[Boatanchors] Looking for Help: Magnavox AC 2
infomet at embarqmail.com
Sun Dec 15 11:36:32 EST 2013
You should put a small, fairly high resistance choke in place of the field.
Then an output xfmr for the VC.
Sent: Sunday, December 15, 2013 11:23 AM
Subject: [Boatanchors] Looking for Help: Magnavox AC 2
First, I will apologize ahead of time if this is a bit out of the Boatanchor
I came upon a very pretty Magnavox AC 2 amplifier yesterday. The unit is
really quite nice physically and the original decal on the front is
beautiful. I would like it to do more than just collect dust so there is
now another project staring me in the face. I am looking for the following
items as various web searches have not been very successful thus far.
1. A schematic. There was a hand-drawn schematic inside the box, but a
verified one would be great. There is one loose wire from the internal
transformer and I think I know where it goes...I think.
2. A transformer for the input side. I found a PDF file of the operating
instructions for both the AC 2 and AC 3 models and it mentions the need for
an 'any standard amplifying transformer' on the input side. This
transformer would connect between the phones output of a radio/crystal set
and the input terminals of the AC 2. I thought I had one some time back,
but I am now worried that I gave it away or it has been lost to history.
3. Any suggestions for the type of tube I should use. It came with CX-301A
tubes, but the spec sheets I have read say this tube is not the best for
power amplification. I may use these for initial trials. Unfortunately the
instruction PDF I have just mentions 'any standard transmitting tubes may be
used, with from 250 to 500 volts on their plates...'
4. The output of the AC 2 has connections for both the field and signal for
a field coil speaker. I am wondering if I can use, say, a universal output
transformer to drive a modern speaker instead. Again, the PDF file is
lacking on technical details. It does show the use of Magnavox Reproducer
R-2 or R-3 but I do not have those and it is not my intent to re-create a
living room from 1929.
I believe I can rig up a reasonable set of power supplies. The 5 volt
filaments should be easy...maybe even use the 5V output from a surplus PC
power supply. I expect the B+ requirements for whatever tubes I need would
require relatively low currents, so I should be able to put something
together myself or find something on Craigslist, etc.
Thank you all very much in advance for whatever helpful advice (or parts)
you may have. Again, my apologies if this is too far off outside the intent
of the Boatanchor community.
Best Regards and Happy Holidays,
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Boatanchors at puck.nether.net
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