700W AMPLİFİER!

[irvynejay]

JAKUB_G
hello im about to test the amp could you pls give me and idea about bias is it 2.2k or 2k trimmer? and bias setting offset dc settings and so on..

ty will post picture later

 

[JAKUB_G]

JAKUB_G
hello im about to test the amp could you pls give me and idea about bias is it 2.2k or 2k trimmer? and bias setting offset dc settings and so on..

ty will post picture later

Hi,
It doesnt matter whether there will be 2k or 2k2. Bias current should be 30mA per output transistor. Measure this current via power resistors in emitors of output transistors.
There is no setting device to set DC offset. To assure he low offset voltage, you have to match the "small" transistors in differential stage to compliant amplification.
Enliven It via some current confining devices, resistors for example. The value for example 22R/ >2W.
Good luck!

 

[irvynejay]

700w succesfully powered up

Good amp,, sound very nice

 

[michelle]

hi irvynejay
greetings nice build
thanking you
michelle

 

[engel]

irvynejay,
the beginning of becoming a leach fan

 

[Sierra]

irvynejay


Very Nice.

Tel me about sound quality of this amplifier? Bass response

 

[irvynejay]

sound quality is good clear and loud punchy bass,, rail voltage at -/+75 volts dc load 4r 600w speakers

 

[Corvett]

sound quality is good clear and loud punchy bass,, rail voltage at -/+75 volts dc load 4r 600w speakers

Some Oscilloscope waves will be good?

 

[irvynejay]

sorry i dont have scope..as soon my scope will arrive i will check it and post result

 

[JAKUB_G]

irvynejay, I am glad you choose one of our projects. And how about output DC offset? Did you match the transistor to compliant amplification?

 

[irvynejay]

700w with step

i forgot dc offset i cant remember it but i sure its mv dc offset i will test again and measure it,yes i did match differential transistors.... and i add apex step drive ir2117 to make it classH voltage rail -/+ 0 62 128 ,heat? cooler compare to AB ..

 

[JAKUB_G]

If you push it to class H, you will loose a lot of dynamic. I compare behringer EP2500 (when I repaired it) with leach amp, and in class H is very less dynamic.

 

[engel]

jakub_g
is it ok to use mpsa42/92?

 

[JAKUB_G]

jakub_g
is it ok to use mpsa42/92?

Of course. But you have to turn them around 180 degrees, because they have changed emitter and collector against BC transistors...

 

[engel]

thanks jacob,
bc546/556 CBE
mpsa42/92 EBC

 

[engel]

jakub_g
my pcb
is it possible and is it ok to make leach gain higher?

 

[JAKUB_G]

engel, yes, it is possible. You have to change resistor, which is in series with two 100uF capacitors to ground. Now there is 620 ohms. You can calculate it with single formula: Uin=Uout/(1+24000/R), where Uin is input voltage, Uout is output voltage for full power and R is resistor in series of those capacitors. When you use 510 Ohm resistor input voltage will be sth. about 800mV RMS. Its better to use lower gain power amplifier and use preamp rather, because power amp with such high gain could be unstable...

 

[irvynejay]

Thank you for the advice ...what is the possible high voltage rail -/+ this amp can handle? can it be feed 100vdc or 120v dc?

 

[JAKUB_G]

No, because output devices will be out of SOA.

 

[A square]

hello sir

can u pls share apex ir2117 step drive ...

thank u sir

Aman...