I dont know
But last time I looked it seemed ground is almost single point ground
It seemed to me like added coupling caps would mess it up
Not sure, but I dont think Nelson have left out coupling caps because he dont like them
Maybe they will just disturb the curcuit
Well, Im just guessing
But last time I looked it seemed ground is almost single point ground
It seemed to me like added coupling caps would mess it up
Not sure, but I dont think Nelson have left out coupling caps because he dont like them
Maybe they will just disturb the curcuit
Well, Im just guessing
You want to see the dark side of the moon 
When I go back home I make a picture to publicate
thank you
When I go back home I make a picture to publicate
thank you
Hi Tintus, i don't speak very good english, so I don't know if filtering and decoupling means the same. If so, papa already answeared, if not I don't know if filtering can disturb the F5.
Anyway, I can try to take them off.
Anyway, I can try to take them off.
i would make it the simplest possible. No decoupling, no current limiters. And see.
Decoupling caps may be a problem if they return to the input ground (depending on the lay out). Decoupling caps like to return separately to a star ground.
Decoupling caps may be a problem if they return to the input ground (depending on the lay out). Decoupling caps like to return separately to a star ground.
Anyway Bobo, this could bring loop ground problems, not to the problem that I have. Hope..
The only difference in the actual schematic, is that I am using IPFP140 IRFP9140N, but I have already used this couple in the other project, and they seems to work enough well togeather, clipping both at 36V
The only difference in the actual schematic, is that I am using IPFP140 IRFP9140N, but I have already used this couple in the other project, and they seems to work enough well togeather, clipping both at 36V
pro said:
Depending on a number of factors, decoupling caps can make the
design oscillate, and that is why you don't see them in the design.
Try taking them off and see what you get.
😎
Thank you Mr. Pass.
First thing I,ll try to do when I go back home.
So, filtering and decoupling is the same thing. What I believe, was that in decoupling caps, the signal passing through it, while in filtering, not.
First thing I,ll try to do when I go back home.
So, filtering and decoupling is the same thing. What I believe, was that in decoupling caps, the signal passing through it, while in filtering, not.
Ehh, I will try
Your "filter" el-caps are auxilary supply caps
The film caps are supposed to improve high frequency, smoothing any remaining high frequency ripple
Accurate size should be determined by a scope
Using a wrong size may screw up things even worse than with no cap added
I never liked them, others think they have to be there
Filter/coupling caps on sensible curcuits to cure high frequency stability problems is a different matter
Mostly in the "pf" range
Doesnt matter
The point is that you are creating ground connection thats not supposed to be there from start
Your "filter" el-caps are auxilary supply caps
The film caps are supposed to improve high frequency, smoothing any remaining high frequency ripple
Accurate size should be determined by a scope
Using a wrong size may screw up things even worse than with no cap added
I never liked them, others think they have to be there
Filter/coupling caps on sensible curcuits to cure high frequency stability problems is a different matter
Mostly in the "pf" range
Doesnt matter
The point is that you are creating ground connection thats not supposed to be there from start
Unbelievable
I would not have ever believed.
Without caps
About 19V clips the positive, the negative something more.
Is it normal 200-300 mV of offset at this voltage?
I would not have ever believed.
Without caps
An externally hosted image should be here but it was not working when we last tested it.
About 19V clips the positive, the negative something more.
Is it normal 200-300 mV of offset at this voltage?
you can't measure effective DC offset at full blast ;
if clipping is approx. symmetric , bring your speakers and enjoy .
if clipping is approx. symmetric , bring your speakers and enjoy .
MONO 😀
but sounds
no hum, very clear. I have measured about 1hom of output impedence. Bias is 350mA, enough for the FIRST WATT in class A.
maybe I'll leave it with this bias, so I can listen in summertime also, withot sweating. I have already the Zen V4 for this 😎
An externally hosted image should be here but it was not working when we last tested it.
but sounds
no hum, very clear. I have measured about 1hom of output impedence. Bias is 350mA, enough for the FIRST WATT in class A.
maybe I'll leave it with this bias, so I can listen in summertime also, withot sweating. I have already the Zen V4 for this 😎
Re: Unbelievable
Perhaps your limiters are kicking in. Are you using 22K for R21 and R22?
😎
pro said:
Perhaps your limiters are kicking in. Are you using 22K for R21 and R22?
😎
How did you measure that?
From PDF:
"...
Measured Performance
The gain of the circuit is 15.15 dB. The input impedance is 101 Kohm, and the output impedance is 0.1 ohms, for a damping factor of 80."
..."
R21-R22 10K.
Maybe the mains was a little bit low because was 23.3 VDC or the couple not matched of IRFP 140N/9140.
Bobo I measured 21.2 V without load, and then 19V with 8 hom load. So 19V/8hom=2.375A. 2.375A/2.1V(the difference beetwen Unloaded and loaded) =1.13 hom. DF=8/1.13=7.
Or not
Mr Pass, this morning I have read the review of your XP-15 phono stage. One of the best in the world at that price.
Ccongratulations.
Maybe the mains was a little bit low because was 23.3 VDC or the couple not matched of IRFP 140N/9140.
Bobo I measured 21.2 V without load, and then 19V with 8 hom load. So 19V/8hom=2.375A. 2.375A/2.1V(the difference beetwen Unloaded and loaded) =1.13 hom. DF=8/1.13=7.
Or not
Mr Pass, this morning I have read the review of your XP-15 phono stage. One of the best in the world at that price.
Ccongratulations.
Do you mean Peak to Peak output voltages ?
The voltage difference is mostly due to output devices residual voltage and emittor resistors drop out.
So, you dit not evaluate the dynamic output Z ( Z speaker / Damping factor) which takes NFB in account.
Though i cannot tell how to measure it...
reduce your signal so that the output voltage is well below clipping.
Now measure the effect of connecting and disconnecting the load.
If it is as bad as 2V then you have built something wrong.
A ClassA amplifier should hardly drop at all, due to the continuous loading on the PSU.
Now measure the effect of connecting and disconnecting the load.
If it is as bad as 2V then you have built something wrong.
A ClassA amplifier should hardly drop at all, due to the continuous loading on the PSU.
Bobo, the measure is made on a resistor.
This is the dark side of the moon. 😀
Andrew, actually the bias is only 350mV so no class A at clipping, but I will do some measure at lower level, as you say, and i'll report results.
This is the dark side of the moon. 😀
An externally hosted image should be here but it was not working when we last tested it.
Andrew, actually the bias is only 350mV so no class A at clipping, but I will do some measure at lower level, as you say, and i'll report results.