Audio Art 260.6XE

[caraudioguy2100]

I will put all the fets in to see if it draws excessive current .

That pic was when only 1 fet was in the supply .

And so far with just 1 fet in the amp idles fine

 

[caraudioguy2100]

I have no clue what’s wrong with this amp at this point :

Every transistor is brand new in the power supply section .

Every resistor has been checked every diode has been checked .

All the fets are brand new .

As soon as I apply remote voltage it blows the fets .

This is has been the problem since the beginning .

Only thing I can think of is the transformer is shorted

Any ideas where to go from here

 

[Perry Babin]

When working on a problem amp, you should work through a limiter and have the FETs clamped. Those make it virtually impossible to blow the FETs.

Did you check the drive signal with the loading cap?

Do you have another amp that you can try the loading cap on to see what you're supposed to see?

 

[caraudioguy2100]

With 1 bank of fets in the power supply the amp ideals perfect .

The problem is with the 2nd bank of fets they blow instantly .

So I will look at that bank to try and figure out what’s causing it to blow the fets if I load it with a cap the waveform gets goofy again .

 

[Perry Babin]

I'm sure that you must have an amp that you have laying around that you can try the cap in to see what the waveforms should look like.

Are you sure that you have two 0.1uF caps in series?

 

[caraudioguy2100]

Yes the cap markings are 104

1 leg goes to gate the other leg goes to source .

The 2 remaining legs get soldered together .

With only 1 bank of fets the amp works and has clean audio so the only problem is with that 1 bank of fets .

I will get 2 different caps and connect them as described and post the waveform .

 

[caraudioguy2100]

Pic 1 is 1 side of the gate resistor .

2nd pic is the other side of the gate resistor that connects to the fets gate leg this is loaded with 2 0.1 caps in series

I know what I’m supposed to have but I’m not getting that at all

 

[caraudioguy2100]

Ok I found a problem . I wasn’t paying attention when I put the gate resistors in the amp .

I bought 47 ohm gate resistors from a electronics shop where I live .

The package was labeled 47 ohm but the resistors are actually 470 ohm 🙄

I will switch the gate resistors and check again

 

[Perry Babin]

What are the ohm readings across the gate resistors?

 

[caraudioguy2100]

The gate resistors are labeled wrong they measure 0.468 K on my meter ,


I bought them and the package says 47 ohm but they are 470 ohm

Guess I should have paid closer attention to the color bands

I will replace them and see what I come up with