Hi Folks,
Thanks for your replies!
40, 60, 80 +10 ....
It lalmost ooks like an Ebay auction!
Apparently my question was not as trivial as I thought.
Anyway, a choke capable of 500mA will surely do.
Analog_sa wrote:
>Conventinal thinking would suggest that a choke following the regulator will substantially negate regulation.
>You can certainly try an unregulated, choke filtered supply
What doe you mean with "negate regulation"?
It does negate the negative sides of regulation (HF polution...)?
However, it should also diminish ripple, shouldn't it?
With a constant current (class A) the voltage should remain stable, or am I wrong?
I tried a choke at the PSU of my Pass Pearls (after the first regulation) and it did sound better.
Any advice is welcome!
Lucas
Thanks for your replies!
40, 60, 80 +10 ....
It lalmost ooks like an Ebay auction!
Apparently my question was not as trivial as I thought.
Anyway, a choke capable of 500mA will surely do.
Analog_sa wrote:
>Conventinal thinking would suggest that a choke following the regulator will substantially negate regulation.
>You can certainly try an unregulated, choke filtered supply
What doe you mean with "negate regulation"?
It does negate the negative sides of regulation (HF polution...)?
However, it should also diminish ripple, shouldn't it?
With a constant current (class A) the voltage should remain stable, or am I wrong?
I tried a choke at the PSU of my Pass Pearls (after the first regulation) and it did sound better.
Any advice is welcome!
Lucas
current flowing on each side of the aleph P is about 25mA so times two makes 50mA each channel. (spice tells me about 30mA per side)
Just one curiosity...
since it's possible to optimize the AC gain by varying the value of the resistor and then act at the output to attenuate the volume (passive output volume control) ....in order to maximize the SNR i understand that it might be better to rise the AC gain and lowe the output signal as much through the output volume control....but.....from the measurements i have made.....by increasing the AC gain it seems that the rising and falling time are increased.
Increasing the AC gain might really impair the bandwidth or other parameters of the preamplifier?
I found a very good noise response by using a 390ohm resistor as gain and an output resistor of 490ohm which gives me the maximum volume for most of the reproduction cases (i have a gain of 0.75) with a noise level of 60-70uV which is very good.
any suggestion, warn, advice?
Just one curiosity...
since it's possible to optimize the AC gain by varying the value of the resistor and then act at the output to attenuate the volume (passive output volume control) ....in order to maximize the SNR i understand that it might be better to rise the AC gain and lowe the output signal as much through the output volume control....but.....from the measurements i have made.....by increasing the AC gain it seems that the rising and falling time are increased.
Increasing the AC gain might really impair the bandwidth or other parameters of the preamplifier?
I found a very good noise response by using a 390ohm resistor as gain and an output resistor of 490ohm which gives me the maximum volume for most of the reproduction cases (i have a gain of 0.75) with a noise level of 60-70uV which is very good.
any suggestion, warn, advice?
Lucas_G said:
Indeed. It's quite simple and you certainly don't need spice. Upper CCS supplies about 29mA. 19mA is the drain current through the mosfet (lower CCS) and the rest goes through R25/R26 to gnd. So, it's 29mA per side or 58mA per channel.
A choke after the regulator will increase output impedance at low frequencies and thus reduce regulation.
It may very well sound better but do you really need a regulator if you are going to use a choke anyway? My guess is that a well tweaked CLC supply may sound better without the regulator.
Stefanoo said:
I was asking anyways for a technical advice that had to do with the gain regulation vs. bandwidth or other parameter
Not sure exactly what it is you're asking. Varying the degeneration will have some effect upon gain, bandwidth and distortion. No idea how audible this is or whether it's worth pursuing.
That's why i suggested something more radical - less parts and better sound
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