View Full Version : Stromberg-Carlson 220 amplifier.


markn2wae
04-14-2012, 10:31 PM
My latest garage\house sale find!:banana:

I always ask if there is any "other" electronics that might be sold or gotten rid of", and was led to this, it was just sitting on a shelf in a cabinet with a "plastic" BSR turntable, I asked what the whole thing came to and we agreed on $30.00 for both items (I figured if I took the TT too, the amp. would get sold).

An initial check with the ESR meter showed the four brown caps. where bad and the big cans still had some life to them, so I replaced the four small ones, and pulled the OP tubes and ran things up slowly with no problems.:yes:

The unit even came with its own schematic attached to the bottom plate!:tresbon:

All tubes are original and tested good, getters are solid silver in the center with a rainbow color around the edges.:thmbsp:

I hooked up my Viking 88 RTR and played music for about 2 hours, everything is working, controls need a little cleaning and the front white panel needs re-gluing to the gold plate.

Tube lineup is as follows-

Output tubes- (4)7408
Drivers- (2)7199
Preamp stage- (1)6EU7
Phono stages- (2)6EU7 with shields

I will try and compare the output power measurements with my Pilot 240.:scratch2:

Mark T.:music:

coman61
04-14-2012, 10:45 PM
Nice find! I have only seen a few of these and never in person. I have been told that they sound way better then they have a right to.:thmbsp: SC used some good iron and it may give your Pilot a good run for its money.:yes:

electronjohn
04-15-2012, 10:31 AM
Sweet find, Mark!!

Tom Bavis
04-15-2012, 10:34 AM
Most of the 220s I've seen were in consoles - they have an offset front panel on brackets. The "C" version with mag phono preamp would have been sold as a stand-alone unit.

gadget73
04-15-2012, 11:38 AM
Nice find. Those S-C units are sharp looking.

jaymanaa
04-15-2012, 11:48 AM
Nice find! I have only seen a few of these and never in person. I have been told that they sound way better then they have a right to.:thmbsp: SC used some good iron and it may give your Pilot a good run for its money.:yes:

Is it the iron or the odd circuits that create that signature sound? I've pondered this and experimented for a few years, but the best I can come up with, is they created or found, some weird sort of synergy between the two. The iron can sound as bad as it looks with other circuits, and the circuits can be pretty bad on other iron (I tried heathkit aa151 stuff once). :dunno: My advice would be to overhaul it and keep all the passive values the same as original. That's probably the first and last time I'll ever make that statement.:lmao:

jt4me1
04-15-2012, 12:54 PM
Nice. I've got a 220B that sounds very good. Glad you got one.

tube-a-lou
04-15-2012, 02:30 PM
Nice Mark, Get out that soldering iron!

Tube

markn2wae
04-15-2012, 06:54 PM
I had the amp. up and running as I previously posted, the bass is clearly there, even on a pair of Advent bookshelf speaker on small angled stands OUTDOORS!:thmbsp:

I still have to compare specs\measurements between this and my Pilot 240 amp.:yes:

Thank you all for the kind and use-full words.:tresbon:

All four OP tubes have a common cathode resister, any reason to change this to separate resisters\capacitors?:scratch2:

Mark T.

jaymanaa
04-15-2012, 07:45 PM
I had the amp. up and running as I previously posted, the bass is clearly there, even on a pair of Advent bookshelf speaker on small angled stands OUTDOORS!:thmbsp:

I still have to compare specs\measurements between this and my Pilot 240 amp.:yes:

Thank you all for the kind and use-full words.:tresbon:

All four OP tubes have a common cathode resister, any reason to change this to separate resisters\capacitors?:scratch2:

Mark T.

Yes, you will only need matched pairs instead of matched quads, and some say it helps the separation thus enhancing the sound stage. Just double the resistance and use one per channel. Try a bypass of around 470uf.

Tom Bavis
04-15-2012, 07:45 PM
All four OP tubes have a common cathode resister, any reason to change this to separate resisters\capacitors?:scratch2:

Mark T.

Will deliver a little more power on peaks with a single cathode resistor. Downside is the need for four matched output tubes, vs. two matched pairs with two cathode resistors.

parvo
04-16-2012, 11:11 AM
Now I'm Jillis! Nice S-C Amp and this one looks nice and powerful!

Allen

tube-a-lou
04-16-2012, 11:14 AM
How do the phono section sound in those?

Tube

JHS2RT
04-16-2012, 11:44 AM
Good deal mark!! Let me know if you ever Bartar Town that.....

markn2wae
04-30-2012, 09:57 PM
Here are two pictures of my S-C amp. one with a case I made for it (I was testing my friends radial arm saw) and another look at the bottom before I repaired it (4 small brown capacitors needed to be replaced).

Sorry for the small pictures, for some reason, when I shrink the pictures to 640 X 480, they still come out over the AK posting limits.:sigh:

Mark T.:music:

markn2wae
05-01-2012, 08:48 PM
I measured the power of the Pilot 240 and the S-C amp and they where very close (11.3 Whats for the 240 and 12.6 for the S-C).

Hooking a small spectrum Analyzer to each in turn showed the Pilot to be flat (loudness off) and the Stromberg-Carlson to have a "loudness conture" built in, as the response flattened out about mid rotation on the "Loudness Control", where as the Pilot "stayed flat" at all volume settings (it did about the same reaction when the loudness switch was "in".

BTW, the Pilot volume control was labeled "Volume" and the S-C was labeled "Loudness".

I did not do a A\B comparison, but to my ears, they sounded much alike.

A friend wants the Pilot 240 for playing vinyl and wants to buy it to replace some SS piece he has.

:music:Mark T.

blankenberge
10-17-2012, 05:56 PM
I am playing the 220 with the magnetic connects and my lord, its sounds absolutely great! i went from using a lafayette ss receiver to this and i will never look back! its like apples vs. vinegar as far as sweetness of sound.. I am proud to say i grew up 20 to 30 miles from where this thing was built.

leoman53
01-21-2014, 11:25 PM
hi, i have a 220 and the volume pots needs to be replaced, anyone knows where to get parts?

also, there are lots of disk ceramic caps, anyone tried raplacing those with film types?

cademan
01-21-2014, 11:28 PM
Do the pots need to be replaced or just cleaned? Disc capacitors hardly ever need replacing.

leoman53
01-21-2014, 11:41 PM
Do the pots need to be replaced or just cleaned? Disc capacitors hardly ever need replacing.

cleaned with wd-40 but still is noisy...
i can replace them with another kind but the knobs will have to go, so that the vintage look goes away...

cademan
01-21-2014, 11:49 PM
Ooooh, WD-40 not good! It might have already ruined them so you might just have to replace them anyway. Usually Deox, tv tuner cleaner or similar is the only thing you want to use on pots. WD-40 may be good for contact type switches and other stuff but not potentiometers. It will sometimes destroy the phenolic wafer and resistor track.