Sansui tube amp/tuner transformers

[John Kolb]

Unless my memory is seriously rearranged (not completely unlikely), the model I
bought about 1965o or 66 was the 1000A. Probably very similar to the 1000.

It should be possible to determine most of the transformer characteristics with
a multimeter.  The primary will have 3 , or 5 in some cases with an 
ultralinear design,
leads with continuity between them, and they will be high enough 
enough in resistance
to easily seperate them from the secondary windings and to determine 
which of the
3 or 5 leads is the center tap. (pretty sure the 1000A was NOT ultralinear).

The secondary wires will probably be common, 4, 8 and 16 ohms, and 
can be determined
which is which with a very high resolution ohmmeter. Or, connect a 
low AC voltage across
two of the secondary wires and measure the AC voltage between each of 
the leads and all
other secondary wires to determine the ratios between taps. NOTE THAT 
HAZARDOUS
VOLTAGES WILL BE PRESENT ON THE PRIMARY LEADS WHEN DRIVING THE
SECONDARY WINDINGS.

Then connect the low voltage AC signal across the highest output pair 
of secondary windings,
and measure the both the AC voltage applied to the secondary winding 
and the AC voltage
developed between the primary center tap and one of the two plate 
leads. NOTE THAT
HAZARDOUS VOLTAGES WILL BE PRESENT ON THE PRIMARY LEADS WHEN DRIVING
THE SECONDARY WINDINGS.

Calculate the voltage stepup ratio between the secondary and primary 
windings, and  assume
that the secondary winding driven is 16 ohms. The primary impedance 
should then be the
voltage steppup ratio squared times 16.  Someone correct me if this 
sounds wrong.

American audio transformers generally will follow the RMA standard 
color codes, but all examples
I found on line don't seem to apply exactly to output transformers. 
The primarys usually will be
red for CT, and blue or brown for plate connections.
http://www.radioremembered.org/outimp.htm
Don't know if Japanese transformers will follow the color code or 
not, but it's a reasonable starting
point to make sure the ohmmeter tests verify identity.

John

At 07:16 AM 8/5/2006, Alex [Temple Boatanchors] wrote:

>Hi Richard,
>
>To my knowledge Sansui only made one tube integrated amplifier, the 
>Model 1000. I searched ebay and found this auction (I have no 
>connection to it), as a reference take a look at the pictures and 
>compare it to your own unit.
>
>Hope that helps you a bit.
>
>-Alex
>
>At 12:05 AM 8/5/2006, you wrote:
>>---------------------------- Original Message ----------------------------
>>Subject: Sansui tube amp/tuner transformers
>>From:    kc8keg at mei.net
>>Date:    Sat, August 5, 2006 12:03 am
>>To:      BOATANCHORS at LISTSERV.TEMPE.GOV
>>--------------------------------------------------------------------------
>>
>>    Hello All, Sorry for the off topic query. Looking for info on above
>>transformers. Transformer numbers are of the 400 5234 series for the main
>>transformer with a 75-3 date code. Then 400 5234A date code 60-2,73 and 400
>>5234B date code 73-2. The chassis is a vacuum tube tuner and amplifer. I'm
>>not finding any model or chassis number on the unit. It suffered some dam-
>>age at anothers hand and I'm only trying to salvage parts. Really want the
>>transformer wiring pinouts but any help will be appreciated. Thanks to all
>>in advance, Richard VanTrease kc8keg   < kc8keg at mei.net >
>
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