Amplifier with output power transistors IRF240/9240

[ostripper]

It’s impressive; we had similar stations at our university.

It came with LM7805's and cheap EI trafo. I added Antek 100VA toroid and those adjustable 317/337. Kept one of the original 7805's for
the digital supply. That 1976 unit came from Georgia tech ( Leach lab). Also got a red LED DMM (1979 -same lab) that I recapped - works nice.
Old stuff is better. Red LED DMM is more accurate than my new Chinese DMM. PS - scope is used student lab (2011) stuff , just 60$.

 

[ostripper]

for speaker systems with an impedance of 4 ohms, it is necessary to reduce the supply voltage to +/-36 volts

Why ? Don't underestimate the SOA of the IRFP9240/240 pair. I've used 55V supplies with big (4R) subs with just a single pair.

 

[Hennady Kovalsky]

Don't underestimate the SOA of the IRFP9240/240 pair. I've used 55V supplies with big (4R) subs with just a single pair.

You yourself answered your own question - possible for a subs, because it is 50% of the power from the entire frequency band.

 

[ostripper]

You yourself answered your own question - possible for a subs, because it is 50% of the power from the entire frequency band.

That depends on the Genre. Techno/rap/rock = >90% is 100Hz and below.

 

[Hennady Kovalsky]

See attachment, I'm trying a high efficiency input stage with a depth of 40 dB. Feedback, distortion is already below 0.01%.

 

[Hennady Kovalsky]

That depends on the Genre. Techno/rap/rock = >90% is 100Hz and below.

this is against the recording standard IEC.
Just don't confuse volume and power.