Why Don't More Phono Stages Have Balanced Input?

zeta4

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Yes you would think that with a cartridge being inherently balanced it would be natural for the
phono stage to be balanced also. However the main problem I think is that a balanced i/p
is inherently +6db noiser (except if you use a transformer).
 

Jules_S

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Cartridges are inherently balanced, but the vast majority of tonearms aren't wired that way. So I suppose it's mainly down to the way the market is that phonos don't take a balanced input.
 

Non-Smoking Man

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VALVE phono stages, to be balanced, require a doubling of components and associated circuitry. So that's why they arent balanced - cost.

There's no inherent reason why the solid state equivalent isn't balanced - its balanced ready, as I understand it.

Chord do a balanced in and out phono, as do Aqvox, there was one similar to Aqvox that just sold in the classifieds, Avid with their TOTR Pulsare and Ayre are companies I can think of. (And, I take it, PS Audio.) The premier Whest model has balanced out. There are others but not that many.

I cant confirm zeta's claim that balanced inputs are 6db noisier - reference please.

My completely balanced 5 way active horn system is really quiet - quieter than my second system, which is unbalanced (RCAs).

Jack NSM
 

The_Krell

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I mailed PS Audio for clarification on this (waiting on reply) as there seems to be some confliction on their website.
Michael Fremer makes no mention of balanced input in his review and given he waxed lyrical over Aqvox I'm sure he would have mentioned it if it were.

Balanced technically is 6db louder (not noisier) than SE due to summing the signal which SE doesn't. 6db = doubling of volume.
 

JamieMcC

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Pro-ject have have a range of turntables that have tonearms which are manufactured to make use of balanced configuration They market the the Project Phono Box DS3 B £529 which has balanced inputs and outputs and a more spendy premium option to complement them.
 

zeta4

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VALVE phono stages, to be balanced, require a doubling of components and associated circuitry. So that's why they arent balanced - cost.

There's no inherent reason why the solid state equivalent isn't balanced - its balanced ready, as I understand it.

Chord do a balanced in and out phono, as do Aqvox, there was one similar to Aqvox that just sold in the classifieds, Avid with their TOTR Pulsare and Ayre are companies I can think of. (And, I take it, PS Audio.) The premier Whest model has balanced out. There are others but not that many.

I cant confirm zeta's claim that balanced inputs are 6db noisier - reference please.

My completely balanced 5 way active horn system is really quiet - quieter than my second system, which is unbalanced (RCAs).

Jack NSM
Simple physics. Take the case of a s/s i/p, there are two noise sources ie Rbb with a differential i/p
in effective series so noise x 2 =+ 6db. With very low noise modern devices this is less of an issue
but there nevertheless.
 

rabski

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Because in most instances the phono leads to the phono stage are less than 1 meter long - as such there is absolutely no advantage to be had in a balanced connection IMO
There are a lot of places in a vinyl front end where noise can get in, no matter how good the screening. The major advantage with true balanced is the rejection of noise pickup. Some of you lot with your moving magnet stuff don't have to worry, but my neat little AT 50ANV outputs a faintly ridiculous 0.12mV. Believe me, with that sort of signal level and with a step-up transformer, hum pickup is an issue.

I've not got round to it yet, but sooner or later I've got to rewire the Well Tempered arm. When I do so, the RCA outlets are going straight in the bin and getting replaced with a nice pair of XLRs, and I'll re-do the SUT so that at least the turntable to SUT is balanced.
 

The_Krell

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Because in most instances the phono leads to the phono stage are less than 1 meter long - as such there is absolutely no advantage to be had in a balanced connection IMO
I don't believe things suddenly start getting hum/interference >1m.

Surely you'd want to reduce any interference especially so close to the source and thus any interference at source level is just going to be amplified much more than interference further down the signal chain.
 

mac72

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Why most phono stages do not offer balanced connection/circuitry ? because it's not worth it , vinyl is inherently noisy with SNR probably at the level of 60dB and any noise induced in the cable should be still below that level unless you run the cable parallel to other high voltage not very well screened cables. Balanced cables do not remove the noise which got there prior to entering the cable but reduce the noise which could be induced over the very long runs like few meters , this make sense in recording studios.
With tonearm in the rest turn the volume control up to the top , can you hear any noise ? if you do you might consider balanced cables if not there is no point as vinyl noise would over power what you cannot hear .
 
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The_Krell

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Why most phono stages do not offer balanced connection/circuitry ? because it's not worth it ,
Which begs the question why some phono stages do offer it?

With tonearm in the rest turn the volume control up to the top , can you hear any noise ? if you do you might consider balanced cables if not there is no point as vinyl noise would over power what you cannot hear .
Just because you can't hear it doesn't mean it doesn't have an effect on the overall sound quality. I think CD's 20k cutoff has shown that.

Also you're just focusing on cables rather than a total balanced circuit from cart through to phono output.
 

mac72

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Which begs the question why some phono stages do offer it?


Just because you can't hear it doesn't mean it doesn't have an effect on the overall sound quality. I think CD's 20k cutoff has shown that.

Also you're just focusing on cables rather than a total balanced circuit from cart through to phono output.
What in your opinion balanced circuit does ?
Sorry what 20k cutoff shows , I must have missed that ?
 

rabski

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I don't disagree Slav, but SNR is not a fixed figure. The noise can be reduced and the lower the 'S' in this case, the more important the 'N' becomes. Can I hear any noise with the tonearm at rest and the volume up full. Damned right I can. Far too much for my liking, and the majority is 50Hz hum. No matter how careful I am with locating the SUT and with wiring, it finds a way in. As above, the 'S' in my case is 0.12mV, so even a vanishingly small 'N' is enough to be problematic. Balanced, at least from the cartridge to the SUT primary windings, could reduce this.

As to the 'why' part of the original question. Cost and potential commercial market. The vast, vast majority of turntables and arms are sold with a single-ended output, so building a balanced phono stage adds cost that won't be of any use to the majority of purchasers.

As above, I aim to do it from cartridge to SUT, but the phono stage is my own build and all valve. A fully balanced valve design either means massive complication or input transformers. Either of those is a very costly solution.
 
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mac72

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I don't disagree Slav, but SNR is not a fixed figure. The noise can be reduced and the lower the 'S' in this case, the more important the 'N' becomes. Can I hear any noise with the tonearm at rest and the volume up full. Damned right I can. Far too much for my liking, and the majority is 50Hz hum. No matter how careful I am with locating the SUT and with wiring, it finds a way in. As above, the 'S' in my case is 0.12mV, so even a vanishingly small 'N' is enough to be problematic. Balanced, at least from the cartridge to the SUT primary windings, could reduce this.

As to the 'why' part of the original question. Cost and potential commercial market. The vast, vast majority of turntables and arms are sold with a single-ended output, so building a balanced phono stage adds cost that won't be of any use to the majority of purchasers.

As above, I aim to do it from cartridge to SUT, but the phono stage is my own build and all valve. A fully balanced valve design either means massive complication or input transformers. Either of those is a very costly solution.
I agree about cartridge /SUT balanced connection but making phono stage balanced from input to output just don't make sense as it means asking for a trouble IMO, overcomplication of the circuit is one thing but also you need to apply RIAA somewhere which in case of "normal" stages looks like easy bit but it isn't and deviation around 0.2dB is quite common due to parts tolerances also you're adding more noise to both signals as to stay truly balanced you amplify them separately and so on .
I've said this before but repeat , if any type of noise exists before entering balanced cable would still be there after inverting the signal .
 
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rabski

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I agree about cartridge /SUT balanced connection but making phono stage balanced from input to output just don't make sense as it means asking for a trouble IMO, overcomplication of the circuit is one thing but also you need to apply RIAA somewhere which in case of "normal" stages looks like easy bit but it isn't and deviation around 0.2dB is quite common due to parts tolerances also you're adding more noise to both signals as to stay truly balanced you amplify them separately and so on .
I've said this before but repeat , if any type of noise exists before entering balanced cable would still be there after inverting the signal .
100% agree. The difference between theory and practice can bite you where it hurts when you actually come to try building stuff.
 

martinpix

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I believe that the internal wiring on tonearms is not balance so adding a balanced cable to a tonearm has very little effect , hence why spend the extra money going balanced on an input . One the signal has been amplified it makes perfect sense then to send the signal balanced on an output . Just my take I could be wrong, I have had a phono stage that had balanced and standard inputs and when I tried it with balanced in , it made no difference. I have also tried balanced and standard on the output and there is a difference that is noticeable. I do however run standard because I could not found any used balanced interconnects at a good price, and I use chord signature cables through out for synergy, if I ever find a pair at a decent price ill swap them out for balanced.
 

rabski

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I believe that the internal wiring on tonearms is not balance so adding a balanced cable to a tonearm has very little effect , hence why spend the extra money going balanced on an input . One the signal has been amplified it makes perfect sense then to send the signal balanced on an output . Just my take I could be wrong, I have had a phono stage that had balanced and standard inputs and when I tried it with balanced in , it made no difference. I have also tried balanced and standard on the output and there is a difference that is noticeable. I do however run standard because I could not found any used balanced interconnects at a good price, and I use chord signature cables through out for synergy, if I ever find a pair at a decent price ill swap them out for balanced.
The connections at the base of a tonearm and the tonearm wiring in most cases is effectively balanced. There is a + and - from each channel and a common ground, usually from the turntable chassis or the arm tube/mount. A standard tonearm DIN socket in most cases has all five connections and would allow balanced wiring. This is, however, usually wired with a standard twin coax cable so the ground and the two - pins are commoned at the tonearm plug.
 
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martinpix

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The connections at the base of a tonearm and the tonearm wiring in most cases is effectively balanced. There is a + and - from each channel and a common ground, usually from the turntable chassis orf the arm tube/mount. A standard tonearm DIN socket allows a balnced connection. The two - lines and the ground are normally not joined. This is, however, usually wired with a standard twin coax cable so the ground and the two - pins are commoned at the tonearm plug.
Thanks I stand corrected , i guess as they run a separate earth cable in most cases that balanced then effectively on a 1m cable makes little to no difference then .
 

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