SX-Amp and NX-Amp

Nice, thanks for the confirmation. I did run into BC547 being obsolete, but did read a prior post from Bill P that he used BC546 in his amp.
 
Regrettably, a lot of these great small signal TO-92 devices are going EOL and will only live on in SOT23 form. Once the kx2 is done, I doubt I will be doing anymore DIY amps using small signal TO-92 (all my commercial designs have sued SOT23 since 2016). The situation will only get tighter for the older packages.

TO-126 will probably be around a bit longer because of creepage and power dissipation benefits - but SOT223 is a pretty nice package IMV - although not as easy to heatsink - great for VAS duty through.
 
Looks like a very long lead time for 771-BZX585-B4V7135. Closest potential sub I noticed at Mouser is 621-BZT585B4V7T-7 , but the zener current is much higher than the specified part.
 
Yeah, at the time I had interest in building an amp, I started using the strategy to buy any discrete through-hole transistors first because they were just fading away into the sunset.
 
sonidos said:
Looks like a very long lead time for 771-BZX585-B4V7135. Closest potential sub I noticed at Mouser is 621-BZT585B4V7T-7 , but the zener current is much higher than the specified part.
Click to expand...

That will still work - just make sure the package size will fit on the board.

Looks like I should revisit the nx-Amp BOM - it’s 9 yrs old this year! Some of the stuff has clearly gone EOL and were in the middle of a semiconductor shortage as well.
 
Andrew, thanks. I'll sit down tonight and review the footprints to make sure nothing is askew with this potential replacement.

Yeah, thanks to the latest projects, I'm comfy with the surface mount stuff, but I know there are some on the forum that are really bothered that the old favs have gone into the thin air.
 
I compared the drawings for 621-BZT585B4V7T-7 and it's a match. I've ordered it from Mouser, so I can confirm this weekend on the fit on the board.
 
Good news/not-so-good news on the 22mF caps that I ordered from Digi-Key. The cap diameter is fine. But the snap-in leads are slightly wider than Panasonic caps. I attempted to seat the caps but they are digging into the solder pads and I am a few mm from getting them seated properly. My thought is to file the leads down so they will seat properly.
 
Update - I pulled out one of my saw files and went to work. I could only get down so far to the body of the cap, but the cap sits about 1/2 mm from seating perfectly. I guess I can lay down some electronic safe silicone adhesive and call it a day.

The Tiger Toroid arrived - a big, smelly, ugly beast that I expect to play fine music soon. I put it in my hot garage to bake some more as the family will be put off by the smell. I'm jazzed to have it and will plug away bit by bit on the amp as a Summer project with completion by the Fall. I have two other projects slated for completion this Summer, plus our privacy fence blew down and the wife made it clear that she needs me to repair it asap.

Andrew, as always, thanks for the help!
 
Is it the rivet that holds the cap snap-in pin that's causing the problem?

(The Tiger Toroid will take a few weeks to stop smelling. The varnish impregnation obviously has not cured fully.)
 
I believe I need to find a smaller file. My saw file started cutting into the cap wrapper, exposing the can. I had to be careful. I'll dig around for a smaller file.

Yes, like Hoover Dam, the toroid is still curing!
 
Andrew, distributors have 0 stock on the Kemet 1000 uF 16V electrolytic. I see it's a general type but available alternates fall short in some parameter compared to the Kemet (life, operating temp, are low ESR, or ripple current is lower than the specified part). Is there any give/flexibility in any of these parameters that would fit the bill?
 
Additionally, D15, which is MSR 941-C566CRFNCT0W0BB3 isn't in their db nor can I find any reference on the web. I'm assuming it's a red LED and the last digit should be a '2' instead of a '3', correct?
 
Javier, I will come back tomorrow. It’s clear the BOM needs a refresh, but I’m in the middle of a house remodeling- workers just took all the walls down. Mayhem for another week 😀
 
Andrew, no problem. Our privacy fence blew down in the most recent storms. Guess who's repairing? Right, this guy! We just had new flooring put in and right when I was on a Zoom call with our team. My boss said he was so tempted to mute me while I had my mike on. Hahaha.
 
Javier, for the 1000uF 16V caps you can use

MSR 710-860020375017

MSR 710-860010375017

MSR 80-ESK108M016AH2AA

The LED - general purpose red LED per your update

MSR 941-C566CRFNCT0W0BB2
 
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