Ex my personal "salvaged" stock
HISTORY:
A long time ago an associate, who had a passion for old audio transformers, gave me a box of his "treasures" before he passed away so that perhaps I could make use of them. Well that never happened did it .... it is time to see if someone else would like to press this audio transformer into service
This transformer was keeping great company in the box I received, being full of lovely Neumann, Beyer gear and "others". I found new homes for the other gear but now it is time for this Astor transformer to leave "home"
Problem is that I don't have a lot of information about this transformer but here goes my effort at describing this "little green beast"
ASTOR (Radio Corporation Australia) - Audio Transformer
Low power (based on the size, which is quite small)
DIMENSIONS:
44mm wide x 31.5mm deep x 51.5mm height
WEIGHT:
220g
All metal case which is completely sealed
Single sided exit/entry of the primary & secondary wires
NO mounting support/holes/brackets can be seen anywhere! I really have no idea how this transformer was supposed to be mounted. Even the curious green external coating shows no obvious wear which might occur if a bracket was being used however I do notice a small rectangular area on the top of the transformer where the paint coating is no longer there, perhaps some sort of spring clip locked into this area although there is no corresponding "rectangular area of wear" on the other side of the transformer. Very odd.
Peculiar that green colour, I often have seen grey, silver or even brown but not green (original colour, it has not been recoloured)
There are 6 colour coded wires, each is 75mm in length
BASIC TESTS:
Unfortunately my suite of test equipment has been dramatically depleted, having already gone to new owners. This means the tests I have been able to make are very limited and do not tell the whole story, in particular Z or frequency response. Considering the era this transformer came from, I wouldn't be expecting anything too exciting for the frequency response characteristics.
Using my trusty multimeter I can tell you this ...
WINDING #1
RED - BROWN - BLACK
RED - BLACK winding measures 765 Ohm DC & BROWN looks to be a centre tap, reading from BROWN to either RED or BLACK measures 397 Ohm DC
WINDING #2
BLUE - YELLOW - WHITE
BLUE - YELLOW winding measures 388 Ohm DC
WHITE has NO electrical connection to any other winding so this must be an ES (electrostatic shield) connection
I have not referred to a primary or secondary winding specifically, these being effectively interchangeable.
Astor are most well known for their range of domestic radio receivers and domestic sound equipment but they also did make equipment intended for the professional, such as this multi-channel audio mixer
I found a website with a lot of technical information (including parts lists) about this mixer but the transformer part numbers (although very close) were not the same type.
I also looked at a few radio receiver designs from Astor but again, drew blanks.
A lot of the Astor equipment uses the 4042 series audio transformers (including the mixer above) but it is the 150 in the part number that doesn't tie up with anything I could find.
I strongly lean towards this transformer being intended for the professional audio market due to the electrostatic screen being fitted on the assumption that for 'normal' domestic equipment, Astor wouldn't bother with an electrostatic shield.
So there you have it, a nice looking old audio transformer which would be fun for someone to "check out" properly and hopefully put to work once again!
