Two totally separate issues here - one is the balanced vs. unbalanced, and the other the "which side of the connection" question. The pot you link to is a balance pot, not a balanced pot - it is intended to adjust channel balance, it is not intended for a balanced connection.
There is no difference between a "balanced" and "unbalanced" pot - the difference is in how you connect them.
TNT is right - you want to keep the interconnect driven by a low impedance, so pot comes the receiving (amp) side of the interconnect.
There is no "sonic superiority" as such in a mono pot - you can make a ganged dual (stereo) pot just as good as a mono pot, the only possible issues are lack of perfect match between the two pot parts (but as two mono pots have no matching at all, I would say "not perfect" is better than "none at all"), and a possibility of some very minor crosstalk - easily fixed by moving speakers 10 cm further away from each other.
hypex ncore
Many thanks TNT and Julf!
Ouch, mixing up channel balance with balanced connection is pretty embarrassing ;-) I haven't worked with balanced connections before, so am still learning.
So I will put the pots as close to the inputs of the NC400s as I can. Yet with mono amps that ideally would have to result in using mono pots for shortest possible wiring after the pots. I remember having seen designs before that used two motorized mono pots with one remote control to keep the pots quite in sync when changing the volume, but I'd be worried to introduce potential RF and other noise into the sensitive NC400 environment with the pot motors (the control board probably could be shielded appropriately), right...?
Many thanks TNT and Julf!
Ouch, mixing up channel balance with balanced connection is pretty embarrassing ;-) I haven't worked with balanced connections before, so am still learning.
So I will put the pots as close to the inputs of the NC400s as I can. Yet with mono amps that ideally would have to result in using mono pots for shortest possible wiring after the pots. I remember having seen designs before that used two motorized mono pots with one remote control to keep the pots quite in sync when changing the volume, but I'd be worried to introduce potential RF and other noise into the sensitive NC400 environment with the pot motors (the control board probably could be shielded appropriately), right...?
Mono amps and volume control is a tricky issue - is there a special reason you want to go for mono amps (like placing them next to/inside the speaker)? If you need volume control, the possible advantages of mono amps is more than undone by the complications involved with arranging the volume control.
I am not sure I would call the NC400 a very sensitive environment. The boards are well laid out and pretty compact.
Synchronizing two motorized mono pots gets pretty complicated.
Not really - it is my (probably pretty paranoid) understanding of 'galvanic isolation' - since the NC400s are connected to the case, not sharing one case but using two separate/independent ones completely eliminates the possibilities of one channel's amp and PS units influencing the other channel's.
Nothing wrong with being paranoid, as long as it is informed paranoia.
I would not worry about two channels in the same case - I haven't noticed any interference even with 4 nc400's and 2 smps600's sharing a case. Even with two nc400's sharing one SMPS, there is no interference.
Another thing is that the worst thing that could happen even if there was interference would be a slight reduction in channel separation. It wouldn't affect distortion or SNR figures, it would just be the equivalent of moving the speakers a tiny bit closer to each other. Is that worth the fuss with trying to control two separate volume controls?
I also have to point out that even with a dual mono setup, you can never "completely" eliminate any influence - they still share a mains feed. So what amount of influence is acceptable to you?
Induced EMF doesn't affect the linearity of an amp* - so no change in distortion. It can cause noise - but in this case it is not random, uncorrelated noise, but noise related to the signal in the other channel - so the effect is that of (very small) crosstalk.
The best way to think about it is "what would I hear from the output of an empty channel when there is a signal on the other channel?".
Go for a DAC with digital level control if thats your only source would be my advice.
//
hypex ncore
Absolutely, this will arrive in a few months. Yet I have another older DAC which I love, a phono preamp and a SACD player, all without volume controls. Would have preferred to omit a preamp if possible.
Is that really better than a pot directly at the amps' inputs...?
Absolutely, this will arrive in a few months. Yet I have another older DAC which I love, a phono preamp and a SACD player, all without volume controls. Would have preferred to omit a preamp if possible.
Is that really better than a pot directly at the amps' inputs...?
Nothing can be taken for granted as being less critical to the success of the implementation. Often wiring up the connectors and PSU can be more critical with modules as it is quite easy to destroy a products excellent objective performance by putting wires in the wrong place.
This is especially true with amplifiers where you have to deal with both low and high impedances, high and low signal levels and high and low current signals and their associated return paths.
So just when you thought nothing could go wrong hehe.
Depends on your definition of "better"
I think the simplest and "best" solution is to put both channels in the same box, and have one ganged stereo pot.
howdy Matt.
And these can have measurable and listenable differences from a perfectly assembled unit?
So can you suggest what mechanisms might be at work to cause the effects described by jojip in post #8123?
Usually speaking with screwed together anodised cabinets electrical contact will be made between the different panels anyway so it's unlikely that removing a layer of the oxide would have done anything. Especially if tapped threads were used anywhere.
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