I am rethinking the amount of Voltage I shall supply the Mooly amp, Mooly has written 45V-0V-45V as a possible voltage to his great amplifier but I am thinking if it would be of some advantage to supply even more.
I am not doing that to play louder but to have even more power so I can use that amplifier to test and drive future speakers.
The gain is 47 times or 33.4dB, And max input from a CD-player should be 2V
You could say that it's 47 gain X 2V, or 94V, but that sounds insane much to me.
How do I dicide on max voltage and ampere?
I am not doing that to play louder but to have even more power so I can use that amplifier to test and drive future speakers.
The gain is 47 times or 33.4dB, And max input from a CD-player should be 2V
You could say that it's 47 gain X 2V, or 94V, but that sounds insane much to me.
How do I dicide on max voltage and ampere?
I'm sure the capacity of the output transistors and everything else in the circuit was taken into account in determining a maximum rail voltage and output power. How much power do you intend to have? It will almost certainly require other modifications than simply increasing the rails.
I do not have a target, unless you say, as much as possible without changing one bit of Mooly's design.
Here are my noob thought. If we do say 45V in and ignore voltage drop and any other change of voltage at all, you could say that if the signal source is delivering 1V and you have 47 x gain, you can almost play at max volume before clipping, but if the signal source is 2V from a CD-player and 47 x in gain, you end up with 94V out or clipping at about 50% volume. I know it have to be wrong some how?
I have read and heard of speakers that needed an above 50W amplifier to be driven correctly, to make the speakers sound best.
I know that the Voltage difference between 50W and 100W is nearly nothing-ish🙂
Here are my noob thought. If we do say 45V in and ignore voltage drop and any other change of voltage at all, you could say that if the signal source is delivering 1V and you have 47 x gain, you can almost play at max volume before clipping, but if the signal source is 2V from a CD-player and 47 x in gain, you end up with 94V out or clipping at about 50% volume. I know it have to be wrong some how?
I have read and heard of speakers that needed an above 50W amplifier to be driven correctly, to make the speakers sound best.
I know that the Voltage difference between 50W and 100W is nearly nothing-ish🙂
My advice? Build a kit as intended and power as intended.
If you're not happy with the results, then modify to taste.
If you're not happy with the results, then modify to taste.
Are you having fun 🙂
Whether the amp had a gain of 1 or 1000, or 10,000 it wouldn't make any difference to the power output which is limited by the rails.
The deliberately high gain chosen was simply because it sounds very good run that way. It is a relatively low feedback design.
The volume control in front of the amp takes care of everything else 🙂
LOL yes I have a ton of fun with the project🙂
Hmm I did read up on gain and stumbled upon an "expert" who wrote that gain was the multiplication of input, so 2 x gain would give 2 x input voltage. That it was important to have enough Voltage to have Voltage enough. I.e. a gain of 23 from a CD-player with an output of 1.86 Volts, would demand at least 42,78 Volt + 10V in head room.
To me did it sound sort of logical but also strange because of the giant Voltages you can calculate.
About the volume control being before the power amplifier, I just got a thought. If you chose to attenuate 1V-2V, do you not work with a tiny signal, that gets some noise added and then amplified?
What if one took the amplified output and attenuated that? The noise from the pre-amplifier would not be amplified but only added into the resulting output. 🙂
Mooly, why did you select 45V?
Hmm I did read up on gain and stumbled upon an "expert" who wrote that gain was the multiplication of input, so 2 x gain would give 2 x input voltage. That it was important to have enough Voltage to have Voltage enough. I.e. a gain of 23 from a CD-player with an output of 1.86 Volts, would demand at least 42,78 Volt + 10V in head room.
To me did it sound sort of logical but also strange because of the giant Voltages you can calculate.
About the volume control being before the power amplifier, I just got a thought. If you chose to attenuate 1V-2V, do you not work with a tiny signal, that gets some noise added and then amplified?
What if one took the amplified output and attenuated that? The noise from the pre-amplifier would not be amplified but only added into the resulting output. 🙂
Mooly, why did you select 45V?
Well the gain of the preamp I built to accompany this amp has a voltage gain of just 1.5 (two inverting stages each with a gain of 1.22).
You always need enough gain to cope with recording that are low in level while ensuring the overall gain is not so high that the volume control is 'one ended'.
Remember that 2vrms from a CD player is the maximum theoretical level possible (most players quote 2vrms for that) and that all recorded music is way below that level.
While it is considered bad form to attenuate a signal only to need to amplify it again, we also have to have a gain control somewhere.
The noise from the preamp is very low and in the scheme of things the levels we are dealing with are high (line level) and so there is no practical issue at all. The volume control can only attenuate the preamp noise as it is turned down.
You always need enough gain to cope with recording that are low in level while ensuring the overall gain is not so high that the volume control is 'one ended'.
Remember that 2vrms from a CD player is the maximum theoretical level possible (most players quote 2vrms for that) and that all recorded music is way below that level.
While it is considered bad form to attenuate a signal only to need to amplify it again, we also have to have a gain control somewhere.
The noise from the preamp is very low and in the scheme of things the levels we are dealing with are high (line level) and so there is no practical issue at all. The volume control can only attenuate the preamp noise as it is turned down.