On this page, I intend to amass information on all of the PA system head unit components that I have collected.
At time of writing, I am currently working on rebuilding my 1A952 preamp/intercom panel to better serve my needs. Pictures and descriptions of the equipment I currently use shall be posted here, eventually.
At some point, I hope to obtain one of these floor-standing Dukane rack consoles, the model shown above. I will commit the grave sin of removing the tube equipment (and safely storing it away, though!) and installing my newer components.
The Dukane 12A906 desktop console contains a 1A951 preamp/intercom head and a 9A1416 switchbank, and was originally provided with a 7A765A microphone, creating a 25-channel intercom (without call-in annunciators) with a 35-watt program amplifier designed to drive a 25v line.
The amplifier is about as musical sounding as typical early transistors—that is, not very. It was fun to blast music through back in the day; but, knowing what I know now, I would strongly avoid playing music through this amplifier.
This particular 12A906, along with eight matching 6A557 speakers that all share 1977 date stamps, was originally owned by Marietta City Schools, Washington County, Ohio (a district neighboring the schools I attended). The system was purchased by me, along with other equipment, at a live surplus auction in spring-summer 2002. This was my first “real” PA system.
Otherwise known as a Turner 251.
I believe I had to connect the extra pair of wires to the extra contacts to control a paging relay, as the above 1A951 does not use that feature. This was the one and only microphone that I had on “PA duty” for about 14 years.
And here’s a Dukane 1A957 head with a 9A1785 switchbank and 110-1998 modular radio/cassette panel, mounted in the 12A906 cabinet.
The 60-watt program amplifier does not sound entirely unlike the 1A3000-series amplifiers, but the sound is shaped somewhat to not cause problems with cheap matching transformers (the difference is not particularly notable unless you use good transformers and really pay attention). The 15-watt intercom is very strong. I have a dream about transplanting the intercom module into the 1A952 (in place of its sticky 4-watt intercom) but I will probably not do that. I have also entertained the idea of putting the 1A957 into my main PA rack only to use the intercom, leaving the other features disconnected, but I don’t have a big enough rack to do that.
I purchased this little pile of equipment because it included two 9A1785 switchbanks and the 17A435 power supply for the call-in annunciators. Completely missing from any of the Dukane documentation (I didn’t see it, anyway) is that the annunciators require a 6vDC supply. I had to buy it to figure that out.