Lookee What I Got (amp porn alert)

[Structo]

Schematic:

http://www.schematics.ca/modules/PDdown ... %20Diagram

[Alexo]

Thanks, Structo.

To get 100 watts out of a pair of '88's, you need just about half the plate voltage at the screens. Looks like SC had a pretty ingenious way to do it - 2 HV windings, each bridge-rectified. The top winding's - node is referenced to the bottom winding's + output and voila! Much better than what I did in a bass amp I built using these voltages, where I just strung a half-dozen zener diodes in series for the screens (worked great though).

...as to parting it out or selling, don't think the wife would let me get away with that one, as it was given under the condition that I fix it up and get some use out of it. Still working on that plan. A blessing and a curse.

I'm hoping the tubes are still good, though my old Hickock tester doesn't do 25W+ tubes. I may just devise a way to test for screen and plate current in-circuit.

...that tone stack is giving me a migraine.

[selloutrr]

Awesome! I don't need another one I just hate to see it stripped.

[Phil_S]

Are these the tubes that amp came with?
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... NA:US:1348
I realize, yours are used. Even so....

[Alexo]

Are these the tubes that amp came with?
http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... NA:US:1348
I realize, yours are used. Even so....

Holy Guacamole!!

Actually, they look more like these:

http://cgi.ebay.com/Matched-Quad-KT88-G ... 500wt_1154

[jelle]

That's why I mentioned new chinese ones...

[Richie]

Awesome! I don't need another one I just hate to see it stripped.

I'll second and third that comment!!!!!

[Alexo]

Don't worry guys, I only endorse one type of stripping and it doesn't involve amps!

[67plexi]

Great score, got to love the kt-88 dust off the univibe and rock out to Trower.
My Park 75 & SVT has the GEC kt-88. When you get the amp up to par Im
sure you will dig it. not to sure if china tubes will live to long with 650-700v on the plates.

[Beerman]

That looks like a later production Sound City (Dallas Arbiter name below power switch) - like my MkIV SC120R... monster... That also came with some amazing valves.

Do yourself a favour, and look up early SoundCity (or HiWatt schematics - Dave Reeves built the early ones) and replace the hissy active preamp, with the much quieter HiWatt version.

Not too hard to do, and the amp is improved out of sight.

[azatplayer]

Thanks for letting me show 'er off, guys.


My immediate plans for the amp involve having a beer or two and staring at it late into the night. After a few days or weeks of that, I'm not certain. One day when no one's home, I may plug all of my speaker cabinets into it and move some furniture.



...and my cat already knows to go hide under the bed whenever he hears the "bzzt-click" of a guitar plugging in.

HAHAHAHAHAHAHA!!

[selloutrr]

http://www.soundcitysite.com/sc_webpages/sc_home.htm

[jelle]

Thanks for letting me show 'er off, guys.


My immediate plans for the amp involve having a beer or two and staring at it late into the night. After a few days or weeks of that, I'm not certain. One day when no one's home, I may plug all of my speaker cabinets into it and move some furniture.



...and my cat already knows to go hide under the bed whenever he hears the "bzzt-click" of a guitar plugging in.

HAHAHAHAHAHAHA!!

With this amp it's more like a 'click, bzzt and it gets dark in room for 2 secondes before line voltage comes back up again' type of warning to the cat!

[Structo]

Heheheh, probably browns out the entire neighborhood when you flip that standby switch.

[roadkingbluzs]

I do not know watts to say!