10-20 Watts Super Single Ended Class A

umut1001 · 9th September 2008, 05:38 PM

hi..i built some single ended designs.i made this circuit and i can say its the best i have heard.and i have some questions...

1-)how we decide the max or best voltage supply value of single ended symmetrical class a amps?(for this amp with irfp240 transistors)

2-)i replaced irfp240 instead of irfp 150 in this circuit.mids and trebles increased and bass reduced..but i always see positive offset of 150mv..i can reduce it to 100mv only by playing trimpots..i can not reduce it anymore..which values of resistors should i change?

3-)what is the technical criterias of sound quality for transistors?
is it low input capacitance?or low Qg?
thanks

best regards
umit

umut1001 · 9th September 2008, 08:52 PM

is there anybody here?thanks

Wavebourn · 9th September 2008, 09:14 PM

Quote:

Originally posted by umut1001
is there anybody here?thanks

You don't want me to comment a diffpair...

umut1001 · 9th September 2008, 09:27 PM

i didnt understand..everyone can comment..here is another one..its 32watts rms..has lower distortion..someone says its one of the best

destroyer X · 9th September 2008, 09:39 PM

try a combination... a fixed resistance plus a trimpot...then adjust and measure your offset.

regards,

Carlos

umut1001 · 9th September 2008, 10:03 PM

thanks i will try..i should change some resistors..there is sth wrong at this amp..
what about the 1. and 3 questions?

AndrewT · 10th September 2008, 10:10 AM

for irfp240 the maximum supply voltage is 240Vdc.
The ideal voltage will probably be less than this maximum.

umut1001 · 10th September 2008, 10:16 AM

hi andrew...there is not a single ended transistor amp works at 200v dc.i meant what is the max voltage value for se class a amps for only one pair of irfp240.whatever.and what about the question 3 ? thanks

AndrewT · 10th September 2008, 11:02 AM

Quote:

Originally posted by umut1001
...there is not a single ended transistor amp works at 200v dc.i meant what is the max voltage value for se class a amps for only one pair of irfp240....

I bet there is more than one.

umut1001 · 10th September 2008, 11:06 AM

i dont understand

9th September 2008, 09:39 PM	#5
destroyer X diyAudio Member Join Date: Feb 2004 Location: Recife - Brasil Northeast	Adjusting R4 value you may reduce your off set to zero try a combination... a fixed resistance plus a trimpot...then adjust and measure your offset. regards, Carlos __________________ Try to build an amplifier folks ... it is pure adrenaline!

10th September 2008, 10:10 AM	#7
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	for irfp240 the maximum supply voltage is 240Vdc. The ideal voltage will probably be less than this maximum. __________________ regards Andrew T.

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9th September 2008, 08:52 PM	#2
umut1001 diyAudio Member Join Date: Mar 2007 Location: Istanbul	is there anybody here?thanks

9th September 2008, 10:03 PM	#6
umut1001 diyAudio Member Join Date: Mar 2007 Location: Istanbul	thanks i will try..i should change some resistors..there is sth wrong at this amp.. what about the 1. and 3 questions?

10th September 2008, 10:16 AM	#8
umut1001 diyAudio Member Join Date: Mar 2007 Location: Istanbul	hi andrew...there is not a single ended transistor amp works at 200v dc.i meant what is the max voltage value for se class a amps for only one pair of irfp240.whatever.and what about the question 3 ? thanks

10th September 2008, 11:06 AM	#10
umut1001 diyAudio Member Join Date: Mar 2007 Location: Istanbul	i dont understand

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