Some advice please

K

Kma4444

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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..
 
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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
 
I have 2 700s and 2 700Bs so all pretty old. Got an estimate on the 2nd one and it is the same cost as the 1st, both of these were 700s they haven't gotten to the B yet, I only took 3 there.
 
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