Preamps and Mics - I guess I slept in that section

[Compyfox]

Some people will be like "OMFG DON'T USE THAT CRAP", but well, too late, and for doing some stuff here and there it's still okay. I'm talking about the Behringer MIC Ultragain 200. Nice little critter, only get's so hot after like 20minutes (after the tube has heated up) so that I can fry an egg on it.

Anyway... I have this thing for a while now, but I always seem to missuse it in some way. So your help would be gladly appreciated. This thinghas a Gain knob (input) ranging from +26dB to +60dB, an output ranging from infinite to +10dB and some knobs inbetween it with 20dB PAD, +48V Phantom Power, Low Cut and a phase reverse button in case I've got some phasing issues.

So far so good. I know that this thing can be used for Line Signal, but also for microphones. And here's where I have my problems with it - how to properly set it up so that it doesn't hiss.

I have a Prefer CMM1420 Condenser mic that's running on a AA battery (so it doesn't need phantom power) and I have several dynamic mics. From basic knowledge with microphones I know, that no mic should be handled without a certain ammount of preamplification. So much about the theory. What's troubling me though are the settings I have to apply.

In case of my Condenser, I need to use a gain of about 50-55dB, and my output should be at 0dB at least. But if I set it up like that and record it in Cubase, I have to get friggin close to the mic in terms of recording to get a decent "loud" signal with like -10dB peak, while the peak meter on the device itself hovers around -6dB to 0dB. Not to mention that it's introducing a certain ammount of floor noise (hissing) spread over the whole spectrum. If I turn down the gain, the hissing vanishes, but the recording is quiet again, until I raise both the gain and output.

Padding would be a nice idea, but in this case, I need to drive both knobs to the max to get a decent volume, which is a no-no in my opinion, and certainly wrong.


So my question out there to the peeps, please help an old stupid "fox" to learn something new:
- How can I setup that device correctly (or any preamp of that sort)
- aren't microphone's different in terms of gain boost? While dynamic mics need the most, and +48V phantom powered very less? Or am I imagining things?
- what about the pad knob? Is that really for Line Signal (keyboards) only?
- (for those who use this thing), the rings around the knob have carvings. Does anyone know in which dB steps they are?


Thanks in advance - and yeah, the manual isn't really helping.

[Arglebargle]

hey man, can't really answer all your questions but I also have the Ultragain preamp. originally tried to use it with crappy dynamic mic from Radio Shack and it was completely unusable (way too much noise). I thought it was the preamp that was garbage (people tend to complain about Behringer products). Just bought a better mic, AT2020, and the preamp works great now. I've spent some time tweaking the settings on the preamp and my mixer and now I can get a good strong signal approaching 0 db with the noise floor at like -60 db. I have both Gain and Output set to around 60%. then it goes into my cheap Behringer mixer and I set the level to a moderate amount. With these settings I've had absolutely no problem picking up signals, even from a few feet away.

I only use the 48v power button, haven't had to use the Pad.


so, umm, yeah I really didn't answer your questions, just wanted to say that it works fine for me.

[where02190]

how to properly set it up so that it doesn't hiss.

Replace it with something that isn't Behringer. There's a reason their shit is so cheap, it's cheap shit.

[Compyfox]

Riiiiiiight... Not all "entry level" material has to be bad (and I said it doesn't have to be Behringer alone - this is also a general topic). But back on topic please.

Arglebargle:
You said you're using the phantom power switch. Does that mean your microphone needs an additional 48V power source (meaning XLR)? If so, it's kinda understandable why you only setup your knobs to about 60% each. Only my output is at about 60%, my gain is at about 85-90%.


This really gives me the question:
Do different kinds of mics really need different gain boosts?

In that order: dynamic mics (max boost) -> condenser mics (powered or not with like 1AA, medium boost) -> Large Membran mics (Phantom Powered, moderate boost)

Or am I getting this wrong? Like I said, I slept a bit in this section.

[G&L_player]

I've never used a mic with batteries in it before. I'd be curious to learn if it carries different characteristics according to the brand and charge of the battery, as a lot of effects do. I'm wondering if your gain might fluctuate with the batteries (i.e. charge)? I mention this because, I've had to turn the level up on a device when they're running down. FYI: some cats can tell you what kind of batteries somebody's usin' by the tones!

As a vocalist, I have a case of mics and find that I have to adjust each one a bit differently (in the chain), not to mention how I approach them. My number one (Groove Tubes) came with its own pre, so I'm not running into any matching problems for the most part.

[Arglebargle]

Arglebargle:
You said you're using the phantom power switch. Does that mean your microphone needs an additional 48V power source (meaning XLR)?

Yeah, the AT2020 is a condensor so it needs phantom power. Also yes it uses an XLR cable.

[speccyteccy]

Replace it with something that isn't Behringer. There's a reason their shit is so cheap, it's cheap shit.

I bought the MIC100 following a very positive review in soundonsound:
http://www.soundonsound.com/sos/mar04/a ... mic100.htm

For £35 it was a absolute bargain - it's worked flawlessly for 2 years and sounds fantastic with both electric guitar and a Rode NT1a.

As for levels, for the microphone I have gain at zero and output around half way and this gives a nice strong signal in my DAW. Only button in use is the phantom power for the mic.

[Compyfox]

But... does your microphone NEED phantom power? If not, wouldn't that damadge the damn thing? (guitars for example)

This is my main essential question where I seem to slept over. Do phantom powered microphones need less gain than non powered (dynamic, battery powered condensers)?


The amp is not important. Hell who cares if Behringer is "crap" to you? Doesn't mean that it's crap overall. (else I wouldn't use it mixer wise for my project studio - back in the day there weren't much alternatives).

[xtp]

http://www.hr-faq.org/index.htm
http://www.tweakheadz.com/microphones_f ... studio.htm

thses may be helpful reading

The info you need is here, difference between condensors with 48v requirement, and dynamic mics...

[Compyfox]

I mean, okay, I know that dynamics and battery powered mics don't need phantom power, but what's troubling me a bit (and it's not really cleared on those pages)...

Condensers need some sort of power for the capacitor. The battery powered ones have that covered with like 1AA battery or 2AA batteries, while the large membran mics usually use 48V for this term.

More power means a higher load of the capacitor, meaning the output is more loud? Is it because of that, that I barely need to use the gain knob on a preamp with a +48V phantom powered mic than with a battery powered one? Sounds logical to me.


Leave's one question... what about the padding? And wouldn't a guitar signal need a lot of gain, too? I mean, a guitar is not a condenser mic (so it's not battery powered or powered with the +48V from the preamp). Which'd make it a HiZ signal) - or is the pad knob (20dB PAD) actually for the LoZ +48V phantom powered mics?


Hm... now this makes all a bit more sense indeed. Thanks for the articles, xtp - though is someone can confirm my "theories", or correct them, that'd be nice.

[pedrito]

Hi
I have a behringer C-3 that I have recently bought. I was looking for a decent microphone under 100 euros. I run on the same problems of you. I mean, to have a nice signal on the DAW I need to push the gain up to 60-70% of max, and moreover I need to be really close of the microphone to get a proper signal. I kissing my pop-filter.
I decided that very soon I will buy a much better mic and avoid low quality bargain products for the rest of my life even if I need to wait to have enough money in my pocket.
Pedro

[frog_jr]

Replace it with something that isn't Behringer. There's a reason their shit is so cheap, it's cheap shit.

Whatever. Behringer gets flames in every bb on the web, I think mostly because of that lawsuit about them ripping off a Mackie design (I don't know the details but I understand Mackie won.) I think they really ruffled some feathers. I'd say they are a step up from stuff like Gemini or Nady or much of Samson. I put them at the same par as ART or much of Reynolds. Not salon gear.

[_niko_]

An idea that, I think, wasn't mentioned before:
Are you using a XLR-cable to connect the mic? If you're using a XLR to 1/4 Jack the preamp will most likely only apply line or instrument level amplification, which would indeed result in a very low output. Most budget pres I know, that offer XLR and line/instrument connectors, work that way.

Could this be your problem?

[joshhunsaker]

how to properly set it up so that it doesn't hiss.

Replace it with something that isn't Behringer. There's a reason their shit is so cheap, it's cheap shit.

actually behringer uses the exact same components and spec circuit boards as all the other name brands that they copy (mackie, ART, yamaha etc.) and sometimes better. The yamaha mixer i have sucks compared to the behringer one that i used to have. The only section they skimp on are the pot and pans. Audio and s/n wise - there is no reason for behringer's products not to match right up to the ones from "big name" companies. Ask anyone who's checked the actual capacitors, inductors, circuits, etc. in both types of models and they will tell you the same thing. There is not that much wrong with behringer.

[C00kie]

- How can I setup that device correctly (or any preamp of that sort)

Start with the 20dB pad off. Make a lot of noise while watching the LEDs. Adjust the gain so it averages around 0dB and doesn't clip (or only clips occasionally) If the gain knob is set below 10 o'clock (loud sources) you may try to switch the 20dB pad on and raise the gain by 20dB.

Now you know that the average sound level inside the preamp (at the point of the LED bar) is within the limits it should be. The keyword is "gain structure": make sure that the level is optimal right at the beginning so you don't have to compensate or drive things outside specifications.

So what's left is the Output control. I'd keep it at a 0dB position if possible. Knowing where that is can be tricky. See what I write about calibration further on...

I have a Prefer CMM1420 Condenser mic that's running on a AA battery (so it doesn't need phantom power) [...] it's introducing a certain ammount of floor noise (hissing) spread over the whole spectrum. If I turn down the gain, the hissing vanishes, but the recording is quiet again, until I raise both the gain and output.

Can't find any info on that specific mic... Maybe this is an impedance issue. What you can try is run it through the TRS input instead of XLR, since that's the high impedance input, and see weather it performs better that way.

- aren't microphone's different in terms of gain boost? Do phantom powered microphones need less gain than non powered (dynamic, battery powered condensers)?

Different mics have different output levels with the same sound pressure coming in. Period. Probably there are exceptions to the rule of thumb you found. The answers are in the spec sheets (how many volts at what impedance at what sound pressure.)

- what about the pad knob? Is that really for Line Signal (keyboards) only? And wouldn't a guitar signal need a lot of gain, too?

It's for cases where the gain would be set extremely low otherwise. So that's for anything louder than the average mic. Mics are softer than electric guitars, and guitars are softer than keyboards. Most keyboards have a signal of the same strength as regular line level. Sometimes I run my guitar straight into the line input of my soundcard and set the gain to +15dB. It's way too strong to be handled like a mic signal but a bit too soft to be handled like normal line signal.

- (for those who use this thing), the rings around the knob have carvings. Does anyone know in which dB steps they are?

They aren't... So you have to perform a tedious calibration procedure to figure that out.

Firstly get MDA TestTone. Let it generate a 1000Hz sine test tone at -6dB. Make sure that all faders in your host and soundcard mixer are set at unity (zero dB.) Connect the line output of your soundcard to the XLR input of the mic preamp (can do with TRS also, but that's not the proper impedance.) Set the pad switch on and set gain all the way down to +26dB.

So what we have is a steady signal at -6dB padded by 20dB so that makes -26dB. With gain set to +26 it should read exactly 0dB at the LED bar on the preamp! Experiment with a fader in your host to see how the LED bar reacts to small increases / decreases of the level.

Probably it won't read out as zero at all. Because the -6dB is relative to the full-scale zero of the DA-converter. What you probably are getting is a signal that leaves the soundcard at -20dBfs shows as 0dB and -14dBfs to read out as +6dB on the preamp. That's because you want plenty of headroom. So you'll have to find out where the zero mark really is. (Wow, this can get confusing...)

You can lower the level of MDA TestTone by say 6dB and find the gain setting where the LED bar shows the same level again. Mark that position as (26 + 6 = ) +32dB. Repeat that with 6dB increments.

We'll have to live with some assumptions though:
1) your soundcard actually outputs zero dB at what the rest of the world calls zero dB
2) the 20dB pad actually attennuates 20dB and not 18 or 22 (very likely...)
3) the minimum gain is indeed 26dB and not 24 or 28 (also very likely)

Assumption number two can be checked: lower the volume of MDA TestTone by 20dB and disengage the pad switch. The LED bar on the preamp should show the same level again.

You may have found that reading out the LEDs isn't very accurate compared to meters found in software. So let's use that instead. Connect output of the preamp to input of your soundcard. PLEASE make sure that the inputs aren't routed back to the outputs, either by the soundcard's control panel or monitoring features of your host.

Now you can start calibrating the output knob. Let's say that a -20dBfs from the soundcard shows as 0dB on the preamp. Find the level of the output know where it shows as -20dB on the inputs of your soundcard again. By changing the sound level by a known amount you can find the proper marking of the knob.

Boy, I hope that made some sense....