Fisher TA-500 (mono)/Potentially Stupid Question

Hi--

Is there any way for me to run my Fisher 500 receiver in dual mono, i.e. two speakers?

Thanks..

IIRC there is a MONO-STEREO slide switch. Put the Selector on FM MPX, then flip the MONO-STEREO switch to MONO. That should work.

Hello Larry--

Thanks for your reply. The TA-500 is a mono receiver from 1957. There is a jack for MPX out, but that would only apply to the FM.

OK. I found the one you have. You've got the original 500. It's MONO SINGLE SPEAKER. Nothing wrong with a single mono speaker. Now if you want to add another in an adjoining room, get a switch box, and wire the switch box between the speakers and the 500. But if both in the same room, get a impedance matching box, and run the speakers thru it. Run both at the same time and the amp only see's the impedance from the switch box. That would be the way to go.

For FM Stereo you'd connect the MLPLX output to an outboard Multiplexer, then the outputs from the multiplexer would go to a 2nd amplifier, then to the 2nd speaker. Apparently there are no provisions for this receiver to play stereo standalone.



Larry

You might want to clarify what you mean by 'dual mono'. If you simply want to drive two speakers with the 500 then that should be pretty straightforward. The 500 has the usual 4/8/16 ohm taps for impedance matching depending on how you wire the speakers. (Or you could use an outboard impedance matching device as Larry suggested, though I am not certain that would be necessary.)

If by 'dual mono' you're looking to achieve stereo using the 500 as one channel then you should review this thread (if you haven't already):

http://www.audiokarma.org/forums/showthread.php?t=208154

That thread references how Fisher used the mono 500 as the heart of a stereo console with the addition of a 30-C mono control amp (preamp), a PR-66 stereo phono preamp and a 30-A mono amp. I still don't know the details involved with the TK-5 modification or even if that was what was used in the '59 Ambassador. I have a late 500 (5881 outputs) with an extra, unused, volume pot which operates in tandem with main volume pot. It might possibly have provided a master volume control for a dual mono setup of some sort. I don't think the early EL-37 versions had this feature, though.

Hello Men--

I've only just checked back here for the first time in a week or two; thanks for your replies.

What I'm trying to get at by "dual mono" is that I'd like to run two speakers in the same room at the same time with my mono Fisher receiver. I know about the stereo conversion for the TA-500, but I think I'd rather not mess with that. Can I simply run the two sets of wires from my 8Ω speakers and connect them to the 4Ω positive/negative posts on the back of the receiver?

On a side note, the mono 500 sounds every bit as good as my 400cx-2 pre/202-R tuner/McIntosh 225 system; just not quite as loud. Sadly, I'm something of an electronics idiot and I have no idea how to work on the stuff myself. I'd like to simplify my life and free myself of the cost/hassle of repairs to components that are seemingly never done right the first time anyhow. The living room at ivan100000 HQ is set up aesthetically for two speakers; thus my interest in running two off the mono receiver.

Yeah you can do that. I'd keep an eye on the output transformer temps tho. If you ran them in series, you could connect to the 16oHM tap. Take the + side from the 500 and run it to the + side of one of the speakers. Then run a wire from that speaker's - term to the + term of the 2nd speaker, then the - side of the 2nd speaker to the - term of the 500. This would be a better arrangement as far as the amp goes. Less load, less heat, less strain. But the tradeoff is a slightly lower volume.

Larry