Current Dumping revisited

[Enkitec]

Initial tests. Voltages and currents according to the simulation.
Still without the dumpers. Just testing the class A stage.
Very nice sound! I'm surprised!

 

[moschfet]

Very nice

Unfortunately all my prototypes have heavy oscillations.

 

[smartx21]

Very nice! Better with chimarrão or KayPirinha?

 

[moschfet]

Very nice! Better with chimarrão or KayPirinha?

No problem, I am not a typical German
Actually I don't drink Beer, I prefer a good Cabernet Sauvignon and sometimes an old Scotch.
But I also like chimarrão.

 

[Enkitec]

Built two boards and installed them inside an old DIY amplifier.
Still listening without the dumpers, just the Class-A stage.
I'm very impressed with the sound quality!

 

[Enkitec]

Installed the dumpers. Listening now. I'm very pleased!
Very detailed and musical. Bass is very controlled. Treble very clean. Vocals unreal!
It worthed the months of simulation in LTspice.

 

[Piersma]

Amplifier

Could you do some real life THD/IMD tests on your new current dumping amplifier creation?

 

[Enkitec]

Could you do some real life THD/IMD tests on your new current dumping amplifier creation?

Will do, as soon time permits.

 

[Enkitec]

RMAA measurements

Did some measurements using RMAA and the internal soundcard of my Intel DH77 motherboard.

Power output was set to 1W due to not using an attenuator at the soundcard input.

 

[Enkitec]

Just for clarification, I'm still using the TL071 opamp.

 

[Piersma]

Current dumping

Looking good ! Heavier load conditions would be interesting to see.

 

[Enkitec]

Looking good ! Heavier load conditions would be interesting to see.

Did some tests with RMAA using 8R resistors as load.

 

[Enkitec]

Did some tests with RMAA using 8R resistors as load.

Please disregard my last post.

There are problems with the test setup that ruined the measurements.

Will post correct results ASAP.

Regards.

 

[Enkitec]

New RMAA measurements.
Using an OPA134.
Power supply voltage is +-25V.
Load is an 8 Ohm resistor.

 

[jan.didden]

What jumps out to me in the measurements is that the noise level is rather high, often much higher than any distortion.
Why would that be? The data in post # 112 was better.

Jan

 

[Enkitec]

What jumps out to me in the measurements is that the noise level is rather high, often much higher than any distortion.
Why would that be? The data in post # 112 was better.

Jan

I have found the noise source is the soundcard output, about 20mVpp. The output level was adjusted via Windows volume control.

I'll have to insert an attenuator between the soundcard and the amplifier, to keep the soundcard output level always at max.

 

[Enkitec]

Another test, same conditions.
Soundcard output set to max.
Amplifier input level controlled by an attenuator.

 

[Enkitec]

One year listening to this amplifier and it never ceases to amaze me!
I think I like it more than my two Leach amp!

 

[smartx21]

Hi! Have you quit FB? We miss you around. Specially at Clube DIY Áudio.

 

[Enkitec]

Hi Max,

Closed my FB account. Fed up of that ridiculous "fact-checking" thing...
Set up a group on Telegram and I'll join.

Regards,
Mark Jordan