Old Amp
I have a Crown DC300A that has been around the block and your block too. I picked it up for free a few years ago when I was wiring some chillers in a bar.
It works but I think the caps have dried up from long term continuous use with high temperatures. The damn thing is almost shrill sounding. It does seem to have a tremendous amount of power. I have the schematics for it and all but what should I do with it? Re-cap it? Throw it in the garbage? Scrap it...for what?
Poor thing, face down on the basement floor. "Don't look at me amp, you make me sick."
Shawn.
I have a Crown DC300A that has been around the block and your block too. I picked it up for free a few years ago when I was wiring some chillers in a bar.
It works but I think the caps have dried up from long term continuous use with high temperatures. The damn thing is almost shrill sounding. It does seem to have a tremendous amount of power. I have the schematics for it and all but what should I do with it? Re-cap it? Throw it in the garbage? Scrap it...for what?
Poor thing, face down on the basement floor. "Don't look at me amp, you make me sick."
Shawn.
Attachments
Steamwhistle
The Old Roundhouse Brew Eh? Good stuff but a little pricy but aren't all the good ones? I must have drank a thousand of those whistles this summer...hmmm beer belly and a drawyer full of bottle openers!!! Ha, I've been mailing them out to all my peeps! BTW if you like good pilsner please try Pilsener Urquell, it is an aquired taste but it is my fav pil.
Now I'm back on the winter beer! Oops Guinness in a Caffrey's glass! How dare I?
bikehorn said:
The Old Roundhouse Brew Eh? Good stuff but a little pricy but aren't all the good ones? I must have drank a thousand of those whistles this summer...hmmm beer belly and a drawyer full of bottle openers!!! Ha, I've been mailing them out to all my peeps! BTW if you like good pilsner please try Pilsener Urquell, it is an aquired taste but it is my fav pil.
Now I'm back on the winter beer! Oops Guinness in a Caffrey's glass! How dare I?
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Hi Tom. My recollection is the lower powered models had a nasty opamp front end - a 741 or similar - and an equally nasty hack for a front end supply. If the 300 is the same that and a re-cap is where I'ld start. Right after upgrading to a Litz power cord of course, just to keep these cranky old guys happy. And keep off my lawn! 
Hi Shawn,
Man, I've rebuilt a number of those over the years. The Metalworks still uses them in Studio "A". The last time I was over there anyway.
That's a class B beasty, or close to it. I don't know if I'd rebuild it ( I might), but the chassis would serve a new design. Very industrial looking. If you remember Martin Audio in Port Credit, I sold them (new) there.
Don't throw it out. If you don't want it, I wouldn't mind it. No shipping then.
-Chris
Edit:
Man, I've rebuilt a number of those over the years. The Metalworks still uses them in Studio "A". The last time I was over there anyway.
That's a class B beasty, or close to it. I don't know if I'd rebuild it ( I might), but the chassis would serve a new design. Very industrial looking. If you remember Martin Audio in Port Credit, I sold them (new) there.
Don't throw it out. If you don't want it, I wouldn't mind it. No shipping then.
-Chris
Edit:
Guinness goes well in any glass! It has taste.
Car Wash
If I get down with this thing, I will take the entire thing apart and rebuild the boards, wiring, power supply...the whole thing. Could be a good fall winter project too. Sandblast the heat sinks and the bell on the XFMR. Make her new again. I might pull it apart tomorrow? I'll need a few boxes and a bunch of glad zip lock bags and label all of it. Take a bunch of pictures...bla bla bla...it could be fun.
Cheers,
Shawn.
rdf said:edit: A car wash would be a good start on that puppy!
If I get down with this thing, I will take the entire thing apart and rebuild the boards, wiring, power supply...the whole thing. Could be a good fall winter project too. Sandblast the heat sinks and the bell on the XFMR. Make her new again. I might pull it apart tomorrow? I'll need a few boxes and a bunch of glad zip lock bags and label all of it. Take a bunch of pictures...bla bla bla...it could be fun.
Cheers,
Shawn.
Hi Shawn,
I can see where you might go through some guinness on that one.
Try Simple Green with a paint brush in a sink. Follow with a water wash, Windex on the shiny bits. If you rebuild it and bypass the caps as well it may just sound much better than original. That's what I was rolling around in my head as an experiment.
I think you have a good project there.
-Chris
I can see where you might go through some guinness on that one.
Try Simple Green with a paint brush in a sink. Follow with a water wash, Windex on the shiny bits. If you rebuild it and bypass the caps as well it may just sound much better than original. That's what I was rolling around in my head as an experiment.
I think you have a good project there.
-Chris
Simple Green
Chris, you always make me smile. I started using Simple Green when I ran the rental department at McKnight's Music in Cape Breton Nova Scotia. I was ....19 years old when the old tech fart gave me his spray bottle. "Use this lad, it works good" I've used it ever since.
Good Times.
anatech said:
Chris, you always make me smile. I started using Simple Green when I ran the rental department at McKnight's Music in Cape Breton Nova Scotia. I was ....19 years old when the old tech fart gave me his spray bottle. "Use this lad, it works good" I've used it ever since.
Good Times.
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Hi rdf,
That would be my plan. Lose the carbon comps. Replace with metal film in early signal path areas. Metal oxide everywhere else except for emitters. They would get non-inductive plate type resistors. All ceramics meet Mr. Hammer.
Time for mica and the poly sisters.
The feedback pole cap would need to be recalculated (empirically) for the newer parts. The non-inductive emitter resistors may actually tame the design a little better. Todays faster outputs would allow for better class B operation I bet.
-Chris
That would be my plan. Lose the carbon comps. Replace with metal film in early signal path areas. Metal oxide everywhere else except for emitters. They would get non-inductive plate type resistors. All ceramics meet Mr. Hammer.
Time for mica and the poly sisters.The feedback pole cap would need to be recalculated (empirically) for the newer parts. The non-inductive emitter resistors may actually tame the design a little better. Todays faster outputs would allow for better class B operation I bet.
-Chris
rdf said:
If I crack it open, I'm replacing everything. I'd post the schematic and request tweaks on the forum, who knows, the old boat anchor could rock harder for another 30 years. I think there is a strong chance to give it a little extra edge? Seriously, I would sand blast it. Obviously it was painted black by some goth tech. The DC300A was never released Black in the 60's or 70's or ever?
The front label looks funny too but I'd have to take it apart to see what the heck is going on.
What does this too much of that class-B goodness mean?
Hi Shawn,
No, those were a kind of chrome face if I recall correctly. Don't sand blast it. If it's apinted, tehn paint remover should bring back the original finish. I'm wondering about the lettering though. If the chrome is toast ..........
Well, if the chrome is toast (it wasn't a flat surface finish), then consider prepping it for replating in a brass or some other cool finish.
-Chris
No, those were a kind of chrome face if I recall correctly. Don't sand blast it. If it's apinted, tehn paint remover should bring back the original finish. I'm wondering about the lettering though. If the chrome is toast ..........
Well, if the chrome is toast (it wasn't a flat surface finish), then consider prepping it for replating in a brass or some other cool finish.
-Chris
But your time will come and we shall meet, you and I! Bah, ha ha ha ha.
Hey Shawn,
Why don't you compile a list of the transistors it uses. Maybe with some substitution...you could.....you know.
What are the output transistors? Anyone have a schematic?
This could be a great candidate for improvements.
Darn it Shawn you got me buzzing....
Q
Oooops just saw the mods intervention....better shift this one too.
Why don't you compile a list of the transistors it uses. Maybe with some substitution...you could.....you know.
What are the output transistors? Anyone have a schematic?
This could be a great candidate for improvements.
Darn it Shawn you got me buzzing....
Q
Oooops just saw the mods intervention....better shift this one too.