HAL PREAMPLIFIERS

[OnAudio]

Hi all,

A preamplifier can provide the extra control that you need over that high powered amplifier and speaker system. Attached is a circuit idea. Feel free to chip in.

kind regards,

Harrison.

[Ian Finch]

Assuming your graph represents full boost action only of the bass and treble controls, there seems to be only minimal boost available in the audible region and a waste or even troublesome amounts of it in the sub and supersonic regions.

It's now usual to shelve the tone control responses to provide more useful boost/cut in the audible region and prevent speaker or even amplifier damage.

[Nico Ras]

Since you have a tone control, why not expand it to bass/mid/treble and for good measure throw in a loudness control and balance control. Some may also like a stereo width control. Lets go back to the era of the fanatic knob twiddler.

[MagicBox]

Originally Posted by Nico Ras

Since you have a tone control, why not expand it to bass/mid/treble and for good measure throw in a loudness control and balance control. Some may also like a stereo width control. Lets go back to the era of the fanatic knob twiddler.

And what about classifying tubes as ASPs from now on.. Analogous Sound Processors. In the eyes of a guitarist this would probably hold easily

[OnAudio]

Thank you all

Balance control is in order
Loudness...not critical the tones will do
Stereo width ....well...

The shape of the curves is an attempt to minimize mid band interaction. Also here we are trying to adjust the fringes of the bass and high frequency drivers, the tone has sub woofer capability . Shelving filters would be away to go to handle this. Found an interesting article here http://www.rane.com/pdf/acceler.pdf

With the shape of the tone controls bass boost, it maybe advisable for your phono preamp to feature a steep rumble filter. The high frequency response could also be shaped with a low pass filter.

In order to avoid fanatic knob twiddling we could go the way of a DSP based preamp with on board computer featuring a mic, auto detect for (sealed box, open baffle, hybrid, ported etc) and auto calibration. On adjusting the volume it automatically compensates the frequency curves and factors in the time of day, ambient noise, mood and music type etc.

The purist will shun op-amp based preamp solutions. Discrete circuitry is the in thing.

If we initially wanted to keep it simple and functional wouldn't this do ? Or what must go or what must be added ?

[OnAudio]

Hi all,

I am thinking, lets knock out the last op-amp. Let the third op-amp that handles sensitivity also handle volume . We could change the function of the fourth op-amp to a rumble filter

kind regards,

Harrison.

[OnAudio]

A quick one

Are low pass, high pass, band pass filters HIFI ? Also depends on definition of HIFI ..

lets pile up

[OnAudio]

Conceptual flow and functionality

[OnAudio]

The preamplifier with all its functionality was swallowed up into one chip . Without this level of intelligence, would we be able to have the bag of tricks at the cinema, arena and even at home ?

[OnAudio]

Although the curves are rather gentle...