mike stehr Posted August 8, 2021 Share Posted August 8, 2021 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. 2 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted August 8, 2021 Author Share Posted August 8, 2021 Original wiring, with burnt screen resistor. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted August 8, 2021 Author Share Posted August 8, 2021 And that's that. No way am I going to deal with wax covered sockets with rotted pins, and rotten wiring. Whatever magic those parts had, (if any) faded away a long, long time ago. I'm hoping it's still in the output transformers... Quote Link to comment Share on other sites More sharing options...
mike stehr Posted August 22, 2021 Author Share Posted August 22, 2021 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 Quote Link to comment Share on other sites More sharing options...
Curious_George Posted August 23, 2021 Share Posted August 23, 2021 Nice… a perfect mid-summer project. Quote Link to comment Share on other sites More sharing options...
seti Posted August 23, 2021 Share Posted August 23, 2021 Those parts were toasted. I love EL84 amps more than I expected. The Fisher I did recently was a PITA but totally worth it... Post progress pics!!!! Quote Link to comment Share on other sites More sharing options...
mike stehr Posted August 23, 2021 Author Share Posted August 23, 2021 1 hour ago, seti said: Those parts were toasted. Then dipped in wax. If carbon composition resistors are hydroscopic, then those resistors are fully saturated with wax. 1 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted September 10, 2021 Author Share Posted September 10, 2021 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. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted September 10, 2021 Author Share Posted September 10, 2021 Back panel with mounted rocker switch. Plates for binding posts ready to drill... 2 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted September 27, 2021 Author Share Posted September 27, 2021 Ready to wire finally... 4 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted October 22, 2021 Author Share Posted October 22, 2021 3 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted November 9, 2021 Author Share Posted November 9, 2021 2 2 Quote Link to comment Share on other sites More sharing options...
JDJohnson Posted November 9, 2021 Share Posted November 9, 2021 Very well done! Quote Link to comment Share on other sites More sharing options...
captainbeefheart Posted November 9, 2021 Share Posted November 9, 2021 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. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted November 14, 2021 Author Share Posted November 14, 2021 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. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted November 15, 2021 Author Share Posted November 15, 2021 2 Quote Link to comment Share on other sites More sharing options...
OO1 Posted November 15, 2021 Share Posted November 15, 2021 16 minutes ago, mike stehr said: Beautiful Job , clean soldering , new parts , new wiring , heat shrink , impressive work - 1 Quote Link to comment Share on other sites More sharing options...
mike stehr Posted November 21, 2021 Author Share Posted November 21, 2021 Done 1 Quote Link to comment Share on other sites More sharing options...
dirtmudd Posted November 22, 2021 Share Posted November 22, 2021 19 hours ago, mike stehr said: Done how does it sound ? what did it test on the bench.... Quote Link to comment Share on other sites More sharing options...
mike stehr Posted November 23, 2021 Author Share Posted November 23, 2021 Er, my bad...I meant I was done wiring. I haven't powered up or tested the unit yet...work and all kinda gets in the way. Quote Link to comment Share on other sites More sharing options...
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