5.81 V peak-to-peak. It is really quite loud, qualitatively. If someone has an SE/30 with solid tantalum capacitors or better yet aluminum electrolytic, they can use the sound file I linked above and repeat this test so we can compare output levels. Your speaker might be a bit different in impedance, but as long as it's a stock SE/30 speaker (unlike
@JDW's) it should be similar.
If I ever get my third board working, I'll repeat the test on it and update this thread with the solid tantalum output level on the same speaker. Not willing to desolder my polymer tantalum caps for this test
Thank you again for your continued testing.
Please don't desolder polymer or solid tantalums unless you want to throw them away. As per manufacturer instructions, once the caps have been soldered onto a board, desoldering them only to later resolver them would put them out of spec. The manufacturer recommends discarding such capacitors and replacing with new. This is especially true for polymer capacitors when have a rather heat sensitive electrolytic. Think what heat does to plastics.
@ttb, when you say "
Speaker Jack" I am led to assume you mean "
the output of resistor R10 which feeds the
onboard speaker? However, in your earlier post you specifically mentioned a 3.5mm plug in the "
phone jack." I must assume it is still the "
headphone jack" where you obtained that
5.81Vp-p measurement. From looking at the SE/30 audio circuit schematic (see my opening post), it appears that when a 3.5mm plug is fitted into the headphone jack, the connections to resistors R1 & R2 are broken, such that
UB10 & UB11 drive the headphone jack directly (the Op-Amp would be unused).
I am still curious what goes on at the INTERNAL Speaker (output of R10), especially because
@aeberbach earlier said he measured "
12V peaks" on
C3,
C4 and/or
C5 -- which I assume was measured by him at the UB10/UB11
chip side of the capacitor (the Positive side of the cap). If indeed there are "12V peaks" present on the positive side of C3 & C4, then according to my simulation, those peaks (if present on both C3 & C4 at the same time, and if the peaks were in-phase) would be DOUBLED by the Op-Amp to yield a
24Vp-p signal on the
output of R10 (at the Positive side of the Speaker) -- which would not be present on a 3.5mm plug fitted into the headphone jack. 24Vp-p across the internal speaker seems highly unlikely, so if
@aeberbach could clarify where those peaks were measured, if they were present on the positive side of both C3 & C4, and if they both were in-phase (which can only be determined on a scope), then we could have better understanding of what was meant by those 12V peaks. I am also very curious if those peaks are measured across
C5 too.
There are 2 things we're trying to determined from all this testing:
1. Is there 12V present at any time on the positive side of C3, C4 and or C5? (If so, a 16V solid tantalum capacitor would be outside it's 50% derating).
2. Does the ESR of C3 & C4 impact the Headphone Jack Output only or also the output of R10 which feeds the internal speaker? (My simulation suggests lower ESR would boost the output at R10 very slightly.)