Well, so I gotta Crown big hummer amp...

jbeckva

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#1
And I've put about ..err.. 50 bucks or so. Here's what's been done..

1. Speaker outputs now heavy binding/banana posts.
2. Rerouted the main ground with a heavy 8 gauge cable.
3. Input op amps replaced with Burr Brown OPA4134's (they're the quad equivalent of the OPA2134's). I tried the quad LM4562's (LME49740's), but they were just "too fast" and made a lot of noise I didn't want.
4. Coupling caps replaced with Nichicon Muses - may bypass 'em if the offset on the input side is decent now with the BB's

So, how's it sound? Probably the best *butt-ugly* beast of an amp I've heard. It's up there now with the PL heheh. Mebbe I should have ya machine a faceplate with meters for it, Lee?? Then it'd really look cool. That'd be a serious Frankenstein there...

Maybe I'll take it "upstate" soon.. blow some lil bitty speakers some guy has up there... :cheers: :roll:
 

Gepetto

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#2
Hi Jerry
You have to find some of the old, original Crown DC300's. Classic (industrial) look with great sound and unbelievable reliability. Well engineered, mechanically and electrically. Like em almost as much as my Phase Linear amps.

Joe
 

speakerman1

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#3
jbeckva said:
And I've put about ..err.. 50 bucks or so. Here's what's been done..

1. Speaker outputs now heavy binding/banana posts.
2. Rerouted the main ground with a heavy 8 gauge cable.
3. Input op amps replaced with Burr Brown OPA4134's (they're the quad equivalent of the OPA2134's). I tried the quad LM4562's (LME49740's), but they were just "too fast" and made a lot of noise I didn't want.
4. Coupling caps replaced with Nichicon Muses - may bypass 'em if the offset on the input side is decent now with the BB's

So, how's it sound? Probably the best *butt-ugly* beast of an amp I've heard. It's up there now with the PL heheh. Mebbe I should have ya machine a faceplate with meters for it, Lee?? Then it'd really look cool. That'd be a serious Frankenstein there...

Maybe I'll take it "upstate" soon.. blow some lil bitty speakers some guy has up there... :cheers: :roll:
You better hurry. That room is about to be emptied. I like the old Crown amps. They made some nice preamps in the day.

Larry
 

jbeckva

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Man I'm trying to.. I swear..

I like these BB chips... nice n easy but still defined. Was a pita tho - they only came in lil surface mount buggies when I needed the DIP's. I made 'em fit.. heh.

Yeah Joe I hear ya about the DC-300.. that one's a legend there. This ComTech 1600's not too shabby tho - not one bit of plastic in 'er, 12 big ole TO3's per side, one bridge rect for each side too... 58 lbs, etc. Not sure what the vintage year is, but still before Crown started putting out those "big sound n lil package" amps.

If I ever had the craziest notion of bridging it, it'll do 1720W into 8 (geesh.. I'd need to wire it for 240 then). Not that I would ever get close to that - I aint got Lee's "titanium coated" eardrums, lol!
 

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Jer, they are not titanium coated, and I let em rest for a couple days after a Mach 8 session. So bridged they do 1.7KW eh??
 

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Glad to see ya went with the Burr- Browns. Just today giot the skinny on something that blows the BB's away---Diodes Inc's new APX 4558. check it out. JRC's 4560, 4580 are killer too.
 

jbeckva

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laatsch55 said:
Glad to see ya went with the Burr- Browns. Just today giot the skinny on something that blows the BB's away---Diodes Inc's new APX 4558. check it out. JRC's 4560, 4580 are killer too.
Ya trying to pull my leg? Those JRC's are what I would typically target for replacing. The APX 4558 has a 1.1 v/uS slew rate at unity gain... hmmmmm, indeed.
 

laatsch55

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The JRC's are known to be very musical,, or audio friendly, as they say. But the BB's have quite a following, and can you really evaluate something just from as data sheet.
 

jbeckva

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The JRC's are used in the Creative SB's - I replaced 'em with 4562's and made a big difference. I'm still leery about that APX tho - the datasheet didn't even specify a THD figure. But yeah.. the "sounds good - go for it" rule always applies, heh.

Those BB's sure sound good tho... I'm betting it was the JFET inputs on 'em versus the typical bipolar differential setup that made the difference in the noise rejection, as opposed to the LM's I tried before them.
 
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