The Siver Shadow 400 Returns!!!

laatsch55

laatsch55

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Halfbiass...Electron Herder and Backass Woof
Warranty job, something smoked....driving the midsection of Stephens Infinity 4.5's. I have a feelin it was the PS caps. The 4.5's are an impedence nightmare, and it starts at 4 ohms and does not get better......

The beautiful copper beast....
 

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R78, R79 on the right driver board, 47uf/100 volt cap on the minus rail right backplane, both minus pico fuses on both backplanes.....and that's just what I can see.....no dead shorts on the outputs...
 

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Joe, this is one we had not rerouted the minus drive feed from the driver board to the backplanes. This one was still in the #3 slot on the backplane instead of the unfused tap...


So, it mirrors the failure mode in the Pig when we were blowing it up....So, he'll get the new driver board outta the pig and we'll get him on his way....
 
laatsch55 said:
Joe, this is one we had not rerouted the minus drive feed from the driver board to the backplanes. This one was still in the #3 slot on the backplane instead of the unfused tap...


So, it mirrors the failure mode in the Pig when we were blowing it up....So, he'll get the new driver board outta the pig and we'll get him on his way....
Click to expand...

Figured that Lee when I saw the fried R78/79 pair.
 
Wow - talk about smoke. It did get a bit warm in there.

It looks like one of the backplane boards will need to be pulled from the amp. I would assume that desoldering the output transistors is a PITA. Can the first gen backplane board accept the socket that is used in the Rev B board? I'd assume not as the hole size would differ between the two but I had to ask.
 
Backplanes are fine Navo, I can replace the cap and reroute the wire without pulling them.
 
laatsch55 said:
Warranty job, something smoked....driving the midsection of Stephens Infinity 4.5's. I have a feelin it was the PS caps. The 4.5's are an impedence nightmare, and it starts at 4 ohms and does not get better......

The beautiful copper beast....
Click to expand...

Mmmmm, coppery........ when are those fins gonna be available to the masses?
 
Board out, Blackgates harvested....
 

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Yeah, half that is labor....they take a little time to make...
 
Backplanes ready to go. 47uf caps replaced, pico fuses replaced, minus drive feed relocated...
 

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The SS 400 is done. The Pig gave up his board (not without protest, jeez, he drives a hard bargain)..

It did drive me nuts after board installation. Even had Joe goin for awhile. I had 65 volts DC on the right speaker out after powereing up the Pig's driver board in the SS 400 the first time. It had taken out the minus pico fuse on the right backplane, rail fuses were fine. So...we isolated the backplane from the driver board, then loaded the driver board with some 1K resistors accross the base drives and isolated the bias circuit with a 10 ohm resistor accross the C-E junction. Still had 25 volts DC leaving the driver board on the base drives. Dropped the 1K resistors to some 150 ohmers and it suddenly was fine....just dropping the 1K's for 150's should not have done that....near as I can tell is I had a cold joint after installing the Pigs board and cured it after all that resistor soldering and unsoldering.


Got it on the horns now......Kicking some Shpongle ---Corridor of Mirrors out....

Knowin Stephen like I know Stephen...this littlew amp will get a VERY comprehensive shakedown before it goes...


PS....thanks Joe...you're patience is very near saintly....:hello1:
 

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ME????? A COLD SOLDER JOINT????? ME?????????

Indeed it can happen....
 
Something very cool in lookin over at that amp and seeing all that coppery goodness hangin out it's ass....
 
That was for the heatsinks Nelson, Sutton was asking about faceplates....
 
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