When to use/how to choose a power conditioner

[Phorize]

I'm adding https://www.audiosciencereview.com/...s/laptop-source-cheap-bad-power-supply.10401/ to this thread, just in case the info might be helpful for the OP. Basically, I was able to replicate PSU noise coming from laptop, then via the USB cable into my DAC, amplifiers, then speakers.

A passive EMI/RFI filter did nothing, but an isolation transformer did helped and the background noise added disappeared.

thanks, that’s helpful. I was looking at this thing:
https://www.ballicom.co.uk/lr1000-tripp-lite-line-conditioner.p834153.html

Looks well made and reasonable priced, but likely to be a passive rfi filter. Out of interest what transformer did you use?

 

[solderdude]

Thanks again for your replies. I have returned to trying to sort this him out. So the hum occurs from both the headphone output and the speakers-the same frequency/pitch from both. It is strikingly audible using headphones across the full range of the volume pot and with and without any other sources connected, and with everything disconnected except headphones, from anywhere in the house. I’m ruling out ground loop at the point but. The amp is an ewa claymore by Colin Wonfor. I sent the amp back to Col and he was unable to reproduce the fault in his workshop-it was fine. He was intending to visit me to look at this at my home but sadly he has become quite unwell and is selling the business and retiring. He may be able to come and test it in situ but for now I’ll need to troubleshoot this myself.

Try the amp without anything but the headphone connected in another house (not the same street), that is if Colin already sent it back.

 

[Phorize]

Try the amp without anything but the headphone connected in another house (not the same street), that is if Colin already sent it back.

I have it back so I’ll do what you suggest. My suspicion is that it will be fine on another mains. This amp is an updated iteration of the old 80’s claymore design-my old claymore had precisely the same problem on t same mains and is fault free on my dads mains.

 

[solderdude]

Then I would suggest a regenerative UPS as a power supply.
That will most likely be the best cure.
An amplifier shouldn't be that picky about the power supply.
Chances are another headphone amp will be cheaper than a good uninterruptable regenerative power supply.

 

[Hipper]

I have a US made amp here in the UK and was getting a hum at 150Hz (measured on REW). This hum came and went with no obvious pattern. I've read that because the amp was designed for 60Hz (as opposed to UK electricity at 50Hz) this might be the trouble. I don't know (I have a good power supply as far as I'm aware).

Using a power conditioner made no difference to the hum. Using a power regenerator did. Replacing the amp with a UK made one (class D) also eliminated the hum.

 

[bigx5murf]

On my PC setup, I was chasing a ground loop. Even plugging audio devices into my UPS didn't solve it. Eventually decided to just plug all audio devices into a panamax 4300 I had laying around and no more ground loop.

 

[solderdude]

I have a US made amp here in the UK and was getting a hum at 150Hz (measured on REW). This hum came and went with no obvious pattern. I've read that because the amp was designed for 60Hz (as opposed to UK electricity at 50Hz) this might be the trouble. I don't know (I have a good power supply as far as I'm aware).

Using a power conditioner made no difference to the hum. Using a power regenerator did. Replacing the amp with a UK made one (class D) also eliminated the hum.

What could be the case here (I assume hum from speakers/headphones) is that the input voltage of the mains varied too much and may have been too low at times. This can cause the regulators to not function properly and let some ripple through every now and then depending on the voltage going into the amp.
This can be cured by feeding it with enough input voltage which a regenerative UPS will do.

 

[Phorize]

Then I would suggest a regenerative UPS as a power supply.
That will most likely be the best cure.
An amplifier shouldn't be that picky about the power supply.
Chances are another headphone amp will be cheaper than a good uninterruptable regenerative power supply.

Ended up buying one of https://assets.tripplite.com/product-pdfs/en/smx1000lcd.pdf

I’ll post back when I’ve tested it. My wife will be happy, nothing pleases her more than me filling the living room of our grade 2 listed arts and crafts house with plastic boxes.

 

[solderdude]

It's not a regenerative UPS but at least it should provide close to a regulated output voltage.

 

[Veri]

My wife will be happy, nothing pleases her more than me filling the living room of our grade 2 listed arts and crafts house with plastic boxes.

I'm sure.

 

[trl]

Ended up buying one of https://assets.tripplite.com/product-pdfs/en/smx1000lcd.pdf

That's about 500 Watts (power factor of 0.5) under max. load, so I suggest not using more than 350 Watts. Inside there should be a relay-based AVR that should deal with power surges and over/sub voltages when will occur.

 

[Phorize]

It's not a regenerative UPS but at least it should provide close to a regulated output voltage.

can you recommend a regenerative one? I can cancel this as it hasn’t shipped.

 

[MRC01]

My "power conditioner" is an Equitech 1.5Q balanced isolation transformer.

View attachment 37383

...

I've always been skeptical that power conditioners are needed for power amps because good power amps already have stiff well regulated power supplies. It's a must-have from an engineering perspective.

The power supply in my amp resembles this photo, a giant toroid with ridiculous amounts of filtration capacitance, once in a while it blows a 20 amp breaker when you turn it on. When you turn it off, the music keeps playing for several seconds as it drains the power supply. For the first couple seconds there is no detectable change in sound quality. I figure if the power supply is stiff enough to handle complete loss of power for seconds, it can handle whatever ripple or variations might be on the AC line. Plus, power conditioners that can handle a big amp's continuous power draw (say up to around 2000 VA) plus whatever the rest of the system uses, can cost as much as the amp itself!

 

[Speedskater]

Plus, power conditioners that can handle a big amp's continuous power draw (say up to around 2000 VA) plus whatever the rest of the system uses, can cost as much as the amp itself!

It's the peak power of big amplifiers that causes grief to the UPS types of power conditioners.

 

[solderdude]

can you recommend a regenerative one? I can cancel this as it hasn’t shipped.

Look for an 'on-line UPS'

 

[trl]

can you recommend a regenerative one? I can cancel this as it hasn’t shipped.

Like @solderdude stated already, you need an online UPS but please consider some facts before purchasing one:
- first you need to ask "a guy" to measure your AC mains FFT and noise from your outlet.
- you need to ask manufacturer of the UPS to send you the FFT of the UPS when loaded with 25...50% of max. capacity.
- expect huge (35...45dB @1m) amount from noise of an online UPS in your auditioning room due to the way these UPSs operates (at least 1 fan working 24/7, even when powered OFF)
- batteries may not last more than 1 year, depending on manufacturer (even when powered off the batteries are still charging and charger's fan still operates)

Unless you have a living proof that your mains power has THD+N issues and maybe lot of noise and DC coming from the energy provider, then I don't think you should invest a huge amount of money into this. But if you really want to, then at least find one that is really low-noise (<30dB @1m).

I've never used "audiophile" UPSs, instead I've used online APC and Liebert/Emerson 3KVA units and both were very noise in my bedroom, so I got rid of those and purchased a line-interactive one from Legrand. All the 3 UPSs from above are true-sinewave and have a very good FFT graph with a very low THD+N, mostly the same under 20-30% load, although I was unable to find any diff. between graph of input 230V mains and output of any of these UPSs (maybe in a "dirty" neighbour things might be different).

 

[Phorize]

Thanks all. I’ve done some reading on ups topology and now get it. Off to research some products. Merry Christmas to all of you. Kris

 

[Phorize]

Looked around for online ups, a lot seem likely to be noisy, not to mention large. Persistence is often a good thing but sometimes the efficient course of action is to throw in the towel. I have an accuphase e202 in pretty much mint original condition that I picked up a few weeks ago. I’ll get that fully serviced and forget about this amp. My supply is clean enough for my other equipment, life’s too short!

 

[solderdude]

IF an occasionally too low mains frequency is your problem (seems like it from remote).
I would suggest to buy a cheap multimeter (costs around $ 10.-) with a 1000V AC setting and measure the mains voltage before investing.
Then check if the mains voltage drops below the nominal value when it hums.

Chances are all you need may be an auto-transformer that can boost the mains a few percent.
The biggest problem could be saturation of the amp's transformer so you may need to watch the temperature of the transformer.
Hand-warm is not a problem hot is.

Another solution could be buying a 100W transformer with a secondary winding of 6-0-6 Volt and connect 1 or both secondary windings in series with mains. This way you can increase or decrease the mains with 6V or 12V.

 

[Wes]

anybody ever measured noise on their AC mains to see if they need one?