[JDUBS]

How about this?

I have a Liebert GXT2 3000-120v double conversion UPS supplying power to a 3000va balanced power transformer.  The Liebert's output impedance is about 6 ohms...so not good.  Not sure what the impedance is after the balanced power transformer but I'm guessing not good, either.  Would a BUSS help out this chain (the impedance), specifically if placed after the Liebert and the balanced power transformer?

Thanks,
Jim

[Speedskater]

A 3000VA circuit should have an output impedance of only a fraction of one Ohm. So 6 Ohms doesn't seem to be correctable.  Was the 6 Ohms measured or is it a spec?

[JDUBS]

Speedskater, it is a calculated value per Liebert.  I asked them about crest factor and output impedance and the response was:

"The crest factor of the GXT2-3000RT120 is 3:1, while the computed value for the impedance at 2100W, 120Vac nominal is 6.85 Ohms. Hope this helps."

-Jim

[Speedskater]

That's not the unit's output impedance, that's the load impedance!

[JDUBS]

Ha!   Woops.  I'll ask them again, specifying "output" impedance.

Is 6.85 ohms decent for a load impedance #?

-Jim

[Speedskater]

It's basic Ohm's Law.
With 120V and 2100W (or 2100VA)  the load impedance is 6.85 Ohms.

With a resistive load, that's the only correct answer.

The unit's "Output Impedance" or the "Source Impedance" from the loads point of view should be a few tenths of an Ohm.

[JDUBS]

It's basic Ohm's Law.
With 120V and 2100W (or 2100VA)  the load impedance is 6.85 Ohms.

With a resistive load, that's the only correct answer.

The unit's "Output Impedance" or the "Source Impedance" from the loads point of view should be a few tenths of an Ohm.

If this is the case (and I have no arguments with Ohm's Law), I thought there were issues with using any king of power conditioner and their (general) inability to keep up with dynamic swings in music due, particularly, to impedance issues?  Isn't a wall like 1 ohm?

Would a BUSS alleviate this concern as it lowers impedance even further than a few tenths of an ohm plus it would have be more than capable of current delivery?

Thanks again - I appreciate the education!
Jim

[roscoeiii]

Don't have the technical chops to comment on the science, but I've found power conditioning to be very system and power dependent. I'd suggest giving it a try and see if you can swing it.

Asked Dave at PI Audio about this yet? He's a great guy. A real pleasure to do business with.

[JDUBS]

Asked Dave at PI Audio about this yet? He's a great guy. A real pleasure to do business with.

Thanks and yep, I figured Dave would read these in-his-circle posts and comment when appropriate.

-Jim

[Speedskater]

If this is the case (and I have no arguments with Ohm's Law), I thought there were issues with using any king of power conditioner and their (general) inability to keep up with dynamic swings in music due, particularly, to impedance issues?  Isn't a wall like 1 ohm?

Would a BUSS alleviate this concern as it lowers impedance even further than a few tenths of an ohm plus it would have be more than capable of current delivery?

Thanks again - I appreciate the education!
Jim

In this case a 1 Ohm source impedance would result in a 17.5 Volt drop at 2100VA.
The source impedance needs to be under 1/10 of an Ohm.

I don't know anything about the BUSS, but it takes a serious circuit to drop the source impedance even a little.

It's easy to measure the source impedance with a Kill-a-Watt meter and an oil-filled room heater.

[Quiet Earth]

How about this?

I have a Liebert GXT2 3000-120v double conversion UPS supplying power to a 3000va balanced power transformer.

Hey Jim,
Your post has me curious about a couple of things.

First, what is the real benefit of using a UPS in an audio system? Is it the AC regeneration that you need?   It seems like a UPS and/or AC regenerator would not be needed if you are using a balanced AC power transformer, but then maybe the AC power is very unstable in your location.

Have you recently bypassed the Leibert, and listened with just the balanced transformer in the chain?

Second, since we are discussing the order of the power chain, and since I was wondering about a Buss myself, I thought I would discuss this warning that I saw on a website describing the Magic Buss :

Warning: the Majik BUSS will not work on a circuit with a GFCI installed
        due to the Neutral to Ground filtration that is used in the unit
 
 The Majik BUSS should not be plugged into the output of a active power
        regeneration such as a PS Audio PowerPlantTM or equivalent due
        to the capacitive nature of the Majik BUSS.  Regenerators should be
          plugged into the Majik BUSS.
 

I think that any balanced power transformer which is UL listed has to have a GFCI circuit installed to comply with the UL standards. Please jump in and correct me if I have this wrong.  You should check the back of your Leibert regenerator to see if it has GFCI also. This in itself will answer your question about the chain of events.

If I get a Buss for my system, I should plug it in to the wall first, and then plug my BPT into the BUSS because there is a GFCI outlet installed in the BPT. I think I have this right . . . .

[JDUBS]

Thanks Quiet Earth...that's something that I hadn't seen before.  I'll check the Liebert for the GFCI, but my balanced power transformer certainly doesn't as I put it together myself (a la Jon Risch).

audiogoober, what's the advantage of using the Buss before the regenerator?  Is it a double-conversion unit like the Liebert?  The Liebert converts the AC to DC and then back to AC again.  I can't see any advantage to having something ahead of the Liebert as any conditioning would seem irrelevant if its conditioning something that just get's converted to DC and then back to AC.

I live in NYC and voltage flucations are a consistent phoenomena here...drives me nuts.  Plus, I'm using a 20amp circuit that is on the other side of the room and I needed a big extension cable to reach my system.  I figured something like the Liebert would help here...with any voltage or other swings (impedance?) that may arise with such a long extension cable.

-Jim

[audiogoober]

JDUBS: I apologize for the confusion. I use a CurlyBUSS into the wall, then a power regulator (not re-generator) into the BUSS. I have removed my earlier response as it does not pertain to this post. My bad and sincere apologies.

[JDUBS]

JDUBS: I apologize for the confusion. I use a CurlyBUSS into the wall, then a power regulator (not re-generator) into the BUSS. I have removed my earlier response as it does not pertain to this post. My bad and sincere apologies.

No worries at all!  Thanks for clarifying.

-Jim

[JDUBS]

Dave, any thoughts on this?

-Jim

[dBe]

Dave, any thoughts on this?

-Jim

Jim,

First my apologies for not seeing this.  We have had quite a year of medical issues in the family and we have been dealing with one for the last couple of weeks which has had a very positive outcome.  Thanks for you patience.

I like isolation and balanced power transformers in about 90% of audio applications.  I do not liike UPS units for audio unless that absolultly have to be in the link to provide data backup like in recording studios, etc.

In my old AC powered system it was configured this way:

Panel>Eaton surge protector>dedicated line>receptacle>Topaz UltraIsoTX>UberBUSS>front end
                                                             >receptacle>UberBUSS>power amps

For "most" power amplifier applications I do NOT like the sound of a BPT due to the reduction in dynamics that usually occurs.

For use with BPT I offer a ground filter circuit lift switch at no charge.  It simply disconnects the ground to Neutral filter that is present in the BUSSes.  That way there is no leakage from the capacitors and the GFI functions normally.  This gives the end user the option of using it with or without a BPT or IsoTX w/GFI.

The BUSS works very well with transformers.  That is what it was designed to do.

HTH

Dave