POWER GAMES:Servo Stabilizer,CVT or Online UPS?

[borg]

A cvt works on principles of magnetic saturation and resonance, it is basically a large transformer with secondary winding tuned with a high voltage capacitor,there will be some humming noise, also by nature it cannot provide high output currents as in case of short circuit output falls to zero (excellent feature for other apps but i am not sure of implications in this application),

It is very reliable compared to a servo or online ups,(only part that can fail is a h.v capacitor), but it is susceptible to oscillations at low loads,

If the load conditions not much dynamic i would say CVT is an excellent choice, provided you can keep it away from your audio equipment to avoid the hum/harmonics pickup

 

[hifiashok]

a CVT is able to offer corrections within 100ms, like good quality o/l UPSs.

a (most) servo is rated @35ms/V!!

a servo's correction is not very accurate, i.e., it corrects beyond the need and then eventually stabilises to a close approximation.

a CVT provides arc protection, complete galvanic isolation, earth choking protection (where a servo would fail), etc. a servo would need a down line isolation tfr.

During 2nd Chennai HFV meet, a technical person was summoned to explain the basics of power conditioning. I remember them saying that Servo stablizer will be more suited for audio applications and a CVT would add hum. Don't know the technicalities involved as to how a CVT works and how and why the hum issue arises. Would like to hear your comment on that.

http://www.hifivision.com/audio-video-accessories/7337-constant-voltage-stabilizer-cvt-explained-3.html#post94325

 

[ajay124]

@hifiashok,prem,arj,borg
What are the branded CVT options in India?
I've read that it is noisy and would need to be kept away from the listening
room.
How far away?
Effectivenss as a power conditioner?
Effect on SQ?
Price?
Maintenance?
Products

 

[hifiashok]

@hifiashok,prem,arj,borg
What are the branded CVT options in India?
I've read that it is noisy and would need to be kept away from the listening
room.
How far away?
Effectivenss as a power conditioner?
Effect on SQ?
Price?
Maintenance?
Products

http://www.hifivision.com/audio-video-accessories/356-voltage-issues-power-supply-inverters-3.html#post32446

 

[GeorgeO]

I had a CVT for many years, and I would say it definitely needs to be kept away from the listening room because of hum.

 

[venkatcr]

Based upon praises from one of our members, I got in touch with Elecon Engineers, makers of Bhurji CVTs. They are offering CVTs with the following specs:

BHURJI Make CVT 2000W
Model BAVR 2400CG
I/P 180-275V O/P 220/230/240V+2%

Voltage Variation: 160 to 275 V
Voltage Regulation: +/- 2% at rated load against specified voltage
Load Regulation: 1.5% against variation of 15% to 100% at specified voltage
Wave Form: Sine Wave
THD: 3.5%
Audible Noise: 30dB to 65dB proportionate to the capacity.

I then asked them some questions that are relevant to this thread.

Q1. Is there a special version for high end audio systems? If so how much will it cost?

Ans: What has been offered is the best suited design - Bhurji UHI-CVT. RFI/EMI and other electrical noises are attenuated (to) the maximum. You may however have to keep the CVT a little away from the systems.We have used them with discos and theaters without any visible problem

Q2. The sound level of 24-65db sounds too high. Is there a possibility of reducing this?

Ans: It is the minimum resonance noise in case of Bhurji CVTs. Keep it near the power source and not near the system to avoid magnetic radiation.

Q3. Do you have any literature in the differences between a CVT and a servo stabiliser?

Ans: It is the instantaneous response and voltage correction within one and half cycles (30 milliseconds) besides ultra high isoaltion from mains - an inbuilt feature - that make CVTs far superior ,

In a servo, the volatge correction is done through a motor that takes a few seconds. The motor cannot react fast enough for random fluctuations. Servos also do not have noise elimination nor isolation from mains.

In my case, I will be placing the CVT outside my HT room and placed after the Audire Zephyr that I already have.

Cheers

 

[GeorgeO]

Interesting info.

 

[borg]

I thought bhurji cvt's were made by bhurji electronics delhi,

65db is quite high, you will need to keep it in a seperate room defenitely

 

[ajay124]

Spoke to Mr.Yogesh at Elecon Engineers,Delhi.09868176425.
Bhurjee CVT with 1900 va output app.22K+vat+shipping
Bhurjee CVT with 2400 va output app.26K+vat+shipping

According to him:
-a CVT is the best option for surge protection,uniform power between 230-240,isolation and noise filtering.
-An online UPS would provide the extra feature of a battery backup but otherwise cannot match the performance of a CVT.
-A servo stabilizer is not a good option for audio video.
-The CVT would have to be kept in a different room,veranda,whatever and a single power cable would transfer the power to a point near the music system.
-Simple installation-plug and play.

Seems like a viable option.Anybody interested in participating in a bulk order
after a little more confirmation of facts may please add their Yeah! to the thread

 

[captrajesh]

Sounds good. Wonder how much do the equipment of similar ratings from other companies cost.

 

[hifiashok]

I thought bhurji cvt's were made by bhurji electronics delhi,

http://www.hifivision.com/audio-video-accessories/356-voltage-issues-power-supply-inverters-3.html#post204175

 

[arj]

this whole input power option is far more complex than it appears. personally ever since i discovered changes being brought in by power cords more than a year back have really been struggling to get this right.

If you are only looking at protection..then any of these can work right.

problem is when you bring quality of power and its impact into the whole frame.

At least in my Apartment quality of power really Sucks...and the quality of sound changes to almost sublime levels post 10:30 pm or so (taking into account drop in Ambient noise as well). And am looking at a solution to getting it to work at htose levels at any time !

Whle the best solution is an APS Purepower regenerator from all sources I could find.. it is far too expensive for me to consider at this momment ( try going through this thread !!

there is another factor to this- any SMPS source further pollutes the power..hence its very important to have your CD/DAC to be completely isolated from your analogue amp/preamp as well.


anyway all this depends on the extent to which one wants to do this...and hence the plethora of options/conditions- i thought I'd rather hold back untill I get clarity on the matter. I would still advise you to get to check this for yourself in your home before taking any big step !

BTW anyone experience with Audires products and costs ? the Sirocco looks interesting from a pure sinewave output view.

 

[hifiashok]

Based upon praises from one of our members, I got in touch with Elecon Engineers, makers of Bhurji CVTs. They are offering CVTs with the following specs:

sir, with all due respect, Elecon Engineers are not the makers but the resellers/dealers of Bhurji CVTs. makers are http://www.hifivision.com/audio-video-accessories/356-voltage-issues-power-supply-inverters-3.html#post204175

 

[prem]

Hi Ajay 124

I have a 1KVA CVT. I brought it from Hyderabad from KB Powercare. Jacob, owner of Rethm, recommended me this supplier. Cost me about Rs 18000. My entire system is on the CVT. Its kept outside the house at the entrance at the top. Its not as noisy as people make it out to be. If your entire system draws a max of 600 - 750 W, you need a 1KVA CVT. Thats the general thumb rule. I personally prefer the CVT in my system to the PS Audio regenerator which i tried for my cd player. And i also prefer it to Shunyata, Powerwing and Haley.

 

[hifiashok]

Sounds good. Wonder how much do the equipment of similar ratings from other companies cost.

my humble submission, though I do not have any interest whatsoever (commercially or otherwise); go with the recognised best in this space. quality of copper, components and design matters. and Bhurji has been closest to a no-compromise product possible. i hav mentioned elsewhere, the Bhurji owner does not believe in compromises, reasonably speaking. the cost differences MAY not warrant the alternates (unless this means upgrading the mains_to_CVT power cord, changing the CVT i/p plug to an MCB and removing the plugs from CVT o/p and soldering the o/p power cord/s direct to the contacts/taps [all that I did]).

 

[ajay124]

Hi Ajay 124

I have a 1KVA CVT. I brought it from Hyderabad from KB Powercare. Jacob, owner of Rethm, recommended me this supplier. Cost me about Rs 18000. My entire system is on the CVT. Its kept outside the house at the entrance at the top. Its not as noisy as people make it out to be. If your entire system draws a max of 600 - 750 W, you need a 1KVA CVT. Thats the general thumb rule. I personally prefer the CVT in my system to the PS Audio regenerator which i tried for my cd player. And i also prefer it to Shunyata, Powerwing and Haley.

The 4 B SST peak power consumption is 900VA.I would need at least 1500VA for everything.How long have you had it?Any difference in SQ without or without the CVT?I have been told that in low voltage conditions the CVT does not function as well as an Online UPS.Also that it should be kept switched off when not in use ??

 

[hifiashok]

65db is quite high, you will need to keep it in a seperate room defenitely

one has to carefully calculate the CVT rating to procure. since a CVT runs @85% efficiency, it runs best (read quietest) on full rated load. so, buying a large CVT and using a smal load would mean more hum; correct load, least hum.

 

[hifiashok]

I have been told that in low voltage conditions the CVT does not function as well as an Online UPS.

everything is ratings based. within the stated range, it will work fine. outside, even a o/l UPS will not.

Also that it should be kept switched off when not in use ??

absolutely (unlike in the case of an o/l UPS that you will NEED to keep turned on 24*7, meaning loss of efficient use of power owing to a device that is not using it but still taking a trickle), why would you want to keep anything turned on if it is not needed (and it is not it's necessity)..

 

[hifiashok]

At least in my Apartment quality of power really Sucks...and the quality of sound changes to almost sublime levels post 10:30 pm or so (taking into account drop in Ambient noise as well). And am looking at a solution to getting it to work at htose levels at any time !

room conditioning. or better still, (nearest to possible and practical) sound-proofing. ........best BOTH!!!

 

[ajay124]

my humble submission, though I do not have any interest whatsoever (commercially or otherwise); go with the recognised best in this space. quality of copper, components and design matters. and Bhurji has been closest to a no-compromise product possible. i hav mentioned elsewhere, the Bhurji owner does not believe in compromises, reasonably speaking. the cost differences MAY not warrant the alternates (unless this means upgrading the mains_to_CVT power cord, changing the CVT i/p plug to an MCB and removing the plugs from CVT o/p and soldering the o/p power cord/s direct to the contacts/taps [all that I did]).

Behind my audio rack is a window and beyond that a veranda with a 5 amp power socket which is also connected to a Sukam inverter.If I connect the CVT to this point in the veranda what is the best option for connecting the CVT to the cdp,pre,power.Ideally I would prefer the shortest,simplest,preferably a direct connection to the CVT.Using an extension board with multiple sockets does not appeal to me and would be the last option.Distance from CVT to audio rack would be 2 meters.
To protect CVT from rain/dust/theft I would need to house it in an iron mesh/box.How much ventilation would it require?Can it be left permanently powered on?