Author Topic: My first Stromberg-Carlson  (Read 5310 times)

Offline Sir Thrift-a-Lot

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My first Stromberg-Carlson
« on: March 08, 2014, 06:20:08 PM »
I found this at a local thrift for $35.   The guy told me it had been there for about two months and was soon headed for the dumpster.   I'm very glad to have rescued it.

All tubes are original S-Cs except the pre tubes which are RCAs.   The previous owner changed them both at once and even bought a spare, which he was nice enough to leave in the cabinet.   A NOS RCA tube is probably worth half of what I paid all by itself.

This will be my next project after I finish the RCA console pull.   That one is a good learning experience, this one will hopefully be much easier.   The layout is almost as clean as my Leak.   I also have a Maggotbox SET waiting to be refurbed, but everything is packed so tight in there that I don't know if I will ever develop the soldering skills to work in such tight spaces.

The tuner is another stupid multiplex unit (which dates the console to early 60s IIRC).   It will end up in the trash unless anyone here wants it.   The cabinet is already at the curb, with the tweeters still in it because I drove a screw through one of them and wasn't sure they would be used anyway.   The ALNICO woofer and full ranges will get used for sure.   Maybe I'll do my first experiment with open baffle.
















Offline MacGeek

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Re: My first Stromberg-Carlson
« Reply #1 on: March 08, 2014, 08:22:12 PM »
Sweet, Mark.  It looks like just a bit of dust to clean and it will sparkle.
MAC C-46 pre, MQ 108 eq, MC 352 amps (2), MR 78 tuner, MCD 500 CD, MPI-4 scope, LS 352 speakers, Sony HDR-F1HD AM/FM/HD tuner, Denon DRS 810 cassette, Denon CDR-W1500 CD recorder, Music Hall MMF-9 w/B&O MMC2, Revox A-77 R to R.

Offline OldiesButGoodies

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Re: My first Stromberg-Carlson
« Reply #2 on: March 08, 2014, 08:35:19 PM »
1960 vintage?  Looks great Mark!  Good score...

Pepe

Spkr: VMPS RM40
Pre: McCormack RLD-1, Rotel 970BX Phono
Amps: Channel Islands Audio D-200 MkII 
Phono: VPI Aries 1,  Van de Hul Frog
CD: Oppo BDP-83 DAC: Young DSD DAC
Cass: Tascam 122MkII
R2R: Revox B77
Sub: Rhythmik FV 15HP

Offline bmwr75

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Re: My first Stromberg-Carlson
« Reply #3 on: March 08, 2014, 09:38:43 PM »
Congrats on the score!!

Hope your refurb goes better than my Pilot mono refurb.  Blew up a brand new polar electrolytic today.
Media: CDs ripped to Apple Lossless files
Source: Mac Mini using iTunes and Bit Perfect
DAC: AudioSmile modded Behringer DEQ2496
Preamp: Rogue Audio Perseus
Crossover: miniDSP 2X4 HD
Amp: Vincent SP-331
Mains: KEF LS50
Subs: dual SVS SB-2000

Offline Sir Thrift-a-Lot

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Re: My first Stromberg-Carlson
« Reply #4 on: March 08, 2014, 09:40:17 PM »
Should be an easy recap.   Cosmetically, I have much bigger plans than just making it sparkle.   I want to get most of it covered and the front tubes caged so that I can keep it in the living area as a daily driver.

Does anyone know a good sheet metal guy?

Offline schwarcw

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Re: My first Stromberg-Carlson
« Reply #5 on: March 08, 2014, 10:53:25 PM »
Congrats!  Very nice looking amp!  I can't see the number on the power tubes?  They look like RCA black bases that have been rebranded.
Carl

Offline Sir Thrift-a-Lot

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Re: My first Stromberg-Carlson
« Reply #6 on: March 08, 2014, 11:09:19 PM »
The output tubes are Stromberg-Carlson 7408 (same as 6V6).   I figure this amp for about 15 clean watts per channel.

Offline Sir Thrift-a-Lot

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Re: My first Stromberg-Carlson
« Reply #7 on: March 08, 2014, 11:29:00 PM »
Am I correct that the only cap I need to replace is the can cap?   Everything else looks like either ceramic or mica.   I have read that those don't need replaced unless there is a specific failure.

Could it be this easy?

SunnyDaze

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Re: My first Stromberg-Carlson
« Reply #8 on: March 09, 2014, 12:24:53 AM »
I'd replace the coupling caps too, same value, just, with films.

Great find! Sounds like you and I both have more tube projects in the works than we have time for! I'm sure you'll do it justice! Please keep us all posted!

You'd probably have to bias them a little hot to get 15W out of PP 6V6's. 10-12 is more realistic, depending on what Stromburg has them set to run and how far certain resistors have drifted. :)

SunnyDaze

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Re: My first Stromberg-Carlson
« Reply #9 on: March 09, 2014, 12:54:32 AM »
As far as sheet metal, what are you looking to have done? I know folks who do that sort of thing. That's the hold up on my SE Maggotbox amp. I'm waiting on the powder coat guy to do the chassis.

I'm also trying to get a cage / cover type thing built for the OT's on that amp. There's not enough room for proper bell ends or transformer covers. I have some DIY ideas I'd love to discuss with you, but, I'm far from a metal wiz.

Offline Sir Thrift-a-Lot

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Re: My first Stromberg-Carlson
« Reply #10 on: March 09, 2014, 01:06:48 AM »
I'd replace the coupling caps too, same value, just, with films.

You'd probably have to bias them a little hot to get 15W out of PP 6V6's.

Which ones are the coupling caps?

I don't know how to bias something.   I'm just replacing parts.   If it needs any fine tuning when I'm done, I'll have to have one of the experts here (such as yourself) help me or send it to Anders.

Offline Sir Thrift-a-Lot

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Re: My first Stromberg-Carlson
« Reply #11 on: March 09, 2014, 01:16:16 AM »

I'm also trying to get a cage / cover type thing built for the OT's on that amp. There's not enough room for proper bell ends or transformer covers. I have some DIY ideas I'd love to discuss with you, but, I'm far from a metal wiz.


When I was Googling for info on the amp, I saw one treatment that I liked but felt could be improved upon.







I like the way this covers up the entire back end in one swoop.   The wooden side caps would be easy enough to make.   I would make mine out of a nicer wood and coat with polyurethane rather than painting.   What I don't like is the gaps between the metal plates.   My idea is rather than making two separate metal plates then a black wooden back, I would round the angles at the top and use one piece of metal which would be heavy enough to mount jacks onto but thin and flexible enough to bend at at couple soft 90 degree elbows.   I think this would look amazing and make final assembly fairly easy.

So I would need someone who could cut me a sheet to my measurements, drill vent holes at the top and cutouts for the jacks on the back.   Plus the holes for the mounting screws.   I would also want a sheet for the bottom cover.

SunnyDaze

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Re: My first Stromberg-Carlson
« Reply #12 on: March 09, 2014, 11:09:00 AM »
I am far from an expert on this crap.

Let me talk to a friend from the automotive fabrication world. Those guys love building stuff out of sheet metal. Sorry for the short reply but I'm pressed for time this morning.

Offline Dicky

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Re: My first Stromberg-Carlson
« Reply #13 on: March 09, 2014, 12:27:48 PM »
Nice find man.  I just scored a Magnavox myself, but it looks too nice to dissect.  I hate that I like these things.
Emotiva XSP-1 pre
Emotiva XPA-2 amp
Technics SL-1200mk2 turntable
BSR EQ3000
Denon DNP-720AE network tuner
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Bose 601 speakers
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Columbia Masterwork 944 Console

Offline Sir Thrift-a-Lot

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Re: My first Stromberg-Carlson
« Reply #14 on: March 09, 2014, 01:30:42 PM »
Well, the turntable was already gone before I got to it.   Plus, presumably someone at the thrift put a huge gouge on the top.   So even if I liked the furniture (which I didn't), it would have been a lot of effort to get it back up to speed.

 

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