10-20 Watts Super Single Ended Class A

[umut1001]

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]

is there anybody here?thanks

 

[Wavebourn]

is there anybody here?thanks

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

 

[umut1001]

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]

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

 

[umut1001]

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

 

[AndrewT]

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

 

[umut1001]

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]

...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]

i dont understand

 

[umut1001]

ok whatever

 

[AndrewT]

.......how we decide the max or best voltage supply value ....... with irfp240 transistors)

for irfp240 the maximum supply voltage is 200Vdc.
The ideal voltage will probably be less than this maximum.

i dont understand

what's to understand?

 

[umut1001]

you said "i bet there is one" i didnt understand this sentence..thanks

 

[ferencz]

Re: Adjusting R4 value you may reduce your off set to zero

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?

Change R1 to 2.5k!
Then play with R3's value if needed...

 

[umut1001]

i changed it but nothing changes!!

 

[umut1001]

everything is allright.it works..thanks