Budget but Great CVT / Stabilizer for AV / 2ch. set up.

[rbalagopalan]

This topic I have put it as a post in some thread but did not draw any attention so I thought a separate thread would benefit the members especially who have tiny set up under 50K and it is meaning less to spend 15K on a Stab.

In my early days I was in need of a Stab for my AV set up after doing lot of research I concluded that CVTs are the most suited ones for AV.

As CVTs can give instantaneously full power even at extreme demanding conditions. For example in a movie track for a blast scene where the amplifier has to kick in more power to the speakers resulting in drawing instantaneously more power from the power source, this in turn will result in sudden dip in the voltage to compensate the demand. In case of servo stab by the time the voltage dip sensed and correction made by the servo motor the whole scene will be over. So in my perspective CVTs are the best choice.

Coming back to the topic here is my suggestion for the best available CVT / Stab., just look out for conventional A/C stabiliser which we used to keep on a wooden stool / on wooden wall bracket in those days. They are normally 4 KVA but never mind its like an asset.

The easy way to get this is keep your A/C mechanic informed so that he will give it to you whenever/ where ever takes it on exchange. Otherwise they are simply putting in scrap for RS. 80/kg. You can get it from the scrap dealer too for RS.100/kg. So over all it should not be costing more than RS.1500/- for 4 KVA. That too if you can get old SYSCOM or ALACRITY or BLUEBIRD you are lucky. Those days only copper winding was there which is more stable now getting copper is difficult including V-guard.

This way I have purchased more than half a dozen and given it in my circle.

The one what you are seeing here in photo costed me just 1.5K of course the digital metre is my handy work. It was in my HT setup, now that I bought a Bhurji CVT for HT this is serving my stereo setup now.

So people think before you spend

 

[Shivam]

4KVA CVT will result in a very high running cost (if I remember the working of CVT correctly) ! Servo is a better option.

Your stab does look good with the digital meter.

 

[shanmune]

As CVTs can give instantaneously full power even at extreme demanding conditions. For example in a movie track for a blast scene where the amplifier has to kick in more power to the speakers resulting in drawing instantaneously more power from the power source, this in turn will result in sudden dip in the voltage to compensate the demand. In case of servo stab by the time the voltage dip sensed and correction made by the servo motor the whole scene will be over. So in my perspective CVTs are the best choice.

If the servo stabilizer has sufficient VA rating to handle the dynamic power, then this should not be an issue. In fact we need to be extra careful in choosing the right VA rating for a CVT since there is a possibility for the output voltage to collapse in case of sudden in-rush in current (even if the in-rush current reaches the limit of the actual VA rating of CVT).

Generally we recommend/prefer one equipment over the other based on our personal experiences which may be specifically suitable for our equipment but may not be suitable for some other setup. I have seen equal recommendation for both Servo and CVT. Both has pros/cons. Let me put this in simple points and this is purely based on what my understanding is and so electrical engineering experts can correct me :-
- If the voltage fluctuation is so erratic (keeps on changing for every few minutes, CVT can prove useful (as servo needs to keep on moving it's mechanical parts to keep the o/p voltage in check.
- If the voltage deviation (on the lower side of the nominal ) is very high (say falling to 200 v or 210 volts), servo would be the better option.
- CVT do complete isolation of your equipment from sudden spikes/surges, but servo can't handle that sudden spikes. At the same time, some servo stabs come with in-built surge protectors and that can give protection to your system.

Others can feel to add some more to the above points or even suggest correction.

In the place where I stay, the voltage fluctuation do exist, but not erratic (in the sense - it doesn't keep on changing very often). During the day time, it almost remains close to 230 volts. While in the evening, it goes to 215 to 220 volts and bounces back to 230v after 10:00PM. So I went for a servo stab with in-built surge protection and I made sure that it has enough VA rating to handle the dynamic power required by the amplifier. For areas having very bad power supply, CVT might be best option.

You might even see people recommending online UPS over servo/CVT, but I do also see that recommendation is more for users having projectors. I am personally not convinced with online UPS, but the case might be different for others.

This topic has come for discussion in several threads in the past. The best would be for a true electrical engineering expert to give right suggestions which a layman like me can understand. The suggestions may be different for different user requirements (based on the setup, power suply condition, etc..).