Topic: Aerco MP-2 Information > $750 new & 1 Month Lead Time

[thegreatgumbino]

fwiw, I've been emailing with Jerry Chamkis, who is the creator of the Aerco MP-2.  He is still manufacturing them and slowly putting together a website at www.aerco.net, but not much exists yet. 

I am not affiliated with Aerco & don't benefit from this post at all.  Just thought there might be interest in the fact that he still produces them.

Here's a synopsis of what he told me:

It's very compact at a little over 1.5x3x4 in a rugged die-cast case, two (gold Neutrik) XLRs in, two RCAs out, one 3.5mm output jack, external gain switches (0-50dB in 10 dB steps), DIN standard 48 v phantom power, Reichenbach input transformers, and runs on three internal 9 v batteries or external 9-18 volts.  It costs $750 and takes about a month to deliver.  There's no problem at all putting in gain pots- that would get a $30 discount as the switch / resistors is more expensive and labor intensive.  The problem with small pots is that they eventually go noisy but that's only with lots of rotations and they're easy to replace. Yup- it does but my goal is to be totally transparent.  The Reichenbach transformers are down a couple dB at like 5 Hz and I think that contributes to the warmth-  especially during earthquakes and thunderstorms.  :-)  The internal batteries are standard 9 volt alkalines.  With no phantom load they'll run the preamp continuously for about 40 hours.  With a heavy phantom load it runs for about 10 hours continuously.  All times are longer for intermittent operation of course.  The batteries are easy to replace after you remove the 4 screws holding the lid in place.  Rugged but not sophisticated.  The power converter is by far the most complex part.  To make everything fit in there I wind the (300 KHz ferrite) power transformers myself-  totally nuts!  Those times are with Alkalines.  I think a better rechargeable would be LiIon cells- six AA cels would give 8 volts with twice the capacity of the alkaline
9 volt batteries.

Q: I also read that you used a die-cast aluminum box on the old ones.  Have you upgraded the > encasing to polystyrene over the years to save weight?  I read something about the unit being RF shielded?  Don't know if that's the case or not, but it may prevent being able to move to a poly box.

A: Yup-  right again!  It's a very hostile RF environment for sensitive high-gain circuits.

Q: If you make one with variable gain, is there any audible click when adjusting it as there is with the stepped gain unit?

A: Certainly not initially but that's my complaint against tiny pots- they -eventually- go noisy.  Even big pots tend to do that- it just depends how much wear and tear the shaft gets.  Just means they have to be occasionally lubricated or replaced.

Q: You also mentioned that the variable gain unit uses smaller pots/knobs.  Hopefully they wouldn't require a screwdriver to adjust.

A: No- everything now is adjusted from external knobs between the RCA and XLR connectors.

Jerry's a really nice guy.  We've emailed a few times about his units.  He's open for business if anyone is interested.  He can be reached at jchamkis@bga.com.

[cmoorevt]

Sweet +T.  Thanks for the update.  There are a few pictures on ts.com, but if you've never seen one of these Aerco pre's, they are tiny.  Perfect for stealthing.

[OOK]

Any chance we could get an updated picture of what it will look like........

[bagtagsell]

http://taperssection.com/index.php?topic=43939.0 for some pics

[Rick]

http://taperssection.com/index.php?topic=43939.0 for some pics

I wonder if we can get some newer pics

[thegreatgumbino]

Jerry said he was going to try and get some newer pics and a spec sheet up on the website in the next few weeks.  He also emphasized that he's pretty open for customization.  I don't know how much he's willing to tinker with though.

[hammerhorror]

I sent this email to Jerry Chamkis this morning. Thought i would share it with everyone. Some of the info is rehashed, but some of it wasn't in the previous posts and I am also including a picture of the unit Jerry emailed me. I am going to have Jerry start building me one asap

MY EMAIL:

"Hi,

 I am potentially interested in purchasing a new Aerco MP-2
 Preamp. First of all, are you still manufacturing them? Secondly,
 is it possible that you could email me some info on the unit? I'm
 looking for specs, price, photo, etc...
 
 I would want one with the variable gain option if possible.

 Looking forward to your response,

 - John"

HIS RESPONSE:

"Hi John-

Attached are a couple of not-very-good pix of the preamp.  It's
really high on my list to get the website in order but there just
never seems to be time.

As you can see from the pix, it's built in a rugged die-cast
aluminum case so it's safe to bang around and very well shielded
against RF interference.  It's a little over 3 x 4 x 1.3 inches and
has three internal 9 volt batteries that will run a self-powered
mic for ~40 hours continuous or a high-consumption 48 volt phantom
powered mic for ~10 hours continuous.  Of course the run times are
longer for intermittent use.  The batteries are in parallel and
there is a built-in switching power converter to provide +/- 16
volts for the preamp and 48 volts for the mic, so you can also feed
10 - 20 volts DC in an external coaxial power jack on the side. 
The external power jack is floating so you can use a positive or
negative or no ground system so it's very flexible about sharing
camera or other available power.

The inputs are on gold-plated Neutrik XLR connectors and it uses
Reichenbach input transformers-  the very best.  Outputs are
single-ended on RCA jacks because the recorder is usually very
close by.  Input noise is right at the theoretical minimum (for
room temperature) at -127 dBm.  Frequency response is within a
half-dB from below 10 Hz to over 60 KHz.  Distortion is on the
order of .01% at normal levels and rises to .1% at +10 dBm at 20
Hz.  There is no problem having continuously variable gain
controls, the nominal range is 50 dB.  There are two options for
the input transformer so you can have 0 - 50 dB gain for rock &
roll or 20 - 70 dB for nature recording.

Sorry this info isn't more readily available on my naked web site,
feel free to ask if you have any other questions.  They're custom
built, usually take about 3 weeks and cost $750 including ground
shipping.

Cheers-
--
Jerry Chamkis
jchamkis@bga.com"


 

[audBall]

That's awesome that he'll still make these.

Do you just put batteries in and the thing is ON?  Some of the older ones I saw switches for power.

[OOK]

That's awesome that he'll still make these.

Do you just put batteries in and the thing is ON?  Some of the older ones I saw switches for power.

Any more info.....on the switches....

[it-goes-to-eleven]

That's very cool.  Who's running one?

[cmoorevt]

Looks like Jerry has updated his website and has this to say in terms of the power:

"The batteries are in parallel and there is a built-in switching power converter to provide +/- 16 volts for the preamp and 48 volts for the mic, so you can also feed 10 - 20 volts DC in an external coaxial power jack on the side. The external power jack is floating so you can use a positive or negative or no ground system so it's very flexible about sharing camera or other available power."

[terrapinj]

Sonic Sense has it listed for $619...although it says the page hasn't been updated in awhile

http://www.sonicsense.com/preamps.html

[phatdats]

FWIW I owned one of these for a long time (back in the mid to late 90's) and it was amazing.  it sounded great, was built like a tank, and jerry was the nicest guy to talk to!  nice to see he is still around. - buy this preamp!

also there was a small slide switch on the back left side for power on/off....

steve

[JasonR]

Christian (musicsherlock) and I were PMing about the Aerco, and I called Jerry yesterday with some questions.  Here's some things that we found out...

• As it says on the site, you can select either stepped gains or pots.  The former is a switched network with 6 positions, and the 6 gain levels can be selected by the buyer.
  
• I asked if it would be possible to have a single 'stereo' gain dial (either stepped or not), and a second 'balance' dial with a center detent.  Jerry liked the idea and said he'd like to offer that option to others as well, but has to check into the availability of a small enough pot with a detent.  His latest followup seemed to indicate that such a piece may not longer readily exist, but he has an idea about how to fashion one nonetheless, though it may cost a little extra to the buyer.
• The RCA outputs can be replaced or supplemented with XLR outputs on a pair of short (or long) cables, since there isn't really room inside the box for a pair of output XLR
  jacks.  However, these would not be balanced, so there's no advantage except for those that find an XLR connector either more convenient or reliable.  The default RCAs aren't quite audiophile quality, though we're looking to see if a better part might exist that will also fit.
• If you really wanted XLR output jacks, you could put them on the back of the unit and skip the internal powering capability, or have Jerry install a pair of 5-pin XLRs on the front - one for intput, one for output.  Again - no advantage except if you prefer the connector.
• External powering is 9-20v.  The box is designed to give priority to the external power connector when sufficient power is plugged in there.  If it falls too low, the box automatically and seamlessly switches to available internal power (3 9 volt batteries).  There is no battery meter or indicator, but Jerry indicated that he could install a momentary switch and LED with a small amplifier circuit which would show if power was being drawn externally or not.  For an extra few bucks it might be worth it for those long festival taping situations.
  

That's about it!  I'm pretty sure I'll be ordering one shortly with gain settings: 0, +12, +18, +24, +30, +42 which gives reasonable 6dB steps in my most used gain range, as well a 0dB setting and what I'd consider a higher than normal gain (+42dB).  Fortunately, going into the 744t, if I really need more gain, it's easily applied.  These numbers seemed like a nice compromise.  And if Jerry can make a workable balance knob, I'll be thrilled.

- Jason

[it-goes-to-eleven]

Great details, Jason.  Thanks for posting them.

I'm a huge fan of the single volume + balance config. Though I have to say that it isn't such an advantage with stepped pots becuase they're easy to move in sync and the jumps are so big that it doesn't matter.