Western Electric tube amplifiers - 310A 328A 154C Trans

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  • Item Category: Tools
  • Source: eBay
  • Sold Date: May 18,2011
  • Channel: Online Auction

Western Electric tube amplifiers - 310A 328A 154C Trans

This Buy-It-Now auction is for two (2 pcs.) Western Electric J64001-W vacuum tube amplifiers.

These are high quality Western Electric tube amplifiers, which were used for testing accuracy of other

Western Electric audio transmission systems and components.

As can be seen in the photo scans of Bell System literature below, these are:

"principally a three-tube amplifier, with frequency weighting obtained from characteristics of interstage

coupling and a varistor type rectifier" .

The C-Message Weighting filter (extra inductors and capacitors between 1st and 2nd tube stages) purposefully changed the

output characteristics of the amplifier from flat response to give a C-Message Weighting response curve. This is basically

a Band-Pass filter placed between the output of the first tube stage and the input of the second tube stage.

The band-pass filter inductors and capacitors between the 1st and 2nd tube stages need to be bypassed to return the

amplifier output to flat frequency response. The interstage wiring between the first and second tube stages should be changed

to closely resemble the wiring circuit between the 2nd and 3rd stage. See schematic diagram below.

The input trans is the Western Electric 270H trans; which is used as the detector input trans of a Western Electric 21A

20-20,000 cps Transmission Impairment Measuring Set. This means that the frequency response of the WE 270H

Input Trans is flat from 20-20,000 cps.

The output transformer is the highly desirable 35 - 15,000 cps Western Electric 154C, with 600 ohm output impedance.

Presently, the output of the 154C Output Trans feeds into a rectifier to change output from AC (audio signal) to DC,

in order to drive a dB meter. Once rectifier is removed from output of the WE 154C Output Trans, the output terminals

of the WE 154C can be connected simply as a 600 ohm pre-amp output to feed either a power amplifier or headphones.

Years ago, I removed the one WE 154C Output Trans from one of these WE amplifiers. I sold that 154C Trans separately.

I would no longer make this mistake today. It will be necessary for buyer to purchase another WE 154C Trans, and install it,

to have a complete Pair of these Western Electric audio pre-amplifiers.

In photos below are some Bell Laboratories descriptions of the Western Electric 1W amplifier, including a schematic.

Tube shields x 6 are included in this auction.

The Western Electric vacuum tubes are NOT included in this auction.

For additional detailed photos of each amplifier,

Copy and Paste following link into your browser: /weAmp1Ww/with154C.htm

Copy and Paste following link into your browser: /weAmp1Wwo/without154C.htm

Secure, double-boxed shipping weight will be 27 lbs. and 24 lbs for both amplifiers. Cannot ship both in same

package due to International Priority Mail size and weight limitations. eBay shipping cost shown is for both amplifiers;

a total of one 27 lb, and one 24 lb package

Actual Post Office shipping cost only. No extra charges.

Also on eBay, we have a Western Electric regulated 6.30 VDC filament power supply for Western Electric vacuum tube amplifiers.

See my other Buy-It-Now auctions for more Western Electric equipment

Above photo: the two capacitors and two inductors band-pass filter visible between 1st tube and second tube must be

eliminated from electric...

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