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Marantz 2235 Phono Input Weirdness

tlite

tlite

Active Member
Howdy.

I have a Marantz 6350 turntable plugged into this passive RCA switch like this:

51rKFJpDoKL._AC_SL1000_.jpg 51hHwN+k8nL._AC_SL1000_.jpg

I have the turntable going IN to the OUT, and want to switch between two receivers for the output. I have an Onkyo TX-NR808 hooked up to "input" #1, and the Marantz 2235 hooked up to #2.

Both receivers have phono preamps onboard.

I made soldered RCA cable for the ground connection from the switch to a bare wire termination to connect to the receivers, plugged into the appropriate respective yellow jacks.

I know, I know- "It's backwards!" you say, but this switch is just a simple mechanical connection selector and according to everything I read and tested with multimeter, it works both ways.

THE ISSUE:
When playing through the Onkyo and the "1" button pushed in, if the Marantz phono inputs are connected to the switch (i.e. the red and white jacks from #2 --> Marantz phono input R&L) then the onkyo sound is really thin, and if I turn up the volume I get a loud, DEEP, hum out of my speakers (Triangle BRO8's). If I unplug the Marantz phono inputs, all is good.

I have checked continuity with a multimeter on everything and all measures like it should. Phase checked, cables checked. Phono plugged directly into either receiver works fine.

Is it possible the Marantz Phono Inputs might actually be pushing a signal back into the switch, causing an issue?

I'm scratching my head here folks...
 
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IMO, it is always better to use the turntable directly into the receiver. There is a possibility of changing the loading capacitance and resistance of the cartridge if you use an RCA splitter that can affect the sound.
 
sanjib said:
IMO, it is always better to use the turntable directly into the receiver. There is a possibility of changing the loading capacitance and resistance of the cartridge if you use an RCA splitter that can affect the sound.
Click to expand...
10-4, would the same be true with a switch like this one (i.e. not splitting the sound, just directing to one output or the other)?
 
rBuckner said:
Does it short the Marantz phono inputs to ground when you hear the noise?
Click to expand...
Well, the way it's wired up it should simply connect the TT ground wire to the appropriate ground wire which is then screwed onto the appropriate receiver grounding point. When you ask if it's shorting the phono inputs- it might be? I.e. the phono source music starts to get intermittent while there's a big bass-y hum? I do think that happens... you on to something?
 
Some Marantz phono preamps have a low frequency "motorboating" if the input jacks are presented with a short from center pin (signal) to the outer shell (ground).
 
rBuckner said:
Some Marantz phono preamps have a low frequency "motorboating" if the input jacks are presented with a short from center pin (signal) to the outer shell (ground).
Click to expand...
Hm. I'm getting this through the Onkyo though, with the switch disengaged from the Marantz and the Marantz off... how would I test the scenario you described with a multimeter and would it still have that effect with the Marantz off?

Guessing I'd do a continuity check on the RCA pins and outer shell (ground) on the cables coming from the switch to the Marantz when the Onkyo outs are selected/active?
 
yes it works in reverse. i always got hum when i tried regular rca switches with turntables never have with the Rek-o-Kut, used them with 10 different tables and around 20 receivers
 
tlite said:
Hm. I'm getting this through the Onkyo though, with the switch disengaged from the Marantz and the Marantz off... how would I test the scenario you described with a multimeter and would it still have that effect with the Marantz off?

Guessing I'd do a continuity check on the RCA pins and outer shell (ground) on the cables coming from the switch to the Marantz when the Onkyo outs are selected/active?
Click to expand...
Ah, I got confused in my early morning fog... Looks like the switch Chris recommends is a good idea and they're only 55 bucks.
 
Chrisxo55441 said:
yes it works in reverse. i always got hum when i tried regular rca switches with turntables never have with the Rek-o-Kut, used them with 10 different tables and around 20 receivers
Click to expand...
Cool- so you just ground the TT to the box, and don't need any further ground connections to the receivers? Looks like a great solution...!
 
i run a ground to the receiver as well, i have one wire from the switch box ground and wire nut it with the other three. i have a few of the switches and the older ones have 2 grounds on them so i use those for ones i have prongs on so i dont have to clip them off or cram them all on one post. you can try it that way and see if it works though.
 
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