Russ' PL 3300 Ser II

laatsch55

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#45
Got the MLCC (multi layer ceramic capacitor) for the phono section. The old tantalums had drifted in value up to 26 and 25 uf, ESR was WAYYYYY up. Anything in single digits above zero is very bad. New ones showed 21.8 uf and ESR in the hundreths....
 

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orange

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#47
No, REPLACE, if I got the gist from Joe. Long time, no likee.
 

laatsch55

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#49
Ok Joe, funny thing....with my scope on the outputs, and the AP in "listen" mode, when I first turn the pre on the scope and the AP show 120hz, and after a little warm up it falls to 60hz as the primary freq, and then it's all over the place at times 6khz to 20hz....the AP is plugged into the phono section with the generators off and also plugged into the unswitched pre outputs...


What was the name of that program I need to get from Tektronix to be able to capture, store and display on the PC? TekVisa??
 

laatsch55

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#50
Pk Joe....

The 5532 replacement brown dog in the phono section I have the de-coupling cap across pins 8 and 4 Vcc-, and Vcc+ not good...

The TLE 2072's in the other 3 locations I have the decoupling caps across pins 8 and 4 also....

I'm guessing some of my noise is coming from this...

The cap should be to ground correct??
 

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Gepetto

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#51
Pk Joe....

The 5532 replacement brown dog in the phono section I have the de-coupling cap across pins 8 and 4 Vcc-, and Vcc+ not good...

The TLE 2072's in the other 3 locations I have the decoupling caps across pins 8 and 4 also....

I'm guessing some of my noise is coming from this...

The cap should be to ground correct??
You will get more effective decoupling if you use 2 caps, one end of each to ground and the other end to pin 4 and pin 8 respectively Lee.

That may not be your problem as the PSRR of these op amps is very high, even without decoupling.
 

mlucitt

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#54
Lee, were those factory caps across the Aux AC inputs? Were they connected together and the common point grounded to reduce EMI? Maybe they were caps that were not rated for AC service? Or, just old? I like a pair of thermistors on each of the AC lines or DC busses to reduce inrush currents (not on the PL700B though, too much current), or better yet, a Metal Oxide Varistor (MOV) or two, or three across the AC lines before the bridge rectifier to reduce voltage spikes. Thoughts?
 
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