Any Phase Linear Experts out there?

[Ken Boyd]

[3662287]Maybe they are a little tricky to adjust, but once they are OK you will see. Simply follow the procedure in the service manual and the suggestions in this thread or let a qualified technician do the job for you. You will be not disappointed.:thmbsp:[/QUOTE]


Yes I like the sound of my PL 400 II, have not been able to use the PL700 II as it is down, but I think I will have someone do it for me, as I don't want to screw it up and cause more problems and expenses. In the future I will get an osilliscope and signal generator and practice with it until I feel comfortable with them before I go a screw around with an amp that I care about. After I get my 700 repaired I think I will send in my 400 and have it gone thru, as I really would like a pair of 700's and a pair of 400's. I the Infinity's need the pair of 700's and I would like to try a pair of 400's on my Phase Linear III speakers, as I don't think they are as power hungry or has as much of an impedence drop as the Infinity's do. If not that I will maybe sell the PL 400 II and use the money and get one of the PL 700b's as I kind of like the analog meters as they look more vintage to go with the Phase Linear III's.

My Phase Linear Rack

 

[P.L.F.]

Very well P.L.F., now it's clear. Very useful also the diagram you posted.

Regarding the oscilloscope I had seen the OWON (which is now sold in Europe) and this one also, which seems to be similar but cheaper than the OWON:
http://cgi.ebay.it/ADS1022-Storage-...ezzature_e_strumentazione&hash=item2559dbb85b
What do you think about it?

I've seen also the following TENMA oscilloscope which incorporates also the function generator.
http://www.mcmconnect.com/tenma/catalog/product.do?sku=72-6805&section=1

It would be nice to have two instruments in one, even if a signal generator would be better. Anyway, as far as you are concerned, is that oscilloscope able to drive a circuit with a signal and at the same time read the resultant wave at the output?

One more thing. At a certain point, the PL test procedure includes a THD and IMD measurement involving the use of a "THD analyzer" (point 5-5 of the service manual). Is that another kind of equipment or is the oscilloscope able to run that kind of measurement?

Releone71,

Glad you found the diagrams useful. I forgot to say about putting the decoupling cap close to the Op-Amp IC pins.

I think my knowledge might be not enough to reply to all your questions on test devices - still restoration of P/L amps is only my hobby. Let me go point by point then:

1) The scope I was looking for had to be simple in use, two-channel and not expensive. If you found good offers on your local market, go for it.

2) TENMA scope which incorporates also the function generator seems to be an interesting option if you wanted a function generator and not an oscillator / audio generator (BTW they don’t inform about the residual distortion level of the device while activating the function generator feature - I'll try to explain why that is important later on). No idea how the scope you said works (concurrent signal generation and its reading) - sorry...

3) THD measurements are difficult in a 'hobbyist environment'. Not sure whether one really needs to perform THD testing to compare with factory specs (0.009% for our P/L amp.!). I personally believe it is more practical to use audio signals generator + scope for identifying possible amp. oscillation risks at HF. But that’s not a voice from a profi … Reasons? See below, please:

Definition first.
[…] The definition of THD in use effectively means that the distortion value is the maximum possible relative error on the peak value of the signal. In other words, if you have a 1-volt peak fundamental sine wave and 0.7% THD, the peak value cannot deviate more than 7 millivolts from its nominal value. […] – source: http://www.audiokarma.org/forums/showthread.php?t=256124&highlight=distortion.

Measuring distortion.
Two types of test equipment are often discussed: audio generators (oscillators) and function generators. An oscillator provides a low distortion sine wave, less than 0.1%. Function generators start out as a square wave and then use some form of filtering to give a sine wave with distortion of at least (usually more than) 1% - source: http://www.audiokarma.org/forums/showthread.php?t=273708&highlight=audio+generator

More info on distortion measurements - useful links:
- http://www.audiokarma.org/forums/showthread.php?t=96968&highlight=distortion
- http://www.audiokarma.org/forums/showthread.php?t=140497&highlight=distortion
- http://www.audiokarma.org/forums/showthread.php?t=102361&highlight=distortion

Practical considerations in view of your question.
- Phase Linear 700 Series II specs define its THD as 0.009% at rated power into 8 ohms at 1kHz.
- The input source distortion of a testing device impacts THD measurements.
- Oscillators give less distortions than function generators, the ones with residual distortion of 0.05%-0.1% serve more in troubleshooting (still very useful).
- To measure your P/L amp effective THD (i.e. when it comes down to ‘testing to specifications’ task), your oscillator should have very low residual distortion, e.g. 0.001% - that's pricey…, and is it worth ?
- THD tends to become audible at about 0.5% with midrange test tones (depends upon the individual, some people are more sensitive to these tones). With music, it is generally said that it needs to reach about 1%-2% THD in the midrange for most to qualify it audible. Low frequencies tend to be harder to hear distortion with, since our hearing is not as sharp there. THD is said to be able to reach near 10% before it is audible below 80Hz or so. In general (according to The Audio Critic) "[…] It may be possible for humans to distinguish distortion of 1% (-40dB). We are not aware of any controlled experiments which show that distortion of 0.1% (-60dB) is audible. […]".

I'll leave it as is for more comments.

Cheers.

 

[P.L.F.]

Hi Ken

Very nice P/L rack, congratulations!

and I'm jealous!!!

 

[P.L.F.]

Not that anybody cares, but this is post #999 for me.

Cool! Of course, noticed:

Properties of the number 999:

Symbolism:

- The justice, the truth.

- In some texts sacred or esoteric, 999 represents the infinitely large, just as 999999.

General

- By undertaking circular permutations of the numbers composing the mysterious number 153, this gives place to six possible combinations: 153, 315, 531 and 351, 135, 513. And:

153 + 315 + 531 = 999
351 + 135 + 513 = 999

- The number 999 is the reverse of 666, the number of the Beast of the Revelation (Apocalypse). This arithmetical strangeness demonstrates that the "power" of the Beast, 666, will be "reversed" by 153, characteristic number of the Christ, to give as result 999, symbol of the application of the divine justice. Thus Satan will be chained for 1000 years, 999 + 1.

- The number 666 to the power 5 gives 131,030,122,140,576. And 131+030+122+140+576 = 999.

OK Don, better make it 1000 ...

Cheers

 

[Ken Boyd]

Hi Ken

Very nice P/L rack, congratulations!

and I'm jealous!!!

No need to be jealous, you look like you have lots of good stuff, and you can fix yours when it fails I can't, I am envious!

But I do have a few more Racks full of equipment.

One full of all SAE bi-amping a pair of QLS-2's, another full of Crown and Rane for a pair of RS-1a's, and another which is incomplete with Mcintosh, but damn that Mcintosh sure holds its prices.

I was just given another smaller rack the 4 foot rack and I want to get Audio Research gear for that one, tube amps for the mid's and Hi's, nice big amp for bass, and then a tube preamp, with a good real nice TT and CD player, probably not put the amps in the rack put them out by the speakers and then just use the rack for the preamp and the sources.

And if anyone has anything to say about my stupid little speaker wires it's just a temporary setup, the wires I got when I purchased the speakers look like something to power NYC and I didn't want to have them running across the room. Also the guy threw in a bunch of interconnects of pure silver, and I couldn't beleive how much they orginally costed as I went online and found them. The interconnects alone cost more than what I paid for the speakers, and I don't know what the speaker wire must have costed, but probably alot.

 

[d3imlay]

I checked two 400's for the phase inversion. One with the PL400C and the other with the PL14a driver boards. No phase inversion.

 

[John in MA]

Anyone have a service manual or schematic for a 4000 Series II preamp?

 

[d3imlay]

Anyone have a service manual or schematic for a 4000 Series II preamp?

Yes send me a PM with an email address that can receive a 5 meg file.

 

[titanstats]

Hi guys. Informative thread. I picked up a 400 last week, and am just about to get around to trying to bring it back to life.

A question about the outputs -- was there ever any concencus as to the best ones to use on the 400? People talked about both the 15024 and the 21196 -- any clear winner between the two? What about the drivers -- what is the best choice for those in the 400? I didn't seem to see an answer about that, just the complimentary setup in the 700.

Any help much appreciated; I'm itching to get this up and running soon!

 

[P.L.F.]

A question about the outputs -- was there ever any concencus as to the best ones to use on the 400? People talked about both the 15024 and the 21196 -- any clear winner between the two? What about the drivers -- what is the best choice for those in the 400? I didn't seem to see an answer about that, just the complimentary setup in the 700.

Hello!

What amp do you have precisely: the P/L 400 (i.e. series I) or P/L 400 series II?

If that is P/L 400 series II, look please to the thread #66, point 4. Last sentences refer to quasi comp. topology and apply to 400 series II model too.

If you have P/L 400 (series I), there are lots of advice on this portal - go to the advanced search to save time (Phase Linear 400 as keyword in threads' titles). Also I'd recommend to do the same in DIY Audio. Both drivers and outputs equivalents for 400 model are widely covered there, including necessary fine-tuning. Please note that depending on the production year(s) there were different transistors installed, so the remedy you might be looking for can be specific. Majority of voices I think are for MJ21196 as drivers and outputs.

For the output replacements suggested by the factory you may visit this page: http://home.earthlink.net/~dimlay/sitebuildercontent/sitebuilderfiles/outputs.pdf - thanks to D3imlay.

If you hesitate which outputs to choose (15024 vs. 21196), some good advice is coming here from Releone71 in the thread #34 and from D3imlay in the thread #36.

I hope the indicated sources were useful ...

Regards.

 

[P.L.F.]

Sure, no problem. Its going to be a few days, due to a busy schedule.

Hello Glen,

Don't take me wrong and pushing but is there any chance to get your kind support by mid of June (just a matter of planning, and hobby sometimes needs to wait before day-to-day duties allow ...

Cheers

 

[waynedb]

New AK member here - hoping to find help!

Hello Everyone,

I am new to the AK forums, allow me to introduce myself. I grew up playing with my dads Phase Linear gear, he is an old school audiophile with some incredibly great tastes in equipment. Recently I purchased my inheritence from dad, here is what I got - A 700 series 2 amp, and a set of the Phase 3 panels - with sub module - both of which dad bought brand new and both of which are in need of repair. I have already found a seperate thread on the phase 3 panels, so I will not bore you guys with any questions on them. The day after buying my inheritence from dad, I lucked up and found a Sunfire Cinema Grande 2 pre-amp, which I think is an incredible center-piece for my sound system.

My immediate concern is trying to bring this old 700 amp back to life. It blows fuses on the right channel when hooked to a speaker, and the left channel will not put out any sound until after you hit the power off - then I get a high pitched whine like a camera flash powering up, then I can hear a faint hint of sound, then it has a nasty ending - not the usual off thump at all. I have contacted the phase tek guys about repairing the amp, but I am extremely worried about sending this amp cross country (I am in NC). This amp is kind of a family heirloom with a ton of sentimental value to me, I could not bear it being damaged or lost. So this is my delima, either find someone local I could take the amp to in person, or try to fix this beast myself. I do have experience with electronics and repairs, and I would love to learn how to work on this amp - seeing as how I plan on keeping it forever.

So my question to you guys is: With the symptoms I have described, does this sound like an output transistor problem? And more importantly, does this sound like a fix that can be accomidated by purchasing the 700 rebuild kit from the guy on ebay? P.L.F. I wish I could send this thing to you, from your post it seems like you are the man when it comes to repairing these things, your postings have inspired me to give it a go on repairing this old amp myself.

Thanks in advance for any help.

 

[laatsch55]

You have as good a shot as any with all the help around here. you have experience with repairing electronics Eh?
Did you get a service manual with it. I can help with this project, I've repaired 4 700's and 20 400's, 4 -Pl 2000"s, 4- 3000's and other pieces. When I falter there will be plenty to lead on.

 

[releone71]

So my question to you guys is: With the symptoms I have described, does this sound like an output transistor problem? And more importantly, does this sound like a fix that can be accomidated by purchasing the 700 rebuild kit from the guy on ebay? P.L.F. I wish I could send this thing to you, from your post it seems like you are the man when it comes to repairing these things, your postings have inspired me to give it a go on repairing this old amp myself.

Sounds like one or more output transitors are shorted, according to the service manual, "...especially if the blown fuses are blackened or silvered (indicating large current surge)".
If you need the manual, PM me and I will send the file.
Anyway be aware that while isolating the shorted transistors in a bank is relatively simple and requires a multimeter, performing the tests in order to be sure the amp will work properly requires a variac, a signal generator, an oscilloscope and a dummy load.
I have a 700 II too and I'm going to replace the output transistors with new devices purchased from that guy on eBay. IMO that kit is useful because contains every part you need to repair the amp. Even if it is not necessary to replace EVERY part in the driver board (better to let them go until they work), the devices in the kit could be useful in case of future faults and if you order the complete kit you save on the final price. Just specify the release of the board and if your 700 is an early quasi-complementary (all TP9054 NPN transistors) or a late full complementary (TP9054 and MJ15025).
You will find lots of useful tips in the past posts from Laatsch, P.L.F. and D3imlay. I can also send you a .txt file where I summarized every suggestion if you prefer. Good luck!!

 

[waynedb]

Output transistor, it must be.

Ok, the blown fuses look pretty bad, blackened and silverish? Looks like I need some output transistors. One question for the forum, should I buy the kit of new transistors and other misc. parts like I had previously mentioned, or should I buy the matched set of original output transistors offered by Eds son trying to offset college expenses?

As far as a variac, a signal generator, an oscilloscope and a dummy load - I may need help with those. My experience in repairing electronics is mostly limited to computers, with some minor circuit board repairs - no expert by far, but willing to give this a go. I have a friend with a scope that I can borrow, I could use some suggestions on where to find a variac and what type, as well as some help getting a signal generator, and then of course the dummy load. I don't particularly want to buy professional gear because I do not want to get into full time repairs, so any short cuts or "that will do" ideas for these will be a big help.

Thanks again guys for the info, I am feeling more confident now that I really can fix this thing.

 

[laatsch55]

To the Moderator, could you e-mail please?
waynedb, I would suggest starting a new thread as this could ( technically ) be (crapping) on releone71's original thread.
Witth that out of the way, get the SM. Without it we are talking to deaf people while signing to blind ones.

 

[waynedb]

waynedb, I would suggest starting a new thread as this could ( technically ) be (crapping) on releone71's original thread.

My apologies to you sir and mr releone71's thread, it would not be my intention to defecate on anyones thread, technically or not. You gentlemen are clearly in a league of your own, as it appears I may be slightly out of mine.

Maybe between purchasing a service manual, and reading over past posts, I can tinker around and make this thing work, as even a blind squirrel occasionally finds a nut.

Again, thanks for your time.

 

[laatsch55]

No apologies needed, reading the forum rules may keep you from being banned, as i was . Don't know about that league of our own, I've been at it a scant two years, there are others here that have been at this most of their adult lives. They are here to help, encourage, cajole, teach, be frustrated, scream, bite their tongue, but mostly to impart some of their hard won and expensive (no doubt) knowledge about 30 to 40 year old gear that would not see the light of day if not for their help.
I believe what they would like is; patience from us , a -getting familiar period to assess ours, your abilities, and to honor their suggestions with an honest attempt to try what they suggest, HOW they suggest it and WITH WHAT they suggest.
The techs here are truly a blessing to those of us who by chance or circumstance undertake fixing gear that otherwise would be relegated to obscurity.
P.S. This was NOT releones's thread. Apologies to ej

 

[P.L.F.]

Maybe between purchasing a service manual, and reading over past posts, I can tinker around and make this thing work, as even a blind squirrel occasionally finds a nut.

Again, thanks for your time.

Hi Waynedb,
Don’t take previous comments discouraging - practical advice. I support laatsch55 to be sure (a) you have skills and experience to start any P/L700 II repairs, (b) you have all needed documentation handy and (c) if all positive, maybe better to draw attention of a larger group of P/L friends & gurus with opening a new topic at AK. I also do share the remarks of releone71 to have a minimum required set of equipment beforehand.
So here is the key point – have you ever repaired a solid state amp? If not, please reconsider the task and send your beast to experts. Don’t worry, you can put it in a box in secure way for the shipment. I’ve collected all my P/L & JBL gears kind of remotely, leaving in Poland… Feasible to send/receive without a damage risk.
If the task is up to your skills / experience and only some guidance is needed not to make a mistake or help you out facing an issue, AK forum is the right place to be. Please bear in mind all warnings from the thread #66 here, there is high voltage presence inside the amp you need to deal with.
A comment about the kit you were referring to: IT IS NOT A BEGGINNER’S QUICK FIX (see the attached intro pages from LDX). The solution calls for similar equipment to P/L service manual specs that you need the get and know how to use:
- low distortion audio signal generator
- Digital Multimeter
- high impedance scope (dual channel is convenient)
- 250 watt 8 ohm dummy load
- variable line transformer – variac (or/and light bulb tester, to me even better)
Don’t forget about spare box of fuses (AGX, AGC see the manual, different values for 230V amp version).
But first things first – get service manual and further bulletins, read carefully and decide to take challenge with the support of P/L friends here, or not.
Happy to advise then.
Take care!

 

[fdejong]

To the Moderator, could you e-mail please?
waynedb, I would suggest starting a new thread as this could ( technically ) be (crapping) on releone71's original thread.
Witth that out of the way, get the SM. Without it we are talking to deaf people while signing to blind ones.

No offense, but I started this thread and it's turned into a general Phase Linear troubleshooting and information thread. I don't see the post as 'crapping' at all.