I emailed Jerry with a couple of questions because I am seriously considering ordering a Aerco. Here are his responses. I asked him if it was ok to post since others may have the same questions and he said post away. Peace OOK
> 1. I have been told you prefer to use step gain for each channel is it
possible to get variable gain pots instead? I am looking for a db range of
Continuously variable pots are available and I now believe a better choice. My
original idea was that the switches would have a very long lifetime but of
course they make it impossible (or at least maximally disruptive) to change gain
during a recording. The pots are available in either smooth rotation or 11
detent steps. We've been using them for years and have yet to have one go noisy-
and they're easy to replace if they do fail.
> 2. Can you order a MP-2 with continual variable gain for both channels on
one pot and balance control on the other pot? I have a SoundDevice 702 with
this feature and love it. Is there any drawback to this type of set up in terms
of your pre? I would still be looking for the same gain range 0-50db.
This also is doable. The only slight drawback is that the dual gain pot is not
available in the detented version, only the smooth rotation. The balance control
however can have a center detent if you wish.
> 3. I have been told you use Jensen transformers currently. Is that the
only option? I know there are Cinemags and Lundahl. Does this really matter or
do different transformers impart a different tonality to the pre?
We do indeed use Jensens. They seem to have the widest name recognition and
some customers insist on them but we do our best to accommodate special
requests. We use the CineMag for the high gain (20 - 70 dB) version as Jensen
doesn't make that transformer in a P.C. mount. I've heard about the Lundahls but
never used them. We have a very high precision LabVIEW analysis system and there
is no measurable difference between the Jensens and CineMags. The idea is for
the transformer to be completely transparent and not color the signal at all but
it would take a person with golden ears to pronounce any difference in the
sound. The ear is a marvelously subtle analyzer- check out the level of
echolocation that some blind people can achieve. The MP-2 is very densely packed
and any alternate transformers would need to be absolutely no larger. (28.5 mm
diameter, 21 mm high)
> 4. I understand you now offer an internal rechargeable battery option. How
long does it take to reach a full charge? What is the average expected run
times? I realize this will depend on microphone draw. The mics I will mostly
use with this pre would be the following:
> Mbho 648- which have a draw of 1.7mA
> Gefell SMS 210- which have a draw of 3mA
> Nevaton MC49- which have a draw of 10mA – I don’t believe this number is
They recharge in a couple of hours. Run time with no phantom load is about 40
hours, at ten ma (the Neuman RSM-190i (?) matrix mic draws 10 ma- one of the
Aerco's early claims to fame in the film industry was that it was the only
portable pre to power it) I'd guess 6 - 8 hours. At 1.7 ma I'd guess on the
order of 15 - 20 hours but I'm ashamed to say I haven't made these measurements
. I have a very long to-do list! In any case, there is a protective circuit
that shuts the preamp off when the batteries reach their minimum allowable
voltage. This prevents damage to the batteries but there is no warning unless
you carry a voltmeter around with you.
> 5. With the internal rechargeable battery is it still possible to hook up
an external battery or AC for even more extended times. I am thinking in terms
of several day festivals where extended run times are needed. Is this possible
even if the internal battery dies.
Yes- the external power jack is active all the time. It accepts 8 - 16 volts
D.C. any polarity, any ground. As long as the external voltage is greater than
the battery voltage, the batteries are not discharged. Note that the power
switch only controls the internal batteries- the external jack is always on so
you would have to disconnect an external battery when not in use.
> 6. Is there a on / off switch. For the pre. I can’t really tell from your
photos on your website. If so how easy is it to switch. I don’t want to
accidentally turn it off if my bag gets moved or kicked.
Yes, there is a recessed slide switch on the back. It's pretty hard to change
accidentally. We can optionally ($25) put a locking toggle switch on the front
instead of the 3.5 mm phone jack output- but that may not fit if you choose the