MOSFET Amplifier IRFP240/IRFP9240

[Boedy]

Thanks for sungestion mr. Max
i will try it..

Regards..

 

[Vrystaat]

HV23 or HV350

Hallo Apex, seeing that the HV23 and HV350 is basically the same and it is only the vas that differs, which is the preferred amp in terms of stability and sound ? How does one choose between them which one to build. Which one did builders preferred ?

 

[apexaudio]

Hallo Apex, seeing that the HV23 and HV350 is basically the same and it is only the vas that differs, which is the preferred amp in terms of stability and sound ? How does one choose between them which one to build. Which one did builders preferred ?

Go to post #470 for HV23 schematic and PCB.
Regards

 

[Vrystaat]

Thanks Apex, thanks for the direction.

 

[Mosfetis]

or you can buy PCB Apex HV23

 

[jmsuter]

PCB for the Apex HV23

Where can I purchase a set of PCB 's .?

 

[zoky2]

Hay, this is my HV23 amp in stereo. The amp is tested at +-30VDC only because i don t have any 100v capacitor yet. It play very good ,the bias is set at 20mA for transistor. Also made PSU-7 for amp, it work but with minor problem.If I connect LED for DC protection indication ,the relay don t disconnect speaker. Without LED everything is OK.
Any sugestion how to fix that?

Regards
zoky2

 

[apexaudio]

Hay, this is my HV23 amp in stereo. The amp is tested at +-30VDC only because i don t have any 100v capacitor yet. It play very good ,the bias is set at 20mA for transistor. Also made PSU-7 for amp, it work but with minor problem.If I connect LED for DC protection indication ,the relay don t disconnect speaker. Without LED everything is OK.
Any sugestion how to fix that?

Regards
zoky2

Nice work,
Regards

 

[AndrewT]

All those transistore bolted onto one fin of that heatsink is not effective cooling for a big amplifier.

 

[djk]

Looks like a SS relay heatsink designed for that type of heat load.

 

[AndrewT]

But all the devices are bolted to the fin instead of being bolted to the backplate.
and the setup looks like the fins are not oriented for best dissipation.

 

[djk]

Something like this:

 

[sajti]

But all the devices are bolted to the fin instead of being bolted to the backplate.
and the setup looks like the fins are not oriented for best dissipation.

That would be good to see a side picture, because I guess that the output devices are bolted to the backplate. The fins are OK for forced air cooling

Sajti

 

[apexaudio]

Like this

 

[zoky2]

Mine heatsink is exactly like in Apex post. I will use 2 fans in push pull configuration to cool heatsink. Apex, what about problem with LED in psu-7?

 

[apexaudio]

Mine heatsink is exactly like in Apex post. I will use 2 fans in push pull configuration to cool heatsink. Apex, what about problem with LED in psu-7?

Replace 4k7 resistors with 10k (in series with LEDs)

 

[AndrewT]

If you are confirming that the devices are bolted to the backplate via the extra spreader plate, then that is good.

 

[zoky2]

Apex, I replace 4k7 resistor with 6k8 resistor and now protection work. With 10k resistor the LED barely gloves so I use smaler resistor.
One picture from side to see backplate of heatsink.

Regards,
zoky2

 

[Shelah]

Sir Mile, i have made two HV23 amplifiers so far and am impressed with their performance. sound is great.

i also looked at Anthony Holton's AV800 and AV1000 amp schematics. as compared to the AV400, i observed that he added a pair of drivers and increased the number of irfp240/9240 outputs. i want to build another mosfet amplifier but my question is can the hv23 or hv350 be upgraded in a similar manner as Anthony's amplifiers? if yes, what upgrades would you recommend on the HV23/HV350?

regards.

 

[apexaudio]

Sir Mile, i have made two HV23 amplifiers so far and am impressed with their performance. sound is great.

i also looked at Anthony Holton's AV800 and AV1000 amp schematics. as compared to the AV400, i observed that he added a pair of drivers and increased the number of irfp240/9240 outputs. i want to build another mosfet amplifier but my question is can the hv23 or hv350 be upgraded in a similar manner as Anthony's amplifiers? if yes, what upgrades would you recommend on the HV23/HV350?

regards.

VAS on HV23 work with 30mA bias and no need to add drivers in OS.
Regards