Here is the test:
My system is silent. This is my integrated amplifier with regulated supplies for all but the output stage, and transformers located far from the input.
I am curious how many systems can pass the test.
Ed
- Set the input selector to an unused input (open-circuit)
- Turn the volume control to maximum
- Place your ear next to the speaker (if needed!)
My system is silent. This is my integrated amplifier with regulated supplies for all but the output stage, and transformers located far from the input.
I am curious how many systems can pass the test.
Ed
Open input is not really a fair test.
It depends on RF and mains interference in the environment, out of control of the amp.
A fairer test would be with shorted input.
Jan
It depends on RF and mains interference in the environment, out of control of the amp.
A fairer test would be with shorted input.
Jan
Test depends heavily on the max gain of the system (including speakers). For example, a system with speakers 85dBSPL/w is going to be quieter than a horn system that is 95dB/W with the same amp/pre. A pre/amp that has a max combined gain of 40dB on the line input is going to be quieter than one with 60. I have several amps and they range from 25.5dB of gain on the low end and 30 on the high. Not sure of the range of gain on pre's. I have only one.
Yes, speaker efficiency matters. My speakers are inefficient (83dB/1V).
All amplifiers should have a gain of 30-35dB.
Ed
All amplifiers should have a gain of 30-35dB.
Ed
It also depends on luck. Move to your neighbour and you've got noise. Or vice versa.
"My amp is slilent because I lucked out".
You're happy with that?
Jan
Jan - An open-circuit input of ~50K should not pick up much noise from the environment. The noise should come primarily from the amplifier's first stage.
Ed
Ed
I tried a silent test by cranking up the volume after a CD had finished, and stuck my ear right by a speaker, it was only when I turned the volume back down, that I discovered that the CD had a hidden track. It came as a supprise with the volume down low....
It will mainly be the equivalent input noise current of the input stage and the thermal noise of that 50 kohm. Both quite irrelevant in normal use.
Mine is very close but not totally, maybe within 6 inches a slight hum/buzz. Specs say the speakers are low 90s for sensitivity, but the noise is there with nothing but the power supply and transformer plugged in.
My speakers are ~94dB and my amp is a buffer, but i use pre. Still no hiss.
We are not compatible unless you are using apogee scintilla.
My amp is also completely silent. No buzz and no hiss. Aleph J in a balanced configuration. This is with interconnects unplugged. Speakers are 86dB/W. No difference between amp on and amp off.
I have two actively tri-amplified systems both comprising ESP power amps (P3a, P101 and P68 which haven't missed a beat in over a decade) and they are silent with ear to any driver while the active crossovers (also ESP) are turned off with their outputs shorted to ground/muted, or with the power amp inputs floating. That is the power amps are silent. With the preamps un-muted and connected with Focusrite USB audio interfaces and PCs up front there is inevitable and very quiet thermal hiss but no hum. It's audible only with an ear within an inch of the tweeter or midrange. There isn't any fancy regulation or other audiophile carry-on and certainly no fool-marketed capacitors or crazy opamps. All power amps have safety ground loop breakers installed. Long cable runs and no balanced connections anywhere. Drivers are Eton Hex, Scanspeak Revelator/Illuminator, Dynaudio Esotar etc. of the usual range of efficiencies.
I want to include both the pre-amplifier and power amplifier, but not source components. The unused input should be line-level.
Ed
Ed
Then you must be enjoying this thread.
https://www.diyaudio.com/community/threads/magnepan-convert-to-active-crossovers.392837/post-7191755
https://www.diyaudio.com/community/threads/magnepan-convert-to-active-crossovers.392837/post-7191755