Hi,
we already have Moskido - Aikido driving push-pull class A unity gain power buffer.
Does anyone have schematics for simple 30W Class AB power buffer with minimal parts, which could be driven by aikido preamp?
I know it wont sound as good as Class A, but also it should be cheaper, lighter, smaller and consume less electricity.
Thank you.
we already have Moskido - Aikido driving push-pull class A unity gain power buffer.
Does anyone have schematics for simple 30W Class AB power buffer with minimal parts, which could be driven by aikido preamp?
I know it wont sound as good as Class A, but also it should be cheaper, lighter, smaller and consume less electricity.
Thank you.
Hi Kacernator,
I have similar need: a powerful buffer AB class ( but 80-100W) to make biamplification.
Little Class A on the mid-tw and class AB on the woofer.
My idea is modify a F4 with less current bias and more voltage rails.
Probabily THD will goes up but I am not so worried...
Just a crazy idea from a rookie!
Cheers,
Paolo
I have similar need: a powerful buffer AB class ( but 80-100W) to make biamplification.
Little Class A on the mid-tw and class AB on the woofer.
My idea is modify a F4 with less current bias and more voltage rails.
Probabily THD will goes up but I am not so worried...
Just a crazy idea from a rookie!
Cheers,
Paolo
Hi,
I can suggest you two alternatives:
-the Thermaltrak diamond buffer by MTlin12 published here on diyaudio that I use together with my Aikido (Paolo: search also on www.audiofaidate.it where I published a revised schematic for correct bias)
-Steve Dunlap's Krill amp, output stage only (also based on diamond buffer). Steve also sells boards and partial kits....
Ciao
Andrea
I can suggest you two alternatives:
-the Thermaltrak diamond buffer by MTlin12 published here on diyaudio that I use together with my Aikido (Paolo: search also on www.audiofaidate.it where I published a revised schematic for correct bias)
-Steve Dunlap's Krill amp, output stage only (also based on diamond buffer). Steve also sells boards and partial kits....
Ciao
Andrea
Krill schematics
Here is the schematics of the full Krill amp with driver and PSU. Users are reporting that Krill sounds fantastic.
http://www.diyaudio.com/forums/attachment.php?s=&postid=1710148&stamp=1231731980
But when looking at the transformer, it needs 24V at 4A for one rail. In my DC-coupled moskido I have 25V at 5A.
I thought I could make 50W class AB amp with smaller transformer, if not I am staying with moskido, although class A amp draws more idle current also the power circuit is a lot simplier with moskido.
Here is the schematics of the full Krill amp with driver and PSU. Users are reporting that Krill sounds fantastic.
http://www.diyaudio.com/forums/attachment.php?s=&postid=1710148&stamp=1231731980
But when looking at the transformer, it needs 24V at 4A for one rail. In my DC-coupled moskido I have 25V at 5A.
I thought I could make 50W class AB amp with smaller transformer, if not I am staying with moskido, although class A amp draws more idle current also the power circuit is a lot simplier with moskido.
Hi Kacernator,
Seems to me there is not much interest about "our" idea/scheme
I do not understand, tubes for voltage gain and solidstate superbuffer for current gain....what is wrong?
I have looked at Krill and the other scheme....beautiful, but to my inexpert eyes the F4 is more "simple" - easy to understand.....
Cheers,
Paolo
Seems to me there is not much interest about "our" idea/scheme
I do not understand, tubes for voltage gain and solidstate superbuffer for current gain....what is wrong?
I have looked at Krill and the other scheme....beautiful, but to my inexpert eyes the F4 is more "simple" - easy to understand.....
Cheers,
Paolo
You are right,
but i have asked to Nelson Pass if is it possible run the F4 in AB class and he has kind responded of yes; just lower the bias and rise the voltage rails........
So I think you can have to say 100w in class AB with the first 10-15W
in A class. IMO it is a good compromise, no?
Cheers,
Paolo
but i have asked to Nelson Pass if is it possible run the F4 in AB class and he has kind responded of yes; just lower the bias and rise the voltage rails........
So I think you can have to say 100w in class AB with the first 10-15W
in A class. IMO it is a good compromise, no?
Cheers,
Paolo
Ok, I am in to do it with F4, at least it will sound more different than with moskido buffer.
So, do you know how much to raise the rail voltages and what should be the standing current? How much current will it draw when at full 100W power?
Are there any PCB shemes available?
How do you hook up aikido with it?
Here is F4 schematics: http://www.firstwatt.com/downloads/f4_om.pdf
So, do you know how much to raise the rail voltages and what should be the standing current? How much current will it draw when at full 100W power?
Are there any PCB shemes available?
How do you hook up aikido with it?
Here is F4 schematics: http://www.firstwatt.com/downloads/f4_om.pdf
Oh, for more specific questions I think better you ask in the Pass section. Anyway I think something +/- 48-50 Volt ofr the rails and for the current .....maybe you have to measure distortions with instruments
But I do not think it is so delicate/precise, I am ignorant about electronic but there is an article in the Pass site about " Leaving the class A" . It appears not so complicate
Some guys have made PCBs if I well remember.
I do not use Aikido stage, I simply use very basics 1930 common cathode circuit; they perform/measure worse but IMO they sound more natural
Actually I use a 6N6P-I.
Cheers,
Paolo
But I do not think it is so delicate/precise, I am ignorant about electronic but there is an article in the Pass site about " Leaving the class A" . It appears not so complicate
Some guys have made PCBs if I well remember.
I do not use Aikido stage, I simply use very basics 1930 common cathode circuit; they perform/measure worse but IMO they sound more natural
Actually I use a 6N6P-I.
Cheers,
Paolo
So far I have tried Aikido preamp with these output stages
1) class A complementary mosfet follower without GNFB, biased at 1.5A - overall good sound, but it could be clearer with more details and with tighter and deeper bass
2) class AB quasi output stage from Nishiki hybrid, also without GNFB - worse then first class A option, didn´t like this sound at all
Still I am not satisfied and looking for more options on output buffers or power amps.
Does anyone know schematics of class AB poweramp which has GNFB, lowe standing current (max 200ma) has gain 10db or less (preferable unity-gain), low THD and high damping factor and uses BJT output, so it can be driven by aikido preamp?
1) class A complementary mosfet follower without GNFB, biased at 1.5A - overall good sound, but it could be clearer with more details and with tighter and deeper bass
2) class AB quasi output stage from Nishiki hybrid, also without GNFB - worse then first class A option, didn´t like this sound at all
Still I am not satisfied and looking for more options on output buffers or power amps.
Does anyone know schematics of class AB poweramp which has GNFB, lowe standing current (max 200ma) has gain 10db or less (preferable unity-gain), low THD and high damping factor and uses BJT output, so it can be driven by aikido preamp?
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I haven't seen many people building HEC outputs, it is still a nfb system and you have to know how to avoid parasitic oscillations.
Your problem is one I have too - looking for Class AB buffer, I started a thread for that before:
http://www.diyaudio.com/forums/tubes-valves/174889-cellini-2-hybrid.html
I really think the Krill output stage is a good option for you to try, it might perform better than Nishiki; others who have built it have been impressed with the results. I suspect it's important to have plenty of parallel output devices so that you have lower distortion (less current swing in each device) and also lower output impedance because the output resistance of each device is in parallel. It would be good to try and get some better results without nfb.
Your problem is one I have too - looking for Class AB buffer, I started a thread for that before:
http://www.diyaudio.com/forums/tubes-valves/174889-cellini-2-hybrid.html
I really think the Krill output stage is a good option for you to try, it might perform better than Nishiki; others who have built it have been impressed with the results. I suspect it's important to have plenty of parallel output devices so that you have lower distortion (less current swing in each device) and also lower output impedance because the output resistance of each device is in parallel. It would be good to try and get some better results without nfb.
Yes, that is another way - no NFB and more parallel output devices. But I want to have NFB in output stage, so I can have one or two output pairs only and mainly the music I listen to sound to my ears better with NFB.
I also have schematic with compensation. Just need to know if I can drive directly Q1 and Q2 with tube preamp or I must add another emitter followers to buffer the input of this output stage.
I also have schematic with compensation. Just need to know if I can drive directly Q1 and Q2 with tube preamp or I must add another emitter followers to buffer the input of this output stage.
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