Calor amp 40 Watts Class A

[Nikos]

This amp promised good listening.
My friend Θυμιος very good job
Bro Boraomega good amp.

 

[dobrivoje]

Yet another proof of Greek-Serbian friendship.

 

[thimios]

Yet another proof of Greek-Serbian friendship.

For ever!

 

[Nikos]

Yet another proof of Greek-Serbian friendship.

 

[Jay]

Tomorrow i will have a small listening test.

Please provide subjective comparison with other amps. I might build this amp based on your report, because basically I don't trust an opamp-based amplifier can "suit" my taste

 

[thimios]

Has anyone built this amplifier???.I am curious.Thank you

> Average output power--------40W/8 ohms (without exiting class A!)
> Power Bandwidth-------------11Hz - 135kHz
> Small signal frequency BW --- 2,5Hz - 450kHz
> THD----------------------------<0.008% (20Hz-20KHz/80%power)
> Phase shift --------------------up to 2,5� in the range 20Hz-20kHz
> Slew rate----------------------85V/uS
> Dumping factor---------------->750

it is something not clear in this schematic.
is the value for C5 15pf or 1p5?

 

[Jay]

1p5 would have no effect for compensation. 10pF is usual. Different opamp may require different compensation. If you're lucky you might need no compensation there.

 

[ivanlukic]

C5 is 15pF.

 

[maxwell007]

Yesterday I started work on this amp. Again by my own made PCB by simple toner transfer method... Some part missing, let´s continue tomorrow Thank you for support Dr. Bora

 

[BC109]

Nice work!
Good luck!

 

[maxwell007]

First test, but is something wrong I have 7,5V on the output.. I have to find, where I made mistake...

 

[maxwell007]

So, now amp running well.. I am dope, i forgot, that I used trans with different pinout... Now I using ZTX450/550 .... Now I have to build proper PSU...

 

[thimios]

So, now amp running well.. I am dope, i forgot, that I used trans with different pinout... Now I using ZTX450/550 .... Now I have to build proper PSU...

This is an old thread but i have the curiosity to know if it is any progress.

 

[donovas]

is there anyway i could obtain the pcb for this amp? i've already messaged maxwell but the thread is 2 years old... and dr.bora has sadly passed away...

 

[stocktrader200]

I did one very similar to this except for mosfet VAS, IRF530 , 9530 fets and LF353 op amp in 1988
used it in the car for 22 years.
class AB with 50ma bias no sign of crossover distortion at all, output amp gain = 6 opamp = 4 total = 24
updated version with IRF9240, 240 fets in SX-3700

 

[donovas]

may i ask you for the schematic?

 

[maxwell007]

Guys, i have a lot of requests for PCB.. dr Bora didn't want to resend any materials without his permission, but situation is changed, and I hope that he wished to get his project aviable for next generation... so, if its someone interested, send me e-mail, and I will send what I get from him... maxwell(@)atlas.cz

 

[maxwell007]

After very very long time .... I decided to bring this amp to live... so today i will try , how does it sound

 

[thimios]

After very very long time .... I decided to bring this amp to live... so today i will try , how does it sound

Waiting for the results when you listen to it!
I have one chanel never completed,no power supply.

 

[Arif Budiyanto]

After very very long time .... I decided to bring this amp to live... so today i will try , how does it sound

Congratulation dear Maxwell007...

I made 3 stereo of them... and all sing very fine... one thing need your attention is we need to use a very good compensation capacitor for the lead compensation C5 - 15 pf. maybe the silver mica cap is a proper one.

Regards