Does the Difference in Hz Affect the Performance of an Amplifier?

Might get a little more power and run a little hotter, but may have no effect at all....

Does it have a switch mode power supply (SMPS)... what does the power input label on the equipment say, what does the manufacturers website say?

I just downloaded the manual... no help there.

If you look through the slots in the cover you'll be able to tell if it's a big transformer of a SMPS. The weight will also tell you.

No prob if it's a SMPS, still prob ok if it's a transformer, but best to not leave it powered when not in use.

Del

The amplifier is quite heavy, so I suppose there is a transformer inside (I´ll open it once it get´s burned!)

I've used a 50Hz amplifier before (220Vac 60Hz in the Philippines) and had no problem. I did have a problem with a digital clock-radio though. The clock used the AC as the timebase causing it to run faster.

That being said, that was in the days before switching power supplies. I don't know what effect the 10Hz difference would have.

regards,

Vulcan

Nope! Just use more amps due to the step up transformer.

Please describe the outcome of the telephone call made to Denon.

The guy from Denon said:我不知道 By the way: do you know what he actually meant???? ;-)

"I do not know".

He bought it to install it on our boat, where it will get a square wave cause 220V are generated from a battery bank by means of a 2000 W inverter.... As returning it is not an option we will probably go the hard way (my next post probably will be to request help to repair the fried electronics... ;-)

I just posted. The Toroidal transformer will try to turn the square wave into a sine.....how good a job it does I cannot say.

An O'scope might be handy the first time! Then you will know!!

the only mechanism for a transformer to modify the waveform has to do with leakage inductance and the magnetic hysteresis of the core. (and also the bulk capacitance of the coils)

for line frequencies this is negligible.

"for line frequencies this is negligible."

But this is not line frequencies, this is a square wave, which is the fundamental frequency and all odd-integer harmonics of the fundamental, so the higher frequency harmonics will be squelched, and the transformer will pass something that looks like an ugly, misshapen sine-ish wave on an osciliscope.

Remember, transformers are effectively, two inductors, linked together by magnetic coupling, Inductors HATE rapid changes in current, so they will resist the sudden swing from positive to negative, and from negative to positive. That's why sinusoidal power is the standard for energy transmission, it can pass through any reactive component without wasting power due to capacitive or inductive filtering, a pure sine wave will pass through and remain a ure sine wave, only shifted in phase.

Also Square-wave power on a boat? Why not just work with simple DC? it'll be much easier on the digital electronics, and I can only guess now much interference that square wave causes for the radio-based equipment. Those 'all odd-integer harmonics' include up into the RF spectrum, so that square wave power is a broad-spectrum white noise generator to radio antennas.

I actually did this test just for you

http://imgur.com/a/nO5tt

Don't accuse me of simply changing the voltage, i have a HP3582A I can rig up to find out exactly what harmonics are squelched, and by how much.

The higher voltage is times 10 probe coming out of a msw inverter.

It then passes through an auto tranformer (i had it turned up close to 1:1) and then into a 5.5 kilogram transformer from.. another msw inverter.

the lower voltage probe is x1 on the output.

nothing significant is lost.

Now if the transformer is run so saturated that the dc resistance of the transformer's primary coil loses the peaks of the sine wave, then you might have a shred of being correct.

furthermore, you have a poor understanding of how inductors and transformers work if you think they resist the change in incoming line voltage. capacitors do that.

Ah, I had my math messed up (did someone slip me decaf this morning?) The transformer doesn't RESIST the voltage swing, it ASSISTS it, throwing in a big spike at the transition.

I don't quite understand why the signal is near zero for about 4/7th of the cycle following the spike, but I've got a lot of projects to finish up today at the plant, so my time for research is limited, I'll look into it later.

Basically I agree with that, especially about the frequencies in a square wave, but producing at minimum a positive and a negative DC, as someone suggested +- 25 volts or more from DC, means a lot of electronic "screwing around" anyway.......far more complicated than buying an off the shelf, true sine wave mains converter to make 120VAC at 60 Hz.....

Also, maybe several +- DC supplies are needed, with no common connection between them.....at least two is my best guess, one for all those LH and one for all those RH channels.....who knows?

It would be great to have an amp expert here, especially for Denon....

OK doc: If you want to save this "fine piece of equipment", you should do this, since you already planned to use a battery power supply and an inverter.

Buy an American made inverter (Peak for example, no endorsement), and it produces just what the thing feeds on - 120 VAC 60 Hz.

I won't charge you for the answer (and that's a good thing because I never do), and you will get the power supply at a cost not too different from the 220-120 V conversion, and you will not burn up your transformer.

Thanks for your input!

Step up trafo and go for it I was originally going to suggest but you won't be feeding it with 60Hz, you said "square wave" ( from boat inverter) more likely a modified sin so your step up trafo is gonna get warm and maybe filter the waveform to a rough sin at 60Hz.

Should be fine.

Save up for a true sin wave inverter.

Have you thought about opening up the amp to see what the internal power supply actually produces on the DC rails?

Per what I have heard, true sin waves are only to be got from the newest types of inverters. Mine is about 10 years old, so I suppose it produces a square wave (this is something I have to check) As soon as my son shows up with the amplifier I´ll do the autopsy to check the internal power supply. Thanks for your input!

If the appropriate power converter is used, it SHOULD work fine. Do not use an older type converter. It must be a more modern version and capable of handling the maximum power consumption of the Denon device.

Hi! in first term, let me welcome you to CR4! The inverter is big enough for the intended use, as the output is 2000 W. Best regards.

you will have a good chance of getting it working if you feed it 100 volts @50 hz rather than 120volts 60hz, but the lower voltage may provide much less peak watts into the speakers

its hard to speculate what the extra voltage will do. yeah the transformer will run much hotter.. but, how much? i have no idea.

it is pretty normal for comsumer equipment to run better on 2/3rds voltage. i have a 1/2hp induction motor for example that i found running it from 90 volts rather than 120 reduced the no load watts from 240 to 100 watts.

the transformers inside audio equipment is often well built but thermally marginal. it is not uncommon for the 135C thermal fuse to blow, it is often buried inside the primary winding. usually it is not difficult to remove and bypass or replace. i'd say there is a 50-50 chance running it at 120v 50hz will cause a saturation problem, and with saturation comes overheating, high no load losses therefore high temperatures.

It depends upon the transformer that you buy, check that its no load output is not above 120VAC, it can be a bit lower, but may I suggest more than 110VAC. A Ring transformer are best but more expensive usually....

The manual talks of 460W, go for a bit more.....say 500W or even 600W....

Unless the amp has motors in it that require the frequency as speed control, which I seriously doubt nowadays, I cannot think of a any other "important" reason why the frequency is important.....

You have the conundrum as to what to do!!!

There is a very small possibility that the internal power supply of the unit, maybe a transformer only built for 60Hz, may overheat at 50 Hz.....never heard of it actually happening, but its theoretically possible. But try it out, what have you got to lose? Leave plenty of air space around it....always a good move anyway....

If it is really modern, it may even have a SMPS or similar, which can handle frequency without even "thinking" about it!!

Has anyone looked inside to see if there is a 120/220VAC transformer, that can be reconfigured with a soldering iron to 220 VAC? Possible.....but I feel unlikely.....

Or sell it and probably lose money.......

I personally would buy a quality "Ring/Toroidal" transformer of the right size, in an earthed metal case, with plenty of air holes, and simply use the amp in the way intended....

Having an amp isolated even further from the mains supply can sometimes be a good thing!!

There is maybe someone here who knows the internal "secrets" of this particular amp.

I have had a Denon "Receiver" for some years, excellent quality, simply no problems, other than getting my brain round the cabling for attaching two (2) twin Sat receivers, a DVD player, a VHS cassette player and one TV......but now its obvious, I don't know why I had a problem, but special video cables (I forget the type name) from ebay improved things dramatically!!

Best of luck!

Hi Andy! In my OP I was actually anticipating a potential issue with the amplifier which is still not in my hands. Now, considering your post: If the inverter I have provides 2000W, and the amplifier drains about 1/4 of that: instead of buying a 220 / 110 V transformer i just replace the internal one to feed it with 12V DC, reserving those 500 W for other purposes? Sounds reasonable GELL (right) ?

You could do that, but don't forget that if they sell with a transformer that you can reconfigure, I have seen many of those over the years, you may only have to buy solder!!

How come you know that it works internally at 12 volts?

I am surprised, but I am not an amp designer......so I could well be wrong!!

I would have expected something more, like maybe 48 volts (guessing only) with such a power output myself speaker wise.....the only Denon amp I found online details of uses 15 volts!!

Best of luck.

Honestly, I have no clue with what voltage the amplifier works internally. But it is something that can be easily be found out with a volt-meter. It sounded more reasonable to me to get those XX VDC directly from 12 VDC instead then by transforming 220 AC into 110 and the latter to XX VDC (just an intellectual exercise for free ;-)

The good point of using an extra transformer in the line, is as I mentioned before, it will tend to remove those "steps" in the 220V converter (this is just in case anyone else is reading this for another reason!).

Furthermore, if you are using a 12 or 24 VDC source, you can buy a mains converter easily for 120 VAC 60Hz or 220 VAC 50Hz. Today, you can even buy ones with a very good sine wave output.....which is always good if you have anything electronic to feed.

Now, if internally the amp is 12 or 24 volts, you are dead lucky!!!

But do remember that you must add DC filtering to any source of DC as (assuming for the moment its a boat or similar) you don't want to hear every time a light switch is operated, or if the engine is running the frequency of the alternator!!

That all hangs around what the internal voltage is, how many "power" supplies are technically in place (even if its a "single" transformer, but with several secondary outputs, as good companies separate the power to left channels and right channels (some maybe for each channel, I am no expert!), depending upon how many there are, 7.1 is what I found in the manual! Which is 8 sound channels....my guess is two power supplies, which if true, you should NOT link together!!

This will cause what I believe is called, "Crosstalk", where the "sound" from one channel, appears on the other....very "low Fi"!!

Now how will you achieve that from one supply of DC????

I personally have NO idea how many power supplies are technically available in that box!! All I can say, is at least one!! But I would guess two......

But you will need some definite data, you need a circuit diagram or an expert or preferably both!!

I personally would just use the mains converter myself, one designed to give a proper sine wave at 120 VAC 60Hz.....Its the simple way......and as I said before, you are further isolated from the power source....and you don't need to open up the amp!!

But as I have mentioned, I am no expert, just bone idle and unwilling to open up an new amp!!

Do let us know what you decide to do.....

My Gainclone (LM 3875) is powered by 18V DC lithium-ion batteries. No ripple in the PS.

We have 220V 50Hz supply in India.For my gadgets with 110V 60Hz I installed step down transformer to convert 220V to 110V and it worked fine for many years.

Audio amplifiers are normally designed to operate with a DC power... The Initial AC power are therefore converted into DC, filtered and conditioned before being fed into the different branches or section of the amplifiers.. The difference in power frequency will only matter on how well the main power supply was designed prior to being converted into the required filtered DC supply! Based on that premise, you should have no problem. The audio amplifier will work and function! Good luck and enjoy your radio!

Thank you!

Stepping down the voltage will solve your frying problem. I'm not sure how well the stepdown transformer will handle the square wave from your inverter, the magnetic reluctance will round the 120 volt out a little and bring it nearer to Sine wave, but may heat up the step down Transformer. The 60 Hz will only affect the clock if it is a realtime clock using the line frequency to sync to. Never use the clock for navigation. Most electronics is after the transformer that step the multiple voltages down for the use of the input interface, the driving voltage circiut, 1st amplfication stage and then to the final driver stage, a voltage that are used to determine the power of the amplifier into 4 ohm speakers, all these voltages are Used as DC biasing voltages and it is highly smoothed by big capacity capacitors that will smooth the voltage better at 60 Hz than with 50 Hz, with the Sound/ac signal riding around the biasing voltage. The 240V to 120V stepdown transformer outside must at least be the same or more VA as the rating of the input requirement of the Amp, about the same weight as the Amplifier as a whole.

For navigation I use a GPS, which is fed with 12 VDC, so no big deal! After checking it has an internal transformer I probably will have it replaced by another one with an input of 12VDC instead of 220VAC. As there is plenty of room under the shelf I´m gonna place it, the 12V internal supply transformer can also be placed outside the amplifier.

You are totaly mistaken, that will be a multi Voltage ouput transformer, 12V for the Control IC's and input interface circiut, but 200W per channel will need a swing of at least 25V positive and 25V negative to get a smooth audio sine wave and that already indicate you nead a 50V centre tap transformer. Get somebody with the correct knowledge to help you.

I actually was speculating about this posibillity. Should it have been possible, I would have hired someone with the technical knowledge to do it.

I like your idea, that is the right way to go!!

But they have already bought the sound system.....its "too late"......

That is what I did years ago for my Caravan, a cheap, but VERY adequate, FM, AM, LW, MP3, car CD player from Aldi!!!

You don't really get much "High" in the "Fi" in a vehicle, but with (only) two good speakers, it has proved to be a boon, underway (I mean parked drinking a coffee or eating, not actually driving!!) with road reports and on site with good music and News!!

In spanish we say: "a caballo regalado no se le mira el diente".... meaning "dont look a gift horse in the mouth" (translated into plain english: when receiving a gift be grateful for what it is; don't imply you wished for more by assessing its value (even if it is a nuisance)

There is already an automotive sound system on the boat (AKA car stereo)... but my son was probably looking for the WiFi or Bluetooth capacities of this amplifier. (please don´t ask: no clue why he wants that!)

Car stereos often have an Aux In source. Just plug in your MPWiFi whatever into it at audio level via 1/8" phono plug.

This gift horse may be better off in the workshop than in a vehicle.

Have you dared to power it up yet?

The best answer so far, today's Automotive sound systems can outperform most other designs, build for shudder, bumps and extreme heat exposure. Will outlive that Denon in a boat for many years.

Do not connect square waves to the amp. The transformer will get burnt by overheating or the integral thermal fuse will blow.

Gajanan Phadte

Hi, after carefully reading your opinions we decided to get rid of the 120V Denon amplifier and to buy a power amp and good speakers for Sony the car stereo installed in the boat.

Thanks to all!

Best move ever.....

I agree with Andy Germany.....

So did you sell the Denon or use it elsewhere?

What was for dinner?

Just some meat, salad and some hectolitres of red wine....

Sounds like a fair trade to me.