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When somebody warranties an amplifier, what does the warranty cover? Does it include some quality controls, i.e. meeting some published specs? Or is it against catastrophic failure?

It sounds like you need to get a bigger dummy load. And enough to do (2) channels (both channels driven) of at least at 500 watts per channel into 8 ohms. I have several dedicated dummy loads: 1.) 1000 watts a channel at 4 ohms (total of 2,000 watts) 2.) 1000 watts a channel at 8 ohms (total of...

With regards to performing signal-to-noise ratio measurements: IHF-A-202 (1978) "the voltmeter shall have full wave average rectifying characteristics and shall be calibrated to read the rms voltage of a sine wave..." Currently I am using (2) NF Corporation Autoranging AC Millivoltmeter/Noise...

A Phase Linear 700 series II amplifier; single channel driven at 1kHz into 8 ohms at 1% THD should be around 510-515 watts. Both channels driven at 1kHz into 8 ohms at 1% THD should be around 440 watts. Both channels driven at 1kHz into a 4 ohm load at 1% THD will be close to 700 watts. NOTE...

Phase Linear as well as a lot of other manufacturer's measured the "frequency response" of their power amplifiers at 1W. So 1W into an 8 ohm load would be 2.83V output. (NOTE: An input voltage of around 78-81mV should get you there.) Phase Linear's frequency response spec was +0/-1dB at 1W. A...

Is that so?

Lee, I wasn't initially going to publish John's T.I.M. measurement results back when I first obtained a copy of this magazine because the results don't look so good in comparison to some of the other amplifiers. However, "it is what it is" as my son (with the BSEE) likes to say. John was knee...

AMPLIFIERS: T.I.M. by John Curl, Sound Advice magazine Vol. 1 No. 4 pg 32 Here are some photos of some T.I.M. measurements: Electro Research, Audio Research D-100, Phase Linear 400 and Threshold

The Art of Speaker Design Parts 1 & 2 by Lynn Olson Part 1 (includes some discussion on Horns and High-Efficiency Systems) http://www.nutshellhifi.com/library/speaker-design1.html Part 2 (The Family of Direct Radiators) http://www.nutshellhifi.com/library/speaker-design2.html

"Flame Speaker-everything you need to know for building the most revolutionary loudspeaker to sound off in 40 years!" Could this be a match to your Flame Linear amplifier? https://www.americanradiohistory.com/Archive-Elementary-Electronics/1960/Elementary-Electronics-1968-07-08.pdf see pages...

I updated my original post with some new links.

I started a new thread on TIM: https://forums.phxaudiotape.com/threads/transient-intermodulation-distortion.8673/ Ed

A Tiny History of High Fidelity Parts 1 & 2 by Lynn Olson. http://www.nutshellhifi.com/library/tinyhistory1.html http://www.nutshellhifi.com/library/tinyhistory2.html

Here is a list of documents I have gathered on the subject or Transient Intermodulation Distortion over the last couple of years: NOTE: I also have all of the AES papers. However, I cannot share them. Audio Engineering Society Papers (NOTE: Most AES/JAES papers are not free. In some cases...

Show me your facts and data. As well as your measurement and test methods. This forum should be a forum where we are sharing data and making improvements in a civilized way. I have shared a ton of information as well as documents and history on this forum. By the way, it should be noted that I...

In performing some measurements I have found the following: the phase shift on a WOPL rev E board with backplanes in a 700 series II amp is better on the low end at 20Hz than a Phase Linear 700 fully comp PL-36 pc board (with the low THD mod). The WOPL doesn't approach the higher levels of...

If you are testing the phase shift at 1kHz you will not see much. If however you are testing it at the extremes on the low end at say 5Hz on a WOPL'd 700 series II amp or 20Hz on some stock 700 series II you should see something. You should also see something on the high end at 20kHz. Are you...

Typically, the use of volume pots (approx. 100K ohms) will affect the signal-to-noise ratio by a few dB and most significantly the phase shift at 20kHz (worst case scenario is) when the pot is at the 12 o'clock position. More to follow.

Here is the schematic from the D-500 owner's manual.

Here is the schematic from the Dual 500 owner's manual.