Ampeg B 15 N

portaflex, tuned cabinet special, James Jamerson, Duck Dunn, Chuck Rainey, 

nice piece, low mileage>

under the chassis schematic>

what a coincidence,  customer calls and asks about a can for a Ampeg amp, as luck would have it, mjrippe had sent a dead pwr xfmr to dissect and the can was collecting dust, amp without pwr trans.

looks like two pwr resistors have been changed and two bypass caps, and a pwr cord, otherwise very clean>

showing the 'tone stack on a chip' thingys,  can still get them at flip tops for $29, some folks say that using caps annd resistors is an upgrade,

this amp does generate weird waveforms if the tone controls are turned past 5, could be the tone chips, or just too much gain from the 6SL7 tubes into the 6SL7 phase inverter,

coupling caps, did not detect and DC on the grid side, a miracle for an amp this old, CDE caps? what does that stand for?

just throwing down some closeups for DIY clone purposes,

preamp area

lots of coax

tone module 1

tone module 2

can't have enuff wiring shots,

hi-tek bak lite lamps

stand by sw gnd goes into speaker cab then back out, wtf?

amp also hums if you use grounded spk jack on chassis for testing,  have to use cable,

coolsville lucite >

CJ said:

coupling caps, did not detect and DC on the grid side, a miracle for an amp this old, CDE caps? what does that stand for?

Click to expand...

cornell dublier?

JR

Wow, glad that got put to good use!  And I agree with John, Cornell Dublier made some fine caps back in the day.

wow, that Dubillier cat was a big wig in the radio thing.

"William Dubilier (July 25, 1888 – July 25, 1969) was an American inventor in the field of radio and electronics. He demonstrated radio communication at Seattle's Alaska-Yukon-Pacific Exposition on June 21, 1909; ten years before the first commercial station operated.[1] A graduate of Cooper Union, he was the first to use sheets of naturally occurring mica as the dielectric in a capacitor.[2] Mica capacitors were widely used in early radio oscillator and tuning circuits because the temperature coefficient of expansion of mica was low, resulting in very stable capacitance – mica capacitors are still used where exceptional temperature stability is needed.

He founded the Dubilier Condenser Company in New York in 1920"

those Tiger Caps go for 29 bucks a pop on evilbay, wtf?  most of those seem to be leaky or shorted,

looks kind of like Edwin G Robinson>

we saved the old black tar but did not know how to get it back in the can with the new transformer,

well, an old frying pan and electric stove solved that problem, you get it to a certain temp and bam, it melts like candle wax, pour it in there and it bubbles like the LaBrea tar pits,  microwave not such a good idea unless you like tar flavored burritos which burn your mouth due to uneven heating,, why can't they fix that?

CJ said:

we saved the old black tar but did not know how to get it back in the can with the new transformer,

well, an old frying pan and electric stove solved that problem, you get it to a certain temp and bam, it melts like candle wax, pour it in there and it bubbles like the LaBrea tar pits,  microwave not such a good idea unless you like tar flavored burritos which burn your mouth due to uneven heating,, why can't they fix that?

Click to expand...

I think there are some microwave ovens with a rotating metal vane that breaks up the standing waves for less hot spots and more even cooking.

JR