What is the input impedance for this unit. I had thought these were used
with a 500 -600 ohm output. I was informed it was 6000 ohms but that
sounds high to me.

Lou D oldradios.com wrote:
What is the input impedance for this unit. I had thought these were used
with a 500 -600 ohm output. I was informed it was 6000 ohms but that
sounds high to me.

What's the DC resistance? It should be around a tenth of the impedance
at 1KC.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Lou D wrote:
What is the input impedance for this unit. I had thought these were used
with a 500 -600 ohm output. I was informed it was 6000 ohms but that
sounds high to me.


Lou,
I was one of those who mentioned the higher impedance. In looking at
the BC-342 book, it appears that the xformer in the book dated 1942
shows a single output Z of only 2000 ohms. In later TM-11-850, dated
1946 (as amended), the output Z of the BC-312 and 342 are said to be
either 250 or 4000 ohms. The TM was the one actually in the field. I've
never seen a single Z BC-312 or 342? The BC-348, on the other hand, is
tapped at either 300 or 5000 ohms. I've got 10-12 LS-11's and will look
at one or two and see if they're marked 2000, 4000, or 6000 ohms.
de K3HVG

Scott Dorsey wrote:
Lou D oldradios.com wrote:
What is the input impedance for this unit. I had thought these were used
with a 500 -600 ohm output. I was informed it was 6000 ohms but that
sounds high to me.

What's the DC resistance? It should be around a tenth of the impedance
at 1KC.
--scott
The DC resistance is 280 ohms.

In article ,
Lou D oldradios.com wrote:
Scott Dorsey wrote:
Lou D oldradios.com wrote:
What is the input impedance for this unit. I had thought these were used
with a 500 -600 ohm output. I was informed it was 6000 ohms but that
sounds high to me.

What's the DC resistance? It should be around a tenth of the impedance
at 1KC.

The DC resistance is 280 ohms.

I would suspect it to be higher than 600 ohms at 1 KC, then. If you want
to be absolutely sure you can make a bridge with a true RMS voltmeter
and a 200CD.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."