Hi DSatz,
sounds like you bought a Mixpre D. I use rechargeables, in this case "Kodak" brand precharged ones for camera use. My reasoning is as follows:
- generating phantom power and power for the preamp means that the 2.4V to 3V of the pair of AAs must be stepped up.
- maximum phantom power requirement (two mics) is abt 1.5W (DC/DC losses included)
- I would estimate preamp power with another 1.5W (including LED meter and headphone)
This gives 1.25A, rather high for alkalines. NiMHs have typically a lower voltage, but also a lower internal resistance.
Energizer lists an internal resistance for its Ultimate Lithium of 90 to 160mOhm. For 1.25A, this gives a worst case loss of half a watt in the batteries alone!
For comparison: the Energizer NiMH 2300mAh cell is listed with an internal resistance of 30 to 40mOhm (3 to 4 times less than the Lithium...)
http://data.energizer.com/PDFs/nh15-2300.pdfThe Energizer alkalines are listed with 150 to 300mOhm per cell when fresh. The discharge curves end at 1A. I suspect Battery life is abysmal with 48V phantom power...
So my conclusion is: use NiMHs with as low an internal resistance as possible, especially with phantom power on. For the price of a pair of Lithium AAs you should be able to buy a set of quality rechargeables.
My 2 ct.
Greetings,
Rainer
who at the moment is listening to Bachs Toccata in F BWV540 played on the Silbermann organ in Dresden cathedral with a Mixpre D as audio interface and Sennheiser headphones