Panda HP Amp schematics explained
Dec 19, 2010 23:40:42 GMT
Post by gommer on Dec 19, 2010 23:40:42 GMT
Hi all,
I thought a thread about the Panda amp, explaining the schematics would be nice. Not all will be interested, but as far as i've seen, there are quite a few electronics savvy people around here. I'm knowledgeable myself, but i can't say that i had practice in analog electronics the latest 15 years Designing switchers, led drivers, digital stuff, that's what i do for a living these days.
I was looking at the schematics and before i knew it i wanted to understand every last detail of how it works. It seems i'm not capable anymore of doing so, but maybe we can solve this together.
Anyway, lets get started. I've attached the schematics of one channel of the Panda amp
The blocks i can identify are:
I'm trying to find how the voltage stage works and how all the bias currents are calculated. After that's sorted it could also be nice to see what all the caps are doing (sure, they're stabilising the amp, but how). It's probably not wise to go change bits and pieces everywere, because tuning an amp is a listening experience and you can calculate all you want, you'll never knwo how its sounds before you've build it. But knowing is a start in trying to tune it here and there.
Things i'm looking fore are: at what virtual impedance do the Fet's works, so i know at what operating point i should match them.
How far can the class A output power be increased.
That's it for now. Bedtime now and we'll see where we get from here.
Cheers, Marc
I thought a thread about the Panda amp, explaining the schematics would be nice. Not all will be interested, but as far as i've seen, there are quite a few electronics savvy people around here. I'm knowledgeable myself, but i can't say that i had practice in analog electronics the latest 15 years Designing switchers, led drivers, digital stuff, that's what i do for a living these days.
I was looking at the schematics and before i knew it i wanted to understand every last detail of how it works. It seems i'm not capable anymore of doing so, but maybe we can solve this together.
Anyway, lets get started. I've attached the schematics of one channel of the Panda amp
The blocks i can identify are:
- Differential amp around Q6 and Q8 for FET input stage
- Voltage amplifier around Q1, Q2 and Q9, Q11
- A 2 stage current amplifier with Q4, Q5 and Q13, Q14
- two voltage followers around Q3 and Q12
- The only (global) feedback with R13, R14
I'm trying to find how the voltage stage works and how all the bias currents are calculated. After that's sorted it could also be nice to see what all the caps are doing (sure, they're stabilising the amp, but how). It's probably not wise to go change bits and pieces everywere, because tuning an amp is a listening experience and you can calculate all you want, you'll never knwo how its sounds before you've build it. But knowing is a start in trying to tune it here and there.
Things i'm looking fore are: at what virtual impedance do the Fet's works, so i know at what operating point i should match them.
How far can the class A output power be increased.
That's it for now. Bedtime now and we'll see where we get from here.
Cheers, Marc