Chris' Pioneer Spec 4 hack job

laatsch55 said:
Joe , what does it mean to have "wave like " undulations as sine waves??
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Sounds like to me the last time they tried to change the damned IV last year at the hospital.

Fortunately they discovered my recovery had far outstripped their diagnoses.
 
Was rummaging throigh the cap collection and Voila'. The 35,000uf CD's are an exact , drop in replacement for the 80 vpolt, 22,000uf Elna's. Love it!!
 

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And I just hapen to have 80 matched pairs of the 2SD555/2SB600 combo. Which was standard equipment in these.
 
Chris wanted gold plated RCA jacks, he got em...
 

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Got my mouser order today. Was pretty well stocked up. Just needed two types of transistors I didn't have... One amp board out of Chris' is done.
 

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In place of the 5 legged 2SA798 I heatshrunk 2 -2N5087's together, tied the emitters together and stuck em in. The 2SA798's are getting pricey and hard to find. The 5087's have almost identical specs, hfe range 250-800 etc. Guess will know before the night is over how it worked...
 
Matching hfe gain on complementary TO-3's is a pain in the butt. Period......
 
Outputs matched and in. I've never heard of anyone running 2-5087's in place of the 2SA798's----pucker time.
 

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laatsch55 said:
Outputs matched and in. I've never heard of anyone running 2-5087's in place of the 2SA798's----pucker time.
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What!!!!! No close ups????? Gotta see it - just can't touch it from here. I'm not talking about the pucker though.
 
Here ya are.....
 

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Cool Lee - nice job. I was just about to post my smart ass photo for this - but you beat me to the punch.
 
Maybe ya better anyway something very embarrassing happened,,,,,,,, ummm back in 20 minutes.....
 
Almost, had assembled the output boards upside down and had the NPN outputs where the PNP's go, and vice versa. Had it on the DBT, which usually messes with the protection circuit (on the Spec 2 for sure) not positive about the Spec 4. Anyway the bulb was way out of character at 20 volts even so I got it shut off before anything burnt. Put em back where they belong, brought it up slowly, adjusting bias as we went and as soon as the relays closed was on the DC offset pots. Everything looking real good so far. Bias 30MV and holding, offset 3MV or less, anymore than that and I zero it back up. Steady as a rock. haven't loaded it up yet, that's when we'll see if the twin 5087's are up the task. Not tonight, I'm toast, and work is 8:00 o'clock away.

All in all I'm pretty damn tickled....

Got the Oppo in today too, too damn tired to mess with it and it's killin me not to......
 
Cool - it's good to have a variac and the DBT can be a life saver. If ya go now you'll miss some of the fifth grade humor!
 
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