WOPL400 “Jesse”

[Carl182]

Hi everyone! Second post ever after my introduction here.
Finally, done with my PL400 restomod. Extremely satisfied with the overall audio experience.
Proud of having made it with my own hands and brains.
Thank you White Oak and Wattsabundant for your work and dedication.
Also, thank you all at Phoenix Audio for the warm welcome and all the invaluable information (including anger outbursts and Nav-babes, all of it!).
Doing this post now to have your comments, thoughts, and critiques; and to hopefully give back something to the newcomers as well!
Enjoy!



WHAT I HAD
- Phase Linear 400 (Series 1, 220-240 VAC)
- Serial No.1243-193A (Unit No.193 built on December 1973)
- Matching power supply capacitor date codes (STM / 91M85RC92 / 5900MFD 85VDC lot code 11607346).
- Matching transistor date codes (Phase Linear “blue label” lot code 7346 – week 46, year 1973).
- Autograph / Name on sticker: “Jesse” (White bar sticker on power cap, with no “classic” orange circular sticker on the inside of frame. More here.).
- Checked for no mechanical or electrical modification: looks like untouched for the last 48 years.

WHY I HAD IT, WHY I DID IT
The unit was just abandoned by the previous owner, a musician, after having burned highly valuable speakers. I have no other background info.
A mutual friend brought it to my attention. One VU meter pegged at turn-up. Some lamps were off.
Checked the original manual, spotted the defect, looks like not worthy per my initial thoughts and general audio approach.
BUT:
I then study Phase Linear’s history and role in audio + I discover Phoenix Audiotape = fuck I’m hooked and here we are, after many hours and EUROs less in my life.

WHAT I DID
- White Oak PL14
- White Oak Backplanes (Full-comp, Dual Mono wiring)
- Wattsabundant Output Relay Board
- New transistor set (ON Semicon MJ21195G + MJ21196G)
- New thermal interfaces (Bergquist SIL-PAD TSP 900 TO-3)
- New rectifier (GeneSiC Semicon 600V 25A metal frame)
- New power supply capacitors (Nichicon 100V 15000uF)
- New speaker binding posts (coherent aesthetics)
- New RCA input connectors (coherent aesthetics)
- Relamping (6.3V incandescent bulbs)
- Rock-solid bias @ 0.370V
- All internal rewiring as per WO specs (AlphaWire, Belden)
- New mains wiring (Belden CYSD03 3x15 AWG + metal braid shield) with IEC socket termination
- ON/OFF switch (old-school lever, sideways and ON position upwards)
- Integrated / Invisible mains cable holder and chassis grounding
- Deep aesthetical cleaning
- Sanding/Repainting of VU Meter frames
- Custom-designed 3D-printed handles (details below)
- Restoration Logbook: includes original manuals and service bulletins (courtesy Wattsabundant), WO+WA instructions (not sharing elsewhere due the profound respect I nurtured for their work), BOM and invoices of new parts, 250+ step-by-step photos as a next-owner-courtesy (we never really “own” these things).

WHAT’S NEXT
- Trying to figure out the LEFT VU Meter problem (see 3rd post on this thread - any help super welcomed!);
- Thinking of implementing WO LED Board;
- Trying to sell all original innards (OG wiring ass.y, transistors, RCA + speaker posts all of which are still perfectly usable, power caps, rectifier, mains wire) (pm an offer I can’t refuse if interested, I’m giving priority here before the bay).

HOW IT SOUNDS
I don’t think I have the right setup and audio approach to let this horse run in the wild – maybe I’m wrong, change my mind. My system currently has a minimalistic and hi-efficiency approach: driving my WOPL400 I have a DIY Nelson Pass B1 NuTube Buffer, while right after I’ve a pair of DIY Fostex FE166e backloaded horns (2.0 full-range, 8 ohms as minimum value along the spectrum, 94 dB/W(m) efficiency).
Sure enough, the setup will express every noise and imprecision, but the meters would not even move, at reasonable listening levels.
That said, after some burn-in hours, I’m highly impressed by its behavior.
It surely is an excellent performer.
Precise yet smooth and round at all frequencies, with a non-existent noise floor.
Maybe a bit too relaxed, but still, it is too early to say and maybe the overall system isn’t just right for it.
Will try to update sooner or later!

RELEVANT PICTURES FROM LOGBOOK WITH NOTES


Jesse now, front view in amazing Technicolor.


Back view. Mains wire and socket, switch, caps + rectifier screwheads, handles and central cover WO screw.

Side view. Slight angle inclination thanks to the integrated feet in the custom handles. Looks great standing on the floor as the system centerpiece.
If you look into the abyss, the abyss looks back into you.


"Jesse".


Let me see you strip down to the bone.




Incredibly intact after 48 years. Still solid substrates, solder joints and sleeves.


Time to go. Classic PL XPL909s (blue labels) and RCAs on mica and goop. Weird to have 5 slot screws among the others. "Craftmanship".

 

[Carl182]

New rectifier and power caps. Fitting those fatsos was not easy. Recycled all chassis existing holes but had to drill 2 new.
At least saved some room in depth, good for the new internal wiring.


Test fit. 2mm diagonal clearance. Sheesh.


Side view. More space on the right side than the originals. Good for thick wire bends.


New cap supports, new rectifier, new power switch, new wires and termination style.
Integrated chassis earthing (scraped a bit of chassis paint and triple-checked the connection.)


Right after soldering WO and WA boards.
(NOTE: Zoebel Network on WA Outupt Relay Board removed afterwards. "Read the instructions" reminder. Thanks Don for your support.)


Chassis cleaned, new rims new tires.


Isopropyl alcohol and ultra-fine microfiber cloth on faceplate and VU Meters. Sanded and repainted the black frames.


The power-block finished and tested.


Incandescent bulbs relamping. WARNING: the PCB traces pop out and are super fragile. DO NOT PRESS OR USE FORCE.
Reflow and wick-out each hole. DO NOT use the type of bulbs you see here: find yourselves bulbs without the plastic body. These ones barely fit the meter holes, resulting in a not perfect liminous uniformity. Otherwise, 6.3V, glass shape and leg lenghts were OK.

Custom designed and 3D printed handles. Key features:
- The front shape is a 3mm offset of the original faceplate. Thus, it protects the faceplate corners;
- They integrate invisible PU feet by 3M, thus rasing the lower faceplate edge by 3mm and giving a slight "angle" to the whole assembly;
- They do NOT look for "design integration", but want to be a clear add-on (shape and deliberate 3DP finishing). My idea was that "nice looking and ergonomic" were not on Carver Team's table in the first place, so "go function";
- They do not require addistional holes nor other modification to the existing chassis.

 

[Carl182]

Placeholder post:
PROBLEMS

 

[D-500 Flogger]

Carl182,

Your creation is stunning. In your intro you are a self-described "industrial designer". It shows in your work.

Your first 2 photos made me think that your amplifier would look perfect in my favorite Stanley Kubrick movie:



One of my pastimes is to locate/study/enjoy items that represent excellence in concept/design/implementation anywhere on the internet.

I include your amplifier in the category I just described.

Bellissimo!

3D (fellow former lurker)

 

[Carl182]

I include your amplifier in the category I just described.

Thank you man!!! Honored to be part of the selection! My "space odissey" was fitting those big fat caps, trust me!

 

[NeverSatisfied]

Excellent project, well done. Nice to see someone not afraid to put their own spin on the esthetics.

 

[Carl182]

Excellent project, well done. Nice to see someone not afraid to put their own spin on the esthetics.

Thank you, really appreciated!
Altough every aesthetical mod i did was either hidden (switch sideways), or time-correct (old-school lever switch, new but same-style speaker and RCA binding posts), my take on the handles is just that "let's make a beauty out of it" was never on Team Carver's agenda - luckily I'd say.
Last but not least, the handle thing is totally "reversible" to original condition: the faceplate is left untouched!

 

[Bob Boyer]

Beautiful work! Nice to have another craftsman among us. Congratulations.

 

[Carl182]

Beautiful work! Nice to have another craftsman among us. Congratulations.

Thank you Bob!

 

[D-500 Flogger]

Hi everyone! Second post ever after my introduction here.
Finally, done with my PL400 restomod.

HOW IT SOUNDS
I don’t think I have the right setup and audio approach to let this horse run in the wild – maybe I’m wrong, change my mind. My system currently has a minimalistic and hi-efficiency approach: driving my WOPL400 I have a DIY Nelson Pass B1 NuTube Buffer, while right after I’ve a pair of DIY Fostex FE166e backloaded horns (2.0 full-range, 8 ohms as minimum value along the spectrum, 94 dB/W(m) efficiency).
Sure enough, the setup will express every noise and imprecision, but the meters would not even move, at reasonable listening levels.
That said, after some burn-in hours, I’m highly impressed by its behavior.
It surely is an excellent performer.
Precise yet smooth and round at all frequencies, with a non-existent noise floor.
Maybe a bit too relaxed, but still, it is too early to say and maybe the overall system isn’t just right for it.
Will try to update sooner or later!

Hi Carl182,

You made a couple of interesting observations, so I thought I'd take a crack at explaining Phase Linear from an American perspective, and maybe with this additional 'cultural context' your amplifier's visual design & performance goals will make more sense?

"My idea was that "nice looking and ergonomic" were not on Carver Team's table in the first place, so "go function";

One of the biggest goals that Bob Carver had was to deliver much more value (sound quality, + watts/dollar) than his competition. While I admired his passion for value (since I have never had 'too much' disposable income :0) ...there are plenty other audiophiles on the internet that find this approach to be offensive. (They fancy themselves to only drive the best cars, eat the finest meals, and listen to only the ne plus ultra audio equipment.)

Thanks to MLUCITT, if you follow this link you can actually read a paper written by Bob Carver back around the time your amplifier was made. In it he's trying very hard to justify his approach to amplifier design, and it even includes several oscilloscope displays showing visible issues that he is trying to avoid. Reading this paper you will get a sense of where his mind was primarily focused. In the land of airplanes you will hear the phrase "Form follows function" ...and I think that Bob & his team followed that no-nonsense approach. (He was working at the intersection of minimalism and affordability. :0)

Then again, recently we were comparing notes about another famous designer (Dan D'Agostino) who used to design no-nonsense, modern/masculine type equipment...and then suddenly came up with this? (Speaking for myself, it was more cartoonish than Kubrick, if this translates?)

For me, the bottom line is that I find Bob Carver's "go function" look very attractive. (Actually I will let you in on a secret -- although I've owned my D500 with the "Cylon meters" since it was new, I actually prefer the big VU meters on your amp. It's just more of a 'classic' analog look..) Problem is, I would no doubt end up bending them in operation, so I'll just stick with what I got, I guess. :0)

****

OK, enough about the looks -- let's talk about the sound. From what I can tell, most of us here chose these amplifiers because they sounded so open, or effortless, especially when you turned them up. But if you listen to them while playing 'easy to reproduce' music, then you may not hear the difference between these amps vs. other (lesser) amps. If you will allow me, I'd like to switch to a car (mechanical) analogy to illustrate how we Americans like both "over the top" + "bang for the buck" together.

1) The 'easy to reproduce' music. I just looked and the most registered Italian car is the Fiat Panda. Let's say that a librarian is driving her Panda to church on Sunday. She doesn't live too far away, and the streets that she drives on are well maintained, smooth, and level roads. So her very basic car is easily up to the task of taking her from home to church & back.



But let's say that our librarian suddenly got a 'bee in her bonnet' and wanted to do drive off-road, in rugged terrain, and do so quickly. (ie: Listen to demanding, Complex music.) Luckily, in Italy she can trade her Panda in for something like this:

I for one would applaud her for her good taste. But if she were to drive the Lamborghini LM002 only to church & back then she may not notice, functionality-wise, all that much difference between the Panda vs the LM002.

Me? When it comes to amplifiers, what I don't like to do is 'grit my teeth' while listening to music in anticipation of the amp clipping hard right when we get to the good stuff. Instead, I like the feeling that I 'don't care'. But that probably doesn't translate properly. How about 'Unconcerned', as in no matter what I choose to listen to next, the amplifier has got more headroom than will be required. Effortlessness.

****

So now to explain the people in this forum. I for one should absolutely own a Rambo Lambo LM002 -- for the sound of the V12 & the 5-speed manual, if nothing else. :0) But demand exceeds supply, and a nice one like Jay Leno is driving costs on the far side of $250,000. Alas, I simply can't afford it.

So, let's say that my first reaction is to go take a serious look at a 2022 Ford Raptor. A very capable machine, closer to the LM002 than the Fiat Panda. Alas, after spending a couple of minutes going through the option list, I ended up with this:



While I may have some of the nicest trash of all, I can't justify spending this kind of money on a pickup to go to the dump with my junk.

Besides, this vehicle wouldn't attract enough attention to suit my style.

Instead, I would much prefer something old-school, like this simple, yet robust truck:

 

[D-500 Flogger]

(continued) ...or maybe a nice, clean, pickup that wouldn't draw undo attention to itself...but those in the know would understand.



In other words, the guys in this forum like to not only "drive something different", but it's something that's affordable, and/or affords you the ability to (re)build it yourself. Much like what you did with your own amplifier.

Last but not least, we need to address the elephant in the room -- the fact that these amplifiers in their youth were often times driven so hard that they were pushed out of the SOA. (Safe Operating Area)


Here's a neat article on what the original looked like when it was being driven with intent.

And this is an even better article where the original driver (Bill "Maverick" Golden) was interviewed over a weekend by the author.

So, when the Little Red Wagon was driven at the edge for a lot of years, this is how the original ended up:


https://www.hemmings.com/stories/20...e-red-wagon-wheelstander-returns-to-the-track

****

So there you have it. You own an amplifier that represents the units where Led Zeppelin was keeping them cool with shoveling dry ice into wooden chutes. Pink Floyd used to tour with them. And rightfully or wrongfully, they generated a reputation that is somewhat larger than life.

And this forum seems to be full of people who are bringing them into the 21st century, and thanks to the efforts of Gepetto & everyone else they are sounding better today than back when they were new. And they sounded *exceptional* back then. :0)

****

For me, it's all about having fun. And restoring my amps will give me the excuse to (re)learn a whole bunch of analog electronics that I haven't gotten to use in years. And hang out with kindred spirits.

Hope this helped...even a little.

Cheers --

3D

 

[J!m]

The little red wagon had a hole in the floor so you could see your way down the track.

-form follows function.

 

[laatsch55]

Carl, I like the personal spin you put on your project!!

 

[Carl182]

Dear 3D, thank you for this!

FIRST THINGS FIRST: here's my 1993 Lindberg 72158 1:25 Scale "LITTLE RED WAGON"!!!!!
The model is actually on my library RIGHT ON TOP of my sound system!
Still can't believe you cited one of my own absolute references!

And this is an even better article where the original driver (Bill "Maverick" Golden) was interviewed over a weekend by the author.

Also thank you for the Maverick interview, I'll read it with pleasure.




That said, I totally got you and I can say (and as proved above ) we're on the same wavelenght.
One thing I'd like to underline: by sharing my thought on aestethics, I did not mean to be disrespectful nor culturally "superficial".
Actually, it was that no-nonsense "attitude" combined with PL's reputation that brought me in.

For me, the bottom line is that I find Bob Carver's "go function" look very attractive.

That's one of the exact reasons why I chose to give my PL400 a full-on go.
This, AND the history behind the people behind it: from designer, to engineers, to factory workers (those hand-signed stickers with actual names...), to audio engineers and bands. This thing just MUST have had something.

For me, it's all about having fun. And restoring my amps will give me the excuse to (re)learn a whole bunch of analog electronics that I haven't gotten to use in years. And hang out with kindred spirits.

I'm a DIYer by necessity, first and foremost. If I can't afford it, how can I do it myself? How can I raise the bar?
How do I choose among the many possibilities of building, restoring and so on?
In each of my builds, I have to choose by REPUTATION first: the rest will most likely turn out into a great journey - as this one turned out to be.

Thanks again for the message 3D!

PS: I forgot to include a shot with the hood open, so there it is!

 

[Carl182]

Carl, I like the personal spin you put on your project!!

Thank you! I learned quite a lot reading you around here...

 

[laatsch55]

I see....well a fine looking amp bud!!

 

[laatsch55]

Dear 3D, thank you for this!

FIRST THINGS FIRST: here's my 1993 Lindberg 72158 1:25 Scale "LITTLE RED WAGON"!!!!!
The model is actually on my library RIGHT ON TOP of my sound system!
Still can't believe you cited one of my own absolute references!





Yeah..... he's weird like that Carl...

 

[VSAT88]

Instead of pushing the like button over and over again I will just say DAMN that turned out really nice ! Love the handles. Hope you were able to source the proper cardboard peice to put in the back left side above the fuse holders / ac cord area. Its a really high tech part. lol.

 

[George S.]

Different and unique looking, I like it! Sort of steam punk looking (can't think of a better term). Looks terrific and I bet it sounds fantastic. Nice job! A amp to keep forever.

 

[FredR]

Another DAMN. Or Lee lingo DAYAM!