PROBLEM! Just bought the DMP3 Preamp...

[cadbawdbawks]

Hi all,

I've just purchased an M-Audio DMP3 Preamp for my studio and realized that not only is the sound unchanged, there seems to be a low humming noise to it as well. I've read numerous reviews mentioning that there is virtually no audible noise/distortion to the preamp and that it's given great warm results to vocals and acoustic guitars with the tascam us-122 (the same interface that I currently use). What could be the problem with my setup? Could my unbalanced TS cables be the cause to this?

I currently have my hardware hooked up as seen below:
Condenser Mics --XLR--> DMP3 XLR IN > DMP3 1/4" out > --TS cable--> Tascam US-122 Line In --USB--> Computer

Any help is much appreciated!

 

[RawDepth]

My DMP3 is completely quiet. (Well, until I get the level turned up too high.) I would try a few things to find the problem.

1. Turn the level control on the Tascam all the way down. If you use a separate preamp then you don't need anymore level boost at the interface.

2. Make sure that the phantom power on the Tascam is turned OFF.

3. Make sure that the Tascam input is set to line level and not guitar level.

4. Make sure both the DMP3 and Tascam are plugged into the same AC outlet.

5. Try using a balanced (trs) cable to connect the two units.

Process of elimination works best.

 

[cadbawdbawks]

My DMP3 is completely quiet. (Well, until I get the level turned up too high.) I would try a few things to find the problem.

1. Turn the level control on the Tascam all the way down. If you use a separate preamp then you don't need anymore level boost at the interface.

2. Make sure that the phantom power on the Tascam is turned OFF.

3. Make sure that the Tascam input is set to line level and not guitar level.

4. Make sure both the DMP3 and Tascam are plugged into the same AC outlet.

5. Try using a balanced (trs) cable to connect the two units.

Process of elimination works best.

Hi there, thanks for the response! I've tried everything but the TRS cables and it still doesn't seem to solve the humming issue. I realilzed though that if I push the phase switch for one channel and not the other, the humming noise goes a little quieter. On another note though, I've been testing both the internal preamp on my tascam us-122 and the DMP3 preamp and there is no difference in sound AT ALL. The only difference I can make out is that when the gain is turned up to about the 2 o clock position the DMP3 clips much easier than the tascam us-122 at a 3 o clock position. The recorded signal is always weaker on the DMP3 than on the Tascam US-122 preamps but the DMP3 clips much easier. I'm absolutely confused and fustrated at this point...totally regretting spending that money on the preamp.

Anyhow, thanks again for your help!

 

[cadbawdbawks]

still trying to figure this thing out..

Any help is much appreciated!

 

[RawDepth]

Hi there, thanks for the response! I've tried everything but the TRS cables and it still doesn't seem to solve the humming issue. I realilzed though that if I push the phase switch for one channel and not the other, the humming noise goes a little quieter. On another note though, I've been testing both the internal preamp on my tascam us-122 and the DMP3 preamp and there is no difference in sound AT ALL. The only difference I can make out is that when the gain is turned up to about the 2 o clock position the DMP3 clips much easier than the tascam us-122 at a 3 o clock position. The recorded signal is always weaker on the DMP3 than on the Tascam US-122 preamps but the DMP3 clips much easier. I'm absolutely confused and fustrated at this point...totally regretting spending that money on the preamp.

Anyhow, thanks again for your help!

The DMP3 uses VU meters instead of digital meters. Since this type of meter shows more of a signal strength average, it takes more signal peaks to get the needle to move higher, (compared to digital metering which is real time.) That is why it appears to clip sooner. At any rate, if it clips frequently then you are recording too hot. Turn it down slightly until it never clips. The peaks on your track waveform only need to be mostly between -10 and -20 dB, (or roughly there about.)

About the buzz:
Have you tried the hi/lo range switch on both settings? Set this according to how sensitive your mic is.

When the preamp volume is set less than 50% you should not hear any audible self-noise from that pre. If you do then take it back. It may be defective. But try a TSR cable first. You just never know, that TS cable may be causing some problem.

Hang in there, man. This is may turn into a good learning experience. Good luck with it.

 

[cadbawdbawks]

Thankyou again for all the help and encouragement you've offered. I really do appreciate the time you've put in to guide me through this. I have actually tried the hi/lo range switch on both settings to not much success.

I'm starting to think though (this may sound absurd) that my headphone out may be the cause to these problems. here's my reasoning:

I've realized actually that my recordings when played through my nearfield monitors are of a sufficient volume and even quite loud (not even close to as quiet as my headphone monitors), which makes sense as to why it would clip. During recording, when I monitor my vocals and instruments at a level that does not clip through the headphones, it seems awfully quiet (barely audible) even when the headphone knob is turned up to full blast. In turn, I am led to believe that I am recording at an insufficient level which then causes me to turn up the line level (to a point which clips frequently and causes a low level humming noise) so I can hear myself through the headphones. This is leading me to believe that my recordings are constantly clipping and have a low humming as a result of the possibly low grade headphone amp built into my interface which does not give me an accurate reference as to what the level my recording is actually at.

Could this be the problem to my frequent clipping? If so would an outboard headphone amplifier resolve this issue?

As for the quality of sound when comparing my DMP3 to the TASCAM US122 built in preamps, I still can't hear any difference...any ideas why?

Thanks again! I really do appreciate all the help you guys offer!

 

[RawDepth]

You should not need to buy a headphone amp. That Tascam already has one built in. That headphone volume knob should offer so much volume that it hurts your ears when turned up all the way.

When you say "a humming noise" do you mean a hiss? Most (if not all) preamps start to add a general background hiss when turned up too loud. It sounds like tape hiss. Is that what you are hearing? The word "humming" led me to believe that you had some sort of ground problem or a minor short. I am thinking you mean a buzzing sound. Can you clarify this more so?

I do not own the Tascam and have never used one before. Both of those preamps are "cheap" or "low budget" units and will probably sound similar. You won't notice much difference between any cheap preamps until you get into the $500 (and up) range of quality for a single channel. And even then, the differences are hard to detect on cheap monitors. However, you would notice the difference when compressing things hard or when stacking (mixing) multiple tracks together. That is when a good preamp starts to shine. But it still needs to be coupled with other good equipment to be effective. (Adding only one high performance part to your street car engine won't make you win the race. All of the parts need to be high performance.)

 

[cadbawdbawks]

That's interesting... I actually always have my headphone volume knob turned up to the max and it still doesn't seem that loud. It certainly doesnt "blow my ears out". It's actually so quiet to the point where I can just barely hear myself in the headphones when recording.

As for the humming sound. It certainly isn't a hiss or a buzz of any kind. I think though that this may just be the cause of my mics. I just tried turning on the preamp with phantom power as well but without my mics plugged in and the sound wasn't there at all. Would this be an indication that the humming was the problem of my mics picking up vibrations?

Thanks again for your help!