[R-390] Radio Shack Impedance Matching Transformer

[R-390] Radio Shack Impedance Matching Transformer

Scott, Barry (Clyde B) [email protected]
Tue, 23 Sep 2003 11:42:01 -0500


Bob,

I found this from an older post from Don Reaves.
------------------------------------------------------------------

Radio Shack has these specifications listed for 
that transformer on their web site.  This must be
a sample of 5 units.




10 Watt 70 Volt Audio Transformer 320-1031 Specifications
320-1031)     Specifications           Faxback Doc. # 9663
Transformer

Dimension measurements are within specification.

Primary Impedance (at 400 Hz 5V):

Secondary      Primary Watts
Loading           Range          No.1     No.2     No.3     No.4     No.5

  4 Ohm        10 W               535      535      540      547      525
               5 W               1025     1060     1040     1035      950
               2.5 W             2020     2000     2105     2010     1900
               1.25W             3905     4035     4050     4050     3850
               0.62              7120     7365     7205     7200     6855

  8 Ohm        10 W               570      595      585      590      595
               5 W               1110     1115     1150     1130     1135
               2.5 W             2050     2090     2245     2240     2240
               1.25W             4205     4100     4150     4305     4100
               0.62              7650     7400     7750     7605     7350

  16 Ohm       10W                555      565      565      555      550
               5 W               1070     1070     1090     1085     1020
               2.5 W             2105     2100     2200     2190     2050
               1.25 W            4070     4050     4100     4130     3960
               0.62 W            7405     7395     7400     7410     7150

Primary Inductance:              7.5 H    7.2 H    7.4 H    7.4 H    7.3 H
Primary Resistance:              198      201      202      197      200
Secondary DC Resistance (Ohm):   0.888    0.892    0.886    0.898    0.917

Insulation Resistance:.............................100 Meg Min. at 500 VDC
Hi-Pot Test:..........................................1000 VAC 60 Hz for 1
                                                  minute without breakdown
Impregnation:..........................................Varnish Impregnated
Frequency Response........................................100 Hz to 10 kHz

Specifications are typical; individual units might vary.  Specifications
are subject to change without notice.

(IR-04/12/95)

Don W5OR

---------------------------------------------------------------------

It appears you want to use the 10W tap but not sure.  Hope this helps.

Barry(III) - N4BUQ





Okay, maybe I'm dense.

I picked up a few of those Cat# 32-1031 70 Volt 10 Watt PA System Line 
Transformers.

First reason:

    One of my R-390As was converted by its previous owner to an 8 ohm 
audio output.

I want to use one of these outboard to take the 8 ohm to the 600 ohm 
input to an Hallicrafter's R-42 Reproducer.

Can someone provide me with guidance to connect which tabs to connect 
the line to the R-42?

It IS clear which to connect the 8 ohm input.

Thanks in advance!

Bob - N0DGN

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