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In Reply to: RE: Very accurate MC phono preamp on proto-board posted by mwhouston on May 21, 2015 at 04:54:30
Include a low voltage led, the sound will deteriorate as the supply voltage drops...
Regards..
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The chip on board, the OPA 2134, can work down to +\- 2.5V. The LED draws 200uA. It has a 100K limiting resistor. I generally change batteries when supply is down to 21V. A 9V battery is considered flat at 7V.
I have built a number of headphone amps with same chip which runs successfully on one 9V battery.
| retro-thermionic |
I have found the high voltage has better sonics, i guess from more swing and headroom, i could always tell when batt voltage fell even by 2 volts, you are running 27 volt which is good most only run 18 , at 18volt it's pretty obvious.
Edits: 05/21/15
The 27V is split so the chip sees about +\- 13V. It only has to deliver a swing of 2V so well within limits. The chip could swing with this voltage about 20V but not needed. I think there is a ton of head room.
| retro-thermionic |
you should see what pops do, recovery is a bitch, try it with a lower supply and see..
Edits: 05/21/15
I get your drift.
| retro-thermionic |
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