• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Sx 780 stk 0050

jcon109

jcon109

Active Member
I have a SX 780 that was working great till last night when the right channel went out and smelled like something burning. I let it set for a few hours and when I turned it back on it was working but the right channel was distorted but did work. I did a search of past forums and it looks like the stk 0050 might be bad (thanks Mark and Echowars). I plan on switching the two around to see if the problems follows. But my question is I cannot find any on line everybody is out and have know idea when they will be in. They do have stk 0060 in stock. Is this a suitable replacement?
 
Register to hide this ad
jcon109 said:
I have a SX 780 that was working great till last night when the right channel went out and smelled like something burning. I let it set for a few hours and when I turned it back on it was working but the right channel was distorted but did work. I did a search of past forums and it looks like the stk 0050 might be bad (thanks Mark and Echowars). I plan on switching the two around to see if the problems follows. But my question is I cannot find any on line everybody is out and have know idea when they will be in. They do have stk 0060 in stock. Is this a suitable replacement?
Click to expand...


Check the emitter resistors first, R264 & R266 at 0.22 ohms. Just in case......

It looks like it, but you would be the guinea pig. Man... I needed some stk0050s and they seemed to be inexhaustible... second spot of bad news in the last 24 hours...:sigh:
 
Last edited:
STK0060 will work (same topology and pinout), but bias current will be less than optimal, since the '60 is designed for a higher voltage supply. This will likely mean higher distortion.
 
I will use that as a last resort. I will try to find the correct part. B&D has them but 3 times the price. Maybe the other suppliers will get more in soon. In the end it might be worth it. Just thought I would ask the Experts!

If I find any I will post

Thanks for your help
 
Checked the resistors and are good. Swapped the Stk 0050 and the distortion follows to the other channel. Looks like I should be in business with a new parts. I think I will change both and keep the good one for a spare.
 
Is there a bias and offset adjustment on the 780? I have one thats running 23mv left and 48mv right.

- Pete
 
When I first took the bottom of my SX-780 I noticed that there was one STK0050 and the other was branded RCA with a paper label showing "RCA" and the part number. The label was peeling slightly, revealing another ID number underneath so I removed the label completely. It was another Darlington rebranded as an RCA.

I neither kept the label nor recorded the part number. Wish I had but at least at one time RCA was selling Darlington STX0050's under their own brand and number. Maybe somebody still has some.

John
 
You must log in or register to reply here.
Back
Top Bottom