Thoughts on filtered power

Here i am, dragging my feet into the digital age. I've finally decided to retire the Studer and go digital. I no longer have a "quiet" room to record in, and recently i've been making recordings by way of direct injection and electronic drums to overcome my lack of recording space. I remember years ago, when hard disk recording was beginning to really take hold there was a premium attached to filtered power. As in, those fancy boxes that you plug into the wall and plug your digital gear into. I've never used one so i guess the question is, does it make a difference? I suppose the answer is subjective, my wall power may be cleaner than yours. I understand that "theoretically" it would make some difference, but objectively speaking, does it make a difference. I'm just fishing for opinions from those who have more experience than i do with recording digitally.

IMO with a proper grounded system, it will not matter at all.

For me, it doesn't make any difference. These main filters don't do more than what's already in the computer's PSU; they deal with transients and micro-cuts.
I have tried with and without and never seen any difference.
The only thing that worries me is that these filters very often have MOV's for surge protection. These can become a liability.
Check this
http://www.groupdiy.com/index.php?topic=41091.msg519049#msg519049
at Reply #10

Thanks for the responses. I had a feeling it was more fluff than stuff.

pretty much but I will say this having a furmann or the like is convenient for having the entire tack on 1 switch and with a light no less.

I may be reading this wrong but when running lots of outboard gear I hear a big difference after I put in an isolation transformer and a voltage regulator. Even tracking acoustic guitars sound way better. Im running Furman stuff btw. 4 AR-20's and 4 IT-20's

abbey road d enfer said:

The only thing that worries me is that these filters very often have MOV's for surge protection. These can become a liability.
Check this
http://www.groupdiy.com/index.php?topic=41091.msg519049#msg519049
at Reply #10

Click to expand...

Although I have not come across with it yet, it is also said that the MOVs can also be responsible for high pitch buzzing noise.

I may be reading this wrong but when running lots of outboard gear I hear a big difference after I put in an isolation transformer and a voltage regulator. Even tracking acoustic guitars sound way better. Im running Furman stuff btw. 4 AR-20's and 4 IT-20's

Click to expand...

Would you mind recording an A/B of this? Very curious to hear.

pucho812 said:

pretty much but I will say this having a furmann or the like is convenient for having the entire tack on 1 switch and with a light no less.

Click to expand...

Would those things cause a sort of surge. I always notice on certain powerboards connected to the wall socket that a spark would sometimes occur when you turn on the main socket if all the units are left on while connected to the powerboard. Does furman have the same issues?

sahib said:

Although I have not come across with it yet, it is also said that the MOVs can also be responsible for high pitch buzzing noise.

Click to expand...

When MOVs are not busy MOV-ing, they act as coupling capacitors.
That's the reason for not using surge protectors with MOVs from the Hot or Neutral to Safety Ground at the equipment end of a power line.

riggler said:

I may be reading this wrong but when running lots of outboard gear I hear a big difference after I put in an isolation transformer and a voltage regulator. Even tracking acoustic guitars sound way better. Im running Furman stuff btw. 4 AR-20's and 4 IT-20's

Click to expand...

Would you mind recording an A/B of this? Very curious to hear.

Click to expand...

Me too!

haima said:

riggler said:

I may be reading this wrong but when running lots of outboard gear I hear a big difference after I put in an isolation transformer and a voltage regulator. Even tracking acoustic guitars sound way better. Im running Furman stuff btw. 4 AR-20's and 4 IT-20's

Click to expand...

Would you mind recording an A/B of this? Very curious to hear.

Click to expand...

Me too!

Click to expand...

x3!  I've always been skeptical of power conditioning to a certain degree and would love to hear some "proof in the pudding" .

So - is it a common consensus that it is wise to remove the MOV's from cheapish Furman type power conditioners?  I currently use an APC SU22003RU 2200VA line-interactive UPS for all of my gear.  Then I have (3) of the Furman conditioners hanging off it (a older PL-8 and two newer M8LX)  - Mainly use the Furmans for the multiple outlets (power distribution) and for their lights

The APC 2200 UPS handles "global" voltage regulation and filtering for all of my gear (all on a single circuit minus power amps) - and obviously serves as a UPS for the PC's as well.  Should I remove the MOV's from the Furman units?  Is it as simple as snipping them out of the circuit?

Thanks for any clarification  8)

I'll see what I can do... Im running over 50 pieces of outboard gear plus a stack of 8 Apogee 16x Convertors, Big Ben, Sync I/O and a Lavry Gold. Its a pain to switch back all the gear to unfiltered. All I can say is I heard a lot more depth and clarity as well as a much better stereo image. If anything I think having so many convertors, thats where I'm hearing the biggest difference in sound.

Speedskater said:

sahib said:

Although I have not come across with it yet, it is also said that the MOVs can also be responsible for high pitch buzzing noise.

Click to expand...

When MOVs are not busy MOV-ing, they act as coupling capacitors.
That's the reason for not using surge protectors with MOVs from the Hot or Neutral to Safety Ground at the equipment end of a power line.

Click to expand...

The Furman M8LX's I just picked up have high-frequency filtering and surge protection from hot to neutral.  Furman brands this as "Contamination free surge protection" or similar.

I have a large APC 2200VA UPS as my primary voltage regulator and surge suppressor.  All (3) of my Furman's plug into the APC 2200 UPS - and the PC's go directly to the APC UPS.  

Q - Would I be better off removing the surge suppression part of the Furmans?
Q - Would I be even better off if I rip out all filtering in these Furmans and make them a hard-wired power distribution with lights?

Otherwords - is the filtering in the Furman's redundant and possibly detrimental when wired in series with the APC UPS?  I'm not really concerned with the Furman's surge protection (would probably prefer to get rid of it) - but if the line filtering is still serving a purpose then I'd prefer to leave it...

Thanks for any clarification!  I'm literally in the middle of re-configuring all of my racks and wring - so now is the time to tweak   ...


Rock On! 8)

Bump for some input on my above inquiry.  Do you reckon I should "gut" these cheapish Furman conditioners and just use them for their distribution and lights?  That's really all I need them for TBH as the APC SU2200 is my primary Regulator/Filter/Power Switch for all gear (minus power amps).

Is the Furman Conditioner's filtering detrimental on its own when talking Analog Preamps/Compressors/AD's and such?

Is the Furman's filtering detrimental when used "in series" with the APC SU2200 UPS' pre-existing internal filtering?


And lastly - are the Tripp Lite "True Online Sine-wave UPS" series worth a darn - or do they fall under the "modified square wave" genre of cheapish toys?  Tripp Lites like these:

http://www.tripplite.com/en/products/model.cfm?txtSeriesID=937&txtModelID=2950
http://www.tripplite.com/en/products/model.cfm?txtSeriesID=937&txtModelID=2949

I'm in a crappy rental space shared with tons of other bands - and there really isn't anything I can do to the power beyond addressing power in-between the wall-outlet and my racks of gear.  I can't say the power is god awful, but I know we get voltage fluctuations and other trash on the line - so the best approach on a budget is welcomed!

Thanks for any input!  8)

Randyman... said:

"True Online UPS"

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should not be a toy, unless they are lying criminally in their marketing blurb. "True Online UPS" should always mean your AC from wall plug is charged into a battery (ie. converted to DC) then converted back to AC. Should be practically total isolation from mains.

It's the best you can get, and you need no other type of filtering with it.

Is this the same kind of marketing like balanced power?
check http://www.equitech.com

Is this possible without negative impact on the equipment?

No, it's not the same. Balanced power is the equivalent of a balanced connection in audio. The transformer will eliminate all common-mode interference, but won't do much for switching transients, which are the main cause of disturbance. Balanced power has the advantage of being more safe, because each leg carries only 55V (for 110V mains).
UPS: Since they use some kind of transformer, there is no reason why their output would not be floating (unless there's a regulation prohibiting it). I've checked the technical data and haven't found any useful info in that respect, but I think the output of UPS could well be floating, making them a source of "balanced" power.
Considering the attractive price and the £250k warranty, the Tripp-Lite UPS seems very tempting. You may try get in touch with them and ask specifically if the output is floating.

So in either case (my "Line Interactive" APC 2200, or the Tripp Lite "Online UPS") -  I would want to "gut" all of the furman rack conditioners so they are basically "Straight Wire" outlets plus lights?

Sometimes you can find those Tripp Lite Online UPS' on clearance, and then I get a discount through my employer!  Might track one down soon, but I did just buy new batteries for the APC 2200 ($120 or so).  Might wait a little while...

Thanks for further clarification!  8)

I would expect the APC to be similar and the output probably floating or balanced.