Topic: V3 & MMe A/D chipset

[dano420]

Does anyone know what A/D chipset the V3 and the MiniMe uses? Cirrus based?

[nic]

I *think* they are Burr Brown(or something that sounds similar) based

[creekfreak]

I believe the bur brown chip is par of the pre-amp, not the A/D

[Jason B]

I believe the bur brown chip is par of the pre-amp, not the A/D

They make both amplifier and A/D chips.

[nic]

well, if the V3 and V2 have the same "pre" then the Bur Brown chip Grace uses is in the AD...just opened my V2 and there is no Bur Brown chip

[chase]

burr brown makes the INA103 (instrumentation amplifier) which is what are used in the grace preamp side.  i believe it is actually made by texas instruments though, so it may not say burr brown on it.  it's an awesome chip, super low noise and tons of bandwith.  not sure what AD chip grace uses for the V3 though.

[muj]

 Crystal 5396 A/D chip

[Tim]

well, if the V3 and V2 have the same "pre" then the Bur Brown chip Grace uses is in the AD...just opened my V2 and there is no Bur Brown chip

there not the same.

V3 has an updated chip set.

Grace said they were "identical" and then recanted.

imagine the shit that would have hit the fan if apogee did the same thing.

[dklein]

I thought one of those units was using the AKM AK4524 (same as the UA-5)

[Tim]

I believe all of this info is on the oade board archives...

[dklein]

yeah - I did a few searches and didn't come up with it but I do remember reading it.  Was it the V3 that uses the 4524?

[chase]

there not the same.

V3 has an updated chip set.

so are you saying that he V3 is not based on the INA103? if so, i would love to know what grace is using instead.

[F.O.Bean]

there not the same.

V3 has an updated chip set.

so are you saying that he V3 is not based on the INA103? if so, i would love to know what grace is using instead.

i dont believe they ever said, they just said they were "identical" then said they WERENT

[Brian Skalinder]

I believe while the V2 uses the INA103, the V3 uses the INA163.  A post on the Oade Bros forum from Michael Grace explaining the differences between the V2 and V3 preamps:

Subject:     Re: V3 tests
Date:     Wed, 30 Oct 2002 17:49:21 - (EST)
From:     Michael Grace <mbgrace@gracedesign.com>

I guess the word "identical" may be a bit strong here.  When we first
started development of the V3 the mic preamp circuit was "identical"
to the V2 with one exception:  Most of the components in the V3 are
surface mount rather than through hole.  This was necessary to
accommodate the additional converter circuitry.  Components that are
not changed to surface mount include the gain control switch,
metalized film coupling capacitors, conductive plastic trim
potentiometers, HPF filter switches and XLR connectors.
  As we began evaluating prototypes it became clear that the V2 style
trim control would not work in the V3 for practical reasons.  (with
the trim attenuator one could be clipping the preamplifier badly and
it would not be visible on the meters)  However, when the trim on
the V3 is set to 0 the circuit "topology" of the V3 is identical to
the V2 with it's trim set to 0.   ....so... If you looked at a
schematic representation of the both preamplifiers with their
respective trim controls set at 0 the two circuits would be
identical. (with the possible exception of the INA163, which shares
the same architecture as the INA103 but may have subtle differences
in its internal circuit topology.  Burr-Brown does not publish
detailed schematics of these devices.)
   It is instructive that Doug has heard a distinct difference
between the V2 and V3 because it points out how important the very
small details in circuit design can be.  How can two preamplifiers
that have the same circuitry sound different?  Here are a few
possible factors that I can think of:

Surface mount resistors have no leads.  They are soldered directly to
the pcb.  Through hole resistor leads have inductance and stray
capacitance which surface mount parts don't have.

Use of surface mount parts permits a "tighter" pcb layout with
shorter traces.  Again, less inductance and stray capacitance.
This translates to better transient response and a better ability for
the circuit to resolve complex harmonic structures and high
frequency wave forms.
Use of surface mount devices also lets us use a more contiguous ultra
low inductance ground plane on the bottom side of the pcb.
The circuit ground is THE foundation of any audio circuit and the
more solid it is the more performance potential the circuit will
have, especially in the upper registers.

I guess I have billed the V3's preamp as "identical" to the V2 for a
couple of reasons.  One is to try to explain that we did not
compromise the preamplifier circuitry so that we could add an AD
converter in the same box.  The other is that I did not want all of
our V2 customers to think that they were sitting on obsolete
equipment when, IMHO, it is still a state of the art preamplifier.
As a manufacturer it is very tricky to introduce a product that
replaces an existing one.  Especially if you don't necessarily want
to participate in a "throw away" society where "out with the old and
in with the new" is what sustains our economy.

Sorry if this is a jumbled bunch of rambling.
-Michael

[F.O.Bean]

good post and reminder brian