steenoe said:That looks unusual! How many watts do you expect to get out of that, 30-40?
Make that: It looks very unusual and interestingEasy to build too.
Steen
naah.
green button missing; brain is in red
another one- familiar to you?
edit - I know that pic from post 1 need few additional lines,too....... but not tonight........
Attachments
Zen Mod said:
naah.
green button missing; brain is in red
another one- familiar to you?
edit - I know that pic from post 1 need few additional lines,too....... but not tonight........
Sure, thats Patricks sweet little headphone amp, alike
Ohh, just want to add, the sound comes cleanly through Patricks LU HP-amp!! Very clean!
Let me have a go and see whether I will make a fool of myself.
The first schematics is a balanced version, one half of which you then drew in the second schematics. Since it is balanced, the speaker is not referred to ground (or positive rail). But I do not see any advantage in using a single rail and input caps.
(Matter of taste I guess. I don't like caps in the signal path).
For me, if I want to do a balanced follower, I'd rather use 2 cascoded JFET in a circlotron follower (see Grey's Newtron thread or many other circuits from Tubecad). Direct coupled, bandwidth from DC to way over 300 kHz, 4 transistors (same number as the DAO follower but half the output impedance and twice the current driving capability). You can even easily modified the DAO PCB for that. DC drift problem, if any, is the same as the DAO.
(Yes I have mockup tested but since I don't have headphones, I am not building it as a follower but want to use it for something else, eventually.)
And Steen, if you want more bias from the DAO, you just change the source resistor to 0R68, like in ZV9. Parallel that a few times, and you get a power amp to compete against the F4. If your speaker is not low impedance, I think the input capacitance would not be too much of a problem, since it is a source follower, and on top of that you have further reduction of effective Cgd due to cascoding.
Patrick
The first schematics is a balanced version, one half of which you then drew in the second schematics. Since it is balanced, the speaker is not referred to ground (or positive rail). But I do not see any advantage in using a single rail and input caps.
(Matter of taste I guess. I don't like caps in the signal path).
For me, if I want to do a balanced follower, I'd rather use 2 cascoded JFET in a circlotron follower (see Grey's Newtron thread or many other circuits from Tubecad). Direct coupled, bandwidth from DC to way over 300 kHz, 4 transistors (same number as the DAO follower but half the output impedance and twice the current driving capability). You can even easily modified the DAO PCB for that. DC drift problem, if any, is the same as the DAO.
(Yes I have mockup tested but since I don't have headphones, I am not building it as a follower but want to use it for something else, eventually.)
And Steen, if you want more bias from the DAO, you just change the source resistor to 0R68, like in ZV9. Parallel that a few times, and you get a power amp to compete against the F4. If your speaker is not low impedance, I think the input capacitance would not be too much of a problem, since it is a source follower, and on top of that you have further reduction of effective Cgd due to cascoding.
Patrick
http://www.tubecad.com/index_files/page0021.htm
I am sure you clever guys can figure out how to change the 3rd schematics (Simple MOSFET Circlotron) on that webpage to work with the LU1014. The transformer is just there for gain and balanced input. No need if you have balanced input anyhow and don't need gain.
Patrick
Bedtime
I am sure you clever guys can figure out how to change the 3rd schematics (Simple MOSFET Circlotron) on that webpage to work with the LU1014. The transformer is just there for gain and balanced input. No need if you have balanced input anyhow and don't need gain.
Patrick
Bedtime
Sure, the input xfrmr is not necesary and as long as you have somthing like a BOSOZ or a P1.7 etc. to drive it your fine... There are considerations not yet discussed here also. I have built a couple proto's of MOSFET Circlotron. They do work good! Low Df and all, if you have the supplies behind it. However, what about bias stability and offset control??? If you keep reading Broske, he addresses the simple servo offset control somewhere...
An LU1014D you say... What about the Newtron??? Another of the Grey creations. It did not generate the enthusiasm I would have expected??? Sorry Grey, if the spelluing is messed up
I found you can spend a few day's at the USPTO tracking down refrences to Circlotron ideas though...
Me? Your gonna ask? Well, I'll help maybe but I have enough projects to finish if I'm actually messing around on the bench
One of them is a MOSFET Circlotron!
Also, I did want to mention the words Inpol and Pathos ???
An LU1014D you say... What about the Newtron??? Another of the Grey creations. It did not generate the enthusiasm I would have expected??? Sorry Grey, if the spelluing is messed up
I found you can spend a few day's at the USPTO tracking down refrences to Circlotron ideas though...
Me? Your gonna ask? Well, I'll help maybe but I have enough projects to finish if I'm actually messing around on the bench
One of them is a MOSFET Circlotron!Also, I did want to mention the words Inpol and Pathos ???
> An LU1014D you say... What about the Newtron???
The two basic circuits I published in the Newtron thread I have built (one MOSFET and one LU1014). They both sound great. Bandwidth DC to 600kHz. Thanks to Grey for the inspirations.
I am now working on a circlotron with no feedback. Output impedance 33mohm. 100W Class A, but 1000W Class AB into 2 ohms.
Patrick
The two basic circuits I published in the Newtron thread I have built (one MOSFET and one LU1014). They both sound great. Bandwidth DC to 600kHz. Thanks to Grey for the inspirations.
I am now working on a circlotron with no feedback. Output impedance 33mohm. 100W Class A, but 1000W Class AB into 2 ohms.
Patrick
Why would you want something else other than the LU1014 ?
It has enough transconductance, can be operated in triode mode, apparently still available in large quantities at affordable prices (matched), .....
I have been asked about the IXYS and the Semisouth devices. I have not tried any of those, and have no intension to, as I still have other (not popular) devices waiting to be implemented in circuits. Nelson is the one with first hand experience with those two. I have no additional opinion to contribute.
Patrick
It has enough transconductance, can be operated in triode mode, apparently still available in large quantities at affordable prices (matched), .....
I have been asked about the IXYS and the Semisouth devices. I have not tried any of those, and have no intension to, as I still have other (not popular) devices waiting to be implemented in circuits. Nelson is the one with first hand experience with those two. I have no additional opinion to contribute.
Patrick
Patrick has a good point - the LU1014 is cheap and can
act like a triode when cascoded.
The Ixys depletion mode part I have played with works
pretty much like a regular Mosfet except for the
convenience of self-bias at about 1.3Amps. It looks to
have good potential for operation with a transformer ala
Hiraga's "Nemesis". I have some transformers on order
to check that out.
I have samples of other parts and some on order, not
available through distribution, which bias at higher
figures, allowing degeneration and direct input coupling.
We'll see how they turn out.
act like a triode when cascoded.
The Ixys depletion mode part I have played with works
pretty much like a regular Mosfet except for the
convenience of self-bias at about 1.3Amps. It looks to
have good potential for operation with a transformer ala
Hiraga's "Nemesis". I have some transformers on order
to check that out.
I have samples of other parts and some on order, not
available through distribution, which bias at higher
figures, allowing degeneration and direct input coupling.
We'll see how they turn out.
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