Datasheets often suggest average values, and state extreme not-to-be-reached ones; designer can freely move around average for his own reasons, just taking care not to surpass limits.
Datasheet suggested designs are just one particular case of acceptable ones, intended as a help for users, not a set-in-stone rule.
Meaning you can find a lot of "different values" designs,all competent and working fine.
As said above, don´t overthink it, just build and enjoy it.
thanks @tomchr and @JMFahey
The amplifier is built and tested both channels with 1.5A 12-0-12v AC transformer. Will upgrade to 15-0-15v AC 5/6A AC transformer as we have varying mains line. The Amplifier drove Indian make 3 way speaker with 12 inch woofer at little louder volume easily. Song was easy listening vocal. The measured voltage at speaker output with Pano's Speaker voltage test files was around 3/4v that means I was just little above comfort level of listening at 16Watts(With out peaks). tomchr, it does produce turnoff thump when switched off. Will put in LED as you have mentioned.
Outof compulsion following components/values were used as it was available online (and shipping was cheaper along with other component combined) otherwise I would have had to travel 60km to mumbai for proper parts.
PS
Regards
The amplifier is built and tested both channels with 1.5A 12-0-12v AC transformer. Will upgrade to 15-0-15v AC 5/6A AC transformer as we have varying mains line. The Amplifier drove Indian make 3 way speaker with 12 inch woofer at little louder volume easily. Song was easy listening vocal. The measured voltage at speaker output with Pano's Speaker voltage test files was around 3/4v that means I was just little above comfort level of listening at 16Watts(With out peaks). tomchr, it does produce turnoff thump when switched off. Will put in LED as you have mentioned.
Outof compulsion following components/values were used as it was available online (and shipping was cheaper along with other component combined) otherwise I would have had to travel 60km to mumbai for proper parts.
PS
- diodes - MUR820
- C3, C4, PS decoupling - 0.1uf Wima 100v
- C5, C6 snubber - did not put will put soon, as mentioned 0.1uf electrolytic are ok ?
- C1, C2 2200uf+2200uf 40V Keltron
- Input capacitor C1 - 2.2uf 250v Philips (Will change to lower voltage as it is physically bulky)(High voltage equals to high resistance?)
- All resistors as mentioned values and are metal film (R5 2.7ohms 2W)
- C4, C6 - 47uf 63v Keltron
- C2 Bipolar Nichicon 22uf 50v (As this was only available in bipolar) (DC blocking ?)
- C3, C5, C7 Wima 0.1uf 100v
Regards
A higher voltage capacitor will have more distance between the capacitor plates (or foil sheets). It does not need to have a higher equivalent series resistance just because it's rated for higher voltage.
C2 does not need to be a bipolar type. It only ever 'sees' the DC offset of the amp IC, which is only a few mV. There's no harm in using a bipolar type, though. Its purpose in life is to lower the DC offset of the amp. With C2 in place, the gain at DC is unity, so the DC offset at the output of the amp will be the same as the DC offset on the input (which is the value specified in the data sheet). If you were to replace C2 with a piece of wire you would get 1+R4/R3 = 23 times the amount of DC offset on the output of the amp.
The purpose of C1 is to prevent any DC offset from the source from propagating to the output of the amp.
I'm not aware of a good way to get rid of the turn-off thump without inserting some sort of muting circuit.
Tom
C2 does not need to be a bipolar type. It only ever 'sees' the DC offset of the amp IC, which is only a few mV. There's no harm in using a bipolar type, though. Its purpose in life is to lower the DC offset of the amp. With C2 in place, the gain at DC is unity, so the DC offset at the output of the amp will be the same as the DC offset on the input (which is the value specified in the data sheet). If you were to replace C2 with a piece of wire you would get 1+R4/R3 = 23 times the amount of DC offset on the output of the amp.
The purpose of C1 is to prevent any DC offset from the source from propagating to the output of the amp.
I'm not aware of a good way to get rid of the turn-off thump without inserting some sort of muting circuit.
Tom
I wouldn't wander much from datasheet values.
I designed a chip amp with valve front end.
As the valve had gain I reduced gain of chip amp accordingly.
I ended up with a RF transmitter !
The chip amp oscillated and sent the signal via RF back to valve which amplified it again !
So looked up datasheet and the chip amp I used had a minimum gain for stability which I had breached.
I designed a chip amp with valve front end.
As the valve had gain I reduced gain of chip amp accordingly.
I ended up with a RF transmitter !
The chip amp oscillated and sent the signal via RF back to valve which amplified it again !
So looked up datasheet and the chip amp I used had a minimum gain for stability which I had breached.
You turned a perfectly working SS amp into a mess of a "hybrid" 😉
Ah, but the "tube warmth!!" 🙄
And the orange glow!!! 😉
There was a thread a couple days ago about somebody thinking a tube valve crossover was a great breakthrough, way above conventional modern ways to do it.
Fact is there are some things Tubes do better, but many they do not, just as that.
Thanks God Transistor was invented .... do you imagine a Tube Computer and even better, a Tube cell phone?
Even something relatively simple as a Tube controlled washing machine?
Ah, but the "tube warmth!!" 🙄
And the orange glow!!! 😉
There was a thread a couple days ago about somebody thinking a tube valve crossover was a great breakthrough, way above conventional modern ways to do it.
Fact is there are some things Tubes do better, but many they do not, just as that.
Thanks God Transistor was invented .... do you imagine a Tube Computer and even better, a Tube cell phone?
Even something relatively simple as a Tube controlled washing machine?
I am just looking everywhere in the forum for your posts, brother @JMFahey - business as usual - technically poor and malevolent with the purpose to insult other forum members - the same thing regardless of the specific topic
Are you answering anything in THIS thread?
Please quote it here.
By the way, "technically poor" is an opinion and as such, acceptable, but calling me "malevolent" qualifies as a personal insult.
Are you sick or something?
Deep breath... Perhaps someone looking for a fight. Or an argument bot. Or someone who had a bad day.
Tom
Tom
Ya know... Actually I hadn't thought about that. It'd be interesting what could be done with a board-mount heat sinks and maybe a pair of switching bricks.
Tom