hey y'all,

i've been lurking here for around 6 months or so, been modifying gear
for a few years. there's quite a wealth of information (and belief)
floating around out there, ranging from the excellent, to the helpful,
to the merely interesting (even the flames- especially the flames!).

i've tried quite a few of these modifications and devloped my own
variations, and sometime soon i'll be taking them to a friend's
professional level studio (http://www.machineswithmagnets.com/) so that
we can do some worthwhile testing in a controlled environment. the goal
is to be able to gather some empirical data on how this modified gear
performs.

here's a list of (some of) the projects we'll be testing:

** Ramsa 8210A mixer -re-capped, power supply re-built, 4560 opamps
replaced with LM833N and NE5532, discrete CN2557's in pres replaced
with 2N5088's, master and bus section 4560's replaced with BB
OPA2604's. this was a project i started in december, and just recently
completed. from a subjective standpoint (my ears), the quality of the
sound has VASTLY improved. clearer highs, tighter lows, noise floor(?).


** Alesis Nanocomp & Microverb- certain caps (.001uf mostly) upgraded
from ceramic to poly-film or mica, chips (TL084/82 or similar) replaced
with LM837N or LM833 or NE5532. we'll be comparing the nanocomp to an
unmodded unit, an EL distressor, and a UA 6176 (kind of unfair to the
nanocomp, eh?).

** MXL microphones- specifically the 990 and the V57M (which i think is
the same as their 2001)mods derived from Scott Dorsey's replacement
circuit design, with credit to Category 5 and Dan Kennedy from this
post:
http://www.3daudioinc.com/cgi-bin/ul...c&f=1&t=001142

** Oktava MK 219 mics- input FET coupling cap upgrade a la Dorsey et
al. as well as a variation of Michael Joly's grill mod. my version
modifies only the front grill. i was hoping to maybe tighten the
pattern- we'll see...

** PZM/ Sony electret mic- removed the circuitry for both of these,
replaced with the famous Chris Hicks circuit for phantom powering and
flatter response. the PZM project is actually a bit more involved, i
went with a modular design for the pre-amp, actually housing two
seperate pres in one enclosure, so i could build all manner of
interesting electret pickups. basically along the idea of changing out
capsules on a traditional condenser, except electrets are far smaller
and cheaper to experiment with. if someone wants to host the project, i
could send pictures along with design notes, and test results from this
near future session.

so, i'm curious to see how many of you are interested in this. please
let me know. also, any advice on testing any of the above mentioned
items would be appreciated (things to look for, common complaints or
problems that may have been resolved, etc.) if there's anything
specific you think would be helpful for this project, feel free to
chime in, that's why i posted.

for anyone in the RI/ southern MA area, get in touch if you're
interested in the possibilities of upgrading your equipment. i run a
guitar/amp/raepair/etc. shop in providence- look us up!

thanks all,
-dave
b sharp music
265 broadway
providence, RI

for spam-related reasons, i won't list our phone or email, but if
you're interested respond to this thread and i can email you.
-d

mainmachine wrote:

** Oktava MK 219 mics- input FET coupling cap upgrade a la Dorsey et
al. as well as a variation of Michael Joly's grill mod. my version
modifies only the front grill. i was hoping to maybe tighten the
pattern- we'll see...

Cutting both the front and back grille makes a huge difference in
on-axis frequency response, not just pattern. The measured improvement
is pretty shocking. Doing just the front grille makes some difference
but not as much. Cutting the top grille even helps! More information
on this ought to be in a Recording issue soon, although sadly there was
not enough room for the before and after plots.

I hope you're gooping the insides up with RTV as well!
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

actually, i used latex caulking compound, beacuase it was on hand and
seemed reasonably good for damping purposes (and it is). cheaper than
RTV i think, too...

so if i remove the rear grill as well, that should "open up" the on
axis response? ok, yeah because with only the front opened up, the
upper frequencies are still smeared going into the back of the
diaphragm, so on-axis and 180 are not reinforcing each other as they
ideally should, right?. i wondered about that, but figured someone who
knows more about mic design would let me know. thanks!

thanks for your input!
-dave

mainmachine wrote:
actually, i used latex caulking compound, beacuase it was on hand and
seemed reasonably good for damping purposes (and it is). cheaper than
RTV i think, too...

Probably works as well, but I bet the RTV is in better shape twenty years
down the road.

so if i remove the rear grill as well, that should "open up" the on
axis response? ok, yeah because with only the front opened up, the
upper frequencies are still smeared going into the back of the
diaphragm, so on-axis and 180 are not reinforcing each other as they
ideally should, right?. i wondered about that, but figured someone who
knows more about mic design would let me know. thanks!

It's not a matter of opening up the response, it's a matter of there being
all of these little resonances from the grille assembly, and they smooth
out when you open the grille up. Even with the front, back, and top cut
out, though, the free air response of the thing without the body is a whole
lot nicer than the response with the case and metal screen on.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey wrote:
mainmachine wrote:

** Oktava MK 219 mics- input FET coupling cap upgrade a la Dorsey
et
al. as well as a variation of Michael Joly's grill mod. my version
modifies only the front grill. i was hoping to maybe tighten the
pattern- we'll see...

Cutting both the front and back grille makes a huge difference in
on-axis frequency response, not just pattern. The measured
improvement is pretty shocking. Doing just the front grille makes
some difference but not as much. Cutting the top grille even helps!
More information on this ought to be in a Recording issue soon,
although sadly there was not enough room for the before and after
plots.

I hope you're gooping the insides up with RTV as well!

I notice that the MK319 has a completely different grille. Does this
help?

Arny Krueger wrote:

I notice that the MK319 has a completely different grille. Does this
help?

I think the whole idea of the MK319 was to fix the grille problems of
the MK219. The electronics are the same, and in fact the whole internal
assembly is the same.

BUT, I think the MK319 body resonances are actually worse than those of
the MK219. I don't know aboout the grille problems due to diffraction;
you would expect they would be improved. But the grille itself now rings
like hell on the 319... just tap on it and it goes clang. So the attempt
to deal with the diffraction problems has made the resonance problems a
whole lot worse. Not a good thing.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Scott Dorsey wrote:
Arny Krueger wrote:

I notice that the MK319 has a completely different grille. Does
this
help?

I think the whole idea of the MK319 was to fix the grille problems
of
the MK219. The electronics are the same, and in fact the whole
internal assembly is the same.

BUT, I think the MK319 body resonances are actually worse than those
of the MK219. I don't know aboout the grille problems due to
diffraction; you would expect they would be improved. But the
grille
itself now rings like hell on the 319... just tap on it and it goes
clang. So the attempt to deal with the diffraction problems has
made
the resonance problems a whole lot worse. Not a good thing.

Thanks.

It makes one wonder...

darn...I thought this thread was going to talk about quadrophenia,
scooters, who, yardbirds, etc....
later,
m

On 19 Apr 2005 11:57:38 -0700, wrote:

darn...I thought this thread was going to talk about quadrophenia,
scooters, who, yardbirds, etc....
later

So did I.