Anyone ever use a mono summing cable (Double Y-connector) for mono vinyl?
nspindel
Posts: 5,343
I was reading up on the Steve Hoffman forums about listening to mono vinyl through a stereo cartridge. He personally advises that in the absence of an actual mono cartridge, that you should use a summing cable to combine the two channels together if you don't have a mono button in the preamp.
The summing cables would basically be a set of in and out Y-connectors. The first Y takes the left and right output signal and sums them together into a single signal. The second Y splits that summed signal apart into two and you feed those two into left and right inputs in the destination. The advice I read is that this should be done after the phono preamp stage.
The rationale is that mono records are actually dual mono, and that there can be some phase distortion between the two channels, in particular noise. By crossing the signals together the phase noise gets eliminated. People are reporting experiencing hearing much less surface noise in their mono records when doing this.
The summing cables would basically be a set of in and out Y-connectors. The first Y takes the left and right output signal and sums them together into a single signal. The second Y splits that summed signal apart into two and you feed those two into left and right inputs in the destination. The advice I read is that this should be done after the phono preamp stage.
The rationale is that mono records are actually dual mono, and that there can be some phase distortion between the two channels, in particular noise. By crossing the signals together the phase noise gets eliminated. People are reporting experiencing hearing much less surface noise in their mono records when doing this.
Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
Post edited by nspindel on
Comments
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While you can split one output to two inputs, you cannot passively combine two outputs into one input.
See:
Why Not Wye?
Dennis Bohn, Rane Corporation
RaneNote 109 written 1991; last revised 4/04
Splitting Signals
Subwoofing in Mono
Unbalanced Summing
Balanced Summing
Output Impedances
http://www.rane.com/note109.html -
http://forums.stevehoffman.tv/threads/if-you-have-a-turntable-you-need-to-play-your-mono-records-in-true-mono-how-to-do-it-cheaply.81073/
Steve Hoffman's personal thread.Good music, a good source, and good power can make SDA's sing. Tubes make them dance. -
Yeah, don't do that after your phono stage. Before it, I'd have to think. The correct approach requires a summing circuit which you can find in the link speedskater gave or there's a special kind of isolation transformer that'll do this. For splitting it back apart, you can use a standard y cable.
What happens with a y-cable after the phono stage is that the left channel will be driving both the line stage AND the circuitry of the right channel.... and vice-versa for the right channel. A lot of equipment can be damaged this way.Gallo Ref 3.1 : Bryston 4b SST : Musical fidelity CD Pre : VPI HW-19
Gallo Ref AV, Frankengallo Ref 3, LC60i : Bryston 9b SST : Meridian 565
Jordan JX92s : MF X-T100 : Xray v8
Backburner:Krell KAV-300i -
On second thought- the impedence is probably high enough that it's OK. I'd still feel better using a summing circuit, though.Gallo Ref 3.1 : Bryston 4b SST : Musical fidelity CD Pre : VPI HW-19
Gallo Ref AV, Frankengallo Ref 3, LC60i : Bryston 9b SST : Meridian 565
Jordan JX92s : MF X-T100 : Xray v8
Backburner:Krell KAV-300i -
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Despite the advice of those smarter than me, I went ahead with the double Y-splitter using a couple of $6 rat shack parts. And all I can say is.... WOW!!! I am having a complete WTF moment right now listening to my 1963 UK Mono of Please Please Me. I listened from the lead in to the count in to I Saw Her Standing There, and then to the dead time before Misery. Then I swapped in the double Y at the point where the tonearm connectors come out of the table, so obviously before the phono pre. Then I replayed from the beginning of the record. What I heard completely blew my mind. So much surface noise was filtered out, and only positive impact to the music. It didn't get any louder or lower, but just cleaner. Before the adapters the highs had a bit of shrillness/fatigue that is gone now, the bass is cleaner, but the pop and crackle noise... is practically gone! Incredible.Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
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For me it was a pretty simple decision - Steve Hoffman is telling me to do this. WTF. Can't believe how much this improves an older mono record. I will see if it has any benefit to some of my newer mono stuff that doesn't have much surface noise to start with, like the Dylan box set. But for an older record with some miles - wow!Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
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all (most) of the surface noise and any rumble will be out of phase between the two channels; so, yes, it goes away when summed to mono. In the good ol' days, preamps (or integrated amps or receivers) had a mono switch on the front panel that did the dirty work for you.
e.g., the "mode" switch on this ol' Yamaha CA-610II...
CA610II and T550 by mhardy6647, on Flickr -
Sgt. Pepper. There just are no words right now. I have never heard it sound so good as I am hearing it right now. I've got nothing. It's that good.Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
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To have this amount of noise removed from these older records, with no adverse affect on the music, is mind blowing.Good music, a good source, and good power can make SDA's sing. Tubes make them dance.
