Burning Amp BA-3

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#881
Wire-wounds ARE COOL !!! ( especially the big ones, with small loads ! ).

Interesting to read Mr. Morgan Jones's comments on WW's of recent...
...very low value one's do have a VERY small inductance...he say's ( a few uH's )...
...ie. like Variac says...the one's people use in PSU's.

Larger one's...according to Morgan Jones...have very little inductance at all...
...ie. over 1/4K or so...series signal-path ones, loads etc.

Heat-cycle on a low oven-temp, with that pizza warm-up...BINGO...stable values, low noise...&...err...PIZZA !

What could be better than that...
...love 'em both.

BBA-3 looks 'tasty' as well !

Cheers

Si.
 
#882
Sorry for " OFF TOPIC "
Can someone help me ?

Where i can find the BBA3 PCB like this ?
I need 2 SET " Green " PCB

Please PM or Email me

Best Rgds
 

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#884
Something weird happening with my BA-3

I'm having a curious problem with one channel of my BA-3...

  • When I turn the amp on, the left channel will often appear to be dead.
  • If I turn up the volume (passive unit before the BA-3), the sound will suddenly turn on.
  • If I then turn it back down to a normal level, it continues to play, but it will sometimes just go off again later.
  • The same remedy will bring it back on again.
Any ideas where I should look for problems?

Thanks,
tim
 
#887
timbarnes said:
I'm having a curious problem with one channel of my BA-3...

  • When I turn the amp on, the left channel will often appear to be dead.
  • If I turn up the volume (passive unit before the BA-3), the sound will suddenly turn on.
  • If I then turn it back down to a normal level, it continues to play, but it will sometimes just go off again later.
  • The same remedy will bring it back on again.
Any ideas where I should look for problems?
Click to expand...

We ran into this sort of problem in mixing consoles in live sound, it usually ended up being either (1) a cold solder joint, (B) a loose or dirty connector, (III) a capacitor, or (d) a wiper making bad contact in a potentiometer.

Maybe look at the electrolytic caps on that channel of the BA-3 board. Also give the preamp the "slap test", see if physical stimulus affects the problem.
 
#889
tinitus said:
yeah, give a good slap and tell it to behave 😀

sorry, couldn't resist it ....have a picture been posted ?



ah ! look at your pot then 😉
Click to expand...

I get the same behavior with two different passive preamps, so I don't think it's the pot. I think it's probably a bad solder joint - the BA-3 is sensitive to being slapped. But I've tried resoldering a couple of times and I can't see any bad joints. Need to try again, I guess.

Today for some reason it's been stable and great to listen to...I guess it's been reading my posts and fears for its life 🙄

First picture is of the two units closed; second is the BA-3 and third is its power supply. The BA-3 is configured as a gain stage, following a passive preamp, and preceding my stereo F4.

tim
 

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#890
Once you catch it when it's dead, check the voltages on R3, R4 (~80mV), and R10, R11 (~1V) to see if you have current flowing through those elements. If it's alive but still no sound, maybe a bad RCA connection or something, or a solder joint as you said. An o-scope would be real useful at that point if you had access to one.
 
#898
I’m the mentioned friend of generg.

Yes I use the Clarity Caps PWA in the BA3 and BBA3, after comparing different PP-foil caps.
The PWA is on my opinion one of the best values for money in NP-designs.
The ESA types are still my favorites due to a bit more punch in the bass and slightly smother trebles, but due to space limitation on the board I decided to use the PWA and I don’t regret it.
 
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