Basic Transformer Testing

nelsress said:
Joe, are you referring to this as a quasi-comp 700B because someone worked on it and installed the wrong transistors? Next I need to open her up and see what's under the hood. I noticed that not everything that's offered for the 400 is also offered for the 700B.

Lee, no I do not have a 700B service manual, not yet anyway. I got my 400 service manual online, I'll go there again for the 700B manual too. I think it was Hi-Fi Engine. I don't have a lot of test equipment though so much of what's in those manuals isn't a whole lot of use to me. Still good to have though.
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No Nelson
Quasi-comp refers to quasi-complimentary output stage as opposed to full complimentary.

Quasi-comp is when the output stage is all NPN (or all PNP) where the lower half of the output current amplifier uses a small signal PNP coupled with a high power NPN transistor to simulate a high power PNP transistor.

Full comp uses NPNs in the upper half and PNPs in the lower half of the current amplifier stage.

Someone did install the wrong output transistors. The 2SD555 transistors should not be used in the output of a PL amp.
 
Gepetto said:
No Nelson
Quasi-comp refers to quasi-complimentary output stage as opposed to full complimentary.

Quasi-comp is when the output stage is all NPN (or all PNP) where the lower half of the output current amplifier uses a small signal PNP coupled with a high power NPN transistor to simulate a high power PNP transistor.

Full comp uses NPNs in the upper half and PNPs in the lower half of the current amplifier stage.

Someone did install the wrong output transistors. The 2SD555 transistors should not be used in the output of a PL amp.
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Thanks Joe, I think I understood what you said but let me run it by you, if you don't mind. Are you intimating that both the 400 and 700B amps leave the factory with quasi-complimentary output stages and one of the big things that you've done is convert them to full complementary? And, as I believe Lee pointed out, the quasi-comp or factory models never came with the NEC transistors that almost completely populate the rear plate? Am I finally understanding or is that just wishful thinking?? Thanks again.
 
There were a few complementary amps that came with the 2SD555/2SB600 pairs. The standard were the MJ15024/MJ 15025 pairs.
Late in the 400/700 manufacturing they were complementary....
 
Almost all quasi comps came with XPL-909 transistors. Later they were MJ15024's PL part number TP-9054's....
 
nelsress said:
Thanks Lee, I was pretty happy with it. Check it out!

Here are some pics of my new PL 700B. It looks as if one of those transistors on the back is fried, could this cause the fuse to blow upon powering it up? There's also a small dent in the one level knob, I tried to get a close up but I'm not sure how visible it is.
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I don't know Nelson - that amp looks pretty fcuked up. I think you should give it to me. :tongue3:

Nice score dude - a beautiful specimen. Do you need someone to whip it into shape. Maybe she can help. This seems to be my theme for tonight:
 

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Nice

NavLinear said:
I don't know Nelson - that amp looks pretty fcuked up. I think you should give it to me. :tongue3:

Nice score dude - a beautiful specimen. Do you need someone to whip it into shape. Maybe she can help. This seems to be my theme for tonight:
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You're right, I don't know what I was thinking, thanks for the offer to take it off my hands. :) Think she could help? Oh hell, what am I saying, who would care until she left anyway? I'm calling this one, 50 shades of Nav!? The timing's right!! LOL Any one of "Nav's Avs" is welcome to swing by and whip it into shape!!

But seriously, thanks, I feel fortunate, it was just a diligence/timing thing, mixed with some luck, lots of luck. I caught the listing at 2 AM and it had only been listed 4 hours before but on the other hand, I've missed out on a bunch of stuff that was listed for 4 hours or less before I got to it. I don't do this for a living, it's only an obsession!
 
The other two pieces

Just heard back from the seller, he said he wants $500 for both the 4000 Series I preamplifier and the 5000 Series I tuner. It would certainly be a nice stack to have and I've heard good things about the tuner but I don't know anything about that preamp, other than it's pretty darn cool looking! :) Any ideas on sound quality, build quality, and upgrades like with the PL amplifiers for these pre's? Any ballpark estimates to what it would take to get the entire stack (amp included) up to spec or better would be much appreciated. It looks like I might be entertaining the thought of selling some stuff, based on what you guys think about these units. Thanks folks!
 
That's about twice what you can get out of em. The 4000 has a lot of issues. The 5000 I'm not personally familiar with.
 
Okay

laatsch55 said:
That's about twice what you can get out of em. The 4000 has a lot of issues. The 5000 I'm not personally familiar with.
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good to know. I thought they were better than that, they certainly look impressive! I'll just stick with the PL amps for now then. Thanks Lee.
 
nelsress said:
good to know. I thought they were better than that, they certainly look impressive! I'll just stick with the PL amps for now then. Thanks Lee.
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There is a lot of "bolt on - go fast" in the 4000 and 5000 tuner. The best products PL made were their amps.
 
Thanks guys

Though cosmetics are a factor, sound quality and build quality are paramount for me so thanks a bunch for the input, I'll pass on the pre and tuner.
 
Yeah, there's better stuff out there for that money. fitz43 has a few pre-amps for sale, very reasonable too...
 
Thanks Lee

laatsch55 said:
Yeah, there's better stuff out there for that money. fitz43 has a few pre-amps for sale, very reasonable too...
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I see fitz43's listing. Based on Joe's comment about mainly being a fan of PL amps alone I was figuring on avoiding PL pre's, of course I could be wrong, maybe the ones he's offering are good ones? I'm familiar with the Crown, which is a decent preamp, or at least at its current age, would be with a good going over and re-cap. I'd love to know which one or ones do you like on fitz43's list, Lee?
 
The 3600, and 3800 are good pre's... They take about 150.00 worth of work to bring em up to snuff. The 3300 II is an excellent pre-amp. My favorite of the bunch followed closely by the 3600. I haven't worked on a 3800 but it's supposed to be better than the 3600. The 3600 and 3800 just need newer op-amps and some recapping to help the low frequency response and they're good to go. Doug's 3300 II is already sold. I've threaded a 3600 fix , Skynard77 had one I worked on and it turned out very well. The 3800 would be just as good I'm sure. Great phono sections...
 
P3300 II Looks Good

laatsch55 said:
The 3600, and 3800 are good pre's... They take about 150.00 worth of work to bring em up to snuff. The 3300 II is an excellent pre-amp. My favorite of the bunch followed closely by the 3600. I haven't worked on a 3800 but it's supposed to be better than the 3600. The 3600 and 3800 just need newer op-amps and some recapping to help the low frequency response and they're good to go. Doug's 3300 II is already sold. I've threaded a 3600 fix , Skynard77 had one I worked on and it turned out very well. The 3800 would be just as good I'm sure. Great phono sections...
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particularly as far as matching the looks of the 400 and 700B's aesthetically and since it's your personal favorite, I'll keep my eye out for one, thanks.
 
Hookay. A stock one requires a little work Ike the 3600.
 
laatsch55 said:
My fave fave is my Spec 1.
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I've heard great things about them but have never seen or heard one myself. They bring pretty good bucks for being a Pioneer and for their vintage. They're not any newer really than a PL 3300 II, are they? For that reason, I have to believe that a Spec 1 would also need a little work, at least some power supply cap replacements, yes?
 
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