Topic: Mixpre gain setup

[Chimney Top]

I've read a few threads discussing issues with the gain on the mixpre.  Haven't really come across a direct answer/solution to how hot the gain is...  I've had to either use the filter or limiter, neither which is going to work for me if that's what it comes down to...

at the LOWEST possible setting it lights up two green lights, then a slight adjustment the red clipping lights are lighting up... what is the solution? or use something else?

There really is no setting that works without using the limiters.  I turned the highpass off for the last 30 minutes last night, and the red lights were coming on every 5-7 seconds, the recording is ok, but the wav files brickwalled.  Tascam DR-100 line -10db  I just bought one and I've used it a few times now.

Thanks

[kirk97132]

(COMMENT BASED ON THE FACT THIS IS NOT MIXPRE-D)I was also assuming it was the recorder being clipped.  I found on the MP-2 that I alsmost always had to run the gain knobs turned all the way down and then depending on the music source, I sometimes had to use the line output rather than the XLR outs.  The XLR outs run hotter. 

[bryonsos]

Use the pads on your mics if they have them. If not, get some attenuators. -12 should be enough. I got mine from Naiant and they work great.

[Chimney Top]

Use the pads on your mics if they have them. If not, get some attenuators. -12 should be enough. I got mine from Naiant and they work great.

Neumann km184's... I don't want to add more equipment.

The preamp sounds great, but this gain issue is rediculous.  It isn't set up to handle SDC mic's/rock shows.

[bryonsos]

Use the pads on your mics if they have them. If not, get some attenuators. -12 should be enough. I got mine from Naiant and they work great.

Neumann km184's... I don't want to add more equipment.

The preamp sounds great, but this gain issue is rediculous.  It isn't set up to handle SDC mic's/rock shows.

Not quite true. Its input transformers provide gain for long cable runs. Granted this is a minor PITA if you're running short cables.

[Chimney Top]

Input transformers do provide gain, but that's not to offset cable loss.  Losses to cables at audio frequencies are negligable, a tiny fraction of a dB.  Step-up input transformers have two major jobs:  excellent common mode rejection (that is important for long cable runs; it eliminates induced noise) and very low-noise gain.  The latter is more important for dynamic microphones.

The downside is that step-up gain becomes a minimum gain figure for the amplifier unless the design provides for an input pad or a transformer bypass.  That minimum gain could be too much for condenser mics used on loud sources, where no gain might be required.  In that case, the solutions are to use the pads on the mics, use inline pads, or select a different microphone or amplifier.

If the preamp has sufficient headroom for the amount of minimum gain at hot input levels, but the recorder cannot handle that output level, then the pad is best placed between the preamp and recorder rather than mic and preamp.  However, if the preamp is clipping at minimum gain, you've got to do something to reduce input levels.

If the preamp doesn't clip and output levels are adequate at minimum gain, then use minimum gain.  That could be proper gain staging for that situation.

Thanks.

Will the pads add any effect on the signal, other than reducing the gain?

[phil_er_up]

Have a MIXPRE-D and use them with sensitive mics and found the same as you I could not turn the gain up at all without it going into the red. At a very low setting you get 2-3 green lights then a slight adjustment it goes into the red. This was at a very loud RR show. I got it to work and did not clip anything. Even though I turned down one channel off twice....arggg. The high end was really pushed though.

To solve this problem: I went to a local free  festival with the MIXPRE-D and jons inline pads that I bought about a year earlier for this exact situation. So what it does it move the position of where the gain starts. The gain still increases rapidly from the new position using the inline pads though - it is easier to control somewhat. In other words, if the first gain position is zero (6:00 o'clock) the new position is about 12:00 o'clock.

I did not put that recording up though I still listen to it to this day on well the mixpre-d works if you have the gear to match it and right position in the venue. Though many time I use one of LB/BB/V3 preamps due to its easier to control the gain with my sensitive mics and I run them on stage a lot and that is LOUD. Or if you have a multi-channel recording unit you can run many different mics/pre-amps in different configs to figure out which ones work best in what situation.

[DigiGal]

A gain trim would certainly have been a welcome addition to the MixPre-D when they updated the product.  I use the attenuation switches on my mics for loud shows. 

My mics will take 12V phantom power and MixPre-D can be set for P12, haven't tried it myself but I wonder if that would help.

[hi and lo]

I'm confused. Are folks here experiencing clipping/overload when running at minimum gain or only when they try to run above minimum gain? This is a fairly common concern for PSP-2 owners, which has input transformers and a very high minimum gain, however 95% of the time it's not an issue.

[F.O.Bean]

I'm confused. Are folks here experiencing clipping/overload when running at minimum gain or only when they try to run above minimum gain? This is a fairly common concern for PSP-2 owners, which has input transformers and a very high minimum gain, however 95% of the time it's not an issue.

I saved toned ears ass on 9/21/12 because his psp2 was clipping hard at 0db. I switched it to -6db and problem solved

[Fried Chicken Boy]

The issue is that the MixPre is a very sensitive microphone pre, very capable of capturing the most subtle of nature sounds with the proper mics.  Not only is the output very hot but the gain knobs are really sensitive to adjustment.  Personally, I've never been able to run mine without engaging the pads on the mics.  With the pads on I've had no issues with my recordings clipping and that's been at some very loud shows including a stage lip recording.

[cd2go]

The issue is that the MixPre is a very sensitive microphone pre

Indeed, especially with hot mics--I have to run mine below 9:00 for most shows and below 8:00 for some, but I love it!

[DSatz]

I don't have a MixPre and frankly, the present discussion would tend to make me think twice about getting one since I mostly use rather high-output condenser microphones. But I feel that something essential is being left out of this discussion: The pad switch on most condenser microphones makes their signals (in effect) noisier by the same amount as it reduces their output level. So the use of that switch is almost always a last resort.

The one time the pad switch on a microphone MUST be used is when the sounds are so loud that the microphone's own internal electronics are being overloaded, or are likely to be. In that case, nothing else will help and the microphone's own pad switch must be used.

But if the microphone itself is doing fine and the problem is that its output is overloading the input of the preamp or recorder that it's connected to, the thing to do then is use a resistive pad at the input of the preamp or recorder--not the microphone's pad switch.

This isn't a question of ideology or opinion. Every microphone--and BTW, this includes microphones that don't have any internal active circuitry, such as ribbons and other dynamic microphones--has some amount of noise in its output. Some is generated within the transducer, and then if active electronics are also a part of the mike (as in condenser microphones), some is generated in the active electronics as well. The pad switch on most condenser microphones is placed at the input to the active electronics of the microphone. Thus it reduces the microphone's sensitivity while (unfortunately) not affecting the noise caused by the active electronics (which generally predominates at higher frequencies where it's more readily audible). Voila, the signal-to-noise ratio is reduced by 10, 12, 15 dB or whatever else the amount of the pad is.

A resistive pad at the input of the preamp or recorder, on the other hand, knocks down the level of both the microphone's noise and its useful signal by the same amount at the same time--it can't tell the difference, obviously. So that approach is preferable by far, and hugely outweighs the inconvenience of bringing a couple of in-line pads along to the recording.

--best regards

[F.O.Bean]

I don't have a MixPre and frankly, the present discussion would tend to make me think twice about getting one since I mostly use rather high-output condenser microphones. But I feel that something essential is being left out of this discussion: The pad switch on most condenser microphones makes their signals (in effect) noisier by the same amount as it reduces their output level. So the use of that switch is almost always a last resort.

The one time the pad switch on a microphone MUST be used is when the sounds are so loud that the microphone's own internal electronics are being overloaded, or are likely to be. In that case, nothing else will help and the microphone's own pad switch must be used.

But if the microphone itself is doing fine and the problem is that its output is overloading the input of the preamp or recorder that it's connected to, the thing to do then is use a resistive pad at the input of the preamp or recorder--not the microphone's pad switch.

This isn't a question of ideology or opinion. Every microphone--and BTW, this includes microphones that don't have any internal active circuitry, such as ribbons and other dynamic microphones--has some amount of noise in its output. Some is generated within the transducer, and then if active electronics are also a part of the mike (as in condenser microphones), some is generated in the active electronics as well. The pad switch on most condenser microphones is placed at the input to the active electronics of the microphone. Thus it reduces the microphone's sensitivity while (unfortunately) not affecting the noise caused by the active electronics (which generally predominates at higher frequencies where it's more readily audible). Voila, the signal-to-noise ratio is reduced by 10, 12, 15 dB or whatever else the amount of the pad is.

A resistive pad at the input of the preamp or recorder, on the other hand, knocks down the level of both the microphone's noise and its useful signal by the same amount at the same time--it can't tell the difference, obviously. So that approach is preferable by far, and hugely outweighs the inconvenience of bringing a couple of in-line pads along to the recording.

--best regards

Great read, thanks DSatz. And a Merry Christmas to you, too!

[Popmarter]

Intresting point from Dsatz.

Correct me if I am wrong. I am using Milab VM44-Link > Mixpre-D > recorder. It's very hard to set levels without having the -20db switch on.
Now, i want these in-line pads, any suggestions on what to get, so i can place in in the chain? (mics have xlr connection). Preferably short en simple.

[bryonsos]

Intresting point from Dsatz.

Correct me if I am wrong. I am using Milab VM44-Link > Mixpre-D > recorder. It's very hard to set levels without having the -20db switch on.
Now, i want these in-line pads, any suggestions on what to get, so i can place in in the chain? (mics have xlr connection). Preferably short en simple.

I use these with my MixPre:

http://naiant.com/naiant/inlinedevices.html

[Popmarter]

Intresting point from Dsatz.

Correct me if I am wrong. I am using Milab VM44-Link > Mixpre-D > recorder. It's very hard to set levels without having the -20db switch on.
Now, i want these in-line pads, any suggestions on what to get, so i can place in in the chain? (mics have xlr connection). Preferably short en simple.

I use these with my MixPre:

http://naiant.com/naiant/inlinedevices.html

Thanks for pointing, I assume you have the MPD Inline Attenuator?

But what is mend by this? (I can ask Jon, I know..)

"Line level pads have input impedance of 7KΩ or higher and are thus not intended for use between microphone and amplifiers, but rather between line level outputs and inputs."

This does not effect anything?

[Todd R]

I'm not sure exactly what you mean by "this does not effect anything", but Jon's note means you should choose the right kind of the attenuators he offers for the application you have.  If you want to attenuate mic level signals, choose the mic level attenuators, and if you want to attenuate line levels, choose the line level pads.

If you choose the right attenuator type for your application, it should not adversely effect things, but I think Jon's note is implying you could get unwanted effects if you choose and use a line level pad when you want to attenuate mic signals, or vice versa.

[phil_er_up]

I am not sure I understand this correctly:

Can someone tell me the difference between these 2 items jon sells and when is the best time to use them: (and with the mixpre)


1 ) GTA Inline impedance converter
http://naiant.com/naiant/inlinedevices.html
Transformer-balanced 200KΩ:1KΩ impedance converters matches instrument input to microphone level output.  Balanced or unbalanced 1/4" TRS input to balanced XLR output.

Also available, 10KΩ:500Ω 1/4" TRS to 1/4" TRS (balanced or unbalanced input and output) for line to instrument level matching.

--------------------------------------------------------------------------------------------------

2 ) MPD Inline Attenuator

Choose 12dB, 18dB, and 24dB microphone level pads, 12dB line matching pad (+4dBu to -10dBV), 24dB line, 40dB line to mic level pad, 620Ω load, or polarity inverter.

Microphone level pads are intended for use with condenser microphones on loud sources.  Microphone level pads have an input impedance of approximately 2KΩ and will thus pass phantom power with minimum voltage loss.

Line level pads have input impedance of 7KΩ or higher and are thus not intended for use between microphone and amplifiers, but rather between line level outputs and inputs.

The special 620Ω load MPD reduces effective input impedance of microphone amplifier for tonal options with dynamic microphones (620Ω load not recommended for use with condenser microphones).

The MPD may be ordered as an XLR adaptor (shown), XLR cable, TRS (female jack) to XLR (male) adaptor, or XLR (male or female) to TRS (male plug) cable.

[bryonsos]

Intresting point from Dsatz.

Correct me if I am wrong. I am using Milab VM44-Link > Mixpre-D > recorder. It's very hard to set levels without having the -20db switch on.
Now, i want these in-line pads, any suggestions on what to get, so i can place in in the chain? (mics have xlr connection). Preferably short en simple.

I use these with my MixPre:

http://naiant.com/naiant/inlinedevices.html

Thanks for pointing, I assume you have the MPD Inline Attenuator?

But what is mend by this? (I can ask Jon, I know..)

"Line level pads have input impedance of 7KΩ or higher and are thus not intended for use between microphone and amplifiers, but rather between line level outputs and inputs."

This does not effect anything?

Sorry, yes. I meant the mic attenuators. I use the -24, but -18 is probably enough.

[Todd R]

I am not sure I understand this correctly:

Can someone tell me the difference between these 2 items jon sells and when is the best time to use them: (and with the mixpre)

The impedance converter is for plugging in (for example) a high impedance guitar output to a mic input that is expecting a low impedance.  I don't think these are anything a typical taper would need.

The attenuator pads depend on application -- which will define how much attenuation you need and whether you want a mic pad or a line pad.  For the mixpre, you might want a mic pad on the input side of the mixpre if it provides too much minimal gain.  Although, if the mixpre itself is fine with the max mic signal on its mic input and doesn't have any internal clipping or brickwalling on the output, you could use a line pad on its output.

For instance, if you have too hot of an output on your external preamp for your recorder to accept on its line input (say the Tascam DR2d, that only takes +6dbu on its line input), you could use a line attenuator between the preamp (output side) and recorder.  If you want to use all 4ch of the Tascam DR2d and connect your external preamp to the mic input of the DR2d, you could use a line pad in that application.  Though you might want to contact Jon in this instance, because you really want to go from a line signal to a mic-level signal.  Jon offers a pad for this, but it is a -40db pad -- you might want a line>mic attenuator pad with a lesser amount of attenuation.

[Chimney Top]

Update:

The gain is ok now (with Neumann 184's)... I have to set the levels at 1 or 2, but the red light does not nessecarily say it's clipping, it's 'close' to clipping... still, as Digigal said, a mic trim would be a good addition to this amp.

[Popmarter]

Chimney, do you really think it is ok now? I mean, i can use my milabs with the mixpre too (without -20db setting in use), and like you i can set it to 1 or 2 on the mixpre. In other words, very very low. Yes, it works but it feels like taking a lot of risk as with the slightest movement of the knob, the signal goes above 0. (Over!)

I need something between the mic and mixpre, so i can set levels a bit better. I have not found any problems on the recorder side. Use the tone oscillator to set maximum level (-20db on the screen, which is about 4.5 on the wheel), some tape over it and off you go. Only keep eye on the recorder.

[Chimney Top]

Chimney, do you really think it is ok now? I mean, i can use my milabs with the mixpre too (without -20db setting in use), and like you i can set it to 1 or 2 on the mixpre. In other words, very very low. Yes, it works but it feels like taking a lot of risk as with the slightest movement of the knob, the signal goes above 0. (Over!)

I need something between the mic and mixpre, so i can set levels a bit better. I have not found any problems on the recorder side. Use the tone oscillator to set maximum level (-20db on the screen, which is about 4.5 on the wheel), some tape over it and off you go. Only keep eye on the recorder.

It could certainly use a trim for rock shows, and possibly some sort of dual level adjustments and a 'lock' or 'hold' feature.

[DigiGal]

Chimney, do you really think it is ok now? I mean, i can use my milabs with the mixpre too (without -20db setting in use), and like you i can set it to 1 or 2 on the mixpre. In other words, very very low. Yes, it works but it feels like taking a lot of risk as with the slightest movement of the knob, the signal goes above 0. (Over!)

I need something between the mic and mixpre, so i can set levels a bit better. I have not found any problems on the recorder side. Use the tone oscillator to set maximum level (-20db on the screen, which is about 4.5 on the wheel), some tape over it and off you go. Only keep eye on the recorder.

It could certainly use a trim for rock shows, and possibly some sort of dual level adjustments and a 'lock' or 'hold' feature.

The MixPre-D has input linking...

Input Linking
Stereo linking allows Inputs 1 and 2 to be controlled as a single, stereo input. This is useful when stereo microphones or stereo line level signals are used with the MixPre-D. There are two modes of operation for stereo linking, X/Y link and MS stereo.
The Linked status of the inputs is indicated by the Link LEDs on the front panel. When both LEDs are off, the inputs are not linked. To cycle between linking configurations hold down both Input 1 and Input 2 Buttons and slide the Slate Switch to the Slate position.

X/Y Stereo Link
When in X/Y stereo link operation, Input 2’s Pan Switch controls the stereo image (L: Input 1 = Left, Input 2 = Right; C: Both Inputs in both channels; R: Input 1 = Right, Input 2 = Left). Channel 2’s Fader controls the overall level of the stereo pair. Input 1 and 2’s High-pass Filters continue to act independently of each other. When linked, Input 1 and 2’s Limiters are also linked.

MS Stereo Linking
When MS stereo linking is selected in the Setup Menu, Inputs 1 and 2 are linked as an MS (Mid-Side) stereo pair. Connect the mid signal (unidirectional / cardioid microphone) to Input 1 and the side signal (bi-directional microphone) to input 2.
Input 2’s Level Control adjusts the overall gain of the MS stereo pair. Input 1’s Level Control adjusts the “spread”, or width of the stereo image. Input 2’s Pan Switch controls the polarity of the side signal (L: Normal, R: Inverted). Reverse polarity to flip the stereo image between right and left. The center (“C”) position of Input 2’s Pan Switch mutes the side signal; only the mid signal is present, resulting in a mono signal. Input 1’s Pan Switch is disabled in MS linking mode. Input 1 and 2’s
High-pass Filters continue to act independently of each other.