original pl700 question

oldphaser

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#24
The world of audio standards is a convoluted mess....i had no idea....
Lee,

I desperately need copies of IHF-A-201 (1966) and IHF-A-202 (1978).
These (2) standards would have been used by Phase Linear throughout the 1970's and early 1980's.

Unfortunately I no longer work for the airplane manufacturer. So I no longer have access to these standards. Nor am I willing to pay any $$$$'s.


Anyone out there who can help?

These standards will be put to good use.

Ed
 

Northwinds

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#25
I tried to read that stuff Ed but it went ZOOM over my head, especially the standards

All I wanted to know if those Topaz transformers could be used to power a monster audio amp. I can get 8 of the one I pictured (5kV version). He has other transformers also like them or are they only good for main current conditioners
 

Northwinds

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#26
Found this Ed, you may have seen it also

The Institute of High Fidelity, no longer exists. In its place, the
Electronic Industries Association has taken the place of the IHF regarding
standards. I find it extraordinarily interesting that amplifier
manufacturers continue to refer to IHF-202 as a marketing technique when it
no longer exists (as IHF-202) and cannot be traced as such. Note also that
references to IHF-202 dynamic power does not mean at all that the entire
IHF-202 standard was followed. That is, the purpose of IHF-202 was to
define methods for measuring amplifier performance. dynamic power was one
of those performance measurements, but certainly not all of them.
Of course, all religious overtones notwithstanding, just because a standard
no longer exists in its original form does not mean that its content is not
good or that manufacturers should not follow it. Its not required,
certainly, by law, but you would at least think that manufacturers would
pony up to a traceable standard to enhance credibility, and quit referring
to a standard that no longer exists. How credible is that!
The IHF standard, as originally published by IHF, was a comprehensive
specification on how to measure both static and dynamic amplifier
performance, and the definition of "dynamic power" was contained therein.
IHF A-202 was re-incarnated in 1981 by the EIA as RS-490, "Standard Test
Methods of Measurement for Audio Amplifiers". Publication rights of the
EIA RS-490 standard are well controlled and belong to the Telecommunications
Industry Association (TIA). You can purchase EIA RS-490 from:
http://www.tiaonline.org/standards/search_results2.cfm?document_no=EIA-490
For those interested in the dynamic power specification itself, note that
this has been passed around among those interested. Even though posting the
text of the standard itself would certainly violate copyright laws, we do
know that the spec consists of. One likely credible source of this
information that I know of is a company who markets amplifier test equipment
capable of testing against RS-490. See
http://www.audiograph.se/powercbe_lead.htm for the essentials of the dynamic
power test specification, which are:
* 1 KHz bursted sinewave with 20 ms on-time and 480 ms off-time.
* During the off-time, the signal is attenuated 20 dB.
* The amplifiers maximum output voltage is measured for each load condition
at 1% THD during the on-time.
I note that some manufacturers still refer to the "IHF standard" (!). Just
do a google search on "IHF-202" and you'll see what I mean What a joke.
Interestingly enough, Both MTX and RF tech marketing departments confirmed
to me, via telephone, that 14.4V was the "IHF standard" without
demonstrating any knowledge whatsoever of the actual standard itself as a
performance spec and test method. It was disgusting to see both the misuse
and misunderstanding of the standard, as well as the use of an obsolete
reference.
Unless someone who has purchased the copyrighted text can correct me here, I
do not believe that RS-490 itself cares about the input voltage, or that the
standard even discusses car audio operating conditions. Indeed, the
standard itself was developed before switching power supplies, or car audio
for that matter, were commonplace, and even the 1981 version, to the best of
my knowledge, does not discuss multi-channel amplifiers. I believe RS-490
deals with the test methods and output performance specifications only.
For hardcore standards junkies, here's an article that discusses the
multiplicity of standards organizations:http://www.rane.com/pdf/09sv18.pdf
 

Northwinds

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#31
So two of these would make a helluva set of monoblocs if someone knew how to build amps around them? Or a 6kV stereo amp maybe w/ dual power supply setup. Have to run it 240v to really take advantage of them eh? I think Joe said your limited to 1440 draw from a 15A socket (in reality 12A)? Or have two plugs running to different outlets that are not on the same string?

Boy, something like that would make the AK dudes jaws hit the floor
 

NavLinear

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#34
Can you get your hands on one of these? Shipping would be high but if the price was right for an isolation transformer of this size I suspect it would be worth the price of shipping.
 
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