Cheap Mic Preamp choice (and what's OPL?)

[TheKeith]

I'm looking into buying a new preamp to be used with a condenser mic for
voice recordings (for flash animation mainly) right now, and I'm wondering
which of 3 preamps I should get. I'm trying to decide between the tube mp,
tube mp opl, and tube mp studio--each of which is $10 more than the
previous. I've read that OPL protects the next device in the chain (i.e.,
soundcard) but I was under the impression that mic preamps were only
supposed to output line level. If something outputs line level, then why
should you need to adjust the output? Sorry, I'm a bit confused. If it turns
out that I should have OPL, why might I need the output VU meter in the
studio version? Can someone help me decide--thanks.

[Scott Dorsey]

In article >, TheKeith > wrote:
>I'm looking into buying a new preamp to be used with a condenser mic for
>voice recordings (for flash animation mainly) right now, and I'm wondering
>which of 3 preamps I should get. I'm trying to decide between the tube mp,
>tube mp opl, and tube mp studio--each of which is $10 more than the
>previous. I've read that OPL protects the next device in the chain (i.e.,
>soundcard) but I was under the impression that mic preamps were only
>supposed to output line level. If something outputs line level, then why
>should you need to adjust the output? Sorry, I'm a bit confused. If it turns
>out that I should have OPL, why might I need the output VU meter in the
>studio version? Can someone help me decide--thanks.

Well, none of them sound very good. They are all basically about the
same inside. Cheesy transistor front end with a fake tube distortion
stage, then a solid-state drive stage.

You need a gain control on the output if you're going into something else
that doesn't have a gain control... because not all line inputs are the
same, and not all sources are the same level either.
--scott

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

[GaryMedia]

OPL=Output Protection Limiting...it's the marketing name for the limiter
feature built into preamp products from ART.
The purpose of the limiter to protect you from digital "overs" if you
have an input that is momentarily too strong.

For example, if someone is speaking/singing normally at -12dB and then
suddently screams/shouts/gets emotional, the input to your soundcard
would be overloaded (up past 0dB) and perhaps a magical recording moment
would be buried in digital distortion. OPL is on the job to limit the
input to something less than 0dB (depending on the way you twiddle the
knobs) and prevent disaster.

I use ART products just for that reason among my inexperienced and
excitable singers.

TheKeith wrote:
> I'm looking into buying a new preamp to be used with a condenser mic for
> voice recordings (for flash animation mainly) right now, and I'm wondering
> which of 3 preamps I should get. I'm trying to decide between the tube mp,
> tube mp opl, and tube mp studio--each of which is $10 more than the
> previous. I've read that OPL protects the next device in the chain (i.e.,
> soundcard) but I was under the impression that mic preamps were only
> supposed to output line level. If something outputs line level, then why
> should you need to adjust the output? Sorry, I'm a bit confused. If it turns
> out that I should have OPL, why might I need the output VU meter in the
> studio version? Can someone help me decide--thanks.
>
>

[Mike Rivers]

In article > writes:

> I'm looking into buying a new preamp to be used with a condenser mic for
> voice recordings (for flash animation mainly) right now, and I'm wondering
> which of 3 preamps I should get. I'm trying to decide between the tube mp,
> tube mp opl, and tube mp studio--each of which is $10 more than the
> previous.

Why, get the STUDIO of course. You have a studio, don't you?

> I've read that OPL protects the next device in the chain (i.e.,
> soundcard) but I was under the impression that mic preamps were only
> supposed to output line level. If something outputs line level, then why
> should you need to adjust the output?

"Line level" is just a ballpark voltage range, of which there are two
common ones, -10 dBV and +4 dBu, but those are just nominal voltages.
you can expect normal speech to vary by at least 10 dB above and below
that level just because we don't talk at the same level all the time.
The instantaneous level that the preamp puts out is a function of the
level of the input (whether you're talking quietly or loudly), and the
amount of gain, which is almost always adjustable.

If OPL means, as I believe it does, that it has a limiter on the
output, this automatically reduces the gain when the signal gets to a
preset level so that it never goes any higher. It can save you from
overloading the next thing in the chain. It can also sound like dogdoo
if it works too much.

To get the best signal-to-noise ratio, you should get as much gain as
you need right at the preamp so there's no need to amplify the signal
(and the internal noise of the preamp along with it) by another device
in the signal chain. By being able to adjust the output level of the
preamp as well as the gain, you can optimize the gain for the best
signal-to-noise ratio, then set the output level so that it matches
whatever your recorder needs. If you need to drop the level out of the
preamp to avoid overloading your sound card (or whatever you're
recording with) on peaks, the output level control is the best place
to make that adjustment rather than the preamp gain control.

A VU meter can be a good thing to watch as long as it reasonably
represents what you're recording. It may or may not on these units,
depending on where it's measuring in the circuit, how it's calibrated,
and whether the nominal output level of the preamp matches the nominal
input level of your sound card.



--
I'm really Mike Rivers - )
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

[Jeff Maher]

"Mike Rivers" > wrote in message
news:znr1071784348k@trad...
>
> In article > writes:
>
> > I'm looking into buying a new preamp to be used with a condenser mic for
> > voice recordings (for flash animation mainly) right now, and I'm
wondering
> > which of 3 preamps I should get. I'm trying to decide between the tube
mp,
> > tube mp opl, and tube mp studio--each of which is $10 more than the
> > previous.
>
> Why, get the STUDIO of course. You have a studio, don't you?
>
> > I've read that OPL protects the next device in the chain (i.e.,
> > soundcard) but I was under the impression that mic preamps were only
> > supposed to output line level. If something outputs line level, then why
> > should you need to adjust the output?
>
> "Line level" is just a ballpark voltage range, of which there are two
> common ones, -10 dBV and +4 dBu, but those are just nominal voltages.
> you can expect normal speech to vary by at least 10 dB above and below
> that level just because we don't talk at the same level all the time.
> The instantaneous level that the preamp puts out is a function of the
> level of the input (whether you're talking quietly or loudly), and the
> amount of gain, which is almost always adjustable.
>
> If OPL means, as I believe it does, that it has a limiter on the
> output, this automatically reduces the gain when the signal gets to a
> preset level so that it never goes any higher. It can save you from
> overloading the next thing in the chain. It can also sound like dogdoo
> if it works too much.
>
> To get the best signal-to-noise ratio, you should get as much gain as
> you need right at the preamp so there's no need to amplify the signal
> (and the internal noise of the preamp along with it) by another device
> in the signal chain. By being able to adjust the output level of the
> preamp as well as the gain, you can optimize the gain for the best
> signal-to-noise ratio, then set the output level so that it matches
> whatever your recorder needs. If you need to drop the level out of the
> preamp to avoid overloading your sound card (or whatever you're
> recording with) on peaks, the output level control is the best place
> to make that adjustment rather than the preamp gain control.
>
> A VU meter can be a good thing to watch as long as it reasonably
> represents what you're recording. It may or may not on these units,
> depending on where it's measuring in the circuit, how it's calibrated,
> and whether the nominal output level of the preamp matches the nominal
> input level of your sound card.

Mike, I gotta hand it to ya. I've been reading your posts here for years
and must have seen you tackle this exact topic (or very similar) a half
dozen times. Still, you took the time to write an excellent primer on
nominal levels, gain staging, etc. And all in response to which ART Tube MP
to buy! (A very "well asked" question by the OP, actually. Newbies take
note).

You, Harvey, Scott, David, Ulysses, Garth and a number of others really
enrich this group with both your knowledge and generosity. I still learn
something new here at least once a week. Thanks.

Jeff Maher
Garage Mahal Recording
Austin, Texas

[Dave]

"TheKeith" > wrote in message >...
> I'm looking into buying a new preamp to be used with a condenser mic for
> voice recordings (for flash animation mainly) right now, and I'm wondering
> which of 3 preamps I should get. I'm trying to decide between the tube mp,
> tube mp opl, and tube mp studio--each of which is $10 more than the
> previous. I've read that OPL protects the next device in the chain (i.e.,
> soundcard) but I was under the impression that mic preamps were only
> supposed to output line level. If something outputs line level, then why
> should you need to adjust the output? Sorry, I'm a bit confused. If it turns
> out that I should have OPL, why might I need the output VU meter in the
> studio version? Can someone help me decide--thanks.

Listen to the responses these guys have provided. The OPL deal is an
ART invention/creation which seemed to actualy work ok. I made the
same mistake as everyone else starting out and thought I needed a tube
preamp. The 3 you mentioned are going to add a lot of color and take
away from any real sound you are trying to record. I now finaly have
some decent preamps, but read some good reviews on the ART TPS unit
and had to get one to try it as a go between from my pod to a digital
recorder. It was ok for that function and the V3 switching function
seemed like a good idea. I tried it miked with a U87 and a L47 and it
was just terrible. The acoustic guitar mode was the worst midrangeey
trebleey boosted mess I have ever heard. Maybe it would sound ok with
a SM57 as that seems to be the market they are going for but I didn't
have it long enough to try it with one.

I think ART is bringing out the ART TPSII so the dealers on line are
all blowing out the origional for cheap like $129.00. I don't
recommend it though. If you really have to have the tube do a search
on the Studio Projects VTB1 some of the guys here like it and it is
cheap. If you need the all in one box look at GC and the Bellari RP503
which has tube preamp, compressor and eq. Before I got my RP220 I
enquired about the RP503 and it is supposed to run at full plate
voltage on the tube from what I was told. It should sound better than
the ART unit. At lest it will add color in a postive way rather than
the ART way if it is anything like my RP220. If you have a GC by you
try it. They have the 30 day guarntee bring it back if you don't like
it like I did the TPS.

Like I said I was in your spot at one point. Do some searches here in
the group these guys have a wealth of info to share and this has been
brought up many times. Hope this helps.

Dave

[TheKeith]

.... I made the
> same mistake as everyone else starting out and thought I needed a tube
> preamp.


I'm pretty new to this stuff, and to be quite honest, I wasn't specifically
looking for a tube preamp per se (not even sure what the difference is
between a tube preamp and a non-tube), but simply a means of interfacing my
condenser mic to my sound card. Currently, I'm using a midiman audio buddy,
which unfortunately, doesn't put out the required +48V phantom power my mic
needs. I also don't need the second channel of the audio buddy, so I decided
to sell it and pick up a one-channel preamp that does put out the 48V. It
just so happens that all of the really cheap sub-$100 ones seem to be tubes,
unless you know something I don't. BTW, maybe somebody can be nice enough to
explain the difference between a tube preamp and a non-tube and give me an
example of their respective applications. Thanks, -- and thanks to everyone
else for their help.