100W Ultimate Fidelity Amplifier

[bimo]

I want to make it have high slew rate, then I change the compensation.
I like an amplifier that have high slew rate very much.

I revise the schematic because I miss type some value.
Please see my simulation file.

 

[still4given]

Terry,
Thank You. Problem was with the 330p cap. Reflowed & now is working. Still have -40mv on output. 35mV across the emitter resistors. Total input power is 174ma idle. How do i adj. the -40ma on output

Rick

Hi Rick,

Yes with what Ivan said. This amp doesn't have an adjustment for offset. You might get it close by a closer match of the BC546 transistors but 40mV will not hurt anything.

 

[olafk]

Nice work, use 1k resistor in series with 1k pot instead 1k5 and set DC offset,
Regards

It's done. Offset is around 15mV (1k8 || 75k instead of 1k5). Nice amplifier.
Next step is to combine with tube stage.

Question: I have just 6N1P and ECC82. Are there any changes compared to the ECC88 / 12AU7?

regards Olaf

 

[still4given]

6N1P has same pinout as ECC88 but is not the same. I have tried using 6N1P in four different circuits designed for the ECC88 and it just doesn't work. I really believe the circuit needs to be designed specifically for the 6N1P.

 

[olafk]

Hi Terry, thanks for the reply. I just try out everything
I'm worried anyway because of the low anode voltage.

We will see.

regards Olaf

 

[still4given]

The last place I tried this was on the Apex Counterpoint preamp. You can see my findings here.

I want to search for some circuits that will work for the 6N1P because I have 8 of them and would like to use them in something.

 

[olafk]

I want to test the Aikido.

 

[olafk]

Your Apex tube preamp looks very nice!

 

[Rick G]

Hi Rick,

Yes with what Ivan said. This amp doesn't have an adjustment for offset. You might get it close by a closer match of the BC546 transistors but 40mV will not hurt anything.

Ivan & Terry,
OK, Thanks guys.

 

[apexaudio]

A4 idea...

 

[UltimateX86]

unusable in non inverting mode and maybe latfet ?

 

[smartx21]

Waiting for the A0 release!

 

[apexaudio]

Waiting for the A0 release!

The advantage of this circuit is rail to rail voltage swing without VAS, only single OP and two outputs is extra benefit.

 

[olafk]

VX120 with tube

Hi, here is the next step with the VX120:
I have the tube module connected with a ECC82 to the amplifier. With shorted input I measure over the 22k resistor 53 volts, which means it flow 2.4mA. That's not much.
Then the Input 0.4Vpp / 1kHz sine. The pictures show all things without changing the input from function generator:
1 No heating, no anode current, input 0.4Vpp, output is zero.
2 heating on, no anode current input is 0.35Vpp, output is inverted 0.2Vpp
3 Heating on, anode current flows, input is 0.4Vpp, output is inverted 0.25Vpp
4 amplifier input is 0.4Vpp, output is 8Vpp and looks good

But, when I connect a speaker or have a look at the scope at very low frequencies, the sound is like a machine gun. A "Blob" come with 5 to 10Hz and the resistors in the rails become very hot.

What is wrong? Sorry, I have absolutely no experience with tubes ...

regards Olaf

 

[still4given]

Oscillation is causing the heat and motor boating. Do you have a zobel installed?

 

[olafk]

Oscillation is causing the heat and motor boating. Do you have a zobel installed?

Yes, Zobel is installed and cool. When I use only the transistor part, all things are ok.

Regards Olaf

 

[BC109]

APEX A4
Not tested!

 

[still4given]

Yes, Zobel is installed and cool. When I use only the transistor part, all things are ok.

Regards Olaf

Maybe the gain is too high in the tube section.

 

[BC109]

Fixed file.

 

[thiagomogi]

I can use BC550c -> BC546 in the AX11 with PSU 35V DC ?