RO gurus:
Transferring my question from an old thread, to see if others
have some insight to my 'dilemma' with the Brick..
first off, I have marginal equipment, i know it, you will know it
but please read on (afterall we are in the Budget Gear section!)
Using Pro Tools LE 6.2.3, and Audiomedia III PCI card which has
SPDIF 24 bit 2-ch IN/OUT and 18bit Analog 2-ch IN/OUT.. For
A/D D/A conversion Midiman(now m-audio) Flying Cow feeds
SPDIF into the AMIII card and feeding output signal to my monitors.
Prior to purchasing 2 Bricks, I have a 2ch ART TPSII tube preamp..
it has lots of adjustability, but still not as warm as the sound Im
trying to get out of it. (thus my venture down the yellow 'Brick'
road) I have 4 mics... 2 Oktava MK319 condensor mics and 2 Shure SM57s...
For my setup I have the Bricks feeding into the FlyingCow which
feeds the digital signal into the AMIII. The ART TPS II now feeds
into the analog inputs on the AMIII.
My problem is the following: The Brick states its output gain is
+25db to +55db for microphones, but Im finding I have to crank
the gain knob anywhere from 3/4 to full gain to get anykind
of decent level into Protools... And there are two gain stages
the signal is seeing! The Flying Cow has a variable input gain
setting which I have cranked all the way for the Brick and still
getting (relatively) low signals when compared to the ART TPSII
I can swapout
the output XLR cable from the Brick to the ART and I cant seem
to know what Im doing wrong here... It just doesnt make
sense! The literature says Brick is great for directly inputting
into computer based recording systems...
1) Gain Comparison
Brick +25db to +55db for Mics, 0db to +30db for direct input
ART max gain 80db XLR-XLR (mics), 74db 1/4-XLR (direct input)
Flying Cow - undocumented.. i cant find the numbers intheir
manual to say what kind of gain is available on-board this device.
2) Output Comparison
Brick - Nominal 4 dBm, max +16 dBm
ART - XLR +28dBu, 1/4 +22 dBu
Flying Cow - see gain comparison above A/D conversion
level is what is my problem, but I dont see how I can adjust
it as it feeds into the AMIII
3) Bandwidth Comparison
Brick - 6hz to 22kHz @ minimum gain
ART - 5hz to 50kHz
4) Dynamic Range Comparison
Brick 118dB
ART >100dB
!
Ok, I dont fully understand the difference between the gain
and the output levels, but the Brick liter. says "the Brick
can provid up to +55db of tube gain to any studio mic. This
is more than enough gain for direct recording into computer
based recording systems or trad. analog formats"
I know a little about dBs from work... rough order of magnitude
type knowledge but I'm no expert...(we try to muffle the noise
from aircraft engines )... 55db is a loud signal (relatively speaking)
Also I'm sure there are differing philosophies on what kind of
level should/needs to be attained for quality recording.. Im
just a hobbyist, nothing professional...
Question 1)
In trying to get a signal of -3 to -6 db on a single Pro Tools track
(using Inspector to get RMS and peak signals) but I cant get
there using the Brick. It seems like the only useable range of
gain on the knob is 3/4 to full gain when feeding signals
into my system...
With the Oktava, I can get about -5 to -6db with gain 3/4 through
on the Brick... with the Shure SM57, ive got to crank it full gain and
play loudly (both acoustic gtr @sound hole and electric gtr miking
directly in front of the amp) and then I only get about -7db...
also direct in with an electric gtr i can get the levels i want but not
the sound i want (i like my amp sound and the adjustability with
pedals, etc)
But I can get the sound level I want with the TPS II without
a problem... I like the recorded sound of the acoustic gtr using
the Brick, but I have to bring the track level up. I have very
sparse arrangements and want/need Ac.gtr up and center and
not in the background..
Any advice/comments to help me achieve better levels?
It seems like a waste of a potentiometer (or whatever is
used for gain adjustment, and finding that only about a
1/4 of the gain range is actually marginally usable for my setup..
I want to like the Brick, but this level issue is boggling me...
Question 2)
I can probably feed the Bricks into the analog ins on the AMIII
but dont want to because its only 18-bit. Also then I have
to go from XLR to RCA and i dont even know if there is a
cable made for that! balanced-unbalanced... seems like
a funny (bad) idea... And I know my AMIII card has a
Gain setting (for analog inputs only)
which can up the Bricks signal.. but seems like
a convoluted way to get the Brick signal up to a level
I like. any advice or comments on this is also welcome..
Thanks in advance for your comments and advice..
If suggesting 'get better gear' I would appreciate it if
you are specific... I.e. replace that Flying Cow with a ______
Edgar
Comments
I have "The Brick" (2 of them) here for review and after readi
I have "The Brick" (2 of them) here for review and after reading your post I went into the CR and plugged a 57 into one .... no problems getting plenty of level into my AI3 converters at the +4dB setting. I can reach digital 0 in Cubase with half of the gain in "The Brick" still left. The problem is not the pre amp.
Keep in mind this is 55 dB of added gain, not that it is capable of only reaching 55 dB. 55 dB is usually plenty of gain in most cases ... Many of the Neve clones offer only 60dB. With pres that have limited gain such as these you might have issues with ribbon mics but not a 57.
Something screwy with input impedance is happening between the mic pre and the Flying Cow / AMII card. First, what ever you plug the mic pre into usually should not be a variable gain input. In most cases, the presence of a gain attenuator suggests there is a stage of pre amp gain to be dialed in. So I suspect you are amplifying the signal twice ... no wonder you are saying it lacks the warmth you are looking for. A line input or an insert return is what you should be plugging your mic pres into. Be careful, many devices have a line in that actually goes through the mic pre ... but that is padded down with passive resistors ... this is still a pre amp. There's no sense bothering with external mic pres, if this is all you have.
My suggestion is to get a different audio interface A/D-D/A and sound card. I can't suggest a specific one. I recommend you post a different topic for that question. The cheap ones are all pretty much the same in terms of quality (very ok) and the more expensive ones all sound great.
Once you change that out, I believe you will find that even your ART pres will sound and perform much better.
Flying Cow and AMIII hey thanks Mike and Kurt for your response
Flying Cow and AMIII
hey thanks Mike and Kurt for your responses so far...
1) Sebatron VMP2000e? ive seen that name around on the RO
forums ill check it out...
2) variable gain input on Flying Cow..
this is normally set to 0db gain when I was using the ART tube pre...
The manual says the optimum signal-to-noise ratio is when its at
0db, not stated
in so many words but follows your advice as how a signal can become
more corrupt before the A/D conversion occurs...
my intention is always to not add a gain stage to the signal unless
absolutely required...
its to convert A/D and there for additional gain as required..
The thing I cant understand is that I can switch between the Brick
to the ART pre to feed analog signals into the A/D but with only the
ART pre can I attain the levels I want...
If I didnt have that ART pre I would tend to agree more with
your postulation that the Flying Cow has something wrong with it...
Im not ruling it out, but simple swaps say a lot...
3) AMIII card... cant change her out.. she's my ticket into
protools... Before I switched to SPDIF, i always had my
analog inputs set to 0db gain...again for the same reasons
as above. Im confident that the AMIII is in working order.
Im just getting the digital signal into the card... once its digital
there is no attenuation... I suspect A/D and D/A are designed
as relatively dumb devices... for instance.. there is no output variable gain.. it just doesnt make sense to have a stage here.. but it
does make sense to have a gain stage on the input to make
use to the maximum the 24-bits you are converting to...
Thats not to say Im not suspect to the Flying Cow conversion
process and matching between impedances between the two
pieces of equipment....
4) Input Impedance...
I understand (limited) what you are saying here.. And for the
Flying Cow, unfortunately it doesnt state anywhere a compatible
input impedance on the input analog signal...
Brick says its output is terminated at 600 ohms...
The ART pre says the output impedance is 300 ohms...
Larger resistance will attenuate the signal more?
I know basic wiring, such as voltage attenuation.. Im assuming
the same concepts apply for an analog audio signal..
Im going to inquire to M-Audio tech support on this for the
Flying Cow..(lets see if they are of any help)...
5) oy! googling input impedance and get op amp circuitry
sties! long time ago i knew of op amps... need to brush up
on how this relates to analog recording signals...
thanks so far... KEEP THE GOOD COMMENTARY COMING! Im
learning a lot here!
thanks in advance,
Edgar
I too can vouche that SM57 + Brick is no problem getting levels.
I too can vouche that SM57 + Brick is no problem getting levels. Especially micing a guitar cab or drum. I guess if you had a really quiet guitar amp on 1 you might have trouble getting levels, but.....
I have found that on loud sources (which are typically things that will also end up loud in the mix), gain is no problem. On quieter sources (which are typically things that will also end up relatively quiet in the mix anyway), you might have to dime the Brick; but it is still not very noisy and can reach adequate output levels.
Sorry this doesn't help much, but I think your problem may lie elsewhere.
FYI: solution/response from GT FYI for all interested, I wrote
FYI: solution/response from GT
FYI for all interested, I wrote GT about this and they came
back with this helpful reply....
Howdy from the lab at GT.
Thanks for purchasing one of our products.
I would suggest going to the guitar center or radio shack and grabbing one of there
line matching adapters.
I think there around 9 to 12 bucks.
That will prevent any loss when uniting a 600 ohm to a 10k ohm impedance.
simple ---take it back and get a Sebatron :wink:
simple ---take it back and get a Sebatron :wink: