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The HH Scott 350 A MultiplexCircuitry

I've been listening some to my 350 Scott but only in mono. However my belief is that it's all stock so I'm hoping that replacing the tubes in the multiplex will clear up the noise and microphonic echo from the 6BL8. Yes, I'm getting loads of grumble and interference from the stereo selection.
An additional multiplex concern however is that the multiplex circuitry in the 350 was a compromise to the refined circuitry of the 310 E. I have procured (thanks to good Audiogon friends) the repair manuals of both the 310 E and the 350 as well as both schematics and I'm hoping/wondering if my local technician will be able to improve upon the 350 multiplex circuitry by comparing it with that of the 310 E? I was told by a friend that this is possible if I were to provide the technician with the repair manuals and schematics for both tuners but I'm still somewhat doubtful.
If anyone ( Al ? ) would shed some light on this and lend a suggestion/s for me to pass along to the technician, then I'd be very grateful. By the way, I have a Telefunken E80CF (6BL8) , A balanced pair of Telefunken 12AU7's and a Telefunken 12AT7, all Amplitrex tested on hold for payment. These I'll take with the tuner and hope that he orders the best capacitors. I want to go full force with this project to the best of my abilities.
Thanks To All!
goofyfoot
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almarg
8,673 posts
 
Goofyfoot, after taking a look at the schematics I have no suggestions to offer with respect to modifying the design of the MPX circuit to be more like that of the 310E. They are simply different animals, to a considerable extent.

And my guess is that once tube, capacitor, and perhaps alignment issues are addressed you'll be quite happy with the stock design of the 350A. Keep in mind, though, that when signal strength is weak or marginal FM is inherently more susceptible to background hiss in stereo mode than in mono mode.

Regards,
-- Al
goofyfoot OP
451 posts
 
Ok, thanks Al! Yes, the band width is wider in stereo mode thus creating more difficulty in receiving the transmission. Currently I use an all-right passive FM antenna and I've found a place where a couple of channels have consistent reception quality.
I'd like to eventually purchase an outdoor antenna that I can place on the window sill of my building but it isn't anything that I need to rush into.
Also thanks Viridian, I may take a look at that other site.
corazon
209 posts
 
Goofy foot, with my 350's I use simple rabbit ears(!) and they perform well. Just thought I'd pass that on.

Best,

Dave
goofyfoot OP
451 posts
 
Thanks Dave. Currently I've been using a Terk Edge without the amplification. I can receive the stations that are close by but have trouble with a couple of stations that are outside of the city proper. These outer stations were difficult to pull in when I had my MD 90 with the ST 2 antenna so I am looking for an outdoor antenna that's apartment friendly. I may check with a HAM/shortwave shop that's relatively close by to see what they've got on offer. Can you even believe that there's still a HAM/shortwave radio store selling icom, etc..?
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atmasphere
7,068 posts
 
The big deal here is to make sure that the unit is properly aligned- for that you need an FM stereo generator- or your tech does.

If I recall right, that unit can beat if its out of alignment- that 'grumble' you mentioned.

If its not been done in a while, an alignment of the entire unit would not be a bad idea!
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