I'll be using the F5 with a source that produces only 2 volts. Do I need to put R220 resistors in positions R5-R8 for more gain?
Most relevant: How efficient are your loudspeakers? And what impedance?
You may need to consider using a preamp that can provide sufficient additional gain. With my F5 I found that I couldn't get the volume that I needed with 87 dB spreakers using a typical preamp (gain ~ 10). I ended up building another higher gain preamp (Aikido) and couldn't be happier with the combo.
PJN
PJN
that should say:The Max output is specified as + & - 20V in my F5 manual. Gain of 15.3db............
The max output is specified as + & - 20Vpk.
This is equivalent to a sinewave of 14.28Vac.
Gain of 6times is equal to +15.56dB
From [{100//100}/10] + 1 = 50/10 +1 = 6
Gain of 5.5 times is +14.81dB
The overall gain through the INPUT Filter and the amplifier will be a bit lower than the amp's basic gain.
The attenuation of the RF Input Filter will depend on the Rin (series) used in the RF filter.
That would account for lower reported overall gain values and would also account for different reported values.
The basic gain of the amp is 6times.
A 1k series resistor feeding into 100k for Rin, reduces the overall gain to 15.48dB, cf. basic gain = 15.56dB
The attenuation of the RF Input Filter will depend on the Rin (series) used in the RF filter.
That would account for lower reported overall gain values and would also account for different reported values.
The basic gain of the amp is 6times.
A 1k series resistor feeding into 100k for Rin, reduces the overall gain to 15.48dB, cf. basic gain = 15.56dB
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My f5 w/91db 8ohm speakers, Cd player and passive pre had enough volume w/200ohm feedback resistors. Not enough volume for use w/my vinyl setup though.
Switched to a Jfet BOZ and 100 ohm feedback resistors. It was the right choice I think.
Even though the F5/200ohm resistor/passive setup had enough gain and volume it seemed to lack punch and dynamics. All was cured when I went to the 100ohm feedback resistors and a preamp. You gain weight and dynamics and lose a little mid-range purity and detail. But it's worth it.
Switched to a Jfet BOZ and 100 ohm feedback resistors. It was the right choice I think.
Even though the F5/200ohm resistor/passive setup had enough gain and volume it seemed to lack punch and dynamics. All was cured when I went to the 100ohm feedback resistors and a preamp. You gain weight and dynamics and lose a little mid-range purity and detail. But it's worth it.
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