Crazy things to do with a PL 3000 Preamp while we wait...

jbeckva

jbeckva

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Since all the other projects are waiting parts at the moment, thought I'd do something with my own 3000 PL preamp. Since my number of sources are limited and most are already switched in and out of the signal path by way of my EQ, I'm looking to eliminate any "moving part" (like a relay) not directly needed for my application.....

So... as I'll need Phono1 and Aux, and be using the NR loop for the pre, this is the plan so far..

1. Eliminate K1, 3-6, 8-12, and 14 (missed that sneaky guy...)
2. Jumper the resulting sockets (NC contacts normally) for K's 8 through 12..

porinoverschem.jpg
 
Cool! Eliminating relays means less can go wrong later down the road!
 
Yep, all done... and it sounds phantasmagoric!! Basically for inputs the only two left are Aux and Phono1, while the EQ is in the processor loop - it has two tape loops so basically that's where my remaining inputs lie.

Ron's 400 should be a comin' soon... I will begin tearing just about everything outta it later...
 
Jer...Tracking number on the rest of Ron's goodies------962223115002214 Fed-Ex.
 
laatsch55 said:
So basically you're a gain stage for 3 inputs??
Click to expand...

2 where they'd normally be.... all "native" tape loops, filters, whatever had a relay "gone"... then up and down through the NR loop (usually jumpered on the back) and onto the vol/tone controls (defeatable) and finally the output amp...

pretty much.. yeah.

The other config this would work for would be if I substituted a dbx 200 or 400 program route selector for the EQ. I had one of those (hmm.. do I still.. gotta go look) but it did degrade things a lil.. to my ears, anyway...
 
Did it get the De-Oxit?? Are there electronics in there?
 
Taking a break (well .. multitasking sorta) from Ron's 400, now it's time to go see what I can do with these preamps (howdy Kev!!!). Came to the realization that the RCA4136's in my old one well... they're basically 4 741's, and although the 741 is an old famous workhorse when it comes to opamps, we probably can do better here...

SO.. my turn to do some brown dogging here... holy crap are them guys small! We're shooting for the LME49860's, and will put two of them on each adapter. Specs on the LME's...

Rail to Rail max - 44 volts
Typical THD - .00003 %
Typical Offset - .12 mV
Slew Rate - 20 volts/uSec

Time to try gluing a fly down, one leg at a time...

20140126_222003.jpg
 
Missed a few specs there Lad, SNR, residual noise......
 
ThaT'S ODD.





















PERHAPS it's so beyond any oter opponent it's likely to be pared with it's a moot point.
 
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