Hello,
I'm going to make AV400 amplifier with self-routed PCB.
I want to decrease power supply voltage to about +-56VDC. How many watts I will have with +-56VDC. Does I need to change any values in schematics for lower voltage and what is the lower working voltage for AV400?
How many OP pairs I need with lower voltage? Or does it better to use 4 pairs anyway?
Does it legal to post a schematics (redraved by me) of AV400?
I'm going to make AV400 amplifier with self-routed PCB.
I want to decrease power supply voltage to about +-56VDC. How many watts I will have with +-56VDC. Does I need to change any values in schematics for lower voltage and what is the lower working voltage for AV400?
How many OP pairs I need with lower voltage? Or does it better to use 4 pairs anyway?
Does it legal to post a schematics (redraved by me) of AV400?
....hallo , to bild this amplifier , 2 pair MOSFET in OP stage its enough , supplied with +/- 55V .Certainly , power output will decrease🙂 My first power amplifier using IRFP 240/IRFP 9240 supplied at rail voltage +/- 60 V here
Hi Stanley
The AV400 will work just fine on 56 volts I would only use 2 x pairs of Mosfets that is all you would require at that supply voltage.
Power out into 8 Ohms will be around 120 watts or so and into 4 Ohms about 200. the later will depend on your supply regulation.
Post a way your schematic its OK.... 🙂
The AV400 will work just fine on 56 volts I would only use 2 x pairs of Mosfets that is all you would require at that supply voltage.
Power out into 8 Ohms will be around 120 watts or so and into 4 Ohms about 200. the later will depend on your supply regulation.
Post a way your schematic its OK.... 🙂
Hi AndrewT
There are no schematics on my web site but the AV400 schematic is easy to find on the internet, just by Googling it 😉
It's getting on a bit now I did the design on it back as far as 1994
when it appeared in Silicon Chip electronics magazine June Issue.
There are no schematics on my web site but the AV400 schematic is easy to find on the internet, just by Googling it 😉
It's getting on a bit now I did the design on it back as far as 1994
when it appeared in Silicon Chip electronics magazine June Issue.
Hello,
thanks for answers 🙂
Here is my modified schematics:
- added a pair of snubber MKT capacitors
- removed clipping detector
- fuses are on power supply board
- does it needed to add these networks to output with inductor and resistor in parallel and capacitor and resistor in series? And what values they must be?
In AV800 schematics there are 2 diodes with zenners in gate protection circuit, does it needed to put this diodes to AV400? And what is their purpose?
Schematics:
Poweramp.pdf
And PCB:
What you think about that way of routing OP part.
The PCB will be double sided. What you could suggest to change in that PCB?
thanks for answers 🙂
Here is my modified schematics:
- added a pair of snubber MKT capacitors
- removed clipping detector
- fuses are on power supply board
- does it needed to add these networks to output with inductor and resistor in parallel and capacitor and resistor in series? And what values they must be?
In AV800 schematics there are 2 diodes with zenners in gate protection circuit, does it needed to put this diodes to AV400? And what is their purpose?
Schematics:
Poweramp.pdf
And PCB:
What you think about that way of routing OP part.
The PCB will be double sided. What you could suggest to change in that PCB?
An externally hosted image should be here but it was not working when we last tested it.
Attachments
One more question: with 2 output pairs how hot are Q6, Q7, Q8, Q9 in voltage amplification stage? Do I need to use heatsink?
Hi Stanley
No you will not need a heatsink for those transistors.
However I have had a look at your schematic and I would change R7 from 120 to 100 ohms.
No you will not need a heatsink for those transistors.
However I have had a look at your schematic and I would change R7 from 120 to 100 ohms.
... no , its not necessary to use heatsink in this project for Q6,Q7,Q8,Q9 except finals MOSFET-s 🙂 http://i14.tinypic.com/29ct3sk.jpg
alex mm said:
You are right. They are dissipating 0,35W at 70V rails, that means about 50°C case temperature at 30° ambient temperature.
... to STANLEY
i replace 15 V zenners with two 7.5V zenners in series , also i use devices terminals like heat sink , to dissipate heat . Maybe this look well 😀 http://i16.tinypic.com/3z84x1f.jpg
sorry .... my bad english
i replace 15 V zenners with two 7.5V zenners in series , also i use devices terminals like heat sink , to dissipate heat . Maybe this look well 😀 http://i16.tinypic.com/3z84x1f.jpg
sorry .... my bad english
Hi Stanley
I think you have a typo error on your schematic
470 Ohms on the Gates not 470K
BC546C will work fine and the zobel on the output change C18
to 0.047nf. This design doesn't actually need the zobel.
I have driven this amp into all sorts of loads and it 100% stable.
I think you have a typo error on your schematic
470 Ohms on the Gates not 470K
BC546C will work fine and the zobel on the output change C18
to 0.047nf. This design doesn't actually need the zobel.
I have driven this amp into all sorts of loads and it 100% stable.
Thanks for pointing me to typo errors.
To The Saint:
Didn't you mean 0.047uF for C18? I saw the AV800 schematics and there was 100nF.
To The Saint:
Didn't you mean 0.047uF for C18? I saw the AV800 schematics and there was 100nF.
0.047nf will not be quite as harsh on the output.
The AV800 requires 100nf because of the extra driver stage.
The AV400 doesn't...
The AV800 requires 100nf because of the extra driver stage.
The AV400 doesn't...
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