100W Ultimate Fidelity Amplifier

[sajti]

The basic concept coming from mc2 audio. See attached file...

Sajti

 

[apexaudio]

The basic concept coming from mc2 audio. See attached file...

Sajti

Yes, mc2 use same topology... and peavey use similar topology floating supply for OP amp to drive OS directly without VAS.
AX2 use same topology as peavey.

 

[still4given]

Terry, it was done as mrmax063 suggested using "Alternate" spice solver. Using original values it oscillate once in the beginning.

But look at UltimateX86 file it works perfect using"normal" spice solver.

Regards
Sonal Kunal

Here is Mile's latest file. It is actually A2 now.
It runs OK but .2 THD

 

[overall feedback]

Here is Mile's latest file. It is actually A2 now.
It runs OK but .2 THD

pay attention to c6 value, 22uF

 

[Dezy]

I am able to get MJL3281aA and MJL1302A........any alternative to these trasistors

 

[still4given]

That helped but still high.

 

[overall feedback]

Try this one.

 

[apexaudio]

Or this one...

 

[still4given]

The latest file from Mile sims the best but when tried the changes on my board it oscillates. If I bypass the diodes I can get it to play a sine wave as long as I don't give too much input voltage but of course there is a bad crossover notch. Once I increase the input voltage it starts oscillating again.

 

[overall feedback]

What if add c3 and c9, about 1n, any changes?

 

[UltimateX86]

Here is Mile's latest file. It is actually A2 now.
It runs OK but .2 THD

One push is not enough to 55V 4ohm, 58mA is not enough for 2SK

it takes at least 120mA / push

it is possible using more than one push with this design ? maybe with driver ?

thanks

 

[still4given]

What if add c3 and c9, about 1n, any changes?

no change

 

[apexaudio]

Some compensation caps add...

 

[sajti]

Yes, mc2 use same topology... and peavey use similar topology floating supply for OP amp to drive OS directly without VAS.
AX2 use same topology as peavey.

The Peavey solution, with the grounded output is very easy to build. The only issue, that the power transformer, and the power supply will be more complicated.

Sajti

 

[overall feedback]

no change

What opamp u using? If compensation not help, maybe opamp is overloaded, add resistor r20 1k.

 

[still4given]

Some compensation caps add...

Worse. With C3 installed, instant oscillation. I removed C3 and we are back to where we started. C15 doesn't change a thing from what I can see.

What opamp u using? If compensation not help, maybe opamp is overloaded, add resistor r20 1k.

I'm using TL071. It is the only single channel IC I have.

I will try the 1k resistor.

 

[sonal kunal]

Worse. With C3 installed, instant oscillation. I removed C3 and we are back to where we started. C15 doesn't change a thing from what I can see.


I'm using TL071. It is the only single channel IC I have.

I will try the 1k resistor.

Are you still using 2SC3423-Y/2SA1360-Y as driver.

 

[apexaudio]

Worse. With C3 installed, instant oscillation. I removed C3 and we are back to where we started. C15 doesn't change a thing from what I can see.


I'm using TL071. It is the only single channel IC I have.

I will try the 1k resistor.

Try to increase compensatio caps value...

 

[still4given]

Are you still using 2SC3423-Y/2SA1360-Y as driver.

Yes

 

[sonal kunal]

2SC3423-Y/2SA1360-Y are 50mA devices maybe because of current limit 2SC3423-Y/2SA1360-Y are getting overloaded.

Check with BD139/BD140 at lesser voltage.