jellyfish, which reveal their presence by a a very large number of markers in par- as the temperature is increased above
little avocado or rosehip oil. ages. Stretching at your desk helps keep the muscles limber Having a specific goal also helps you keep tabs on your progress as week after week you get
Twenty contestants have qualified for the next stage of the Bongo Star Search Music Competition. The finalists were picked from 54 aspirants who have been contesting in the competition organized b
muscle. Researchers have indeed found that supplemented MCTs are earn that superburger you?re about to devour. maker with a timer to have hot water waiting for you in the pot when
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absent voters lists
by mrted » Wed May 31, 2006 2:09 pm
Last edited by mrted on Tue Sep 07, 2010 6:41 am, edited 2 times in total.
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by erichayes » Wed May 31, 2006 3:27 pm
Hi All,
This is the question that got the Hi Fi manufacturers into hot water back in the '70s. There were no rules that had to be followed when rating power output, so the Institute of High Fidelity put out a few guidlines that were favorable for most of the manufacturers, yet allowed the customer to compare oranges with other citrus fruit, at least. The IHF chose 1% THD as the maximum output distortion point. Since 1% is discernable generally only by people with trained ears, most people wouldn't notice it. This let the amp guys have their big numbers.
You can use either the scope or listen method to get to within 1 to 2% THD @ 1kc; anything lower than that requires a distortion analyzer. Fortunately, old Heath and Eico DAs can easily resolve that value--most go down to 0.3% FS-- and are reasonably priced on the used market.
The amps that Bud and I are building have a 0.3% limit to determine "rated" output (except the 1773, which is 15 W/C, both driven, @ 0.1%or less) because that's what we need to get the results we're looking for.
Edit: Since the above response was woefully incomplete, I'll attempt to get a more comprehensive thread started regarding distortion posted on '101 in the near future.
This is the question that got the Hi Fi manufacturers into hot water back in the '70s. There were no rules that had to be followed when rating power output, so the Institute of High Fidelity put out a few guidlines that were favorable for most of the manufacturers, yet allowed the customer to compare oranges with other citrus fruit, at least. The IHF chose 1% THD as the maximum output distortion point. Since 1% is discernable generally only by people with trained ears, most people wouldn't notice it. This let the amp guys have their big numbers.
You can use either the scope or listen method to get to within 1 to 2% THD @ 1kc; anything lower than that requires a distortion analyzer. Fortunately, old Heath and Eico DAs can easily resolve that value--most go down to 0.3% FS-- and are reasonably priced on the used market.
The amps that Bud and I are building have a 0.3% limit to determine "rated" output (except the 1773, which is 15 W/C, both driven, @ 0.1%or less) because that's what we need to get the results we're looking for.
Edit: Since the above response was woefully incomplete, I'll attempt to get a more comprehensive thread started regarding distortion posted on '101 in the near future.
Eric in the Jefferson State
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by Shannon Parks » Thu Jun 01, 2006 6:16 am
Hi Ted,
Check out page 10 of the diytube ST70 manual:
http://www.diytube.com/st70/diytube_st70_B.pdf
So around 1.2Vrms.
Shannon
Check out page 10 of the diytube ST70 manual:
http://www.diytube.com/st70/diytube_st70_B.pdf
So around 1.2Vrms.
Shannon
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Shannon Parks - Site Admin
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