POWER GAMES:Servo Stabilizer,CVT or Online UPS?

[ajay124]

SURT series and similar Liebert, UPS'S belong to so called "transformerless" category, meaning they wont have bulky iron cored transformers like the old generation UPS's.They employ high frequency dc-dc conversion and the only transformers you can find are small ferrite cored pcb mounted tfrs for bias supply etc

Will the bulky iron cored transformer of Mikrotek be inferior in performance to the ferrite cored pcb mounted tfrs?
APC at 30K and Mikrotek at 20K means there is a huge price difference.How do they compare on the performance front?

 

[square_wave]

I know two very experienced audiophiles who use the APC 2kva. They are very happy.
The UPS fan can create a low level hum. This sound is much less than that of a ceiling fan or the fridge running in the house. From what we noticed, if you are a "general music" listener, if one sits some 10ft away from the speakers, you cannot discern this noise at all.

Since Ajay is a classical listener, this could turn out to be a problem since you have extended periods of very low level music in classical. You may start hearing the hum along with that lone violin

 

[borg]

Will the bulky iron cored transformer of Mikrotek be inferior in performance to the ferrite cored pcb mounted tfrs?
APC at 30K and Mikrotek at 20K means there is a huge price difference.How do they compare on the performance front?

The two transformers cannot be compared as their functions are totally different.I just mentioned there is a tfr in this for the sake of it APC surt is basically a transformerless UPS with triple conversion(1)mains ac-dcwith power factor corrected rectifier,2) battery dc to higher dc bus and then3) DC to ac output).The advantage of these topology is higher efficiency, sleek, compact footprint etc, it is a very complicated circuit with microprocessors. ASIC's and possibly DSP's. there is a lot of H.F switching involved so there will be some rfi/emi

I am not really aware of microtek's design, if it is a conventional transformer based ups then it will have a charger tfr and inverter tfr, mains is fed to the chr tfr which steps down and feeds a scr rectifer connected parallel with battery and then the dc is converted and stepped up to the required ac output, these are bulky and less efficient than transformerless ups, but being a simple design more reliable especially in indian condition. Switches at lower frequencies due to transformers so there should be less rfi/emi, but indian manufacturer's dont care abit emi so i dont think these complies to any emi standard, apc is cispr 22 class A

in UPS business high efficiency and less footprint are very good selling points so nowadays these transformerless ups's are getting more popular, apc unit should be the more silent one because there is no humming tfr, only the fan noise and probably a little bit noise from the h'f inductors. you could probably find a low noise fan with same cfm and size and replace the noisy stock ones

Long back we had linear online ups's they were actually high powered transistor amplifiers,i think this the technology used in some of the exotic power regenerators for audio apps, there is no switching circuits and therefore no rfi/ emi like the apc surt like ups's

 

[square_wave]

Long back we had linear online ups's they were actually high powered transistor amplifiers,i think this the technology used in some of the exotic power regenerators for audio apps, there is no switching circuits and therefore no rfi/ emi like the apc surt like ups's

Yes. you are right. Are you aware of any other Manufacturers other than exotic audio application guys who are doing this ?

 

[anm]

is 2kva sufficient for an avr, tube pre, 200watt amp? Or should one try power backup for sources/ pre etc only, and keep power amps on surge protection (or cvt) only, due to their dynamic current requirements?

 

[sam9s]

The general consensus seems to favour an online UPS.
It would be nice if the owner's of the brands mentioned :
APC,Microtech and Emerson Liebert could post more information about
The positives
The negatives
Load handling.What happens to the system in case of a power surge?Cut-Off?Standby?Carry on without a hitch?
Number of units connected.Directly to the UPS or through an extension box?
Dealers
Prices
Servicing,Warranties,Amc's.Problems encountered if any.
Aesthetics.Is the battery built in or on a seperate rack/box.
Since the UPS is big and cannot be hidden away,the look and finish is important.
@prem
Why did you finally opt for a CVT?How noisy is it?Have you kept it in the same room or a different one?

Well I have not faced any issue as such to share with my microteck 2kva online ups. Has worked as advertised, was able to handle voltage as low as 120 and as high as 290. And being in ghaziabad you can understand the fluctuations in summers, heavy and too much and the ups took care of it all nicely. These days voltage is usually 280 plus and sometimes even crosses 295. At 295 the system cuts off to batteries. But that rarely happens. Batteries are external and are kept in the trolley. Asthatically it looks pretty decent with lcd providing enough information of the ups. More details on the link I provided. Finally about the noise, yes fan noise is there. But only when nothing is running. Else you don't hear it while watching TV or movies. That's about it any specific information needed let me know.
Yes cost. 20k including batteries and trolley.


Sent from my HTC Desire using Tapatalk

 

[unleash_me]

YouTube - PS Audio Power Plant Premier

 

[ajay124]

Shortlisted these two model:
Emerson Liebert GXT-MT+ FOR 28K
http://www.prasa-pl.com/pdf/ups/GXTMT-123-kVA.pdf

APC SRC2000XLI-CC FOR 30K
https://www.apcc.com/products/resource/include/techspec_index.cfm?base_sku=SRC2000XLI-CC&tab=models

Anybody with knowledge of both?
Fan in Emerson seems a little more noisy.
But Emerson has a pleasing LCD Display.
1 year warranty for Emerson.
2 years for APC.

 

[sam9s]

LCD Display of microteck is exactly same as Emerson. AFA warranty goes, 2 years warranty on UPS and 1 Year on batteries .....

 

[Kittu]

What is the backup time on all these above models?

 

[hifiashok]

ASIC's and possibly DSP's. there is a lot of H.F switching involved so there will be some rfi/emi

the people i was referring to earlier used this specific/prime aspect to recommend the CVT over UPS, since this could intro' avoidable harmonics.

they program the DSP/s in their UPSs. ASICs usually are for higher level apps., IMHO (since much costlier to develop/volume).

 

[sam9s]

What is the backup time on all these above models?

I did not go for backup but everything else that ayaj has described, however the backup time still is around 30 minutes on 50% load

 

[hifiashok]

http://www.my-hiend.com/vbb/showpost.php?p=115045&postcount=15

power cleaner, etc., related.... furutech

 

[ajay124]

Back up on the Emerson/APC models with internal battery pack has been quoted as roughly15 minutes by the dealers.On models with external battery connection,I was told that you could choose to attach the number of batteries according to the backup time desired.
Back up is the least important issue for me.I don't intend to play music once the back up kicks in.Simply want enough time for a proper shutdown of equipment.On back up mode there is a constant beeping sound, which would make listening to music impossible.Maybe there is a defeat option for the beep.
Until yesterday my system was connected to a power socket which was connected to a 1.4 kva inverter.Assuming 70 percent efficiency the inverter was probably not meant for handling a big power amp.Yet I only got around to realising that maybe I should not be running my system on the inverter today.Anybody doing so should check the load carrying capacity of the inverter and the peak power consumption of the equipment.In many cases it may not be a good idea to use an inverter.Whether there are issues or not,I think it is advisable to know the peak power consumption of your equipment.This is an aspect on which I have never really focused before.

 

[borg]

You say your 1.4 kva inverter couldnt support your equipment? then are you sure these 2kva units can support? did the inverter tripped due to overload? is your inverter sq wave/mdified sq wave?

 

[hifiashok]

Back up on the Emerson/APC models with internal battery pack is 15 minutes.On models with external battery you can buy more batteries to extend battery time.

this may not be a linear statement.

But back up is the least important issue.I don't intend to play music on back up batteries.Simply want enough time for a proper shutdown of equipment.

u need to revisit the o/l UPS working tech.

In any case on back up mode there seems to be a constant beep which would make listening to music impossible.Maybe there is a defeat option for the beep.

usually is.

Until yesterday my system was connected to a power socket which was connected to a 1.4 kva inverter.Assuming 70 percent efficiency the inverter was clearly not big enough to handle my cdp/pre/power.Yet I only got around to understanding my mistake today.Anybody running his system on an inverter in case of power failure, should carefully check the load carrying capacity of the inverter and the peak power consumption of the equipment.In most cases it would probably not be a good idea to use an inverter.

inverter, very bad for digital equipment. mostly 'coz not a sine wave o/p. ok for ceiling fans and light bulbs (not even CFLs).

 

[ajay124]

You say your 1.4 kva inverter couldnt support your equipment? then are you sure these 2kva units can support? did the inverter tripped due to overload?

The inverter seemed to be supporting the system,but recently the inverter fuse blew,the moment I powered on the 4B SST and I don't want to take chances.In case of electricity failure,the inverter was not only powering my cdp/pre/power but also a few lights,fans etc.
The 4B SST has a peak power consumption of 900 VA.I am assuming that a capacity of 2kVA/1400W(APC) or 2kVA/1600W(Emerson) should be adequate for the power amp+the cdp and pre.I don't intend to add any more equipment.

 

[hifiashok]

like an air-conditioner, a lot of amps., esp. tube amps, MAY have a high load at the time of being sw-on. this could lead to a brown-out like situation. however, once in the running, the load necessity stabilises (and actually MAY come down).

one way of managing this could be an equipment start-up sequence.

 

[ajay124]

like an air-conditioner, a lot of amps., esp. tube amps, MAY have a high load at the time of being sw-on. this could lead to a brown-out like situation. however, once in the running, the load necessity stabilises (and actually MAY come down).

one way of managing this could be an equipment start-up sequence.

The Bryston 4B SST has a soft start circuitry for power on.Still there seems to be a huge rush of current before the lights turn green from red.In the new 4B SST Square,Bryston claims to have improved the soft start circuit and has also replaced the membrane switch.According to James Tanner,the idea behind the memrane switch was that since the switch had no moving parts,there would be less wear and tear.But a lot of users,including me,feel that this switch is the biggest flaw in an otherwise excellent amp.
Powering on,or an airplane taking off,is the moment of truth.Once up and running,there seem to be less chances of a crash.

 

[ajay124]

Random links
Uninterruptible Power Supply (UPS): Buying Guide
Online UPS
http://www.apcmedia.com/salestools/SCON-7JHL2T_R1_EN.pdf
http://www.laaudiofile.com/tripplite.html