Thoughts on power conditioners?

[Thomas savage]

I'd be interested to know why your amps don't like balanced power...

Don suggested its possibly because of the grounding scheme , that neutral and earth potentials are assumed the same (0) ..the amp was being pushed into oscillation.

i have a vastly superior soundstage now and totally clean female vocals right up the volume ladder.. It's most obvious on a frequency sweep though. However I have lost hall ambiance on live recordings .

I could ask Dave Belles but he tends not to answer inquires like that in my expirance.

When I first put them on balanced mains they put a leg of voltage (115v) onto the case work and gave me multiple electric shocks . That was a nightmare to get sorted and mr. Belles was consulted, he said he did not design the amps to run on balanced power lol ( according to the distributor, I never talked to Dave Belles personally) I'm not aware of him mentioning they will not run correctly though. Like most things he probably does not know himself and never thought about it... Humans ! Can't trust them to know what they should know.

 

[fas42]

You're on an interesting journey now, Thomas - you've got a step up in quality which is enough to hear what is still not right, and it's "sortin' out time!!". I have a technical background, which means I have no problems diving in and trying out things which "you shouldn't do" - but I learned a lot from doing that; I would recommend doing some experiments to try and gauge how sensitive your rig is to mains quality.

That filter you showed has similarities to what I designed and added to my cheap HT setup - but it didn't use coils, so there was no issue with saturating cores.

 

[amirm]

FYI in the US balanced power is against electrical code in residential settings. It is only approved in commercial installations which presumably has an engineer approving the design.

 

[RayDunzl]

FYI in the US balanced power is against electrical code in residential settings.

Do your 240V appliances not use a form of balanced power. Get rid of them now!

Go to your breaker box. Those "paired" breakers are drawing from both 120V phases.

Here, that includes the electric range, electric water heater, electric clothes dryer, HeatPunp compressor, and additional heating element for the heat pump if the weather gets too cold (it doesn't).

 

[amirm]

Do your 240V appliances not use a form of balanced power. Get rid of them now!

Go to your breaker box. Those "paired" breakers are drawing from both 120V phases.

Here, that includes the electric range, electric water heater, electric clothes dryer, HeatPunp compressor, and additional heating element for the heat pump if the weather gets too cold (it doesn't).

The code requires point to point connection for 240 volt. That is, only one device can live at the end of 240 volt feed (e.g. dryer). This is not so with an outlet fed by technical power (balanced). Multiple devices can be connected some of which may have alternate grounding (e.g. a cable box). That can create problems that exist when you do that and hence the reason for it being an end to end designed system.

 

[fas42]

https://en.wikipedia.org/wiki/Split-phase_electric_power.

 

[watchnerd]

Which is what happens when the SQ is good enough - the mind does the sorting out then ...

Sadly, I don't think it works for microphones.

My recordings would be so much better if I could just get the microphones to fill in the gaps in the acoustics by having minds of their own to sort this out.

 

[watchnerd]

How much, if any, of the approaches to power conditioning change if the PS is SMPS?

I know how to deal with a SMPS on the circuit board side. No idea what, if any, implications it has for the outlet side.

 

[DonH56]

How much, if any, of the approaches to power conditioning change if the PS is SMPS?

I know how to deal with a SMPS on the circuit board side. No idea what, if any, implications it has for the outlet side.

Most of this y'all already know, natch, and I am no power supply expert but here's what I have picked up designing and working with them over the years. We have to design them for our systems and work closely with the regulator manufacturers to ensure solid designs. They can be tricky little beasts and there are some subtle "gotcha's" in their design and layout -- especially layout (building one from the schematic without a serious layout review usually results in a doomed design). My comments below are essentially background and at the module level rather than the low-level circuit design and operation.

SMPS' generate a lot of high-frequency noise so need broader bandwidth decoupling. Isolating types, i.e. the type used to generate voltage from the incoming supplies, usually have a transformer to provide isolation. Because the switching frequency is fairly high (50 kHz to 500 kHz or more) the transformers and decoupling (filtering) components can be much smaller than typical linear supplies. That also means noise coupled onto the mains is much higher, Various regulatory agencies require power factor correction and filters to correct voltage/current phase (which can be pretty far off for a switcher) and to prevent SMPS' from sending "hash" back down the mains (note that the diodes in a linear supply also switch and can send noise back to the mains, again with a transformer to help reduce their magnitude and bandwidth). Note SMPS' must include feedback and thus tend to have much "tighter" voltage control at the load in addition to much quicker response (due to their high switching rate) compared to (unregulated, much lower input frequency) linear supplies.

Early SMPS' had noise issues, coupled and radiated, but improved designs and tighter regulations have cleaned them up considerably. With PF correction and a few input filter components, plus better control circuits and output decoupling and shielding, SMPS' these days should not need any extra thought or "conditioning" on their input side.

FWIWFM - Don

 

[watchnerd]

Early SMPS' had noise issues, coupled and radiated, but improved designs and tighter regulations have cleaned them up considerably. With PF correction and a few input filter components, plus better control circuits and output decoupling and shielding, SMPS' supplies these days should not need any extra thought or "conditioning" on their input side.

FWIWFM - Don

That's what I thought.

Thanks for the confirmation bias!

 

[DonH56]

A quick Google search found this site with pix of a lot of basic SMPS topologies the geeks among us may find interesting: http://www.smps.us/topologies.html --there are also tutorials that explain the operation, at least in a general way.

Most of the major SMPS chip makers (IR, LTC, TI, etc.) have detailed white papers and design guides though most of the chips are non-isolating (i.e. take a DC input and convert to a different DC output without completely isolating the input and output). The high-power designs require off-chip components, natch.

 

[Balle Clorin]

Here is some simple meaurements on Isotek and other mains filters using a cheap mains noise meter
https://www.youtube.com/channel/UCBejmHalNONJzWBVKjXg-aA

 

[Speedskater]

The only place that power line noise matters is in the signal-to-noise ratio at the power amplifier's speaker terminals. (or other audio outputs)

 

[Balle Clorin]

The only place that power line noise matters is in the signal-to-noise ratio at the power amplifier's speaker terminals. (or other audio outputs)

Like this....on amplifier output. Simulation and real life photo
I don not think mains noise can make much of a difference for a power stage at least I cannot measure any artifacts higher then 0.6mV ( and that is mostly from the amp itselv and not so much mains), it can he heards a s very low hum with the ears into the 96dB/w speaker. 1 foot away it is inaudible, so not an issue when listening.. But can mains noise effect more low level stages as Dacs and preamps/streamers?.
The noise filter I tested did not impress me, especially not the Isoteks that demand a high price for little damping of noise

Or over a resistor and a oscilliscope probe, airborne noise

EMI/FRI
occirs at line frequency intervals, in the room

 

[amirm]

Here is some simple meaurements on Isotek and other mains filters using a cheap mains noise meter
https://www.youtube.com/channel/UCBejmHalNONJzWBVKjXg-aA

Welcome to the forum and thanks for the videos! Alas, they are hard to interpret given lack of verbal commentary and plugging and unplugging.

I am not a fan of the device he is using for measurements. It down converts high frequency noise to audible band, making one think they are really audible frequencies. They are not.

The problem with mains filtering is that they all operate at pretty high frequencies (hundreds of kilohertz if not megahertz). Filtering audio band noise at full current requires huge devices which these are not.

 

[Balle Clorin]

Sorry about poor video , it wasoriginally made to help me remember and not publishing, look at the text below the video, that should make it clearer what was done

 

[amirm]

I tried to do that but ran out of patience. What is the summary of it?

 

[Frank Dernie]

Back in the 1990s Goldmund produced a mains filtration system called the AC-Curator. It had 3 types of filter but it was not in production all that long since they decided to incorporate the appropriate filters into each individual item, which seems logical to me. If an item is sensitive to aspects of the mains supply re-designing such that it is not just seems like sensible engineering to me.

 

[Speedskater]

The only place that power line noise matters is in the signal-to-noise ratio at the power amplifier's speaker terminals. (or other audio outputs)

That would be with the entire hi-fi system operating in it's normal modes and levels. While the amplifier itself may not be sensitive to the line noise problem, upstream problems are more easily measured at the amp's speaker output.

Line noise problems are often caused by the other hi-fi components power supplies, so everything needs to be turned on.

 

[Balle Clorin]

I tried to do that but ran out of patience. What is the summary of it?

The Isotek Filters are very poor and can be replaced with cheap filter at a fraction of the cost that perform better.