TEARING DOWN Two 1940s Tube PA Heads
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- Опубліковано 23 січ 2018
- In this video, we will strip the transformers, tubes, and other parts from a pair of late 40s tube PA heads - a Stromberg-Carlson Model 32 and a Knight 14S. These stripped down chassis have been sold to Tony Dorris of Volition Amps to be used in his rebuilds. The transformers and tubes I will keep to be re-purposed into future builds. Subscribe to Tony's channel to see what eventually becomes of these beauties: / @que721
Man, that Knight chassis is a work of art!
Those chassis(s) are things of beauty
Nothing wrong with giving the chassis a new life!! Would be nice to see them done! I'm sure they will look and sound great (better then ever). Great video!
8:10
Great video!
Hopefully you can have Tony come back in with these when he's done with them, I'd love to see and hear what he'll buint in these! That Knight looks killer!
Nice one Brad. Cheers big ears. ;)
I just rebuilt a Stromberg Carlson Model 207 P-P 6L6 PA amp with 2x 6SJ7s to a 6J5 then to a 6N7 for PI....Those parts are worth a lot, because they were designed to operate at a 100% duty cycle.
Just a little advice. If someone bumps into a transformer were it's not clear what the primary or secondary side is. You can easily see the difference when measuring the resistance.
Yeah, Tony needs to come back on once hes finished them and give us a screamin' demo!
You need a set of sidecutting linesmen pliers for cutting those heavy cables!
The fail rate on old xfmrs that are not potted, that have been in damp basements and what not is very high when they are brought back into service. Heating them up gently and exposing to high vacuum could help but you have to be able to pull a really high vacuum. If you are going to the trouble of doing a new build, use new transformers. The only old transformers I will use are mil surplus potted ones or ones that are NOS that have been stored in known dry clean spaces.
I love the way they made amps back in the day , all hand wired, chassis it built like a tank. My dad used to built heath kits stereo equipment. One day he threw it all out, i almost cried. After i found out about it years later. I would have rather give this stuff to you Brad.
I hate to admit to being old enough that I serviced these things, but yea.. The reason for the big floppy resistor is that a prior model used a field coil on the speaker between the rectifier and the main B+ cap. No kit version ever that I know of. Some of the later ones built in the 50's and 60's were pretty nice, had low-z input transformers, and had switched to 12AX7's for gain and driver stages. Things lasted forever! Usually bad caps would be when they got scrapped.
according to a pdf catalog from early 50s, the Stromberg Carlson AU - 32 PA mixer is a 15 W RMS amplifier. That's really low for 6l6 but i have an au-32 and it sounds super nice and seems like it is about 20watts. as far as i know, those were made in Rochester New York and used Hammond transformers
305 on the output transformer of that S-C is Standard Coil. It's possible the power transformer was also made by them.
So you got the first one for like, $9. I’m guessing it’s safe to say you got a really killer deal since just one of those antique tubes is worth more than your buying price?
Someone send Brad a nut driver set! LOL
Brad : As far as I know Stromberg Carlson never produced any kits, they made good quality equipment and they had excellent line of home radios that were moderately high quality sets !! they also produced lots of telephone equipment in the day.
I was fascinated with Jews Harps and my elementary teachers electric dulcimer. She would play it for us using those fake plastic pics that fit on the finger tips Some of my earliest and fondest memories. I was probably 9 and it was the mid 70's.