Chris' Pioneer Spec 4 hack job

[fitz43]

fitz, it was the one Joe recommended the DV-983H.

Thanks. One day I'll replace my carousel with something better.

 

[laatsch55]

The 2N5087's did not work out for a sub. Temperature co-efficients must have been different, went way squirely under a load. I have thusly swapped those out with a pair of 2SA979's a 100 volt rated part, compared to the 50 volt 2SA798, which run at 66.5 volt. The 979's lack the gain of the 798's we'll see how it affects performance.

 

[laatsch55]

Big caps going in....

 

[laatsch55]

Pioneer was a firm believer in the Star ground method..... All big caps in......Meter amp board next then this puppy is done..

 

[Gepetto]

The 2N5087's did not work out for a sub. Temperature co-efficients must have been different, went way squirely under a load. I have thusly swapped those out with a pair of 2SA979's a 100 volt rated part, compared to the 50 volt 2SA798, which run at 66.5 volt. The 979's lack the gain of the 798's we'll see how it affects performance.

Lee you should find out why you have 66.5V. That is a problem that needs to be fixed. It should only be about 28V

 

[laatsch55]

Unless a feller wants to unwrap 20 something wires the meter board is left in place. Not much room, but the effort/benefit ratio isn't there to take it out.

 

[laatsch55]

Lee you should find out why you have 66.5V. That is a problem that needs to be fixed. It should only be about 28V

Inherent in the design???

 

[laatsch55]

Joe the only thing I can see in the way of that 66.4 volts going to the collectors is a paralled 470 ohm resistor in series with a 330pf cap. Is that enough to drop it to 28volts???

 

[Gepetto]

Nothing you can do except use the correct device here Lee. The Spec4 has 66+ volts across the front end by design, the Spec2 has ~28V, much more normal.

Just use the rigth transistor, the 5087 gave you odd results because they were breaking down. The 798's are in the same boat. The 2N5401 looks like the only reasonable device for this location.

 

[Web Police]

Looking good Lee, Maybe one day I will send my Spec4 in for some TLC.

 

[laatsch55]

Nothing you can do except use the correct device here Lee. The Spec4 has 66+ volts across the front end by design, the Spec2 has ~28V, much more normal.

Just use the rigth transistor, the 5087 gave you odd results because they were breaking down. The 798's are in the same boat. The 2N5401 looks like the only reasonable device for this location.

How about a KSA992, Or Zetex 795A??

 

[laatsch55]

Looking good Lee, Maybe one day I will send my Spec4 in for some TLC.

Been waiting for a couple years now......

 

[laatsch55]

Joe, the Fairchild 5401's I have have a gain of just under 200. Should be ok, I'll pull one of the 2SA 979's and see how it does.

 

[Gepetto]

How about a KSA992, Or Zetex 795A??

The KSA is a better choice Lee, get the F grade

 

[laatsch55]

Yep!! FBU!

 

[laatsch55]

Got a miniature drawer full of em. That's almost as much as a trash sack full.

 

[laatsch55]

A pair of matched KSA 992FBU's. Well soon Know!!

 

[laatsch55]

Joe the 992's worked out great. have another problem. On the meter amp board had an NPN and a PNP TO-220 reversed. I think I have wounded a cap....

 

[laatsch55]

Was not a wounded cap, but a TO-126 was bad. hoking up to the AP now and enjoying the "Pig" pushing the Oppo. Sweet combination. Jan's making some coffee from resh ground beans, the kid didn't get any time. The judge even questioned on record why the case was even brought, proceeded to ream the county attorney on just who forgets their kid in the car, recited a list from a 2009 Washington Post article ranging from a rocket scientist to a pediatrician . He also mentioned there was a dramatic increase after the law stating that infants be in the backseat and TURNED TO FACE THE BACK was passed. The Wyoming law he was prosecuted under is so vague the judge said," Any parent out there could be prosecuted uner this law. Tell me County Attorney, does every parent need to be in jail? Now the state says it's criminal to forget??"

Juries and good judges are what keep us from being a totalitariain regime......

Political rant iver. The cat wants kitty cuddles and the AP is warmed up.

 

[Gepetto]

Glad it all worked out Lee. How's Squidley doing these days?