How can I tell if PL 700ii has had upgrades/repairs?

SPOautos

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#21
The problem has never been about their sound, but more about their reliability.
When they go DC, you can kiss your speakers goodbye, or at least all your woofers.
The one essential 'mod/add-on' I'd recommend, is some sort of DC speaker protection.
What do most people add for DC speaker protection? I'll also look to see if it already has some.
 

SPOautos

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#23
Watts Abundant, Don Imlay
WOW, reading the instructions, that sounds like a fairly in depth half day project...I didnt realize the DC protection was such a big job. I'm not sure if I could do that or not...it has pretty in depth instructions so maybe if I practice soldering first I could do it. I know very little about how electronics actually work and just figured it would be simple, like soldering in some fuses somewhere or something.
 

MarkWComer

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#26
Don's protection board monitors the waveform and acts much quicker than a fuse. By the time a fuse opens the voice coils could be toast with the power available from that transformer.
Saved my speakers when the outputs on my 400/II failed!
VERY MUCH worth the money!
 

SPOautos

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#27
(Suppressing the urge to shamelessly plug my video series on rebuilding my 700/II).

Shit… What the hell…

https://m.youtube.com/playlist?list=PLYiWdKX5NXBLLWKWuje8a7hZq_tqUOMFL
Plug away! I found your videos today and started watching them! I'd had noticed on some older threads I was reading that you were posting here.

Yeah, it definitely sounds like they need DC protection! That whole WOPL setup you documented is a beast of a job....I'm afraid way too advanced for me (I've soldered a couple wires together like 3 times in my life). I'd have to limit my project to just the necessities like DC protection or things that are fairly easy.
 

MarkWComer

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#28
I try my best to make the videos for those who don’t have much electronic experience, but there’s no hiding the fact that it’s a big job. To be truthful, I am far from being an expert, but most of the higher- ups will tell you that I ask a LOT of VERY ANNOYING questions! Through all that they’ve been nice to me and let me stay.
 

MarkWComer

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#29
The first thing you'll notice is the amazing space 'above' the music. It's called 'headroom'.
Yup! Headroom! Makes ALL the difference! Even my “little” 400/II is a tireless beast!

Something to consider: look through catalogs these days at what’s being offered. How many do you see that go above 70 watts/channel? There aren’t many, and the prices are steep for what you get. I had a fairly nice Marantz before rebuilding my first WOPL project that just couldn’t deliver, supposedly a “high current” amp, but it didn’t make me dance- just wasn’t able, it was a 70 watt per channel Fisher-Price!

Anything that claims high wattage these days are usually class D amps, pulse modulated digital switching circuits, not linear gain circuits. Yeh, they work, sorta…. You’ll also see the industry pushing Dolby 5.1 “home theatre” systems also claiming to be high power amps- but they’re also class D. However, if you push these things real hard at a party, you’ll end up with something being fried! Those class D amps often have excessive superhigh frequency issues that will fuse the voice coils in your tweeters!

I know I’m giving you a barge of unsolicited advice here, call it horse shit if’n ya wantsta, but I’ve NEVER been as pleased with an audio system as much as I am now! Don’t buy new, buy vintage!
 

Northwinds

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#33
The problem has never been about their sound, but more about their reliability.
When they go DC, you can kiss your speakers goodbye, or at least all your woofers.
The one essential 'mod/add-on' I'd recommend, is some sort of DC speaker protection.
This all day. $100 or so cheap insurance policy
 
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