RCA Cogent Forum Products Mill System
Vintage Audio Classics   

 

Vintage Audio Classics is the place where you can take a look at, and purchase, some of the finest audio components ever made. Most of the items here were fully professional components, never intended for home use, and built to last in a way we no longer encounter. Nothing is shown here which is not significant from a sonic and or aesthetic perspective. All items come with an appropriate guarantee or warranty- there are no items sold as Vintage Audio Classics which have not been fully serviced, tested, and guaranteed as properly functioning. Many of these pieces were made before the stereo era, and if only a single unit is being offered, please do not inquire if we have a stereo pair- if two exist, this will be indicated in both the text and pictures. Click on photo to enlarge.

All prices by inquiry only.

In an era which has seen obscene heights reached in the market for contemporary art, classic automobiles, and other collectables, the one area which seems to have remained in the underground is that of classic audio.

 

COGENT

Although not vintage per se, Cogent field coil loudspeaker mechanisms were inspired by the best: the RCA MI 1428B.

OMA has a very limited quantity of brand new Cogent DS 1428 field coil compression drivers for sale. These are the finest sounding drivers for the critical midrange ever made, bar none. On the right horn, usable frequency response from 250hz to 10khz. Incredible build quality, essentially hand made, but with aerospace machining. A step beyond the RCA MI1428B in every regard. OMA can design horns and entire systems around this driver. Inquire for price.

 

 

JBL 537-500 exponential horn and lens, as found in the legendary Westrex monitor system. Shown with the original bubble back JBL 375, whose original tag has fallen off due to the age of the glue, but is shown and of course is included with the driver. The other drivers in this system, recovered from a mono studio enclosure, include the JBL 150-4c woofer (also shown and for sale) and the crossover network. Dimensions are 13.5 inches diameter, 17 inches approx. length, 2 inch throat. The 375 and the 150-4C can be purchased individually or as a group with the horn and the crossover. Near mint condition, Extremely rare. Remarkable sound quality for such a short horn- the lens does indeed work.

JBL 150-4C Extremely rare woofer as found in the monitor system being shown here, as well as the Heartsfield, etc. In near mint condition. Working perfectly.

 

 

 

 
A single Vitavox DU 120 12 inch coaxial speaker with separate tweeter in absolutely pristine condition. Complete with adjustable attenuator network for the tweeter, as shown in the photos. Superb construction, rare.

 

Shure SE-1 Tube Phonostage Very rare Shure Brothers tube phonostage and microphone preamplifier, using the ECC83/12AX7. Separate power supply chassis. Unit is serviced and in excellent working condition. UTC output transformers.

 

SOLD

 

 

One pair of RCA MI-9472-A autoformers. These were used to match impedances for RCA loudspeaker systems in the 1950, allowing 600 ohm speaker lines from the projection booth, for example, to be converted to speaker level impedances, such as 8 and 16 ohms. These extremely high quality autoformers may be the finest sounding examples ever made. We use them at the Mill to attenuate compression drivers, as well as myriad other tasks.

 
Fidelity Research MC201 low output (.12mV peak at 3.54 cm/sec/1kHz, .16mV r.m.s. at 5cm/sec/1kHz) moving coil cartridge, rebuilt by Soundsmith with a ruby cantilever and fine line contact stylus. Tracking force approx. 1.5-2 grams, load impedance of 10 ohms, thus requiring a correct step up transformer. Original Ikeda design, an early moving coil classic, rebuilt as new with a better cantilever than the original, but same stylus profile. Approx. 7.5 grams weight, should be mated to an appropriately medium to high mass arm, though I tried it briefly on the Schröder Reference, which worked well. Will give most of today's high end carts a run for the money.

 
I did an experiment in the last year, acquiring three identical early Ortofon S-15T moving coil cartridges, and having two retipped by Soundsmith, one with a modern ruby cantilever and fine line contact stylus, and one with a conical stylus on the original Ortofon aluminum cantilever. The third unit retained its original elliptical stylus and aluminum cantilever, as it was in pristine condition. As the S-15 T was so named because it had a built in Jorgen Scheu step up transformer in the cartridge itself (which is why the cartridge is so long) like the earlier SPU, I felt it made an ideal candidate to see how the different stylus profiles and cantilevers effect the sound. I am selling all three units now, which compare to the much more well known SPU from Ortofon. The built in step up transformer is a blessing for those who don't want to try to match an external SUT to a moving coil cartridge- Ortofon has already done it, and the JS trannies cost $1000 or more as external units. The compliance on the original stylus units is 20 dyne, and the ruby should be in the same region. Tracking force is considerably less than for the SPU even though the cartridge is heavy- I tried these at about 1.75 gms. Output is considerable at 10mV. Remember, this and the SPU T are the only moving coil cartridges that do not need either an SUT or a head amp. A real classic, and each have only about 2 hours play time on the stylus.

 
Ruby cantilever fine line contact stylus Soundsmith rebuilt Ortofon S-15T moving coil cartridge.

 
Conical stylus, aluminum cantilever Soundsmith rebuilt Ortofon S-15T moving coil cartridge.

 

Early 1980's vintage Ortofon SPU A type stereo cartridge, with conical stylus, newly rebuilt by Soundsmith. With original paperwork. Made in Denmark, with Japanese marks on box and paperwork. Guaranteed restored cartridge.