Some advice please

K

Kma4444

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Feb 8, 2020
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So I have a fair amount of PL stuff from my dad. This is in regards to the three 700s I took to Norman's in ATL to evaluate. I wanted to do them myself but honestly just haven't had the time. Of course since they have been there over 4 months and this is the first thing I have gotten as far as a diagnostic, I haven't gained much time. I just really would like to get them in service again.


He has found issues on the amplifier board and the driver board. It will need a lot of work – he has found several bad transistors and about 15-20 bad caps. There are also some bad connections that need to be repaired due to age.



The estimate will rage form $800-$875 – There is some room there in case he finds some other issues once he gets it up and running to a point.



Hope to have estimates on the other amps in the next few days - please let me know if you want approve this one so we can order the parts. The parts can take 10 days to two weeks to get.



Any advice besides I should have bought all WO pieces and rebuilt them myself months ago.

I appreciate it.
 
Do you trust the shop? Got the money to do it? Are you going to sell them when your done? Probably more margin in selling a non-operating 700 than an operating one right now..
 
I think I can trust the shop, based on what I've seen. They've been around for a long time, family owned. I suppose they are OK.

Not selling, just want to relive some of my childhood, dad blasting his music. I have his huge LP collection and it will be nice to play them through some of his equipment.

I can afford it, but don't want to spend this money only to find I will have to spend more for upgrades that would make what I spent now pointless.

I'm just not an expert in this arena so just looking for smarter folks than I for opinions.
 
Are these the Phase linear 700B or 700 Series II amplifiers? The shop likely charges $80.00-$100..00 per hour labor. Many technicians on this Forum will charge less. Just food for thought. And, four months to wait for a diagnostic is ridiculous.

You mentioned the amplifiers are being serviced in Atlanta, where are you located?

The shop is probably going to re-cap the existing control board, that was a good move in the 1990's. The original, single sided Phase Linear control board is like an old powerboat. You will keep dumping money into it and in the end you still have an old powerboat. It will continue to have problems.

Mr. Laatsch has good ideas that you may want to consider. You can sell some Phase Linear pieces to pay to upgrade the Phase Linear 700 the right way. You will be happier in the end.

You are not the first Phase Linear owner to confront this situation. There have been many before you. They all eventually upgrade with White Oak Audio components and never look back. There have been no complaints, just happy Phase linear owners.
 
Cut your losses. Spend the same or a bit more with Eric or others here that will do an absolute top notch rebuild to exceed the original in every way using Joe’s white oak parts. Stuff your dad would surely have done if he could.

You will not be worrying if it’ll burn your house down either.
 
I think I will pick them up and try to find someone to do the WO work on them. I am in Anderson SC. The shop I took them to is on the east side of ATL a bit over an hour from me.

I would like to connect with folks here who would be interested in doing this.

I originally got them and posted a thread here. When I went back and searched it was 5 almost 6 years ago. Crazy that I've let this sit that long which is why I ended up taking them to a repair shop. I was hoping it would be a few minor repairs to get them working, bla bla bla, and I could use them while I worked on getting to the WO phase of their lives.

They are 700B amps.

Thanks all
 
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I can understand your position regarding sentimental desires to just get the amps functional in stock form, I went through that same scenario with my father a few years ago on his PL gear originally purchased in the late '70's.

As mentioned above, a few things to consider to help inform your decision moving forward:
- Most of the stock components are past end of life, not only age but also time at temperature and physical stress
- Most of the original wiring has very brittle insulation and does not respond well to manipulation during service
- The original solder joints with massive coating of uncleaned flux have degraded over time and thermal cycling
- Some of the design decisions PL made back in the day were heavily influenced by bean counters and resulted in very marginal reliability
- PL struggled to correct output stability issues that resulted in oscillation and output latching
- Most of the amps I have personally rebuilt had significant assembly issues from the factory or other repair attempts

Based on my personal experience of repairing stock amps with only replacing non functional components have resulted in multiple followup repairs for the next weakest link. Just the act of shipping or transporting the amp after repairs will generate further functionally issues. I no longer repair stock amps if shipping is required for this reason. I've had amps working perfectly on the bench and fail for reasons outside of the repair after shipping... You can only imagine the customer support issues this scenario creates!

To wrap up, I paid the slight increase in cost to completely upgrade my fathers amp and the trouble free enjoyment he has experienced to me is... priceless.

So, for these reasons (and many more), when you see most of the experienced people on this forum recommend rebuilding with White Oak components, it's coming from a sincere desire to help people in the best way based on that experience.

-Eric
 
I guess that I will "step out" of this line of thought just a bit . . . . If these are series-II, the control boards have most of the issues worked out, and the mods to ensure no latchup or oscillation are less than $1 in parts (4x 1N4148 diodes and 2 180 (or so) pico farad caps). Electrolytic cap wise, there are 4 on the driver card, plus the mains. The ones on the driver card are less than $5 total in parts. As far as bad semiconductors, if the amps were working, that is questionable at best . . . there are tech notes from PL that some devices may read as bad and be totally fine . . . that, and the crazy long time to review these really makes me question your shop. Main caps are about the only expensive part ($28 each for my 400's for 10,000uF name brand), more for a 700 - the driver cards are identical.)

The single side board is a BS argument as I see it . . . . electrically, that means nothing, and if you don't roast it, traces stay put. It also depends, I guess, how long and hard they have been run. The early amps dumped a lot more heat out of the dropping resistor on the board. (Mine looked new, my "beater" purcase was a bit browned, but intact.) Older amps and amps used in PA duty may be a lot rougher . . . Yours was familynowned, so I would hope trend towards the "better" side of the curve.

Having said that, I refreshed my 400 (and another bought in "goofy" condition (bias wouldn't set, and oscillated) for about $60 each in parts, and an hour for mine, and more like 2 hours for the other. If dumping more money in can make them sound better, that's beyond my ears ability to discern, and in the 40 years I have had mine, I've failed *one* output transistor (which took out *one* fuse) in total . . .

Oh, and I added the DC protect board by Watts Abundant more on principle than anything else while I was "in there".

So, *IF* you can do it, (at least on a Series-II), a "refresh and try it" is cheap and quite easy. If you decide to WOPL, the main caps stay put, so that cost is not lost. If you do the work yourself, you are out about $5 in parts, and a bit of your time at most . . .

While you certainly can't go wrong with a WOPL conversion, it's definitely the $pendy route if you are starting with a working amp . . .

Others will likely disparage and attack me for saying this, but it's been my experience with most old electronics . . . . (and I've never needed to rework anything twice!)

YMMV . . .

- Tim
 
TimD, nobody is gonna flame your ass over this. I rather enjoy your presenting the other side. And your arguments make perfect sense IF you do the work yourself.
Its kind of a fine line when deciding how far to go fixing a stocker. And shipping is not easy on any electronics.
I've enjoyed both approaches. The challenge of rooting out a truly elusive prblem and the quick five mimute fix were fun. Both as a user and doing work for other people.
Not every customer understands why his 50 year old amp quit again in two weeks after a 300.00 repair. And shipping nowadays really precludes not anticipating known weaknesses and dealing with them.
Im glad you've experienced the otherside of this conundrum we're all imvolved in here.
When i fixed a stock unit it was guaranteed till something else went wrong or you plugged it in, whichever came first. When I did a WOPL, its guaranteed for life. I've had a few returns on that guarantee and all were honored, even the questionable ones. Given my age that guarantee isnt ss impressive as it once was,
I'm glad you're here TimD we need that perspective.
Where's that pic of your bench??
 
Let me add a few points here. Yes, a well behaved Phase Linear Series II amplifier is a thing of joy. And if it only has a few issues, spending $5 and a few hours of your time may provide many more years of use. However, let us see what a (generic) $350.00 WOPL upgrade can give you:
1. The White Oak Audio Rev G1 Control Board is a two-sided board (as previously mentioned) but was not mentioned was the redesign of the circuit traces on the board. The 100V traces are much wider to handle increased current. The signal traces avoid proximity to DC voltage traces, and the layout is more efficient (with no capacitors in the signal chain) due to computer-aided circuit design, unlike the Phase Linear board.
2. The solder mask (the green conformal coating) is very heavy and prevents solder from spilling out over the soldered connections. It also protects the copper and tinned surfaces from corrosion, unlike the Phase Linear board.
3. The silk screening on the White Oak Audio board is clear and legible to identify every part with correct polarity markings for diodes, transistors, and electrolytic capacitors, unlike the Phase Linear board.
4. The White Oak Audio Control Board has four precision regulated power supplies, +/- 15V for each channel, with test points provided, unlike the dropping resistors on the Phase Linear board.
5. The components included with the White Oak Audio Control Board are the best available at any price. This includes ON Semi transistors and diodes, Japanese Nichicon Audio "MUSE" electrolytic capacitors, German WIMA polypropylene film capacitors, 1% tolerance metal film resistors, and quality stainless steel hardware, unlike the lowest bidder Phase Linear board components.
6. The White Oak Audio Control Board uses an improved Grounding scheme including a complete copper mask under the "Front end" or sensitive input component area. This includes the area around the Texas Instruments, Burr Brown Division "SoundPlus" OPA134P OPAMP, a significant improvement in characteristics over the LF356 OPAMP on the Phase Linear board.
7. Finally, and most importantly, the White Oak Audio Control Board is a true "Dual Mono" board, there are no connections between the Left and Right channels. The benefit here is increased soundstage (the effect of where the musical instruments and voice come from) due to the improved channel separation, unlike the Phase Linear board.

Testing the output of the White Oak Audio Control Board with my Audio Precision Distortion Analyzer reveals total harmonic distortion and noise figures that are almost unmeasurable due to the regulated power supplies and the higher quality and tolerance of the individual components. My testing exceeds all listed specifications found in the PL700 Series II Service Manual by a significant margin.

Everyone has opinions regarding the sound quality of their amplifier, but the items listed above are just truths. My old ears may not hear the difference after installing a White Oak Audio Control Board, but I will tell you the sound is less fatiguing than the OEM amplifiers. I personally listen to a White Oak modded Phase Linear PL700B all day while I am in my shop and it just sounds good all day with a stream from XM Radio.
Some customers have reported that they hear different instruments or more distinct/clearer notes after installing a White Oak Audio Control Board. But the real benefit is that the dramatic sonic improvement, if any, and the reliability of the amplifier will last long after all of us are gone.
 
laatsch55 said:
TimD, nobody is gonna flame your ass over this. I rather enjoy your presenting the other side. And your arguments make perfect sense IF you do the work yourself.
Its kind of a fine line when deciding how far to go fixing a stocker. And shipping is not easy on any electronics.
I've enjoyed both approaches. The challenge of rooting out a truly elusive prblem and the quick five mimute fix were fun. Both as a user and doing work for other people.
Not every customer understands why his 50 year old amp quit again in two weeks after a 300.00 repair. And shipping nowadays really precludes not anticipating known weaknesses and dealing with them.
Im glad you've experienced the otherside of this conundrum we're all imvolved in here.
When i fixed a stock unit it was guaranteed till something else went wrong or you plugged it in, whichever came first. When I did a WOPL, its guaranteed for life. I've had a few returns on that guarantee and all were honored, even the questionable ones. Given my age that guarantee isnt ss impressive as it once was,
I'm glad you're here TimD we need that perspective.
Where's that pic of your bench??
Click to expand...
Thanks. It really shows the difference in site admins, place to place. I made a similar tone post on "thecarversite" regarding restoring relays (that conflicted with Nelion always replacing no matter what) and got banned for it, if you can believe that.

Bench pic inbound next time I am in the shop . . .
 
Been banned a few places myself.....
And we all live with our decisions, I always wanted a place where we could share the consequences of those decisions, regardless , and probably catch some good humored shit in return.
I believe its getting there..
 
TimD said:
Thanks. It really shows the difference in site admins, place to place. I made a similar tone post on "thecarversite" regarding restoring relays (that conflicted with Nelion always replacing no matter what) and got banned for it, if you can believe that.

Bench pic inbound next time I am in the shop . . .
Click to expand...
We are pretty easy going here, as long as it is kept civil and legal.
 
Thanks. All I had done there was disagree that removing oxidation by light burnishing of a mute relay was viable when the contacts were accessible, and that those don't typically switch under power, thus not typically burning. The rest was backing my opinion to the admin, who more or less stated "the vendor funds the site, so you are wrong, and I am banning you", despite offering credible industry references . . . it was bizzare . . .
 
Completely restored a PL 400 here years ago pretty much stock with WO filter caps and Don's output protection board. The mainboard and even the outputs were not changed out except what were bad or old electrolytics and a friend wanted about a year later and has been using it ever since hooked to a set of Polk SDA SRS2's and he does not mind jamming it hard out by his pool and has had no trouble with it period. However as has been said above, I did the work myself. It would have been foolish of me to do it money wise at a shop due to the hourly cost. And these guys here without them helping me all the way through the restoration I would not have been able to do it, They "held my hand" all the way through and even sent me parts. Several of the guys sent me parts I should say... No charge at that... So no, no flames... Now I have a WOPL Phase Linear Series II Model 700 thanks to Lee and there is no way possible I would ever go back to that original stock Phase Linear equipment after hearing Joe's White Oak. It's that much better and I am not worried every time I turn it on staying in the room with it like I did with the old one like I do when I am running my tube equipment. Your call.
 
The shop . . . I have a lot of other parts and spares in another room as well . . . (a bit of a mess right now, but about to finish the TX-11 and get some order back . . . )
 

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