Here are some calcs based on the CL-60 datasheet that someone posted early.
If I am correct, which I think I am, at 8 A bias (2 A each therm) these guys get pretty HOT over 90 DEG above room temp
Just something to keep in mind if someone's thinking about using them.
By the way this is an excel file zipped on the mac. Winzip should open it just fine.
If I am correct, which I think I am, at 8 A bias (2 A each therm) these guys get pretty HOT over 90 DEG above room temp
Just something to keep in mind if someone's thinking about using them.
By the way this is an excel file zipped on the mac. Winzip should open it just fine.
Aleph X DC out stability(vs GND)
Hi to everyone concerned by this thread and building of an Aleph X.For some reason,the outputs seem to float a few volts above or under Ground,which is acceptable if we use the output balanced,i.e.without ground connection for the speaker.
I think the circuit is difficult to stabilize for DC output parameter,due to the resistor required to link each output ( before RC parallel feedback network ) and the common node for the sources of the mosfet differential.
So I have an idea,might be silly but hell.Who knows?Nelson said he had a trick to avoid this situation in the commercial XA series,other than the 2 power resistors from output to ground.
Here is what I propose to do:
We have this resistor in double that works to give Supersymmetric connection.I propose to add a P device operating as buffer ( no voltage gain ) with its gate linked to the output(before feedback network) standing at 0V DC or so;the drain of the P device is linked to positive supply voltage through a resistor,or current source if requred,and we take the source of the P device at +4V,i.e.same voltage level than the differential sources must be;then we link this to the sources of the differential through resistor already available,and this for the 2 halves of the circuit.
NELSON ? Would this work? Or is there a better solution for the task,that someone would have in mind?
All feedback welcome,as my aim is to learn
sorry for my english
Anael
Hi to everyone concerned by this thread and building of an Aleph X.For some reason,the outputs seem to float a few volts above or under Ground,which is acceptable if we use the output balanced,i.e.without ground connection for the speaker.
I think the circuit is difficult to stabilize for DC output parameter,due to the resistor required to link each output ( before RC parallel feedback network ) and the common node for the sources of the mosfet differential.
So I have an idea,might be silly but hell.Who knows?Nelson said he had a trick to avoid this situation in the commercial XA series,other than the 2 power resistors from output to ground.
Here is what I propose to do:
We have this resistor in double that works to give Supersymmetric connection.I propose to add a P device operating as buffer ( no voltage gain ) with its gate linked to the output(before feedback network) standing at 0V DC or so;the drain of the P device is linked to positive supply voltage through a resistor,or current source if requred,and we take the source of the P device at +4V,i.e.same voltage level than the differential sources must be;then we link this to the sources of the differential through resistor already available,and this for the 2 halves of the circuit.
NELSON ? Would this work? Or is there a better solution for the task,that someone would have in mind?
All feedback welcome,as my aim is to learn
sorry for my englishAnael
Wrong tentative
I didn't mean it.Sorry my english is real bad.
I think DC at the output is somehow constant,more or less.
The proposal I made first doesn't work.So I would correct launch and propose the following:
We would still use a P device as a buffer.But this fonction is of no interest here.The Drain of this P device would be definitively linked to V- rail,through resistor ( or current source ).The Source pin would be linked to V+ through appropriate resistor value,giving about +4V or so referenced to Ground of course.The gate is connected to output (speaker out I mean).Then through resistor value in the 1k-4k7 range,we link the Source of this P device to the sources of the differential,and would do the same for the second halve of the amp.
This would act like a level shifter transistor,and as far as we connect its Source to the tied 2 sources differential,it wouldn't give more errors to correct,and it would have no Miller effect .This way I think we could give the SuperSymmetric connection without affecting the DC stability of the amp,and the 2 halves of the output circuit should measure 0VDC referenced to Ground.
Hey Pass sensei !!! Give a piece of advice please
I need to LEARN......!!!THANKS!!!!!
I didn't mean it.Sorry my english is real bad.
I think DC at the output is somehow constant,more or less.
The proposal I made first doesn't work.So I would correct launch and propose the following:
We would still use a P device as a buffer.But this fonction is of no interest here.The Drain of this P device would be definitively linked to V- rail,through resistor ( or current source ).The Source pin would be linked to V+ through appropriate resistor value,giving about +4V or so referenced to Ground of course.The gate is connected to output (speaker out I mean).Then through resistor value in the 1k-4k7 range,we link the Source of this P device to the sources of the differential,and would do the same for the second halve of the amp.
This would act like a level shifter transistor,and as far as we connect its Source to the tied 2 sources differential,it wouldn't give more errors to correct,and it would have no Miller effect .This way I think we could give the SuperSymmetric connection without affecting the DC stability of the amp,and the 2 halves of the output circuit should measure 0VDC referenced to Ground.
Hey Pass sensei !!! Give a piece of advice please
I need to LEARN......!!!THANKS!!!!!
Ehh... I didn't take the time to read the following posts but I saw 4 thermistors in parallel on the X-200 pictures on page 39, leaves me one question:
Thermistor==>Negative Temperature Coefficient resistor==>four resistors parallel, most of the current is going through the resistor with the lowest resistance, resistor heats up, resistance decreases, more current, more heat, lower resistance...
What I'm trying to say is it looks to me like the other three thermistors in there are just doing nothing since they won't share the current equal, or am I mistaking??
leroy
The parallel Thermistors appear to be operating at
the same temperature, so I believe we are not
experiencing current hogging. They are not at the
steep end of the temp/resistance curve in this use.
Ref Q4, R15, R16, you simply set the values up so
that you don't blow up the negative output stage, so
I set them fairly high, and it takes a short to ground
to trigger it. In the Aleph X, you don't need them at
all if you can be certain of not shorting to ground, as the
positive current sources will set a limit for you.
the same temperature, so I believe we are not
experiencing current hogging. They are not at the
steep end of the temp/resistance curve in this use.
Ref Q4, R15, R16, you simply set the values up so
that you don't blow up the negative output stage, so
I set them fairly high, and it takes a short to ground
to trigger it. In the Aleph X, you don't need them at
all if you can be certain of not shorting to ground, as the
positive current sources will set a limit for you.
Give each secondary it's own rectifier bridge and cap, and
then series them at the caps. Then wire the the primaries
in series and see how it turns out. This should work if
The current flows from V+ to V- on average.
Then see to it that each +/- supply uses one of each
transformers, so that the draw will be equal.
Keep in mind that you will get two sets of about +/-
16 Volts this way.
Better yet, go get the right transformer, because this is
a bit of a stretch.
then series them at the caps. Then wire the the primaries
in series and see how it turns out. This should work if
The current flows from V+ to V- on average.
Then see to it that each +/- supply uses one of each
transformers, so that the draw will be equal.
Keep in mind that you will get two sets of about +/-
16 Volts this way.
Better yet, go get the right transformer, because this is
a bit of a stretch.
Here is the latest schematic posted by other member. For more info check page23 of Aleph-X thread.http://www.diyaudio.com/forums/attachment.php?s=&postid=43959