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![x2[1].gif](/community/data/attachments/54/54615-bd787a17c2fa70bc40d890602e3ee047.jpg)
Banned
Joined 2002
Hi,
no you don´t have to build two PSU´s. You can ofcourse use + and - 90V. Only change the resistor that sets the current and use enough heatsinking.
One advantage of the current source is that you can use lower supply voltage (especially the negative one) for higher efficiency without any performance disadvantages.
William
no you don´t have to build two PSU´s. You can ofcourse use + and - 90V. Only change the resistor that sets the current and use enough heatsinking.
One advantage of the current source is that you can use lower supply voltage (especially the negative one) for higher efficiency without any performance disadvantages.
William
Banned
Joined 2002
Hi,
yes I can help but first I would like to know why you want to build an "old" design. There are a few X-BOSOZ on the forum (with or without current source) wich do perform better than a BOSOZ with current source.
I would go for one of these.
Building an assymetrical power supply isn´t such a problem either. You only need two (smaller) transformers instead of one and connect the ground togheter or maybe ou can get a transformer with 60V and 20V windings.
William
yes I can help but first I would like to know why you want to build an "old" design. There are a few X-BOSOZ on the forum (with or without current source) wich do perform better than a BOSOZ with current source.
I would go for one of these.
Building an assymetrical power supply isn´t such a problem either. You only need two (smaller) transformers instead of one and connect the ground togheter or maybe ou can get a transformer with 60V and 20V windings.
William
Banned
Joined 2002
Dear all
I have long wondered.
Why do we need any negative feedback loop for such a simple single stage gain BOSOZ?
If we see A P1.7, it looks like having a feedback resistor from the drain of the gain FET to its gate. But, I think that the main role of the resistor is to place the drain potential of the gain FET at certain point between the +rail and the ground because it has +rail only. The resistor is not really for the negative feedback (X-feedback), IMHO!!!
I like X2 having NO negative feedback loop.
I am still wondering why we need the X-feedback loop to the simple single stage gain preamp.
Is it really improving the sound in positive way????????
Regards
I have long wondered.
Why do we need any negative feedback loop for such a simple single stage gain BOSOZ?
If we see A P1.7, it looks like having a feedback resistor from the drain of the gain FET to its gate. But, I think that the main role of the resistor is to place the drain potential of the gain FET at certain point between the +rail and the ground because it has +rail only. The resistor is not really for the negative feedback (X-feedback), IMHO!!!
I like X2 having NO negative feedback loop.
I am still wondering why we need the X-feedback loop to the simple single stage gain preamp.
Is it really improving the sound in positive way????????
Regards
Hi,
I don´t think there´s a definite version cause everybody build it a bit different. I made one without CCS and plus and minus 60V supply and another one with CCS and +40V -20V supply.
Some use bjt´s for the current source others use fets. Some have 20mA bias, others up to 50mA.
Since the circuit is so simple and doesn´t use many (expensive)parts it is easy to build a few variations. The only thing you have to think of beforehand is if you want to try it without CCS. If so you´ll need a symmetrical power supply with at least +-30V.
A current source is always possible although with higher losses in case of a symmetrical supply.
What seems to be true for all those variations is that they sound very good without using all sorts of fancy caps and resistors.
William
I don´t think there´s a definite version cause everybody build it a bit different. I made one without CCS and plus and minus 60V supply and another one with CCS and +40V -20V supply.
Some use bjt´s for the current source others use fets. Some have 20mA bias, others up to 50mA.
Since the circuit is so simple and doesn´t use many (expensive)parts it is easy to build a few variations. The only thing you have to think of beforehand is if you want to try it without CCS. If so you´ll need a symmetrical power supply with at least +-30V.
A current source is always possible although with higher losses in case of a symmetrical supply.
What seems to be true for all those variations is that they sound very good without using all sorts of fancy caps and resistors.
William
Kari is working on a X-CCS-BosoZ layout.
http://www.diyaudio.com/forums/showthread.php?threadid=53396
Can't wait to get some of those boards
Steen
http://www.diyaudio.com/forums/showthread.php?threadid=53396
Can't wait to get some of those boards
Steen
I think the big advantege of the schematic from the first post of this thread is lack of the input cap.
The circuit kind of remind me Aleph P 1.0, that I like soniclly very, very much. I think this might be just a better version of it - IRF610 instead of IRF244 and negative CCS that allows to use no cap at the input.
Bartek
The circuit kind of remind me Aleph P 1.0, that I like soniclly very, very much. I think this might be just a better version of it - IRF610 instead of IRF244 and negative CCS that allows to use no cap at the input.
Bartek
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Joined 2002
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