Evaquad
Hi Pawel, You also have the opportunity to ask to Eva directly (she's back on this forum in January 2016)
diyAudio - View Profile: Eva
Hi Pawel, You also have the opportunity to ask to Eva directly (she's back on this forum in January 2016)
diyAudio - View Profile: Eva
Even though output devices are still same/same polarity, there is a difference between a Class AB amplifier (like a normal quasi) and a Class AA amplifier (like Circlophone).nothing compares it with quasi. Maybe its better as i think.
What the Circlophone can do better is broader (lifelike) dynamic spread, "Elvee Watts" are incredibly effective and there's a nearly negative noise floor. You can hear.
I didn't know what I was missing until I used a Circlophone. After that, the fact that I made my TDA7293 imitate what I liked about the Circlophone, doesn't detract from the Circlophone at all. In fact, I have to keep it around as a comparison tool to help me check and see if my current project has performed passably in the areas that Circlophone does best. It is helpful to check that.
Sonic signature of the Circlophone that I built (the simple version, not Piersma's) is located at the lower treble, which is much less noticeable than a typical Class AB amplifier directly on ear sensitivity peak frequencies. The disadvantage of my simple sample is that it does have a sonic signature. I have to note that it wasn't very loud and didn't cause any serious interference to the music. The advantage of different frequency (at my sample of Circlophone) is that there's NO blare (an ear is not hindered). It doesn't occupy the frequencies for that.
I'm looking forward to hearing Piersma's refinements, at some point after I have managed to pay for it (he didn't tell me yet). What I desire is pretty much the same thing, except with the sonic signature at less amplitude. Even the notion of that was worth the purchase, that I'm still trying to complete. No rush, I'm just checking in so I didn't miss it.
Also, if that notion works, I'll probably send a tip/prezzy to Elvee, not only because that is the proper thing to do (every Circlophone is still his), but also because it could be fun. In that case (whenever I have benefited by his design), then I ought to figure a prezzy that I like, is useful and is non-boring.
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thanks for the response,
how about this reinvention of circlo
<-- satellite, satellite 
i want it simple as possible. <-- satellite, satellite
P.S. If I want to use two npn darlingtons as output devs, This allows me.
I dont need compensation here ? between Q3 and Q7 bases and collectors ?
how about this reinvention of circlo
<-- satellite, satellite i want it simple as possible.
<-- satellite, satellite P.S. If I want to use two npn darlingtons as output devs, This allows me.
I dont need compensation here ? between Q3 and Q7 bases and collectors ?
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My inv jfet Circlophone arrived
My inverted jefet Circlophone amp just arrived - thanks Piersma.
I just finished the Dx PSU that makes a clean +/-37v with 6mV ripple. I still need to mount the Circlophone amp to a heatsink and can test it out with this power supply tomorrow.
My inverted jefet Circlophone amp just arrived - thanks Piersma.
I just finished the Dx PSU that makes a clean +/-37v with 6mV ripple. I still need to mount the Circlophone amp to a heatsink and can test it out with this power supply tomorrow.
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Hi mosfet54,
Darlington and Hexfet versions use same layout but with slightly different component values. I tested both and they sounded very well despite darlington version had an overshoot issue that seems requiring extra compensation work. Hexfet version doesn't have such behavior with values suggested by Elvee in post #16.
My pcb layout try-out is here:
http://www.diyaudio.com/forums/soli...n-parts-accessories-beginner-friendly-23.html
Inverted JFET Circlophone testing
The inverted JFET Circlophone works! On one of the amps, I had a problem with a micro-perforated insulator (Kapton tape punctured by a micro burr on the heatsink), after fixing that and replacing a fuse, it is now playing music. It sounds fantastic! Like a class A amp but with lots of power on tap. Very powerful dynamic sound with great bass authority.
A very nice amp - perhaps one of the best sounding ones I have heard.
The inverted JFET Circlophone works! On one of the amps, I had a problem with a micro-perforated insulator (Kapton tape punctured by a micro burr on the heatsink), after fixing that and replacing a fuse, it is now playing music. It sounds fantastic! Like a class A amp but with lots of power on tap. Very powerful dynamic sound with great bass authority.
A very nice amp - perhaps one of the best sounding ones I have heard.
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Nice!The inverted JFET Circlophone works! On one of the amps, I had a problem with a micro-perforated insulator (Kapton tape punctured by a micro burr on the heatsink), after fixing that and replacing a fuse, it is now playing music. It sounds fantastic! Like a class A amp but with lots of power on tap. Very powerful dynamic sound with great bass authority.
A very nice amp - perhaps one of the best sounding ones I have heard.
What's the DC voltage feeding the CP boards and total capacitance fron PSU?
Thank you.
That's a 250VA 25v rated Avel Lindbergh toroid which produces +/-37v using the Dx PSU with qnty 4 x 4700uF 50v Nichicon caps.
Here is closeup of PSU - it's very simple and works quite well.
An externally hosted image should be here but it was not working when we last tested it.
Here is closeup of PSU - it's very simple and works quite well.
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A full day of listening with my new Inverted JFET Circlophone amp and I can now declare it as the best sounding amp I have so far. All the benefits of true class A with gobs of power and just a little more heat like a hot class AB. I put all sorts of test tracks through it and they all surprise me with the clarity, low distortion, smoothness and weight of the bass authority. Piano is a great test for distortion, and jazz trios are a great test for articulation and transient response.
Truly a wonderful design.
Thanks to Elvee and Piersma for this amp!
Truly a wonderful design.
Thanks to Elvee and Piersma for this amp!