202-T How to connect Multiplex????

larryderouin

I'm VERTICAL and Breathing...most of the time.
Subscriber
Working on a 202-T for Wharfcreek........bringing it up, changed out the DUAL 1000uf/35v cap with separates underneath (for Filament heaters only) testing tubes, etc.

I connected it up to my SX-1010 (the only thing I had handy that had jumpers for the amp.) Mono FM, and AM sounds pretty good. This thing has one of the best TUBE Tuners I've heard. On the internal AM antenna, picks up everything from a Station in Chicago to Boston, after Dark. Daylight is just as good. I was picking up a station in DC that I can't get on any other tuner in my stock. And I haven't heard that station in years.

FM is Pretty good. On a 6'ft piece of wire, I got most of the stations I get on the SX-1010, but a bit weaker. Turns out the 6AQ8 was flakey and causing a fadeout and fade-in after about a 1/2 hour on. Tube tested good. Subbed a 6DT8 and it stayed up all night.

NOW for the problem I have. Not having a an owners manual for this monster, and with it having the preamp integrated into the tuner, how would I connect an EXTERNAL FM Multiplex so I can listen to Stereo without having to have two sets of outputs and switching them everytime to listen to phono or tape. There is a switch on the back named FM-AUX/AUX which I suspect has something to do with it.

Here's my scenario.

Outputs are "A", "C", "B" for Left Center and Right. These are the only outputs other than the multiplex out.

The multiplex I have(EDIT: SHERWOOD S3MX MPXR) requires a mpx signal and one channel, "a".

"A" Channel out, and mpx out to MULTIPLEXER.

I suspect I take the MPX OUTPUTS and connect them to the AUX IN and throw the FM-AUX/AUX (on back) to FM-AUX. Then turn the selector to AUX to listen to STEREO?

Now comes the problem.....OUT TO THE AMP. Do I Split the "A" channel with a "Y" splitter or what??

It does have a 9 pin connector for an internal mpx unit. I could figure out the inputs to the mpx and outputs back to pre, but right now it's a testing thing.

Would splitting the signal cause any problems with out of timing, off phase, or other items???

If someone has a 202-T and can help with this I'd appreciate it. An operating manual would work as well.

It DO SOUND GOOD IN MONO! You almost need a Master's in EE to work it tho. (And I thought my SX-1010 was complicated).

thanks

Larry
 
Last edited:
attachment.php


:lurk: :scratch2: :dunno:
 
S3MX schematic
attachment.php



Ok. I mulled this over in my head all friggin day while doing yard work. The FM IN on the S3MX (SHERWOOD) to the MPX is just for MONO. And the 202-T has a FM Mono function that is separate from the MPX setting. SO, Here's how it goes and is running right now.

MPX OUT from 202-T to MPX IN on S3MX. (Single RCA Cable)

CHAN "A" OUT to CHAN "A" AUX IN on 202-T.
CHAN "B" OUT to CHAN "B" AUX IN on 202-T. (Duplex RCA Cable)

Chan "A" OUTPUT to Main In on SX-1010
Chan "B" OUTPUT to Main In on SX-1010 (Duplex RCA Cable)

FM-AUX / AUX Switch on Back of 202-T set to FM-AUX

1.)Selectors set to AUX, Mode to STEREO. I get Stereo. :banana::banana:
2.)Selectors set to AUX, Mode to FM (A). I get Mono. :thmbsp::thmbsp:
OR With Selector and Mode set to 1, Switch Mono/Stereo switch on S3MX back and forth gets Mono or STEREO. Separation is OUTSTANDING using S3MX to control Mono/Stereo. Using Mode to Select between Mono and Stereo is only fair.

SO IT ALL WORKS.

Hope this helps someone down the road with a similar setup!

Pic's of the lash up.
attachment.php


attachment.php

Larry
 
Last edited:
Sweet. :thmbsp:

I was worried about having to connect the 9-pin socket next to the place where the Fisher MPX would go.
Your directions make the Scott instructions make sense now.


Steve
 
The nine pin socket was for the MPX 20 drop in. It was setup for the Crosby version and wouldn't be compatible with the current mpx setup. If you have the schematic for a mpx 65, or 125 you might be able to use the plug for B+, mpx out , and L&R inputs Plus ground
 
Hey Larry, as long as I don't have to use the nine pin socket, I'm good.
I see where the RCA connects from your picture.

Thanks,


Steve

BTW, how is the volume tracking?
 
Not too shabby considering neither unit has been recapped yet. I did do the dual 1kuf.35V cap on the 202-T for the 12AX7/12AT7 filaments and replaced the selenium rectumfrier. It was putting out 9.3 v instead of 27. Needless to say NONE of the 12--7's were heating up.

Steve; You intimated that you have paperwork on the S3MX??? Anything would be helpful for this unit. Or a location to get it.

Thanks
Larry
 
I am going to be using a Scott (pictured) 335, not a Sherwood.
I have the 335 PDF somewhere.


Steve

replaced the selenium rectumfrier. It was putting out 9.3 v instead of 27. Needless to say NONE of the 12--7's were heating up.

Larry

attachment.php


Is this the one you replaced?
 
Last edited:
Back
Top Bottom