Milliammeter to die for? Set your bias current in style!

[Bob]

A Sensitive Instrument Research Corp. model JW. This was something I bought at auction 35 years ago for the sole purpose of setting up the bias current on my then modified ST70. This is an edgewise panel mount meter, but is fully encased in a heavy cast metal housing finished in black wrinkle varnish. The scale is white with a gold mirror strip to minimize parallax when reading the 0-100 ma scale. The scale is marked in 2 ma increments. Zero adjust screw is on top and connection is made via a pair of terminal posts in the rear. It features a diamond pivot movement. And, it's got it's own serial number. This thing must weigh about 6-7 lbs. I always thought it would look great mounted in a walnut panel or in a piece of audio furniture of the period. Only date on this thing is 1960. For $100, I will carefully pack it and ship it (CONUS only, please) to your door.

[burnedfingers]

I think that your price is a little bit on the high side on this one. I've seen them go for $25 on ebay. Its nothing special. I would suggest putting it on ebay.

Since most amplifiers generally have a small value resistor from cathode to ground it is customary to use a VOM and measure the voltage across the resistor and set the bias that way.

[Blitzen]

Without a picture of it, kind of a hard sell.

[Ty_Bower]

Without a picture...

I found a model S, but I'm still searching for JW.

http://www.worthpoint.com/worthopedia/a ... instrument

[Bob]

Without a picture...

I found a model S, but I'm still searching for JW.

http://www.worthpoint.com/worthopedia/a ... instrument

The JW is actually a panel mount meter. I would be happy to send anyone interested some pictures. Just PM me with your email address.

[Bob]

I've posted some pix of the JW meter that are now in my gallery.

[Bob]

I forgot I still had this meter and perhaps my original price was unrealistic. How about $50 shipped to CONUS?