Nelson Pass said:Works fine - just put some (preferably big) caps to ground after it.
Nelson, do you mean Big caps after the capacitance multiplier?Aren't they supposed to be before the cap multiplier? As I understood, usually there were some small capacitors (220uF elko bypassed by a 1uF film) after the capacitance multiplier (zen v3 and v4 for example). Why big caps now? Are they necessary in case of higher bias currents?
Regards,
Vix
We are DIY...there is no such thing as too much.
Or, to put it another way:
If some is good, then more is better, and too much is just enough!
I'm in the beginning stages of planning (yet another) tweeter amp. I'm flipping coins at this point, but the most likely configuration at this time is RCLC, followed by an optional capacitance multiplier or regulator, followed by--you guessed it--more C.
Grey
Or, to put it another way:
If some is good, then more is better, and too much is just enough!
I'm in the beginning stages of planning (yet another) tweeter amp. I'm flipping coins at this point, but the most likely configuration at this time is RCLC, followed by an optional capacitance multiplier or regulator, followed by--you guessed it--more C.
Grey
Bipolars work just fine. Go for it.
For that matter, you can use anything you happen to have in your junkbox--MOSFETs, even JFETs work just peachy (as long as your current requirements are modest). If you need more current and and can get by with just an N-ch device, then there are power JFETs.
Note that the "speed" of the device isn't really relevant, since all you're amplifying is DC and most anything can handle that.
Grey
For that matter, you can use anything you happen to have in your junkbox--MOSFETs, even JFETs work just peachy (as long as your current requirements are modest). If you need more current and and can get by with just an N-ch device, then there are power JFETs.
Note that the "speed" of the device isn't really relevant, since all you're amplifying is DC and most anything can handle that.
Grey
Incidentally, for those who have commitment issues...(a lot of guys around here, right?)...or want to experiment:
Note that it's easy to lock the voltage in a capacitance multiplier. A basic capacitance multiplier uses a voltage divider to "set" the output. So use a switch. Put a Zener in the position between the control element (Gate or base) and ground instead of the resistor. Instant simple regulator.
Turn the amp off. Flip the switch to lock the voltage. Turn the amp back on.
Two caveats, neither all that difficult to deal with. First, the resistor between the rail and the control element needs to be chosen to bias the Zener decently--generally a few mA will do the trick. Second, the pass device will need a heatsink if you're going to be dropping much in the way of voltage. In extreme cases, you might want to consider paralling pass devices to help dissipate the heat.
This will give you an easy way to compare capacitance multipliers and simple regulators sonically, for very little money.
Why?
Why not?
Grey
Note that it's easy to lock the voltage in a capacitance multiplier. A basic capacitance multiplier uses a voltage divider to "set" the output. So use a switch. Put a Zener in the position between the control element (Gate or base) and ground instead of the resistor. Instant simple regulator.
Turn the amp off. Flip the switch to lock the voltage. Turn the amp back on.
Two caveats, neither all that difficult to deal with. First, the resistor between the rail and the control element needs to be chosen to bias the Zener decently--generally a few mA will do the trick. Second, the pass device will need a heatsink if you're going to be dropping much in the way of voltage. In extreme cases, you might want to consider paralling pass devices to help dissipate the heat.
This will give you an easy way to compare capacitance multipliers and simple regulators sonically, for very little money.
Why?
Why not?
Grey
Babowana: I presume that was the way Grey was thinking with just having a swith to put in the zeners in parallell to the cap.
Rod have an idea to the multiplier too. A second order filter:
http://sound.westhost.com/project15.htm
Rod have an idea to the multiplier too. A second order filter:
http://sound.westhost.com/project15.htm
Lovan said:
You are right. It sounds so.
By the way, when you put the big cap after the multiplier or
the regulator, I highly recommend to bypass the big cap with
nice 4.7 to 10uF film. I get better high frequency sound from my Zen5
with the bypass film cap (probably, my big elec cap had bad ESR
value?)
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