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Pilot SA-232


mike stehr

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Picked this up a few weeks ago locally.

 

I've been wanting a EL84/6BQ5 power amp for some time, and wanted to go the Dynakit ST-35 route.

But due to shortage of parts, that may be some time from now...

 

Seen the Pilot listed local, and started searching online for information about SA-232. Seems to be some praise, maybe dying off a bit over that last 6 years.

I didn't want another console stereo 6BQ5 push-pull amplifier, but the output transformers looked to be decent size.

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  • 2 weeks later...

PS transformer has been torn down, inspected for broken wires, with the endbells re-painted.

The lamination stack was crooked from heat...I corrected that. 

DCR was checked, and then I went ahead and ran the PS unloaded for a couple hours. It sort of got warm...

Voltages with 117VAC go in line with the Pilot schematic...I think it will be okay.

 

Output transformer DCR numbers match between each other, and should be fine.

 

Transformer hardware was replaced with stainless steel.

 

Bought new sockets, with hardware (screws,nuts) being stainless steel. A CE replacement multi-capacitor of 40/40/40uF at 525vdc is on it's way.

I've got the chassis gussied up a bit so far, the wood endcaps are Wenge.

 

Mike

DSCN3823.JPG

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  • 3 weeks later...

Have all the parts ordered except for binding posts and a thermistor.

 

I didn't like the idea of the having the input jacks on a back plate with AC outlets, then having the input jacks go through and over AC secondary and heater windings to get to the 12AU7 input tube. So I drilled the input jacks on the front of the chassis, as close to the 12AU7 socket as I could get.

DSCN3836.JPG

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  • 3 weeks later...
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Wow lot's of work great job!

 

I had one of these a long time ago and ended up doing major surgery as well. Looking at the schematic had me thinking it wasn't worth wiring back how it was originally so I decided to keep the same tube compliment but shifted things around a bit. I moved the 12AX7 to the input stage and wired the 12AU7 as a long tailed pair vs the original paraphase splitter.

 

What is your experience with the CE multi-section capacitor cans? I am in a few different antique and ham radio groups and many of us had bad experiences with them. I don't purchase multi-section cans much anymore as I prefer now to just very carefully open the crimp around the wafer and pull the guts out. The machine shop lets me set up a lathe to spin the cap slowly while the tool slowly opens the crimp. I then stuff with high quality caps, it's amazing how small they have become over the years to allow this to happen.  Many in the group also do this but use a tubing cutter to open the can but this often leaves clues that the can was once opened.

 

I am going to be following this thread definitely.

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On 11/9/2021 at 1:07 AM, captainbeefheart said:

What is your experience with the CE multi-section capacitor cans?

I have read about others having bad experiences with the multisectional CE capacitors, but I guess I have been lucky.

My 345A Altec amplifier uses the CE cans. I rebuilt that amplifier in 2008-2009, and I've had no problems.

 

Knock on wood, however...if the CE can fails, I have a JJ multisectional capacitor that I can swap in. 

The only reason I used the CE can cap, is for cosmetics.

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