Hi
Without buffer the sound was constrict, and i had sensation to loosing control and energy in the bass frequency
With buffer no more these sensations
Now the input inpedance of DCB1 it's 28k and Res I/V is 2K
Hope my poor english was clear
Marco
Inviato dal mio GT-S5300 con Tapatalk 2
Without buffer the sound was constrict, and i had sensation to loosing control and energy in the bass frequency
With buffer no more these sensations
Now the input inpedance of DCB1 it's 28k and Res I/V is 2K
Hope my poor english was clear
Marco
Inviato dal mio GT-S5300 con Tapatalk 2
Bias point drift?
I have been some kind of "bias drifting"
With a senoidal signal of 1kHz, output is clean an undistorted in the first minute.
After 1st minute, negative half-wave becomes clipped.
If signal is square, 1kHz, no clipping.
If signal is senoidal, 40 kHz, no clipping.
If turn-off some time, 1kHz senoidal is unclipped again 1st minute.
I have fed the circuit with batteries and a regulated psu too. Results are the same independently of what PSU you use.
I believe that the capacitors are responsible for some kind of drift when they get charged, but not sure.
I have been some kind of "bias drifting"
With a senoidal signal of 1kHz, output is clean an undistorted in the first minute.
After 1st minute, negative half-wave becomes clipped.
If signal is square, 1kHz, no clipping.
If signal is senoidal, 40 kHz, no clipping.
If turn-off some time, 1kHz senoidal is unclipped again 1st minute.
I have fed the circuit with batteries and a regulated psu too. Results are the same independently of what PSU you use.
I believe that the capacitors are responsible for some kind of drift when they get charged, but not sure.
I have been some kind of "bias drifting"
With a senoidal signal of 1kHz, output is clean an undistorted in the first minute.
After 1st minute, negative half-wave becomes clipped.
If signal is square, 1kHz, no clipping.
If signal is senoidal, 40 kHz, no clipping.
If turn-off some time, 1kHz senoidal is unclipped again 1st minute.
I have fed the circuit with batteries and a regulated psu too. Results are the same independently of what PSU you use.
I believe that the capacitors are responsible for some kind of drift when they get charged, but not sure.
Your absolutely right, i had the same problem with some other russian film caps. But then i switch to Nichicon Muse caps and had almost no detectable DC leakage. - Nothing i could detect with my basic equipment anyway.
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Your absolutely right, i had the same problem with some other russian film caps. But then i switch to Nichicon Muse caps and had almost no detectable DC leakage. - Nothing i could detect with my basic equipment anyway.
mmmm... interesting.
Ouch! I have read BOM and saw *bipolar* caps.
Mine are polarized caps
mmmm... interesting.
Ouch! I have read BOM and saw *bipolar* caps.
Mine are polarized caps
you can use polarized caps
Your "drift" is very likely due to leakage in your capacitors.
Patrick
I have tested today two new type of caps:
Polarized Elna Silmic
Bipolar Nitai electrolityc
Polarized cap ended with a great clipping.
Bipolar Nitai don't
I will try Nichicon Muse next days.
I have measured harmonic distortion with the Nitai's and found 2nd harmonic below 30 dB of fundamental with only 0,2Vrms of signal (18V psu)
Probably i will get some litycs of low leakage for testing
>
So to be on the save side, I would not use anything less than 220uF for signal current up to 2.8mA rms (or +/-4mA).
If you want to use higher signal current, you should increase the cap value proportionately.
Thank you reply.
Is it necessary to use 100 ohm gate resistors AD1865 case?
Hi All
after long trial i finished my output stage of my Copland
It have CEN for I/V and Gherard Buffer for LPF
For Cen i choose Wima MKS 10uF for decoupling Cap and Texas Tx2352 for resistor I/V
The sound it's wonderful, grainfree and very clear, never heard CD's sound so well
So, Patrick, THANK YOU!!
after long trial i finished my output stage of my Copland
It have CEN for I/V and Gherard Buffer for LPF
For Cen i choose Wima MKS 10uF for decoupling Cap and Texas Tx2352 for resistor I/V
The sound it's wonderful, grainfree and very clear, never heard CD's sound so well
So, Patrick, THANK YOU!!
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