In the matter of facts they have very similar characteristics under every aspect...
The Power Totem is a little bit more dynamic, maybe because it's an open-loop amplifier (?)
Mr. Pass helped me measure my Class AB SRPP Power Buffer at 01/20/10.
He copied the results in floppies for me.
But my floppy drive of my desktop is broken.
My dad's floppy drive of his desktop is broken, too.
So I dug out my antique laptop to read the floppies.
Here are the THD measured results.
The bias current of it is only 0.75 A.
It has 100% negative feedback.
I am very satisfied about these result.
He copied the results in floppies for me.
But my floppy drive of my desktop is broken.
My dad's floppy drive of his desktop is broken, too.
So I dug out my antique laptop to read the floppies.
Here are the THD measured results.
The bias current of it is only 0.75 A.
It has 100% negative feedback.
I am very satisfied about these result.
Attachments
I found a BJT SPRR amplifier from a diy forum in China.
An externally hosted image should be here but it was not working when we last tested it.
Hi.
Of course your circuit works much more better than the Vetruvio's SRPP.
Vetruvio's one is a too much minimalist concept for superior performances.
Mr Pass knows it very well.
I presented it just for to show a solid state SRPP that is identical to the tubes ones. About this it can be intersting. It can also be a nice week-end for some beginner that wants to have a result not exactly ugly with few money in few time. None of Vetruvio's models for sale is using this circuit, so, I suppose it's just a joke or a curiosity.
If I was you, I wouldn't be worry about.
Best regards.
Hi.
Listen Wensan: If you want to insert the Power Totem in a negative feedback loop for to improve it's characteristics, there is a very simple way.
The transistors are always six, but is necessary to increase the number of the other components. It's not necessary to invent nothing, but simply to joint the input stage of the JLH '69 with the Power Totem as shown in the schematics here attached.
Try it...
Attachments
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Wensan, The THD of your amplifier looks good. It's nice to be able to measure those things. Did you have a chance to see if it is mostly 2nd & 3rd harmonic ?
Right now I'm starting on the mechanical bits for my own SRPP. I have 4 small boxes and I will have a panel meter installed in each one by end of tomorrow. One of them will be SRPP.
Right now I'm starting on the mechanical bits for my own SRPP. I have 4 small boxes and I will have a panel meter installed in each one by end of tomorrow. One of them will be SRPP.
Mr. Pass didn't test the spectrum of distortion.
But we saw the wave form of cross-over distortion when it worked in Class AB mode.
Hmm... This looks like J2 variant, isnt it?
Btw, hows your exploring on J2? You seems to have stop pursing or have you found the holy grain?
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The crossover distortion was remarkably low when crossing
into Class B territory, much better than the SRPP circuits
I have made in the past.
Member
Joined 2009
Paid Member
The crossover distortion was remarkably low when crossing
into Class B territory, much better than the SRPP circuits
I have made in the past.
Hi.
In the last days I developed a version of Vetruvio's Power Totem in the tentative to improve its performance.
This stage is a SRPP 100% negative feedback with very low distorsion.
Now the Power Totem is a " symetrical" push-pull because the signal driving the lower Darlington has the same amplitude of the signal on the gate of the upper one and becomes an output buffer because doesn't gain nothing any more. So, it needs an input gain stage. It could be a common emitter stage in the place of the two 100 K resistors.
I think it's interesting.
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We are impatient to see.
For now , i am gathering all the parts for building an Aleph J including your enhanced SRPP output.
I will be able to start soon, i hope.
I hope also the following schematic to be correct.
Though i hesitate on the red pointed resistors values. (8 ohms load wanted)
Your advice would be great
Attachments
Do you know the associated magazine, in which this concept was presented ? Perhaps from the same author than the attached MOSFET SRPP circuit.
In this case this URLs are also of interest:
http://www.tubecad.com/2009/10/blog0174.htm
http://www.diyaudio.com/forums/pass-labs/170695-zen-mosfet-srpp-power-amplifier.html
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