1980's Australian designed, manufactured
Ex Broadcast Industry audio line output module
Great for re-purposing where a high quality low level single channel audio is required OR extract the very nice HARBUCH transformer and use alone in a different project.
Unbalanced Audio Line Level Module
Single Channel
Dates from the late 1980's period
Module uses a SINGLE rail supply of 24V DC
Input is unbalanced
Output is unbalanced and the output signal is "split" into two mono channels because this module was originally intended to feed a stereo headphone output although the input source material was monoaural.
Active device is NE5534
NO onboard gain adjustment
Module measures: 80mm length x 46mm wide x 35mm height
Weight (mainly the transformer) is 120g
CONDITION:
Excellent
NO damage to any component
"Tails" have been left which enable easy identification of the connections
Red - Green = single channel audio unbalanced
Black = Common/Ground (only on the output, which went off to a standard 1/4" headphone socket)
Orange - Black = 24V DC input
TECHNICAL NOTES:
THE TRANSFORMER
Designed and manufactured by Harbuch Electronics located here in Sydney. This company designs and manufacturers very high quality transformer based products and many of their components can be found in broadcast equipment of this era.
I used to supply Siemens ferrite products to Harbuch in the 1980's but I don't know what they are up to these days, they appear to have moved from Hornsby to Artarmon. The website now is pretty "flakey" - it looks like a "work in progress" you can try having a look yourself HERE
On their website it does state:
"Individual data sheets are available for each transformer type listed in this guide. These sheets have a photo and mechanical drawing, response, THD and phase plot, specification panels and an oscilloscope photo of the response to a 2kHz square wave at a level just below maxium rated output or input."
So according to that info, a phone call may glean more technical information that could be required
The former is a standard laminated E core
Size: 34mm wide x 30mm deep x 31mm height
The base is held securely by the PCB pins soldered to the board, there is no additional support
Besides the PCB pin access to the windings, there are also solder tags on the primary and secondary sides
MARKINGS:
HARBUCH ELECTRONICS
AT-206
All connections are made to the PCB module using solder pins - easy to re-use
Specifications are difficult to come by these days but I can assure anyone interested of the following:
Designed for line level use - this is NOT an audio input transformer
Frequency response would be to AT LEAST 15KHz - this is pretty standard for broadcast audio equipment
Turns ratio 1:1 + 1 (+20dBu) REFERENCE
This means there is one primary winding and two independant secondary windings.
If access to this link is difficult (intermittent access was my experience) it really seems to be a bit flakey at the moment, further evidenced by there being NO photographs at all
THE AMPLIFIER
Based on the common NE5534 high performance Op amp and it appears to be configured as a voltage follower/buffer amplifier.
There is no gain adjustment on this board, level control was achieved using a panel mounted pot.
Single rail supply, 24V @ pins 4 & 7
TESTING
Prior to removal from the original audio equipment, this module has been tested and is working fine
