Balanced power and switch mode power supplies

[barrows]

@skatbelt,  This is an interesting question.  I think it is likely true that not all power supplies will "like" balanced power at their input.

Back in the old days, of the earlier generation PS Audio Regenerators (the P-300, P-600, P-500, & P-1000), SMPS would often make trouble for those PS audio regenerators.  This trouble was actually caused by the high amount of capacitance that SMPS had across the AC line a their input.  This large amount of capacitance was often a problem for these older Regenerator designs to power (being essentially power amplifier circuits the Regenerators did not like a lot of capacitive loading).  I do not know if the current PS Audio regenerators (which are considerably different in design) have the same issue with SMPS loading. This may be the reason for Paul's posting RE balanced power and SMPS, or it may not be.

 

As to your situation, I would contact Chord technical support directly, and ask them point blank if there is any detriment to powering the DAVE via balanced power as you are.  There are so many factors involved in power supply design, that it would probably be assuming a lot to make a general recommendation.  Of course, balanced power is not "standard", so if in doubt, one is a bit "safer" to not use balanced power.  I would be interested to hear what Chord has to say about this in reference to DAVE.

[barrows]

1 hour ago, skatbelt said:

Barrows, one more question, in your opinion, is it more likely that Paul's statement is more related to the other design principles of the older PS Audio regenerators than them having balanced power output?

I should probably not try and read into what Paul has said further, and I would just be speculating.  As to whether balanced power is "good" for SMPS, or not, I think it would be a big generalisation to suggest either way.  The first step (after the input filter) in a SMPS is to rectify the AC to DC, and once that happens certainly the rest of the circuitry could care less if the incoming AC was balanced before rectification.  I am no expert on SMPS though...  Maybe someone reading here might know more about SMPS design and how balanced power might affect it?  From the level of understanding I do have, I do not see how having balanced power coming in would be a "problem" for a SMPS. 

[barrows]

1 hour ago, Speedskater said:

Henry Ott writes about SMPS instability when receiving power from sources like UPS's and regenerator's.

Basically it's a problem of the SMPS adjusting to the UPS, while at the same time the UPS is adjusting to the SMPS.

Any references to share for further for further investigation of the subject?  I am finding it hard to conceive how this instability might be caused?