Phase Linear 700B which has been modified

[ksrigg]

Well, I couldn't resist...I mean $200.00? And I know the seller (Bill) is probably lurking on here somewhere maybe.....but anyway, after I saw this amp and it's price I asked a question or two of the seller, only to find out he was a good friend from years ago, and well................we made a deal, and I should have the amp on Monday or so...


Here she is:

http://www.ebay.com/itm/251078195267?ss ... 1423.l2649

Question is..what would you do to this amp? I know the meters probably must stay as is...and not much can be done to the faceplate... I am thinking, put Joe's PCB in the amp....put Don's DCP in the amp...put 20,000 uf or higher caps in the amp.....but would you put the RCA 410 (is that right) drivers and the Phase Linear original outputs back in her, or would you bite the bullet and buy new On-Semi's for her? Or a combination of new drivers, and old outputs...or what? She obviously isn't a museum quality amp in pristine condition, but you don't listen to cosmetics....plus I don't want to drop a ton of money in her, so that is why I'm considering using the original transistors...heck, maybe I could just modify the existing PCB and see if that will drive her without "motorboating" but I am thinking it will take Joe's PCB to get the amps' outputs stable enough to not need to be precisely matched? Just looking for ideas....What would you do with this baby? Replace the Fan toggle with a PL Knob and move the fan to the heatsinks, if I can find one? Or get rid of all the non- PL 12 VDC circuitry to alleviate any possible noise?

Just looking for your thoughts and ideas...

 

[laatsch55]

First of all send it to me and we put it through the Audio Precision torture and see what works and what doesn't . Evaluate the mods for what they are worth, and go from there.

 

[laatsch55]

Don't swallow all that gain matching crap for the outputs. That's what the emitter esistors are for. In extreme cases----maybe-----. If you need the 200.00 back let me know and I'll get the cabbage case headed your way.

 

[kevin]

He better send it to ya...... She finds this one and he may end up in that cabbage case himself !!!!

 

[ksrigg]

I think it may have to come to you Lee. You have the ability to test everything and see what works. I can also send you all the transistors I have, and you can choose what is best to go into the amp based on Audio Analysis, and human ear.. I'll pack it really well, so there is no need to send the case. I don't want to spend more on shipping than the damn amp cost. I'll pack it well, insure it for about $700-80. and hope it makes it in good shape. I'll send a return label as well, so you won't have any worries there. I think I'll have it on Monday...I gotta send some amps out to Skratch to, so I'll make a morning of packing amps for travel..
Do you want me to order a PCB and DCP and have them shipped to you, or do you just want to have me send the money for them to ya?

My only interest is in keeping the cost of rebuild as low as possible while still making her sound great. Looks like she'll need your special rack handles and probably a repainting of the bezels...I wouldn't put a meter board in her. I'd try maybe to retrofit the existing board to work with some leds for backlighting the logo area, but I don't think we need to light up the meters...I'll leave it up to you though...I was going to put the transistors which are in the amp now on eBay to try to recoup some of the cost of the upgrades, but I don't know if I can get anything out of them or not. I know they are no longer in production, and the last ones that sold went for about 15 bucks a pop...If I could only be so lucky..I hope this amp doesn't turn into a money pit..

 

[laatsch55]

Well yesterday you were all hot to trot to send it to Mark beins I was so busy and I agreed with your assessement of my schedule. Was this post before or after that PM?? Sutton either way is fine with me -really- just let me know what the FINAL answer is, thank you.

 

[ksrigg]

I am still trying to figure out what to do. I'll get Joe and Don's boards and some new transistors, and get them in the 700B and then go from there. I will just see how it goes. It'll probably end up with you Lee or maybe with Mark, but I'll give it a shot first.

 

[laatsch55]

No sweat man. If you don't want the 2SD555's, I am the official "Home for Wayward NEC Devices".

 

[ksrigg]

http://www.ebay.com/itm/Vintage-Carver- ... 1c2802f900
Look at this Carver. Does it look like Joe's White Oak PCB would work in this amp? I can't really tell, but maybe someone here has experience with this amp. I've never seen one before this one.

 

[laatsch55]

It's heritage is awfully familiar. Give it a shot.

 

[Gepetto]

The ID was better on his early PL stuff. This lacks symmetry of the earlier PL gear.

 

[wattsabundant]

Maybe a little late to reply, but I worked on one of these before. As I recall it was nearly identical to a P/L SeriesII. I got the impression it was Carver Corp's first product after Bob left P/L.

When I do a repair on an amp I always change the outputs. You don't know the history of abuse. Usually when an amp fails you only take out one output in each rail. I assume the weakest one goes, but the others that didn't fail were close to the edge. Since I have to warrant the repair I don't want to take any chances.

The one time I reused outputs was on my own 400II. I was out of stock on Mj21196's. I've got coffee cans full of various devices. So I matched them by date codes. The amp was left on 7/24. A couple months later it blew the MJ15024's in one channel just while idling. That confirmed my position and I replaced all of them 24's with 21196's.

http://www.ebay.com/itm/Vintage-Carver-c500-c-500-Ampli-Monster-Pre-Amp-Phase-Linear-/120930367744?pt=LH_DefaultDomain_2&hash=item1c2802f900" onclick="window.open(this.href);return false;
Look at this Carver. Does it look like Joe's White Oak PCB would work in this amp? I can't really tell, but maybe someone here has experience with this amp. I've never seen one before this one.

 

[THD+N]

I have two of these amps - C500. One bought from ebay worked and did not appear to have any issues. The other, bought from a "virtual" friend I met on ebay 10 years ago. This C500 was in such bad shape that Carver Corp. would not even fix it. They sent it back to my friend saying it was too far gone, so I picked it up for a song.

Anyways, the C500 is similar to a PL400II, but with slightly more power and an extra output transistor per bank (4 instead of 3). The C500 PCB is not the same as a PL-36, but similar. If you needed to get the amp working, you could probably retro-fit a PL-36 into it, but not all the features would work.

One notable difference between the C500 and a PL400II is the VAS... Carver ran the VAS in the C500 much hotter. According to what I have read, this was done to get extended bandwidth and high slew rate from the amp. The C500 was also internally bridged, you could run it mono just by using the two "hot" speaker outputs.