WOPL Specs and Summary

drugolf

drugolf

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So I have had my fantastic WOPL400 for a couple years now and absolutely love it. When I talk to folks about it, I really don't have a lot I can say in terms of technical info etc.
Is there a place where what a WOPL re-built amp actually consists of (old parts and new parts)? How about the specifications of the resulting amp 400 and 700 amps?
I can't seem to find anything the sums it all up.

Thanks!
 
MarkWComer

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I think Ed (OldPhaser) in this forum is attempting to do just that. I'm curious myself, as I'm in the throes of revamping a 700/II. I'm curious to know exactly what I'm getting in terms of the usual stated performance specs. Interesting stuff. Regardless, I've been running my 400/II for a few years now, all I can say is that it sounds beautiful and runs tirelessly. It's an audio workhorse!

http://forums.phxaudiotape.com/show...s-Some-Amps-(Phase-Linear-amp-White-Oak-Audio)
 
laatsch55

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I have documented several 400 and 700 rebuilds complete with before and after specs...
 
oldphaser

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Gepetto said:
Some info for inquiring minds...
Click to expand...
Joe,

In order to gain a better understanding, I have some questions:

Were all of the performance specifications/measurements obtained with test equipment? Or are some SPICE model results?

You mention a 90.8KHz input filter. Could you tell me a little more about this?

Could you perform your "square wave slew rate tests" at 10% and 90% of the full amplitude of the rise time? I am also curious what the results would be at "2dB below the rated output for a single tone because the square wave spectrum contains less fundamental frequency power than a sine wave" (REF: Tektronix Cookbook of Standard Audio Tests).

The last page of your document talks about total noise. I see only (1) plot. Is the plot for left or right channels or both? I am assuming you may have used the analyzer portion of your 8903B? Did you perform an unweighted or "A" weighted measurement or something else (i.e. CCIR/ARM, etc.)? Are the results from average, RMS or peak values? Also were the inputs on the amplifier shorted or terminated with a resistor? Were the volume pots fully CCW, at 12 o'clock or fully CW? Did you reverse the amplifier power line cord and see any differences in results?


In order to get a better idea of were your test results may be also be derived from, I have an old Excel spreadsheet with test results from 7/12/2011 which indicated that you were using the following equipment:
Oscilloscope: Tektronix 2024B
Audio Analyzer: HP 8903B
DVM: Fluke 8050A
Variac: General Radio W5MT3
Cooling Fan: Howard Model 3-15-1300
Test Load: 8 ohms, 100W maximum

Are you now using any other test equipment? I would assume that you now have a load resistor larger than 350 watts since your pdf indicates results at 350 watts.

Are you recorded results/plots from the 8903B or 2024B?



Thanks!
Ed
 
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drugolf

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I started this thread looking for a simple summary of what the WOPL version of the 400 and 700 are as compared to the original PL versions. What are the main pieces/parts/sections that are replaced and or up graded and the key attributes of those?
If there are some new up dated numbers for the main specifications - the ones that mere mortals can qualify and understand - what might those be. Pretend for a moment that I am the marketing dept and I want something to put in an add.
 
oldphaser

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Parameters & Specifications List

David,

Here is a list of parameters Phase Linear stated specifications for in their sales literature, owner's manuals and service manuals over the years for 400 and 700 series amplifiers.
NOTE: (SEE MY FOLLOW-UP REPLY TO THIS THREAD FOR LINKS TO THESE DOCUMENTS.)

I have also added a few extra at the end of the list.


Ed

1.) Power Output RMS (at rated THD) (i.e. .25% for 700/700B or .09% for 700 series II)
Watts per channel, both channels driven into 8 Ω 20Hz – 20kHz:
Watts per channel, both channels driven into 4 Ω 20Hz – 20kHz:

2.) Power At Clipping Point
Watts per channel, both channels driven into 8 Ω 20Hz- 20kHz
Watts per channel, both channels driven into 4 Ω 20Hz – 20kHz:

3.) Total Harmonic Distortion (redefined as THD+N) (20Hz to 20 kHz) (4Ω and 8Ω)
Maximum level at rated output
Maximum level at 1W
(NOTE: This may have been in IHF-A-201. It was not reported by Phase Linear)
Maximum level at 250mW
(Per IHF-A-202 3.1.6. Not reported by Phase Linear)
NOTE: Worst case scenario is typically at 20KHz at very low levels (i.e. 250mW or 1W) and at rated output.

4.) I.M. Distortion (SMPTE) (60 Hz: 7kHz=4:1)
at Rated power into 8 ohms:
at Rated power into 4 ohms

5.) Frequency Response
at 1W +0 dB / -1 dB
at 1V +0 dB / -1 dB
(Note whether using direct coupled or normal inputs.)

6.) Power Bandwidth
Frequency Response +0 dB/ -3 dB


7.) Signal To Noise Ratio*
(inputs shorted) (Referenced to Rated output) (vol. pots CCW, 12 o’clock and CW)
Unweighted
“A” weighted (IHF or EIA) (measuring device per IHF-A-202 2.9.2. “A” weighting see IHF-A-202 2.9.8)
NOTE: Today’s standards typically reference the signal-to-noise to 1 watt instead of rated output

8.) Residual Noise (measuring device per IHF-A-202 2.9.2. For “A” weighting see IHF 2.9.8)
(inputs shorted) (Referenced to Rated output) (vol pots CCW, 12 o’clock and CW)
Unweighted
“A” weighted
NOTE: Measurement may be obtained at the same time as signal-to-noise ratio measurement.

9.) Damping Factor (at 8 ohms)
at 20 Hz
at 50Hz (IHF-A-202 3.11.2) (Phase Linear never used this frequency)
at 1kHz

10.) Input Sensitivity (at 1 kHz)
Volts RMS for rated output

11.) Slew Rate (NOTE: Measurement is taken between 10% and 90% of the full amplitude of square wave rise time.)
Volts per microsecond
NOTE: State frequency and V p-p at which measurement(s) were taken. “Amplifier should be operating at its rated output.” “Rated power indication on the analyzer will be 2 dB below the rated power for a single tone, because the square wave spectrum contains less fundamental frequency power than a sine wave.”
(NOTE: From what I can find regarding slew rate is that this is a "large-signal" measurement which is not clearly defined.)

12.) Rise Time (small signal) (Not clearly defined)
Microseconds

13.) Phase Shift
Leading At 20 Hz
Lagging At 20 kHz

14.) Square Wave Response
Tilt(%)
Undershoot (%):
Overshoot(%):

15.) Input Impedance
Controls fully CCW
Controls fully CW
NOTE: For 700(A) (direct coupled input, input levels bypassed)
NOTE: For 700B/700II (Note where position of potentiometer is (i.e. fully CCW, 12 o’clock or fully CW and whether in normal or D.C. mode)

16.) DC offset (Stated in service manual only)
millivolts

ADDITIONAL SPECIFICATIONS
17.) Channel Separation (a.k.a. “Crosstalk”) vs Frequency (IHF-A-202 3.14)
(NOTE Differences may occur depending upon whether you drive an 8 ohm or 4 ohm load)
(output level set at -3dB down from rated output)
Results shall be expressed in dB
at 100 Hz
at 1 kHz
at 10 kHz

18.) Dynamic Headroom (see IHF-A-202 3.2 or CEA-490-A 5.2)
NOTE: Stated in later Phase Linear DRS series amplifiers

19.) Transient Intermodulation Distortion (TIM)


* Measuring instrument used for signal-noise ratio measurements: shall respond to the average value, and shall be calibrated to indicate the RMS value of a sinusoidal waveform.
 
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