Hi padamiecki
In your last schematic the PSU is for both channel ? Or the PSU are two?
Regards
Volavola
In your last schematic the PSU is for both channel ? Or the PSU are two?
Regards
Volavola
Hi,
psu is integral part of the amplifier. from its quality depends the sound. Here you can see 1 completely channel. you cannot use psu for both channels, it is impossible.
as adviced, if you use high bias you have to oversize the heatsinks.
psu is integral part of the amplifier. from its quality depends the sound. Here you can see 1 completely channel. you cannot use psu for both channels, it is impossible.
as adviced, if you use high bias you have to oversize the heatsinks.
Hi padamiecki
The Feedback resistors are between the gate and drain, but for change the bias (current) +/- how can I do ? In a magazine here in Italy there is a schematic like your but with some different that have a bias circuit start from a drain and go to other drain with led's and diode
and has a floating PSU, with a secondary of the main transformer without center tap. But in your where is the bias ?
REgards Stefano
The Feedback resistors are between the gate and drain, but for change the bias (current) +/- how can I do ? In a magazine here in Italy there is a schematic like your but with some different that have a bias circuit start from a drain and go to other drain with led's and diode
and has a floating PSU, with a secondary of the main transformer without center tap. But in your where is the bias ?
REgards Stefano
volavola said:
bias is set with those resistors ratios R7/R4 and R8/R5.
Try to use 18k resistor + 5k multiturn pot in series to regulate bias/symetrise (as R7 and 8).
In fact setting right bias in this way is long process, now I would recommend you a circuit with a single transistor which regulates the bias, like in conventional circuits.
Hi padamiecki
How many mA you measured across R7 & R8 ?
When you put in the circuit a Resistor (1 ohm maybe)before the gate of the M'fet, how many Ampere I need to read across the resistor for a correct (sound good) bias?
Regards
Stefano
How many mA you measured across R7 & R8 ?
When you put in the circuit a Resistor (1 ohm maybe)before the gate of the M'fet, how many Ampere I need to read across the resistor for a correct (sound good) bias?
Regards
Stefano
volavola said:
Hard to say, as higher bias, as sounds better, 700mA woud be OK, remember to oversize the heatsinks.
I cannot give you measurings now.
Try to simulate your circuit, you should get results close to the reality (for such a simple design).
just looked at first schematic, looks like you might get a bit of second harmonic, having a resistor on the positive side, but not negative..........
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