Another new guy. Zach C.

Zach C.

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#1
I'm not new to audio electronics, just this forum.

I found my interest in audio hardware from a shared love of music within my family. Dad had a stereo that I was not allowed to touch, and I loved music. Dad used to do sound work for a local band, and so this sort of thing was around in my childhood. I found an old Rat Shack book on speaker building in his books, and had to find out more.

Years later, with the arrival of the internet, finding out more got a lot easier, so I started building speakers and reading the Parts-Express and Madisound discussion boards (back when the mad board was the shiznit.) I spent a lot of time confused and annoyed at my lack of understanding of the physics and math (curse you John k :D), so I went back to school to study engineering. I'm finishing my last class to get my Associates Degree in "pre-engineering." I will likely stop my studies here since I can't get classes that go with my work schedule, and nobody has volunteered to pay me to go. Oh well, I've learned a lot.

Occupationally, I'm half owner in an auto electric shop specializing in accessory electrical.

So, I've done speaker design, and various electronics repair over the years, and I've got a decent basic test bench.

Of interest to you guys, I've got a PL4000 preamp that I have repaired/ restored, a 3300 pre, and a 300 amp as well as piles of other crap. The main reason I joined the forum though, is that I have a 700B I'm restoring that's giving me some trouble. I've made a lot of headway, and it's working now, but needs more lovin'. I'm just finishing up on a WO board for it, and before I install it, I want to take a chance to finish diagnosing some weirdness is exhibits before I swap out the boards. I'm guessing the board may fix the issue, but I'd like to know why it's doing what It's doing and fix that before the swap. That's where you guys come in...:)

I'll start a thread on that in the near future. days?

Thanks for reading.

Zach
 

rtp_burnsville

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#2
Welcome Zach,

Sounds like you will fit right in here. BTW, I came across the old Rat Shack speaker building book this past weekend.

I am sure the PL guys will be along shortly to say hi.

Robert
 

NavLinear

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Welcome to Phoenix Zach.:wave:

When time permits I think a few of us would enjoy hearing what you did to the 4000 preamp.:toothy8:
 

Gepetto

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#5
Welcome Zach
You will get more advice on your PL700 than you can bear on this forum :) Just kidding, this is a great place to share your project trials and tribulations.

Joe
 

laatsch55

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Zach, I believe I have screwed up a 700 in every way possible. Mr. White Oak (Gepetto) is the resident amp guru but he can't say he's shorted out every component on the board, I have that dubious distinction. Eventually I get it right and the smiles that come your way when someone hears their White Oaked PL, is worth every second of frustration involved. We call them WOPL's here, after they've been converted. Welcome to Phoenix.
 

NavLinear

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#10
Other than sell it the first chance ya got??
Ok - maybe selling it is easier - but the challenge of improving or at least attempting to improve this preamp could be interesting. I have a mental sketch of what I'd do to keep the mother board from flexing (something made from PC or ABS) and reflowing the solder is simple enough but there are a butt ton of boards in this beast - this is not a simple preamp. Don't forget the ass ton of electrolytes from the bypass caps to those in the audio path, among others, and a new BrownDog type daughter board to upgrade the RayCo op amp ICs. What about all the interconnects? Doesn't this sound like fun?

Maybe one of these days - for fun of course. If this ever did happen I'd send it your way for a listen and of course a critique.

Zach - I may have overstated the number of us that wanted to hear what you did regarding the 4000 - maybe it's only one (me) but - hey that's better than none. :roll:
 

Zach C.

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...Zach - I may have overstated the number of us that wanted to hear what you did regarding the 4000 - maybe it's only one (me) but - hey that's better than none. :roll:
Thanks for the warm welcome, fellas. There's always time to change your minds later. :happy11:

I know there's not a lot of love for the 4000, but it's not really that bad. I can't say that I did anything special with it. Mine was already in pretty good mechanical condition. i.e. not a lot of broken joints, the foam pads that steady the boards were there and in good condition, etc.

When I got it, the main problem it had was fairly strong dc on one channel due to a bad cap.

What I did do is:

Complete recap- that's a lot of caps I tell you. Where I could, I replaced them with better quality audio caps, but many (most) of the caps are axial, and I couldn't find the replacements I would have liked, but whatever. Elec's are close enough. Every single cap was out of spec. All of them, yet it worked after replacing the last one in the line that was leaking dc.

Reflowed all solder joints on the mother board- again, mine weren't bad, but everybody says there are problems here and reflowing is free, so I did it.

Cleaned all pots and switches with deoxit.

Repaired/ reshaped the contacts on the accessory a/c output relay- apparently, the amp that was hooked up the it when the cap outed dc was not happy about this at all. Those contacts were rough, but the relay is open and not too hard to access, so I took a swiss file to them and re-domed the contacts.

That's all I can think of at the moment. I can't say that it's the pre to beat all others, but it works fine, and has some cool features that you rarely see elsewhere. Besides, like my wife said when I brought it home, "Does that thing have a joystick? That's soooo cool!"

I like good sound, but for me, "HiFi" is only part of the fun, so an item can be excused if it's not the ultimate in sonic bliss if it's got something else going for it.

I still have to collect my thoughts on the 700B, and take a couple of measurements since it's been a while since I looked at it, and I want to get most of the pertinent info in my first post in the thread.

soon, hopefully.

Zach
 

laatsch55

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Nav, I would love to see what he did also, remember I've got one sitting here too. 83 caps is what I counted and I had plannedon putting radials in place of the axials like I did in the 3300 Ser II.
Thanks for the info Zach, post up on the 700, you'll get lot's of help there....
 

kevin

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Welcome Zach.... Boy did you ever come to the right place !!!! Several of these guys on here can fix PL's while they are asleep....
 

Zach C.

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Nav, I would love to see what he did also, remember I've got one sitting here too. 83 caps is what I counted and I had plannedon putting radials in place of the axials like I did in the 3300 Ser II.
Thanks for the info Zach, post up on the 700, you'll get lot's of help there....
There's really not much more to say about the 4000, but I'd be glad to answer any questions I can. I really didn't get into anything too technical with that one- just a recap and refresh really. I was afraid of long term problems with radials in that application especially since most of them are oriented sideways on the daughter boards. I'd offer to take pics of the innards, but it's hooked up in the kitchen system right now. After I get the 3300 recapped, I will likely have it out, so I could photograph the inside them, or might have some pics from when it was apart come to think of it. hmmmm.

Is there anything in particular you're wondering about?

Thanks for the offer of help on the 700B. I'm going to be busy for the next couple of evenings (that's when I get a chance to fool with this stuff) and I still want to take a couple of measurements before I post on that. Where should I post that? The WO archive, or amps?

Zach
 

Zach C.

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Welcome Zach.... Boy did you ever come to the right place !!!! Several of these guys on here can fix PL's while they are asleep....
Thanks.

Of possible (if fleeting) interest to you, is that I have the original set of Linus Arrays that I got from Dr. Griffin. He's a great guy I thought I was going to use them in my gym area, since they are rather tall, but after the wife got a listen, she said they are staying put in the living room. So far, I've let her have it her way.

Zach
 

kevin

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Wow.. How cool is that... My buddie ''Sutton'' and I built two pair of them... As you can see I'm still using mine and so is he. Dr Griffin was in Atlanta Ga. I Believe with the pair you have... Thats been several years ago. I've got a PL 700 on mine.... lol.... MAN THEY SOUND GOOD... but I am using a sub.... Small world !!!!
 

Zach C.

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...I've got a PL 700 on mine.... lol.... MAN THEY SOUND GOOD... but I am using a sub.... Small world !!!!
I can only imagine...for now. I can't wait!

I've got a couple of 12" subs running below 80hz with mine, but they don't want for much by themselves, without the hi-pass. They'll play quite loud on little amps. I'm running them off a 100w amp now, and that'll get damned loud with the subs, but you know this. :iconbiggrin:

Zach
 

laatsch55

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#19
Zach, on the 3300, if you change out the TL072 , and 5532 op amps with Burr-Brown OPA 2134's it's like a whole new world....
 
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