zAh-ng amplifier, my amplifier..

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#21
lineup said:
MultiSim. How I make my FFT.


Good luck!
Click to expand...


You are the MAN, Lineup! Thank you.

My first results:
 

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#23
Quick learner 🙂 MJL21193
(sorry, will disable account after any 30 day period without post Lineup forum Warning
you will have to sign up again. at 0 posts)

You may prefer some other format of output, but
my settings are the following:
Fourier Analysis
Results
V Display as bar graph
V Normalize graphs (refering all to zero)
Display: Graph
Verical Scale: Decibel

Will give the following style of results output:
 

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#24
lumanauw said:
The 800ohm joint connected to 150ohm joint, is this making positive feedback?
Click to expand...

As I see it.
An attempt to equalize C-E voltage across the both Diff VAS BD140 (and BD139).

The voltage will follow output signal.
The effect is a kind of Bootstrap.
If voltage across each 800 ohm resistor is ~4.x Volt,
we may end up the C-E stays rather equal and constant.
 
#25
Sorry for hi-jacking your thread....

Hi John,

Hope you are well. Yes I am happy with my headphone amplifier, but it is much different from the one you have seen.

John I meant to ask you to lead me to your speaker building thread I want to do those curved baffles you did about a year, or is it two years ago.

Kind regards

Nico
 
#26
darian said:
Hello

I think you should think about something better to set the bias of your output mos... The Vgs on of these devices is not really reliable. Other than that it's just the super classic amp topology... Look at this one from France, very good sound indeed, simple schematic but the cascode on the VAS is a nice addition
http://pagesperso-orange.fr/jm.plantefeve/nrds2.jpg
Click to expand...

Sorry did not see the circuit from France. I simply used Nikwal's circuit and reduced it to a more basic circuit. Took me about ten minutes using MicroCAP and another four to optimize. No big deal and no authenticity claims - for me, it remains Nikwal's amp.

I have no idea why you claim Vgs of the devices not to be reliable. Imagine Toshiba writing in their data sheet, Vgs unreliable???
 
#27
lineup said:

You may prefer some other format of output, but
my settings are the following:
Fourier Analysis
Results
V Display as bar graph
V Normalize graphs (refering all to zero)
Display: Graph
Verical Scale: Decibel

Will give the following style of results output:
Click to expand...

Thanks again, lineup.
I have made the adjustments and the result is below.

Nico Ras said:
John I meant to ask you to lead me to your speaker building thread I want to do those curved baffles you did about a year, or is it two years ago.
Click to expand...

Hi Nico,
Thread is here

Mine are still not finished. In the middle of re-painting and I don't have the amps done yet. All in good time though.
🙂
🙂
🙂

Nikwal, sorry for this other stuff. Your amp looks very good and I think I will play with it as my first non-bjt project. I like it simple.
 

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#28
MJL21193 said:


Hi Nico,
Thread is here

Mine are still not finished. In the middle of re-painting and I don't have the amps done yet. All in good time though.
🙂
🙂
🙂
Click to expand...

John, do you have a problem if I crib your design. It is aesthetically one of the most beautiful pieces of sound furniture I have seen. I urge the other members that have not seen them to sneak a peak!
 
#29
Nico Ras said:


John, do you have a problem if I crib your design. It is aesthetically one of the most beautiful pieces of sound furniture I have seen.
Click to expand...


Nico, you make me blush! Now, how much do I own you? 😀😀

Go ahead and be my guest. It really wasn't my design anyway, but I did make some refinements. I don't know if you would use the same drivers as I did, but they are very good and play very well together.

Send me the latest schema on your headphone amp. I will be doing a lot of amp projects over the winter, so I'll not have a problem finding time to do it.
 
#31
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