100W Ultimate Fidelity Amplifier

[wattaniya]

Is this correct Sir??

hi qq12,
is this amp working and what about sound?
can u share pcb in pdf.

 

[JOHN BALI]

Hi Apex
& everyone
the AX17s now singing...
the sound is natural
the one one the left is more mid in sound
the one in the right is more clear sound to me
by the way they are just good...

I enjoy those AX, will be made AX14 too to compare
Thanks a lot to Apex...
this is best gift for me in this year

Best Regards

Happy New Year
Good Luck for all

 

[naf]

Add zobel network on amp out 100nF+10R, and try set bias. With HF instability you get bias and offset instability.

Thanks Mr. Mile, Yes it now work!, adding zobel as you suggest, i easily set bias to 15ma on 0R33, with dc offset 8.3mv.
Now may i set back my dc servo?

regards
naf

 

[apexaudio]

Hi Apex
& everyone
the AX17s now singing...
the sound is natural
the one one the left is more mid in sound
the one in the right is more clear sound to me
by the way they are just good...

I enjoy those AX, will be made AX14 too to compare
Thanks a lot to Apex...
this is best gift for me in this year

Best Regards

Happy New Year
Good Luck for all

Nice work, this is the best gift for you from yourself

 

[apexaudio]

Thanks Mr. Mile, Yes it now work!, adding zobel as you suggest, i easily set bias to 15ma on 0R33, with dc offset 8.3mv.
Now may i set back my dc servo?

regards
naf

Set back R36 (1k) and measure dc offset, if ok remove 220uF cap,
Regards

 

[naf]

Mr. Mile,
I've set back R36 (1k) but my dc offset still high, i've tried another NE5532 and get about 26mv. What should i do?

thanks

 

[apexaudio]

Mr. Mile,
I've set back R36 (1k) but my dc offset still high, i've tried another NE5532 and get about 26mv. What should i do?

thanks

26mV with or without 220uF cap?

 

[naf]

26mV with or without 220uF cap?

with 220uf cap.

 

[apexaudio]

with 220uf cap.

What is voltage measurements on NE5532 pins?

 

[naf]

What is voltage measurements on NE5532 pins?

on pin 4 and 8 of NE5532, i've got measurement 31.14 v

 

[AndrewT]

Is the 5532 being used as a DC servo?
It has the wrong input impedance for Servo duty.

 

[naf]

Is the 5532 being used as a DC servo?
It has the wrong input impedance for Servo duty.

Yes, it used as DC Servo as schematic of Ax17S

 

[AndrewT]

Search out the DC Servo Threads and find out why and how they work.
They need a high input impedance opamp.

 

[naf]

Ok, Mr. AndrewT thanks for your suggestion i'll search and read it, as this is my first build Solid State Amp.

 

[JOHN BALI]

AX14

Nice work, this is the best gift for you from yourself

Now I'm going to AX14, I already design PCB for this AX
It look symmetrical & the size is small also (8 x 6cm)
but I feel not confidence
maybe it not good
I will try it, wish me luck...

Regards

 

[apexaudio]

on pin 4 and 8 of NE5532, i've got measurement 31.14 v

on other pins?

 

[apexaudio]

Now I'm going to AX14, I already design PCB for this AX
It look symmetrical & the size is small also (8 x 6cm)
but I feel not confidence
maybe it not good
I will try it, wish me luck...

Regards

Nice work, but you need star gnd,
Regards

 

[apexaudio]

Ok, Mr. AndrewT thanks for your suggestion i'll search and read it, as this is my first build Solid State Amp.

Use LF353 instead NE5532, and use 10k instead 1k for R36.

 

[naf]

on other pins?

could you be more spesific on what pin i've to measure?

thanks

 

[naf]

Use LF353 instead NE5532, and use 10k instead 1k for R36.

ok i'll try to find lf353 on local source, and give you result.

thanks