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Discussion Starter · #1 ·
On the onecall.com website, some of the product descriptions (the HK7200 for example) claim "high current" as a feature, which presumably would help drive certain speakers better like my Paradigm Studio 60s which are reputed to respond well to more power.


Is this just marketing hype on the part of HK or onecall.com?


I ask because I have decided that quality power output is my primary desire in a new receiver. I think that "headroom" will probably have a greater influence on my 2-channel listening experience than any other factor in an A/V receiver.


Can anyone comment on this "high current" business, and also point me in the right direction regarding the highest powered receivers in the $1000 range?
 

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power = voltage x current


a high current amplifier will be able to drive difficult load speakers below 4 ohms


most speakers specs showing just nominal or average impedance of say 8 ohm or 6 ohm however like b&w 800 series can drop to 3 ohm minimum so these speakers will need high current to push the drivers. basically impedance varies with frequencies so it is not constant. low bass may have impedance drop to 3 ohm while high frequencies up to 32 ohm while on average is still 8 ohm as stated in specs


think of water pipe you need water pressure to really push out the water and current is similar


that is why some amps use very high quality of toroidal transformers and large capacitors to store electricity and fast supply of current
 

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Discussion Starter · #3 ·
How can I tell if it really is high current from the technical specifications instead of just blindly accepting "high current" listed a feature on a website?
 

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how high is high? i really dont know


but then good amps with output more than300W/channel should be able to output huge current


if in doubt you have to get separate pre/pro and power amps
 

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One way to judge an amps output is to look at the amperage that it produces peak to peak. Other factors to look at are the 4 ohm wattage figures and the 2 ohm wattage figures. Quality amps will publish these numbers, most receivers do not publish this information.


B&K published 42 amps peak to peak on their receivers. B&K Reference amps run 75 amps peak to peak on the 7270 for example. I suspect current production is similar.


I have read unverified information that the Denon 5803 is about 17 amps peak to peak. B&K publishes 4 ohm wattage but does not publish a 2 ohm figure for its gear.


My Pioneer VSX-49TXi has been clocked putting out 235 watts all channels driven as it blew a fuse on a 4 ohm load. Its 8 ohm figures run from 128 to 144 watts all channels (6) driven depending on the magazine doing the test.


The bottom line is that when the manufacturer does not publish the information, the information is likely to be less than ideal.


Bill
 

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There are other companies that offer high-current amps besides HK. A "high current amp" is an amplifier that has a significant amount of current that it can deliver, largely because the amplifier 1) has a very large power supply, and 2) has high quality output transitors capable of using that power to deliver the signal to the speakers. You can spot a high current amp because the manufacturer will almost invariably specify how much power in "amps" can be delivered by the amplifier. The dynamic headroom rating tells you how much additional power the amp can deliver for a 10 millisecond period over its rated power. So, for example, a 75 wpc amp that can deliver 1.0 db of headroom is capable of hitting 100 wpc for short bursts (in order to respond to the music signal). A 3 db headroom rating will mean that the amp is capable of doubling its rated power for short bursts.


Other good things to look at in ampifiers are slew rate and damping factor.
 

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Quote:
Originally posted by MrMcGoo
One way to judge an amps output is to look at the amperage that it produces peak to peak. Other factors to look at are the 4 ohm wattage figures and the 2 ohm wattage figures. Quality amps will publish these numbers, most receivers do not publish this information.


B&K published 42 amps peak to peak on their receivers. B&K Reference amps run 75 amps peak to peak on the 7270 for example. I suspect current production is similar.


I have read unverified information that the Denon 5803 is about 17 amps peak to peak. B&K publishes 4 ohm wattage but does not publish a 2 ohm figure for its gear.


My Pioneer VSX-49TXi has been clocked putting out 235 watts all channels driven as it blew a fuse on a 4 ohm load. Its 8 ohm figures run from 128 to 144 watts all channels (6) driven depending on the magazine doing the test.


The bottom line is that when the manufacturer does not publish the information, the information is likely to be less than ideal.


Bill


The Harman kardon 7200 has been measured by S&V (highly respected lab) as delivering 340 Watts into a 4Ohm load. Rated at 100wpc all channels driven its been measured delivering 140wpc all channels driven.


As for the Amp rating...Harman Kardon says: High Instantaneous Current Capability (HCC) : ±75 Amps


For under $900 you can't beat this...
 

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You also need to remember that the H/K isn't pushing 75 amps at all times. I don't know if it will actually reach this level, but it does have a robust power supply. Most of the time, depending on the price point, "high current" is simply a marketing tool. Its kinda like a TV manufacturer rating the contrast level at 3000:1. The H/K will have plenty of juice, but just don't get caught up in all the marketing hype. Being that the 7200 actually retails for closer to 2k, it doesn't really fit into the 1k category. However, most units in the 1k category and below, are simply using "high current" statements for marketing purposes.
 

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Quote:
Originally posted by Cougar
Being that the 7200 actually retails for closer to 2k, it doesn't really fit into the 1k category. However, most units in the 1k category and below, are simply using "high current" statements for marketing purposes.
Cougar - check this link please:

http://www.jandr.com/JRProductPage.p...uct_Id=3691600


And this isn't a "marketing statement", it is a fact that you can hear.
 

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The H/K 7200 is a $1000 street price amp. Look at the OneCall.com web site.


The 7200's amp section is typical H/K. The S&V figures look good, but test conditions must have changed from 8 ohms to 4 ohms. The wattage more than doubled from 8 ohms to 4 ohms which is very unlikely. I suspect that the 4 ohm test was for one or two channels, not all channels. The 75 amp figure is on H/Ks web site and is a very good number. Unless the speakers' impedance curve is very difficult and/or the sensitivity is low, the 7200 should do an excellent job.


I have no idea of the current output on the Proceed Amp5. I suspect that it is good, but would want to see published specs for 4 ohms all channels driven and 2 ohm dynamic output.


Bill
 

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H/K puts out about as much current as any other receiver you'll find from any other model at any comparable price point. The drawback is that H/Ks are generally a little devoid of features, but some people don't like tons of knobs and buttons that control useless features they'll never use, so that may be a plus for you.
 

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From what I have read the new 7300 will have some new features, including Faroudja DCDi video upscaling to output 480P on all analog video inputs. Here is a link:

http://www.audioholics.com/ces/ces20..._day3h_HK.html


Of course DVI switching would be even better.


Dsmith
 

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"High current" is pure marketing drivel. Could you build a low current 200 wpc amp? How about a high current 5wpc SET?


And Dsmith, DVI is already dead
 

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Quote:
Originally posted by Tom Grooms
"High current" is pure marketing drivel. Could you build a low current 200 wpc amp? How about a high current 5wpc SET?
What rubbish :rolleyes: . Compare the power supply from a 100W Technics poweramp (or a cheap poweramp with torodial) to a Krell 100W poweramp.


The Technics will probably use a cheap switched mode power supply. The Krell will use a large torodial transformer. The cheap poweramp will use a small torodial.


Not forgetting storage capictors either.


I have used 15W amps that outperform 100W av amps.. the 15W can handle 4 Ohm speakers.. yet the 100W av amp cut out..
 

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OK, I should have said, HK's "High Current" is marketing drivel.
 

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High Current usually refers to the power supply. You could have a 1000 horse power car (400 watts) that go's 0 to 60 in 2.5 seconds but it won't go any where without some gas (current).


If your listening at reasonable volume levels your probably only using 8 -12 watts. Look at speaker efficiency. 89db @ 1 watt/meter as an example. To go to 90db double the power, 90db @ 2 watts - 91db @ 4 watts - 92db @ 8 watts - 93db @ 16 watts, etc. We do most of our listening in the mid 90db range. Start moving over 99db for extended time and you will have some hearing damage that you will regret as you age.


I would much rather have a well designed low watt high current amplifier than a high watt unit with an inadequate or low current power supply.
 

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Yes my prior comments were pointing out the fact that the 7200 is in a whole other league, or at least should be when compared to other 1k receivers. It did and still lists for 2k msrp. This is not a correlation between its current "street price" that you see at onecall. A 2k unit should perform as well as it does, so I will once again restate that all the "high current" talk is mostly marketing hype or "drivel".
 
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