One less solder blob later - success 🙂
//
//
@TNT
R6 is directly in the feedback circuit as such it affects the overall gain of the amplifier. 117 ohms versus 100 ohms is about ~ 17% difference. Running through the calculations your overall gain will drop at most by about 1 dB.
If you are okay with that, then go ahead. Just make sure you do it for all the channels. You can always substitute 100 ohms later.
I of course, defer to Papa…
Best,
Anand.
R6 is directly in the feedback circuit as such it affects the overall gain of the amplifier. 117 ohms versus 100 ohms is about ~ 17% difference. Running through the calculations your overall gain will drop at most by about 1 dB.
If you are okay with that, then go ahead. Just make sure you do it for all the channels. You can always substitute 100 ohms later.
I of course, defer to Papa…
Best,
Anand.
That sound perfectly OK for me - thanks for the quick feedback. I will also use 22k for that slower start...
//
//
I woke up early this morning just to help my swedish colleagues…that…and the wife wants to go shopping at IKEA…
Best,
Anand.
Best,
Anand.
Hi everyone,
There is a bias problem on one channel, but there is music playing on both channels.
On the problem channel, when I get vb to 0.3v, I am not able to keep vo above 10v. When I try to get vo to 11v, vb increases to 1.5v. This makes the transistors very hot.
Things seemed to work fine on initial running in(1st 3 hrs), but I think my kids threw some toys on it when I was not around and burning it in.( all I found was a monster truck on it, might have shorted the speakers leads)
Now I am not sure where to start problem shooting. Solder joints are fine, resistors aren’t burnt, within spec.
1)Replace the output transistors
There is a bias problem on one channel, but there is music playing on both channels.
On the problem channel, when I get vb to 0.3v, I am not able to keep vo above 10v. When I try to get vo to 11v, vb increases to 1.5v. This makes the transistors very hot.
Things seemed to work fine on initial running in(1st 3 hrs), but I think my kids threw some toys on it when I was not around and burning it in.( all I found was a monster truck on it, might have shorted the speakers leads)
Now I am not sure where to start problem shooting. Solder joints are fine, resistors aren’t burnt, within spec.
1)Replace the output transistors
Last edited:
Like ZenMod always says, print and stare at the schematic, then the BOM shows up in your head 💡
No need for printed BOM’s then
!Best,
Anand.
What was the solution? Removing the monster truck? Turning the pots to minimum and restart biasing?
May I do this for the output DC blocking caps C2?
I'm only gonna use the Mini for HF duties above 1,5kHz.
Is it:
a) Dangerous
b) Silly
c) wrong fo calculated - you will not hear anything...
d) Ok, if you must... 🙂
//
I'm only gonna use the Mini for HF duties above 1,5kHz.
Is it:
a) Dangerous
b) Silly
c) wrong fo calculated - you will not hear anything...
d) Ok, if you must... 🙂
//
a/ Not at all. Its all low voltage stuff.
b/ Erm 🙂 not necessarily so. The reasoning to do this is fine, however,
c/ Probably (as in you will not hear any difference, not the calculation*)
d/ Absolutely.
What I would probably do though is bend the leads so that one is at 90 degrees to the cap and solder the cap flush with the PCB. The second leg wont reach and so it needs a bit of wire extending the trace a bit further across.
Aesthetics are everything 😉
* I was assuming you meant adding these across C2... or do you mean instead of C2?
b/ Erm 🙂 not necessarily so. The reasoning to do this is fine, however,
c/ Probably (as in you will not hear any difference, not the calculation*)
d/ Absolutely.
What I would probably do though is bend the leads so that one is at 90 degrees to the cap and solder the cap flush with the PCB. The second leg wont reach and so it needs a bit of wire extending the trace a bit further across.
Aesthetics are everything 😉
* I was assuming you meant adding these across C2... or do you mean instead of C2?
Instead of C2 - and the mounting/soldering on the pic is not final.
First impression last ;-)
//
First impression last ;-)
//
So impedance of the load is going to be a major determining factor in whether 10uF is big enough.