In that case 1m=1000u=1millifarad
What I would like to know is if the folded cascode circuit is essentially a voltage amplifier.
Listenin' to the circuit I had the impression of a lack of current amplification.
In the other hand , listening to a power source follower, it is obvious the lack of a voltage amplification.
That's becouse I am thinkin'of it as a combination---folded cas.+ source follower---- even in a preamp mode.
For "current amplification" I mean the source follower-common drain- in opposition to a cascode-common gate- operation.
What I would like to know is if the folded cascode circuit is essentially a voltage amplifier.
Listenin' to the circuit I had the impression of a lack of current amplification.
In the other hand , listening to a power source follower, it is obvious the lack of a voltage amplification.
That's becouse I am thinkin'of it as a combination---folded cas.+ source follower---- even in a preamp mode.
For "current amplification" I mean the source follower-common drain- in opposition to a cascode-common gate- operation.
stefanobilliani said:
Well it would have voltage gain, sure.
The common-gate portion wouldn't
contribute any current gain, though,
if that is what you mean.
What gave you that impression? In
other words, what did that sound like?
Erik
It did sound detailed , the soundstage was wide , a view of the piece of a precise focal length.
But if I can made a comparison with the drums , their skins wasn’t too much greasy.
😎
Input/output impedance
Hi,
after searching for a while to find a nice preamp for my Aleph5 and upcoming Aleph-X I think I will try an X-BOSOZ (with the easy option to try it as an BOSOZ)
Since I will use it with balanced and unbalanced sources and balanced output I would like to attenuate the signal at the output with a 5K (or 4k7) pot (balanced) and no pot and the input.
Now for the questions:
1. When I leave the input pot (P101/P102) out what will be the input impedance? Am I correct in assuming it will be around 10k?
If so I would like to make it a bit higher (20k-47k).
Can I simply put a resistor (10k-37k) in before R120/121?
2. What will be the highest output impedance with a 5k pot (balanced) When I try to calculate this I get around 1120 ohms single ended and 2240 ohms balanced (for 6dB attenuation). Is this right?
william
Hi,
after searching for a while to find a nice preamp for my Aleph5 and upcoming Aleph-X I think I will try an X-BOSOZ (with the easy option to try it as an BOSOZ)
Since I will use it with balanced and unbalanced sources and balanced output I would like to attenuate the signal at the output with a 5K (or 4k7) pot (balanced) and no pot and the input.
Now for the questions:
1. When I leave the input pot (P101/P102) out what will be the input impedance? Am I correct in assuming it will be around 10k?
If so I would like to make it a bit higher (20k-47k).
Can I simply put a resistor (10k-37k) in before R120/121?
2. What will be the highest output impedance with a 5k pot (balanced) When I try to calculate this I get around 1120 ohms single ended and 2240 ohms balanced (for 6dB attenuation). Is this right?
william
1) Depends on the pot setting, but running X feedback means
lowering the impedance as seen at the Gate of the transistors,
so your input impedance will go down. Of course you can
insert greater value pots, and the lower the level set, the
higher the input impedance.
2) That seems about right.
lowering the impedance as seen at the Gate of the transistors,
so your input impedance will go down. Of course you can
insert greater value pots, and the lower the level set, the
higher the input impedance.
2) That seems about right.
Henrik's x-bosoz
Looking at Henrik's schematic, my instincts tells me that R122 should be connected between R108 and R121 and R123 between R107 and R120 to get the x effect.
Why am I wrong?
Thanks in advance.
Vinay
Looking at Henrik's schematic, my instincts tells me that R122 should be connected between R108 and R121 and R123 between R107 and R120 to get the x effect.
Why am I wrong?
Thanks in advance.
Vinay
Re: Henrik's x-bosoz
Essentially becouse the X circuit needs negative feedback.
If we think at a generic op amp draw we will see that to have negative feedback , the output must communicate to the inverting input (- in). If , for a while you don't care about the balanced nature of the XBOSOZ , you will see also that each halve of the circuit is a phase invertin' amp.
So each half has its negative feedback(R122 and R123) and the sole comunication between the halves is R115 ( short for max gain ) that ultimately forms the X.
That will be POSITIVE feedback .
Essentially becouse the X circuit needs negative feedback.
If we think at a generic op amp draw we will see that to have negative feedback , the output must communicate to the inverting input (- in). If , for a while you don't care about the balanced nature of the XBOSOZ , you will see also that each halve of the circuit is a phase invertin' amp.
So each half has its negative feedback(R122 and R123) and the sole comunication between the halves is R115 ( short for max gain ) that ultimately forms the X.
That will be POSITIVE feedback .
Attachments
Algar_emi, you asked me for more specefic deatail on my x-bosoz - by e-mail, I thought I would answer your question on the forum, so here it is.
The rating of the torodials is as I remember, not far from the scematic.
The powersupply is inspired by Andrea Ciuffolis powersupply on his Powerfollower 99, an idea from Technics called "virtual battery" and has some similarities with ESP´s Cap. multiplyer. It works pretty good, very silent, and remooves most turn on thumb if there is any. Because of this I omitted the original 22 Ohm filtering resistor before the last PS caps.
Regards
The rating of the torodials is as I remember, not far from the scematic.
The powersupply is inspired by Andrea Ciuffolis powersupply on his Powerfollower 99, an idea from Technics called "virtual battery" and has some similarities with ESP´s Cap. multiplyer. It works pretty good, very silent, and remooves most turn on thumb if there is any. Because of this I omitted the original 22 Ohm filtering resistor before the last PS caps.
Regards
PSU-problem
Hi guys.
I'm having a slight problem with my power supply. With 15k load V+ I get +60V but -62V at V-.
At the +80V-point i get +88V
Why? Is that acceptable?
I'm using 2 x 120VA.
Then I tried to connect a second supply in pararell after recifting but something went wrong and I think I blew a transistor or two.
Is it possible to connect two supplies the way I did?
// vit
Hi guys.
I'm having a slight problem with my power supply. With 15k load V+ I get +60V but -62V at V-.
At the +80V-point i get +88V
Why? Is that acceptable?
I'm using 2 x 120VA.
Then I tried to connect a second supply in pararell after recifting but something went wrong and I think I blew a transistor or two.
Is it possible to connect two supplies the way I did?
// vit
more problems, serious problems
Thanks Henrik!
More problems:
Source of Q101/Q102: -2,8V
Gate of Q101: 0V
Gate of Q102: 1,7V
Drain of Q101: 57,8V
Drain of Q102: 2,5V
I've checked all connections a million times. R102 gets very
. I've changed both Q101 and Q102 twice, the problem remains.
cheers // vit
R.I.P Anna Lindh
Thanks Henrik!
More problems:
Source of Q101/Q102: -2,8V
Gate of Q101: 0V
Gate of Q102: 1,7V
Drain of Q101: 57,8V
Drain of Q102: 2,5V
I've checked all connections a million times. R102 gets very
. I've changed both Q101 and Q102 twice, the problem remains. cheers // vit
R.I.P Anna Lindh
Hi Vit
If you still have the problems you mentioned in your last post, I can help you to morrow. let me know.
Regards Henrik.
If you still have the problems you mentioned in your last post, I can help you to morrow. let me know.
Regards Henrik.
Hi Henrik!
Problem solved! It was a bad cap that caused the problem.
When I was done friday night with soldering connectors. I wanted to check a last time that everything really was OK. Previusaly all measurements was perfect.
But when I fired it up the +60V-wire snapped from the socket and short circuited something. I reattached the wire and fired it up once again. After 3 seconds one of the transitors on the power supply board went up in smoke. With sparkels and a bang.
I've spent the whole weekend to replace fried components.
The PSU is now working.
One amp board is working. But it take about two minutes before I get the stablised 31V reading on the drains of Q101/Q102.
The other amp board acting really wierd. I get a negaive reading on the drains. It starting at -30V and falling slowly to -55V.
And I thing I get the same negaitve reading att the source pins as above.
What's wrong?
Problem solved! It was a bad cap that caused the problem.
When I was done friday night with soldering connectors. I wanted to check a last time that everything really was OK. Previusaly all measurements was perfect.
But when I fired it up the +60V-wire snapped from the socket and short circuited something. I reattached the wire and fired it up once again. After 3 seconds one of the transitors on the power supply board went up in smoke. With sparkels and a bang.
I've spent the whole weekend to replace fried components.
The PSU is now working.
One amp board is working. But it take about two minutes before I get the stablised 31V reading on the drains of Q101/Q102.
The other amp board acting really wierd. I get a negaive reading on the drains. It starting at -30V and falling slowly to -55V.
And I thing I get the same negaitve reading att the source pins as above.
What's wrong?
finished!!!
I've found the error. It was a fried resistor!
What a sound!!! Sweet and soft with trillions of details! I could never thoght that a preamp could do this!!!
Thanks a lot Henrik, your the man!
And Nelson of course.
Next up is to x-convert my SOZ
I've found the error. It was a fried resistor!
What a sound!!! Sweet and soft with trillions of details! I could never thoght that a preamp could do this!!!
Thanks a lot Henrik, your the man!
And Nelson of course.
Next up is to x-convert my SOZ
2-stage X-BOSOZ ?
Hi there, X-Gurus
I already have a nice BOSOZ that drives my AlephX, and I was just wondering if I could go a little bit further...
So I'm wanting to "X" my Bosoz, and Henrik's work looks promising to me, but I have a question : my bosoz is a 2-stage one, namely two "native" bosoz cascaded. The first stage provides gain, and the other acts as a buffer (gain #1). The reason is that I wanted to keep the input and ouput impedances cosntant, wathever the volume setting...
So I was wondering how to "X" such a beast. Do I "X" each stage separately (local), or do I include all the mosfets in the "X feedback"? Which is one would sound the best ?
Here is the second solution, at least the way I plan it. Does it seem OK to you ?
(Yes, I know, a lot of stuff's missing, but you get the idea 😉 )
Hi there, X-Gurus
I already have a nice BOSOZ that drives my AlephX, and I was just wondering if I could go a little bit further...
So I'm wanting to "X" my Bosoz, and Henrik's work looks promising to me, but I have a question : my bosoz is a 2-stage one, namely two "native" bosoz cascaded. The first stage provides gain, and the other acts as a buffer (gain #1). The reason is that I wanted to keep the input and ouput impedances cosntant, wathever the volume setting...
So I was wondering how to "X" such a beast. Do I "X" each stage separately (local), or do I include all the mosfets in the "X feedback"? Which is one would sound the best ?
Here is the second solution, at least the way I plan it. Does it seem OK to you ?
(Yes, I know, a lot of stuff's missing, but you get the idea 😉 )
Attachments
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