Re: A Non-Review of the Olimex EEG-SMT

Gregory

The good folks that developed the openEEG project have arrived at their
destination 7 or so years ago and have left ship!

I have written a mini-review of available amps a few months ago and you can
read it here:
http://openvibe.inria.fr/forum/viewtopic.php?f=11&t=526

I stay in South Africa and find trans-border exchange also very
frustrating, especially the huge amounts of shipping and conversion charges
that are charged.  But that is life.  Fact is, if an American Co would be
selling a device comparable to SMT-EEG, it would cost 5x as much!  So
either buy an Australian Pendant, a Bulgarian SMT-EEG, Bulgarian Optima2 or
an Argentinian Focus, or pay substancially more for J&J, BrainMaster, etc.

SMT-EEG is save.  The DC/DC converter is rated at 3000VDC and the TI
capacitive-based digital isolator is rated at 4000Vpeak.  Having said that,
I personally would not use such a device with an electric storm brewing,
and even less, if lighting comes thundering down at my front door.  But
that is a personal view only.  Others would disagree.  I just like playing
safe. (I have already pointed this view, regarding lightening, out on this
forum, only a few months ago.)

You should realise that there is a lot of crap being sold all over.  I
regard the SMT-EEG a 500% better designed product than the silly Pendant -
just as an example.  The Pendant has it's electrode inputs
connected STRAIGHT to the instrumentation amplifier's input pins.  There is
no static isolation and there is no RF filter(!)  I, as a professional EE,
I want to puke when I see something like that.  The Pendants are build into
some MP3 player's plastic enclosure, a badly fitting one, for that.  I
think some Chinese manuf. made these casings and they where most
likely rejected by the Chinese MP3 player manuf.  And then sold as dirt
cheap scrap to Neurobics.  The double sided PCB is just as bad.  The
soldering looks like bird droppings, there is no proper silk-screen, the
whole thing reminds you of the build quality of a cheap Chinese toy.  Yes,
there are many, many Pendants in the field, in the hands of both home- and
full-time neurofeedback partitioners.  Most seem happy enough with the
performance of these devices (judging by my many years readings of the
braintrainer forum).  Seeing the hardware, I am surprised.  I would have
expected it's performance to be equilivant to dog poop.

Let's take another example.  You can pay over $2000 for a 4-channel QDS
Excalibur - I guess you could get them marked down these days... but the
official list price was over $2K.  Read my comments on the above mentioned
link.  The Excalibur's build quality is reasonably good... BUT what is the
use in providing electrical isolation with opto-couplers rated at 3000V or
whatever, and then criss-crossing the isolated and non-isolated hookup
wires.  Cheap PVC wire is normally rated at 300V.  So if iso- and non-iso
circuit wires touch each other, you end up with a rated isolation of
600V(!)  What a dense schmuck does that?  And this is for an amplifier
costing over $2000!  What they SHOULD have done is to neatly and carefully
route those wires, so that the two sides have a fair distance between
them.  But that is not surprising, comming from my "zero nV" noise friend,
Dr. D. Rocatti (QDS proprietor), who advised forum people to rap their
EEG-amplifiers in tin-foil, so as to reduce the noise.  (I guess then you
get less than zero noise?)  Fact is - he made this statement generic, not
amplifier specific.  The tin-foil will act as a nice conductive path
between the DIN-input connectors and the non-isolated RS232/USB connector
on the other side of the EEG box, potentially by-passing any isolation
inside the box.  Go figure!!

I would LOVE to receive high res colour pictures of the inside guts of any
other amplifiers.  You normally get what you pay for.  In case of SMT-EEG
you get much more than what you pay for.  Do you get what you pay for from
a J&J, BrainMaster, ProComp, NeuroAmp, Nexus,Nexstim, gTec, etc.?  I expect
them to be good, albeit over priced.  But who knows, I might even find
fault with devices in that sort of price bracket.  You ASSUME that a BMW
must be better than a KIA.  Well my BMW's fuel gauge doesn't even work
properly.  New BMWs don't have a oil dipstick.  Must I now trust the
electronic oil level sensor to tell me that my oil is OK, Mmm?  And replace
the silly sensor for an arm and a leg price tag, if it misbehaves?  The
whole world went nuts.

Trust No one.  Trust nothing.  Everyone is taking the consumer for a ride
(of his life), ha!

Regards
Stefan

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