Yep, building a good Turbo v3 is a big challenge. So don't go balanced.
It's a kind of thermal balancing act. Getting rid of all the heat that's the big difficulty with a v3.
The challenge is to keep your MOSFETs (at their body) at max 70 Celsius and the heatsinks at max. 55 Celsius. So a good distribution over the heatsinks is a must, and good thin mica or Kerafol.
Also your MOSFET's need good matching for equal current distribution. I even matched the source resistors.
The amp has a way of getting a thermal runaway, so good placement of the NTC's is also important.
And then there is the voltage over the source resistors, if you bias them high, the MUR3020 starts conducting, and your amp becomes a burning amp
So build slow and ask a lot of advice here.
Walter
It's a kind of thermal balancing act. Getting rid of all the heat that's the big difficulty with a v3.
The challenge is to keep your MOSFETs (at their body) at max 70 Celsius and the heatsinks at max. 55 Celsius. So a good distribution over the heatsinks is a must, and good thin mica or Kerafol.
Also your MOSFET's need good matching for equal current distribution. I even matched the source resistors.
The amp has a way of getting a thermal runaway, so good placement of the NTC's is also important.
And then there is the voltage over the source resistors, if you bias them high, the MUR3020 starts conducting, and your amp becomes a burning amp
So build slow and ask a lot of advice here.
Walter
32V - 2V losses = 30V max
30V positive phase + 30V negative phase, of balanced amp, gives 60V across speaker using existing transformer.
The standard F5 is specified as 25W into 8ohms on ±25Vdc supplies.
One might get 27W into 8r0 when tested before the distortion due to the onset of clipping starts to increase.
27W into 8r0 is equivalent to 20.8Vpk.
That is 4.2V below the supply rail voltage.
Using that for a 32Vdc supply rail gives a maximum output of around 27.8Vpk
The maximum power into 8r0 would be around 48W. A monoblock would need at least 300VA transformer.
If one were to use a 600VA transformer to allow use of 4ohms speaker, one has no hope of getting 27.8Vpk from the sagged supply rails trying to send all that current to the load.
One might get 25Vpk, equivalent to 78W into 4r0 (6.25Apk) and clearly into ClassAB.
One might get 27W into 8r0 when tested before the distortion due to the onset of clipping starts to increase.
27W into 8r0 is equivalent to 20.8Vpk.
That is 4.2V below the supply rail voltage.
Using that for a 32Vdc supply rail gives a maximum output of around 27.8Vpk
The maximum power into 8r0 would be around 48W. A monoblock would need at least 300VA transformer.
If one were to use a 600VA transformer to allow use of 4ohms speaker, one has no hope of getting 27.8Vpk from the sagged supply rails trying to send all that current to the load.
One might get 25Vpk, equivalent to 78W into 4r0 (6.25Apk) and clearly into ClassAB.
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