Topology Federmann, HQQF-55 ...

[Federmann]

I dedicate audio 40 years, I never disclose their topology until the last years. Here is one of my latest amplifier topology.

[Federmann]

Site photos

[Federmann]

Technical parameters of PS

Size 108 x 170 mm
Strength 2.5 and 3 mm
Strength Cu 75 and 105μm
Double-sided, plated
Solder mask, printing, tin plating


Technical parameters of amplifiers 4Ω

Driver HQQF-55-502D
Involvement HQQF-55-503W-4-2
End transistors 2 x 4 x IRFP240/9240
Power supply AC 230V + 2 x 48V (I recommend 300 ÷ 800W)
Cooler, thermal resistance of 0.20 ÷ 0.08 ° C / W, according to the transformer
Rectifier bridge 35 (25) A non-PS
Filtration 16 x 1m/100V (16mF ÷ 64mF)
Additional filtering capabilities block 48 x 1m/100V, separate PS
Worm Up Maximum output voltage ± 65V (46V UEF)
Burden, typically 4Ω
Power, maximum 2 x 500W (2 x 250W/8Ω)
Current protection around 17A
BOM components 4Ω!
Amplifier is to dimension the continuous maximum power transformer using 1.5 kW, which is required to use the cooler thermal resistance of 0.04 ° C / W (not recommended)



Technical parameters of amplifiers 2Ω

Driver HQQF-55-502D
Involvement HQQF-55-503W-4-2
End transistors 2 x 4 x IRFP240/9240
Power supply AC 230V + 2 x 34V (I recommend 300 ÷ 800W)
Cooler, thermal resistance of 0.20 ÷ 0.08 ° C / W, according to the transformer
Rectifier bridge 50 (35) A non-PS
Filtration 16 x 2m2/63V (35mF ÷ 140mF)
Additional filtering capabilities block 48 x 2m2/63V, separate PS
Worm Up Maximum output voltage ± 45V (32V UEF)
Burden typical 2Ω
Power, maximum 2 x 500W (2 x 250W/4Ω, 2 x 125W/8Ω)
Current protection around 35A
BOM components 2Ω!
Amplifier is to dimension the continuous maximum power transformer using 1.5 kW, which is required to use the cooler thermal resistance of 0.04 ° C / W (not recommended)



Technical parameters of amplifiers 8Ω

Driver HQQF-55-502D
Involvement HQQF-55-503W-4-2
End transistors 2 x 4 x IRFP240/9240
Power supply AC 230V + 2 x 66V (I recommend 300 ÷ 800W)
Cooler, thermal resistance of 0.20 ÷ 0.08 ° C / W, according to the transformer
Rectifier bridge 25 (35) A non-PS
Filtration 16 x 1m/100V (16mF ÷ 64mF)
Additional filtering capabilities block 48 x 1m/100V, separate PS
Worm Up Maximum output voltage ± 92V (65V UEF)
Burden typical 8Ω
Power, maximum 2 x 500W
Current protection around 8.5 A
BOM components 8Ω!
Amplifier is to dimension the continuous maximum power transformer using 1.5 kW, which is required to use the cooler thermal resistance of 0.04 ° C / W (not recommended)

[Federmann]

I always look at the amplifier's own eyes. I described the causes Transistor sound here.
Federmann Bohumil. Tranzistorový zvuk počítačové simulace příčin jeho vzniku. Perspektivy elektroniky v roce 2009: 26. 3. 2009. Rožnov pod Radhoštěm: SŠIEŘ RPR, 2009, s. 19-25. ISBN 978-80-254-4052-0.

Please add your experiences.

[mlloyd1]

i notice there are emitter followers to drive all those output mosfets. therefore, i'm curious about the distortion versus frequency performance.

[Allen Wright]

Milloyd,
Where are the emitter followers you mention? I can't see any EFs ANYWHERE in his circuit in Post #1.

Regards, Allen (Vacuum State)

[PMA]

Originally Posted by mlloyd1

therefore, i'm curious about the distortion versus frequency performance.

I would like to see measured distortion plots vs. frequency and amplitude as well, into 4 ohm.

[mlloyd1]

sorry, you're right allen. i meant to say "I notice there are NO emitter followers to drive all those output mosfets"

Originally Posted by mlloyd1

i notice there are emitter followers to drive all those output mosfets. therefore, i'm curious about the distortion versus frequency performance.

[tiefbassuebertr]

Originally Posted by Federmann

I dedicate audio 40 years, I never disclose their topology until the last years. Here is one of my latest amplifier topology.

after a quick inspection, I noticed the following:
1) only N-channel MOSFETs: I think, in the negative half you must use P-channel devices by the presently used driver topology
But better solution it must be, to use only N-Channel MOSFETs (to get more information, go to my link collection about
Only N-Channel MOSFETs (NMOS); better Audio from non complements by Audio Power?
2) the average connection of the potentiometer for the idle current to the base to the transistor for the variable voltage source isn't a good solution, because the max possible idle current (shorting current of your power supply) runs through the output devices in case of a pot-break. Replace your potentiometer between base and emitter and introduce a fixed resistor between collector and base to this transistor. This must be done always, not only in this case.
But the input circuit looks very interesting

[Federmann]

Involvement of my drivers HQQF-55-502D, ± 100V power supply, FT transistors is more than 100MHz