Stepdown converter for AVR..recommended?

[Sylar]

After spending some time here, I understand the PSU within the AVR is a critical component as it dictates the ability to deliver high currents. I am considering of importing AVR's rated at 110V / 60Hz. Here we use 220V / 50Hz. Hence this would require a stepdown.
My question is, Is it recommended to buy 110V rated AVR using a stepdown with it, or should I only buy one that is rated for 220V & avoid a stepdown? It is cost effective for me to import, let go of warranty & use a stepdown. But am not sure if there can be any issues with using a good stepdown.

I intend to get a custom made stepdown converter. I also intend to use a regulator as we have inconsistent voltages here & would not want to risk my expensive PSU of the AVR to be damaged.

 

[PENG]

There is not much wrong using a step down unit that also converts the frequency, but it you are serious about SQ then it is best to get an AVR that is designed for your region. To try explaining the potential issues is a complicated thing and it depends on many factors. Simply put, having another such device between your wall outlet and the AVR is typically not a good thing. Also to consider, a converter of any decent size/rating almost certainly will produce an audible hum, produce extra heat and losses that you don't need to have.

 

[Rickster71]

Most companies make dual voltage AVR's. Why not just look into buying one of them?

 

[Sylar]

Most companies make dual voltage AVR's. Why not just look into buying one of them?

This catches my interest.
Do you have any specific recommendations. I am currently in search of an AVR for the PSB T6. Have created a thread in search of one over here.. Would appreciate if you can add your suggestions there.

 

[Sylar]

There is not much wrong using a step down unit that also converts the frequency, but it you are serious about SQ then it is best to get an AVR that is designed for your region. To try explaining the potential issues is a complicated thing and it depends on many factors. Simply put, having another such device between your wall outlet and the AVR is typically not a good thing. Also to consider, a converter of any decent size/rating almost certainly will produce an audible hum, produce extra heat and losses that you don't need to have.

What is SQ?
I have a decent background in electronics. A couple of links or if you could list what the issues can be would be wonderful, i can google and try understand what they are.

 

[markw]

SQ = Signal Quality.

I'm assuming that to satisfy the power draw of the unit, particularly the amplifier stages, when pumping out the power, your transformer will have to be a fairly formidible piece of metal. Otherwise, it may not deliver the power needed for maximum performance.

 

[PENG]

What is SQ?
I have a decent background in electronics. A couple of links or if you could list what the issues can be would be wonderful, i can google and try understand what they are.

I meant sound quality. I am not familiar with converters suitable for home audio applications that convert 220V 50 Hz to 120V 60 Hz. If they are available I suspect the price of a high quality unit will be high enough that you may as well buy an AVR that is designed for 220V 50 Hz.

 

[Sylar]

I read a couple of reviews of this site...not sure if this is a scam or if it is reliable.
http://www.220-electronics.com

 

[markw]

I read a couple of reviews of this site...not sure if this is a scam or if it is reliable.
http://www.220-electronics.com

You won't know until you talk to them. Ther are "converters" for some things, but no one size fits all.

 

[M Code]

Before spending your $ for a 120V AVR for use in Europe be aware there may be technical differences for:

A. Tuner frequency steps
B. OSD/GUI will be in english
C. Different video standards

Just my $0.02..

 

[PENG]

I read a couple of reviews of this site...not sure if this is a scam or if it is reliable.
http://www.220-electronics.com

That's exactly what I worry about, they step down the voltage but they don't change the frequency. As I said before, if you are not overly serious about SQ, just go with a slightly lower voltage you will be fine, otherwise stick with 60 Hz for AVRs that are designed for use in the US.

 

[Sylar]

...Also to consider, a converter of any decent size/rating almost certainly will produce an audible hum, produce extra heat and losses that you don't need to have.

This might be a dumb question...is this audible hum from it through the devices and then through speakers, or is it at the convertor itself.

 

[PENG]

This might be a dumb question...is this audible hum from it through the devices and then through speakers, or is it at the convertor itself.

I referred to the transformer itself. However, depending on the product, it could also cause the power supply transformer in your AVR hum a little louder.

What kind of AVR do you have in mind anyway? You should make sure the step down is large enough for the AVR. For example, if the AVR has a 600VA transformer in it, I would suggest your step down be rated at least 25% larger so 750 to 1000 VA would be good. I will say it one more time, if you are serious about sound quality, buy one locally so you don't have to worry about the extra voltage drop, core losses, heat, hum, and different frequency. It is not something like a toaster or electric shaver, it is the heart of your home theater, so you should not compromise if you have a choice.

 

[Sylar]

I referred to the transformer itself. However, depending on the product, it could also cause the power supply transformer in your AVR hum a little louder.

What kind of AVR do you have in mind anyway? You should make sure the step down is large enough for the AVR. For example, if the AVR has a 600VA transformer in it, I would suggest your step down be rated at least 25% larger so 750 to 1000 VA would be good. I will say it one more time, if you are serious about sound quality, buy one locally so you don't have to worry about the extra voltage drop, core losses, heat, hum, and different frequency. It is not something like a toaster or electric shaver, it is the heart of your home theater, so you should not compromise if you have a choice.

Just read your post. Had kinda ditched this idea of using stepdown and was searching for other alternatives. Will search a bit and then if no other better choice then I think I will go this route.

I was looking of the likes of 4310/4311, which was suggested in my other thread. I am not too keen on the option of having to be aware of my volume knob using a less capable AVR. At some point either me or else at home will push it to the limit.
AVR for PSB T6.

People who took this route back here at home, suggested to use a Isolation type transformer. Unsure, what n why. Will come back to this if no better choice.

 

[k_lewis]

I went through a couple of AVRs, had similar humming issues. Seems to be a design of the internals. You may be able to stop or minimize the humming by lining the internal unit cover with dynamat, or using silicon on places where the case touches metal to metal. It depends though if the hum is vibration induced or an electronic hum inside the components themselves. If the latter, not much you can do about it.

I ended up going with a Tripplite Isobar HT7300PC. Has been rock solid, no hum, and even has IR remote control so I can shut down the entire unit or switch on / off individual outlets from within my centralized remote system. It is powering a 65" LED Samsung, Integra 80.1 pre/pro, Arcam P7 amplifier (7x150w), two 500w Genesis sub amps, Pioneer BD, active shielding power blocks for all of my Synergistic interconnects and main speaker cables, and a couple of game consoles. No issues at all.

 

[Sylar]

At the time I was exploring this option I had also queried a couple of other sources. For someone else who might be exploring this option, some more info.

Normally, it is NOT necessary to convert frequency for DC-power based electronic circuitry. The ONLY exception is if they use timing circuitry by feeding off the frequency of the input waveform (done only by very cheap electronics that don't even use timer ICs; but I have seen in the past in a Sony alarm watch that used AC frequency for its clock!! When used in India, the clocks ran slower!)

Most high-end electronics have inbuilt oscillators/crystals/timer-ICs that are used to obtain clocking signals. I expect that an expensive receiver should also use such separate circuitry for clocks, especially if they market the device in multiple regions (50Hz/60Hz).

Other than that, the concern that you note is whether the 220V->110V->DC conversion will be "clean". Note that for this, the 220V->110V transformer should be of a sufficiently high rating. If your peak power o/p of the amplifier is 400W, size the transformer to at least 1kw. What this means is that the transformer can reliably supply a high enough current without clipping/saturation. For hi-fidelity, you want a sine-wave to remain a sine-wave - you want to avoid saturation.

 

[Sylar]

I had also written to denon.usa customer service.

I am exploring the option of buying a denon receiver from the US & import it to a different country. We have a different power supply standard as compared to the US. Hence I require to use a stepdown convertor. The convertor needs to convert, 220V - 50Hz to 110V - 60Hz.

Hence my question is,
1. If I use a stepdown convertor to convert the voltage from 220V to 110V, would the 50Hz frequency cause any problems which are different from 60Hz.

I intend to use the following front speakers with the Receiver.
http://www.psbspeakers.com/products/Image-Series/Image-T6-Tower
It is recommended to use a 4Ω capable amplifier.

Note: I haven't decided on which particular model to purchase yet.

Denon's Reply:

We cannot support the use of a step down transformer. The frequency difference should not cause damage to the unit however we can make no promises when converting it for a power source it is not designed for. This unit may be able to drive a 4 ohm speaker however it is only rated for 6-16 ohms, therefore I cannot recommend using speakers that are lower than 6 ohms.

 

[k_lewis]

Wow- nice 'non committal' response from Denon. I suppose though that is the best you'll get on the subject from them. Have you tried posing this question on AVS Forums? There are a number of electronics gurus over there, may be of some help.

 

[PENG]

At the time I was exploring this option I had also queried a couple of other sources. For someone else who might be exploring this option, some more info.

That fellow is mostly right but it seems he isn't clear in making his point about transformer saturation. The fact is, feeding 50 hz to the AVR could cause prematured saturation of the AVR's internal power supply transformer. Again, I don't want to write a page to explain in details the effects of the different frequency. If you wish to proceed, go right ahead but you have been advised of the potential adverse, though could be minor effects. I just can't see how you can save money, having to purchase an oversized transformer in a decent enclosure for safety and noise reduction.

 

[Sylar]

That fellow is mostly right but it seems he isn't clear in making his point about transformer saturation. The fact is, feeding 50 hz to the AVR could cause prematured saturation of the AVR's internal power supply transformer. Again, I don't want to write a page to explain in details the effects of the different frequency. If you wish to proceed, go right ahead but you have been advised of the potential adverse, though could be minor effects. I just can't see how you can save money, having to purchase an oversized transformer in a decent enclosure for safety and noise reduction.

I ditched this idea after I got replies from you guys...have already purchased the 7005 back from home itself with bill & warranty, so no stepdown et al. (got a decent deal, maybe a $300 more that I wuda liked it to be). Awaiting for it n T6 to arrive...another couple of dayz at least