WOPL Rev E PC Board (w/ or w/o Backplane Boards) Performance Specifications Wanted

oldphaser

Chief Journeyman
Joined
Sep 8, 2012
Messages
652
#1
Here is my request for the performance specifications for a White Oak Audio (WOPL) Rev E pc board (w/ or w/o back plane boards) installed Phase Linear 700 and Phase Linear 400 amplifiers.

If the specifications are different for use as a quasi-complementary or fully complimentary configuration then I would like those specs as well.

Likewise, if the specifications change when using the optional back-plane boards then I would like the specifications for that as well.


The list is as follows:

1.) Power Output RMS
a.)Watts per channel, both channels driven into 8 Ω 20Hz – 20kHz:
b.) Watts per channel, both channels driven into 4 Ω 20Hz – 20kHz:

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

3.) Total Harmonic Distortion (THD+N) (20Hz to 20 kHz) (4Ω and 8Ω)
a.) Maximum levels at rated output:
b.) Maximum level at 1W:
c.) Maximum level at 250mW:

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

5.) Frequency Response
a.) at 1W +0 dB / -1 dB:
or
b.) at 1V +0 dB / -1 dB:

6.) Power Bandwidth
a.) Frequency Response (at rated T.H.D.) +0 dB/ -3 dB:

7.) Signal To Noise Ratio
(inputs shorted) (Ref. Rated output)
a.) Unweighted:
b.) A weighted:

8.) Damping Factor (at 8 ohms)
a.) at 20 Hz:
b.) at 1kHz:

9.) Input Sensitivity (at 1 kHz)
a.) Volts RMS for rated output:

10.) Slew Rate
a.) Volts per microsecond:

11.) Rise Time
a.) Microseconds:

12.) Phase Shift
Leading At 20 Hz:
Lagging At 20 kHz:

13.) Square Wave Response
a.) Tilt(%):
b.) Undershoot (%):
c.) Overshoot(%):

14.) Input Impedance
a.) Controls fully CCW:
b.) Controls fully CW:

15.) Channel Separation (Crosstalk) vs Frequency
(output level set at -3dB down from rated output)
a.) at 100 Hz:
b.) at 1 kHz:
c.) at 10 kHz:

16.) Dynamic Headroom
a.) dB:


NOTE: The majority of the specifications listed above were quoted in Phase Linear product literature (i.e sales brochures, owner's manuals, and service manuals) over the years.

Ed
 
Last edited:

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
3,894
Location
Arizona
Tagline
Screw it
#2
Ed, what exactly are you asking for? Do you want results or are ou asking for the guys to use this format for testing?
 

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
3,894
Location
Arizona
Tagline
Screw it
#3
Square wave testing? Would you know what a pass and fail would look like after running? Not many people would know how to read the results and that would include YOU and me.
 

Northwinds

Veteran and General Yakker
Joined
Mar 18, 2013
Messages
7,292
Location
Coventry, CT
Tagline
Fondler errrr... fan of all Nav's avatars
#5
Even if dumbasses like me can't understand the results, at least we will have hard facts for when I make a recommendation as I get messages just about every week for me to find someone to build them a WOPL on AK or performance specs which I can't give (since I know very little, just what I experience using one) but hopefully will now get the info other people feel is so important before they plunk down their trust and money. It would be nice to have published real world facts as to what these amps can truly do so I for one am interested. Specs do matter to a lot of folks over there (and visitors here) so this will be major cool!!!

EIT: I assume this will be real test figures and not modeling
 
Last edited:

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
3,894
Location
Arizona
Tagline
Screw it
#6
I run testing on my amps and have cold hard results. I'll do it my way, he can do it his. Ed is not in charge of QA and when he starts building WOPL's, maybe then we can talk (not on the phone though).
 

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
3,894
Location
Arizona
Tagline
Screw it
#7
And, is this directed to the guy who builds his own amp or the guy that builds 10? Down the road when the guy that built one amp for his own enjoyment and decides to sell it, what happens if he has no test equipment? Is the QA department coming to the rescue???
 

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
3,894
Location
Arizona
Tagline
Screw it
#8
Then, where do we stop??? Do we get somebody qualified to reject the substandard soldering??? Or how about the guy using chineeze parts???
Bad soldering can have a detrimental effect on amp quality too. Do you make the guy rebuild it if he happens NOT to fudge on his testing???
 

Northwinds

Veteran and General Yakker
Joined
Mar 18, 2013
Messages
7,292
Location
Coventry, CT
Tagline
Fondler errrr... fan of all Nav's avatars
#9
When we talked on the phone about this Perry, I saw your point. I think if there is a standard that builders can attain, it will bring Joe's design and WOPL amps in general to the level of other competing amps who do extensive testing. I know every amp can be different, I can see with my own eyes how wires are routed, different lengths between builders, hell even types of wiring and choices of components used. My aim is to bring White Oak Audio to be viewed as a serious contender and not just a "modded" curiosity. Awhile back, there was talk the WOA was going to have it's own line of amps, not just parts for PL's so there must be some sort of standard for specifications. I think a audio show was mentioned but did not get done. I still hope to see WOA with it's own line of amps, I think this is what Joe was thinking for the future eventually

I can tell all these people that a WOPL can beat down amps that cost 10-15x more but people ask for specs instead of relying on an old hippies opinion in hyping these amps as I have done for several years

I am not Ed and I get the gist he just wants to see how the Rev E compares to the old PL board vs the WO upgrade specwise. I have no dog in this game other then being a longtime supporter of Joe's work and cheerleader of these amps but it would be nice if I could actually talk about something I know about or give people info they want in making a decision

I think Ed needs to realize that these are not PL's anymore and comparing the old components with new is sort of a moot point, it's just a PL carcass with Joe's hard work in it but the specs from a business standpoint should be out there, at least what can be attained by very competent builders

Your right totally Perry, a shadetree builder without all the proper equipment probably can build one BUT will it sound as good and perform as reliably as folks here that have all the right equipment and what Joe was thinking in designing these wonderful WO upgrades? Folks should aspire to build to the highest standards right down to the soldering. A shit job by a hack can destroy a fledgling brand and that is what I fear most. Look at the BS about flame linear... people doing things the amps were never intended to do and poor PL being stuck with that moniker. We can't let shit like that tarnish a WOPL, word of mouth works both ways
 
Last edited:

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
3,894
Location
Arizona
Tagline
Screw it
#10
I think these amps were put out in this kit form for guys to have fun and get a sense of accomplishment by building their own shit. And you are correct, this aint PL anymore unless you consider a transformer and meters still PL. I myself, I'll keep on truckin....
 
Last edited:

oldphaser

Chief Journeyman
Joined
Sep 8, 2012
Messages
652
#11
Ed, what exactly are you asking for? Do you want results or are ou asking for the guys to use this format for testing?
Perry,

All I am asking for from Joe is what specs the average guy who builds one of these amps utilizing his pc boards can expect.
Kit companies like Heathkit, Dynaco, Hafler, etc didn't have a problem quoting performance specifications.

I am not expecting guys who are building the amps for themselves to necessarily perform tests to validate all of the performance specs. After the initial design work (i.e. SPICE modeling, etc) is done on a new product a proof of concept (reality check) is performed to confirm all published specs. Subsequently, only a limited number of tests should them be performed such as those Phase Linear has outlined in their service manuals.

Ed
 
Last edited:

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
3,894
Location
Arizona
Tagline
Screw it
#12
Although having specs published may not necessarily be a bad thing. I think it may be too late. We already have hundreds of thes amps out there and as I tell my customers, if you aint impressed with the performance, send it back. Numbers mean something to some, and mean NOTHING to others. Some like having a custom printout of their amps specs but don't know what it means. Crosstalking is NOT talking about people who Cross Dress......
 

Fishoz

Veteran and General Yakker
Joined
May 20, 2014
Messages
4,253
Location
Northeast Illinois
Tagline
Always learning!
#13
Gotta tend to agree with you Sniff. Numbers mean nothing to me. Lee provided a nice little booklet with everything but it's Greek to me. I'm electrically deficient, couldn't tell a resistor from a light bulb....but I know what sounds good to me. If the amp Lee built me didn't sound good it would have gone on the sale block and I would have been looking for something else. If someone wants to see the numbers on my amp I would not show them until they heard the amp. Don't buy based on numbers, buy because of how it sounds to you. The only way to prove my system to 90% of the people out there is to have them listen. The 10% number watchers will make a decision on what they read, not by listening.

Hope this makes sense - don't want a "huh" from the Sniff....
 

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
3,894
Location
Arizona
Tagline
Screw it
#15
Here is my request for the performance specifications for a White Oak Audio (WOPL) Rev E pc board (w/ or w/o back plane boards) installed Phase Linear 700 and Phase Linear 400 amplifiers.

If the specifications are different for use as a quasi-complementary or fully complimentary configuration then I would like those specs as well.

Likewise, if the specifications change when using the optional back-plane boards then I would like the specifications for that as well.


The list is as follows:

1.) Power Output RMS
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 (THD+N) (20Hz to 20 kHz) (4Ω and 8Ω)
Maximum levels at rated output:
Maximum level at 1W:
Maximum level at 250mW:

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:
or
at 1V +0 dB / -1 dB:

6.) Power Bandwidth
Frequency Response (at rated T.H.D.) +0 dB/ -3 dB:

7.) Signal To Noise Ratio
(inputs shorted) (Ref. Rated output)
Unweighted:
A weighted:

8.) Damping Factor (at 8 ohms)
at 20 Hz:
at 1kHz:

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

10.) Slew Rate
Volts per microsecond:

11.) Rise Time
Microseconds:

12.) Phase Shift
Leading At 20 Hz:
Lagging At 20 kHz:

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

14.) Input Impedance
Controls fully CCW:
Controls fully CW:

15.) Channel Separation (Crosstalk) vs Frequency
(output level set at -3dB down from rated output)
at 100 Hz:
at 1 kHz:
at 10 kHz:

16.) Dynamic Headroom
dB:


NOTE: The majority of the specifications listed above were quoted in Phase Linear product literature (i.e sales brochures, owner's manuals, and service manuals) over the years.

Ed
I don't believe I see anywhere in here where you say "Hey Joe, I need this from YOU".... That could have been directed at anybody who has done testing on the 700 and the 400......
 

laatsch55

Administrator,
Staff member
Joined
Jan 14, 2011
Messages
55,890
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#16
I'll be more than happy to supply Ed with any measurements I can. Ed's undertaking is not an easy row to hoe. Yeah 90% of folks won't give a rats ass, but that doesn't stop me from documenting a build by testing and furnishing the paperwork.
Sure, anyone can fudge test results, and that's where integrity comes in, which Ed has in spades.
Some of these tests I'm not going to be able to do. IMD for one requires a 600.00 option card, can't handle it right now but I will eventually. The square wave response is an interesting question. I think that takes a scope with storage IIRC..

I for one, think this is an interesting subject...

from an "audiophool" standpoint, a WOPL, from it's THD & N specs alone does not represent state of the art, and it would be to thgeir detriment to base their opinion on that alone, but as Joe has told us, that is based entirely on topology, and it so happens that, that sound we love so well does not test well on THD & N. If folks can't make that distinction, we are wasting our breath anyway.
Now, when it comes to residual noise and SNR a WOPL is VERY DAMN CLOSE to state of the art if not right there, and that does take testing data to PROVE, and ya can't cherry pic the test data, I feel I have to document all of it, the good, the bad and the indifferent. I've been braggin these WOPL's up since the first A boards came out, and where I can, I like to put those specs out there.....

They are the finest amp I have ever heard, I haven't heard em all but I have a bud that damn near has and he says the same thing, and he is aware of the THD & N specs, and he understands why, some never will regardless of what you say.

I have 4 Spec 2's, great THD & N specs, in the "mud" as they say, but I don't listen to them anymore because they sound sterile to me compared to a WOPL.

Guys, we are not going to convince someone to invest in a WOPL by spec sheet alone because there are amps with better specs.....but that sound.....there it is...
 

Skratch

Chief Journeyman
Joined
Dec 27, 2011
Messages
566
Location
Huntley Il.
Tagline
Life is short, so take your time
#17
I was told many years ago that there is no such thing as State of the art, It was a sales gimmick
 

grapplesaw

Chief Journeyman
Joined
Aug 13, 2014
Messages
1,386
Location
Vancouver
Tagline
---
#18
I am in on this testing thing. Let’s keep it on the tracks. Those who do not want to participate are welcome to sit this one out.
 

Northwinds

Veteran and General Yakker
Joined
Mar 18, 2013
Messages
7,292
Location
Coventry, CT
Tagline
Fondler errrr... fan of all Nav's avatars
#19
that sound we love so well does not test well on THD & N
See, I never get the gist of that. I listen for how quiet as well as dynamic an amp is. Just what is the THD + N for a well built WOPL?

I agree, there is just something about the sound of a WOPL that sets it apart from everything else I have owned. It's not coloration either... it sounds "real" to my 53 year old fried ears

I will tell you this though, that CV A-2200 amp I use in the garage is VERY close in sound to the Clair and I can't figure that out for the life of me. The dynamics are there and I don't detect any coloration of sound either. The Dynaco 400M I had sounded like shit, the Levinson 333.5 sounded sterile and ran hot as hell. THOSE amps had a coloration to them, seemed to me to be most pronounced in the midrange for both. I wish someone could explain what I hear, that's why I thought knowing specs could maybe pinpoint where coloration starts in a power amp. I have heard the term "house sound" bandied around for Marantz, Pioneer, Sansui, Technics etc... where does "house sound" start and how do they make it?
 

Gepetto

Administrator
Staff member
Joined
May 15, 2011
Messages
7,225
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
#20
Interesting thread and responses.

The White Oak Audio product designs are based on the same topology as (some of) the original PL amp products in order to keep the sound that so many listeners have enjoyed for years and drew them to PL in the first place. I say some of because PL had many different implementations for their control board over the years but while they had these many variations, they also reused the same topology. White Oak Audio has employed a universal board concept from the start. We have no current plans to stray from that philosophy. Our goal is to resurrect as many old PL amps as possible and to keep them running for at least another 4 decades.


White Oak Audio has focused on reliability of the amp product by employing the best possible components everywhere:
  • by providing clean modern board layout optimized for very short signal path, low noise
  • by fixing the known problems that PL users complained about over the years (latch up, thump, flameout)
  • by cleaning up the wiring inside the chassis and going to multilayer backplane boards to improve power delivery and decoupling
  • by making all White Oak components drop in replacements for the original components
  • by making replacement cosmetic components with improvements to shore up the weaknesses in those original parts
  • by using USA manufacturers for all White Oak Audio custom parts (limited by the fact that nearly all electronic component parts are made outside the USA now)
  • by employing USA based assembly for all our assemblies
  • by offering wiring hints to improve the noise floor in the original amplifiers
  • by fully SPICE modeling our complete design to assure proper phase margin and stability
  • by listening extremely carefully to our customers and suggestions they have for making products even better and responding to those observations
  • By having some great and trusted friends who are willing to invest their time into beating up these White Oak Audio products harder than I do (or can do) to make them even more reliable.


If you want the specs, open the original PL service reference manual.

A carefully assembled conversion will do better in some or all areas of those original specs. One that is not so carefully assembled may do worse. Since each conversion is a creation of the owner and the care invested in that conversion, it will vary as much as kit built Dynakits did in their heyday.

Thanks for listening...
 
Top