Over the past few weeks I was able to put together β24 amp, custom enclosure pending.
Got few issues during the setup/alignment process for both the channels/boards.
1st issue was very similar to Nishant's post https://www.amb.org/forum/nishants-beta24-alpha10-integrated-amp-build-log-t2193.html which was resolved (for both boards) by shortening the GND wires.
2nd issue (board 1) was cold solder joint - had to reflow.
For Board 1:
Was unable to setup with input as 4V(R7). Was getting very similar results as to Pieterh https://www.amb.org/forum/initial-set-up-issue-beta24-board-t3689.html. By increasing the value to 4.5V, the setup completed successfully.
Issue:
Q11, Q12, Q15, Q16 become too hot as compared to Board 2.
For Board 2:
No issues during setup. Was able to configure with input as 4V(R7).
Issues:
None
Components stats:
IDSS (in mA)
jfet Board-01 Board-02
Q1 9.36 8.97
Q2 9.35 9.17
Q3 9.59 8.61
Q4 9.58 8.62
Q41 9.64 7.08
Q42 9.61 7.04
Q43 9.48 7.56
Q44 9.48 7.46
BJT hFE
Board-01:
550C 560C
Q5,Q7 Q6,Q8
499, 498 450, 451
Q10,Q12 Q9,Q11
500, 502 441, 440
Q14,Q16 Q13,Q15
509, 509 437, 438
Board-02:
550C 560C
Q5,Q7 Q6,Q8
506, 510 470, 475
Q10,Q12 Q9,Q11
512, 513 425, 424
Q14,Q16 Q13,Q15
516, 515 478, 482
I've seen Ti's response in another thread on the reason why the BJTs (Q11, Q12, Q15, Q16) are getting too hot.
Question: Is it safe to operate in this mode or do I need to make any changes to Board 1?
Appreciate everyone sharing their experience as well as Ti's contribution.
Pictures coming soon ...
Thanks!