1 to Tape 2
•Two power amplifier (main) outputs
Controls:
•selector
•tape 1/source/tape 2
•mode (left/right/stereo/rev/mono)
•balance
•volume
Specifications:
•Gain: Phono Stage 40 dB (phono overload 100 mV at 1kHz)
•Line Stage 21 dB
•Distortion: less than .1% THD or IMD
•Response: bandpass 2Hz to more than 75kHz
•RIAA Equalization: +/- .25 dB (20 to 20 kHz)
•S/N Ratio: Phono Stage 80 dB below 10 mv input
•Line Stage 94 dB below 2.5 volt output
•Phase: Phono Stage is phase correct, Line Stage is phase inverting
Mechanical:
19” x 3″ x 12″
The first pic is the unit itself.. more of the actual unit will be added when it's out of the shelf.
Other pics are from the 'net
- CJ Pre (1594 x 411).jpg (27.82 KiB) Viewed 491 times
- conrad-johnson-pf-1-preamp-back.jpg (179.42 KiB) Viewed 491 times
- conrad-johnson-pf-1-circuits.jpg (147.84 KiB) Viewed 484 times