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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: cleantone on January 07, 2007, 11:30:35 AM
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Hey! I have had a V3 for a few years. I always would record with the AES output to a MOTU unit. I now will be using an Alesis HD24XR. This unit takes +4 balenced 1/4 inputs. In the past I have given an analog feed to various recording units and they have always been hot. Tascam DA types, various consoles, and others. I used my new recorder over the holiday for three nights. I had to run the V3's inputs almost all the way counter clockwise to keep the signal to my recorder under 0. I really wish this unit could be calibrated like a lot of other two channel preamps. I thought there was a jumper for the output but when I looked into it I realized there isn't one. When I had my unit's polarity fixed I asked about checking the outputs and Grace said they would run all of the tests. I assume it is not just my unit. I don't have a full grasp of the physics of sound. I know the difference between -10 and +4 but would have assumed that the V3 would play nice with the Alesis unit. Anyone else run into this? What the hell gear is this thing supposed to play nice with if I can't use it on a +4 input? I can't remember an instance of using the analog section with normal results. I hate to think of using pads inline. I also hate to think of not using my V3 anymore. I only have 6 channels of rackmount preamps as of now. I have a Soundcraft Spirit for a bunch of preamps too of course. Any ideas? Reports?
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from the manual..
""The V3 can be used as a line level A/D converter. If input signal levels are not expected to exceed +15dBu (i.e. consumer unbalanced signal from a CD player, DAT recorder, home stereo receiver or cassette deck) then simply connect an unbalanced signal into the V3, set the input gain control to 10 and adjust the trim control for optimum recording levels. See the figure below for proper unbalanced input termination. If professional balanced signals are to be used, set the internal 20dB input attenuator jumpers. Remember to reset these before recording with a microphone again.""
Im not sure if this helps...
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In responce to Eric,
hhhhm. Thanks. I don't think this would help me here. Using only the analog sections padding the input would not effect the output stage. I want to be able to run the input at a normal level (almost peaked) to get a good sound. Then that sound should be able to come out of the analog outs at a level that my recorder can handle. All without external pads. I feel like this should be quite possible. The Alesis is not he most high end piece of gear but it is not a peice of crap either.
I looked over the manual a little bit. The meters seemingly show the output levels. It says that 0 on the V3 is +25dBu on output. That is for a balenced connection. It is supposed to be +19 with an unbalenced connection. The Alesis is supposed to have a maximum input of +19dBu. According to the manual the V3 is +19 when the meter reads -6. I seem to recall the meters being closer to -15 or less. Maybe I had a little more headroom though. I guess my first step would be to use an unbalenced cable for the V3 > HD24 connection. That should be a start. I just wish when I first sent a tone though the V3 that the meters would have been equal on the two units. I guess I shouldn't be surprised that it is not that simple. That is why I wish there was a little recessed output trim pot for the V3 like on my other preamps. Then you can just calibrate the preamp to work with any recording unit. That would be nice.
Anymore input would be great (a little less output would be too) < that is a pun ;)
In responce to Moke,
If that was the case between these two units I would have no issue. I couldn't come close to amber without clippin the Alesis. At least that is how I recall it. I'll have to hook the stuff back up to be sure. Thanks! +T to you both.
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Ah! That helps a bit. But the Alesis has no input level control. When I'm using a console I can send it though there to play with the trim on a line input channel. The bugger is that a lot of the time I wont be bothering to have a console with me. In fact I'll phase that out as soon as I can afford some more outboard preamps. I want to have a variety of preamps. I want to stay away from presonus and other crap like that. I would ideally like to have a wide variety of boutique preamps to choose from for different applications. A lot of remote rigs have 24 channels of the SAME PREAMP. That seems a bit limiting to me in a lot of ways. I'll have to figure out the best solution for this somehow. I wish the Alesis had 2 channels of AES/EBU for this use.
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I ran into this same problem the first time I ran a V3 into my HD-24. My eventual solution was to use the V3 as the master clock for the HD-24 and just record the V3 tracks onto a separate recorder (MT2496 in my case). It's easy enough to align the 2 extra tracks since the two units are running off the same word clock and now I have 26 tracks to work with each night.
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Pretty good solution Scott. I was just hoping not to have to lug my old Mac based rig around anymore unless I had to go above 24 channels. For important recordings I could clock my MOTU 896(s) from the V3 and link to the Alesis. That way I could not only record the V3 channels on my Mac but I could "back up" other rooms mics, or subgroups to help make a faster reference mix. Save me from having to mix ALL of the multitrack tracks for a reference. A fair amount of work for sure. Again I just wish the outputs had a trim for calibration. That would be the ideal. Maybe I'll just stop using the friggin V3 thought I hate to think of that happening.
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Maybe I'll just stop using the friggin V3
Let's not say anything we'll regret in the morning! :o
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Thanks guys! I'm concerned with gain staging though. I know the V3 is a pretty quiet unit. I still want to run my preamp (any model) at a good level. I have to assume running the unit peaking at -18 or something (on the unit) would screw up the signal to noise ratio. I know other preamps, espessially tube pre's wouldn't sound as good when run very low. See my dilema?
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The HD24XR actually has pretty damn good converters. That RME is a nice little unit but I'd rather buy a new preamp than one of those. I have a couple of MOTU 896's and I could sync the clocks and use those AES inputs if I really wanted to. If I'm not mistaken (at a glance) I'd lose 6 channels of audio using that RME unit. Well, I suppose using other preamps with a/d's, or a/d's themselves could be used along with the V3 with the RME. Bottom line is that the V3 would be much better (for my needs) with an output trim pot. Most preamps have them because they come in very handy. Thanks.
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I'm not quite clear on what you're trying to accomplish. Here's what I think you're trying to accomplish:
Send the V3 an analog signal (from mics, presumably, but could be other sources). Amplify that signal with the V3's preamp. (Do not use the V3 ADC at all; ignore the V3 level meters outright.) Send the V3's analog output to an outboard ADC that does not have input trim. Adjust accordingly using the V3's stepped and variable trim gain so the V3's analog output to the outboard ADC achieves desired levels.
Is this correct?
If so, you really only have two options:
- Run the V3 with internal input attenuator jumpers set to 0 (i.e. not attenuating), and use however much / little gain you need to achieve proper levels on the outboard ADC. I would expect this option to work if you're sending the V3 a mic-level signal.
- Run the V3 with internal input attenuator jumpers set to -20 dB, and use however much / little gain you need to achieve proper levels on the outboard ADC. I would expect this option to work if you're sending the V3 a line-level signal.
Unless I'm missing something, one of these two options should provide the results you desire. Am I missing something?
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Thanks! Maybe I have a misconception. What you said is true by the way. This part made me a little puzzled:
ignore the V3 level meters outright
What exactly are the meters showing me? Input? Output? I have always assumed that the meters would be showing input gain and that level would be the same as the output. The V3 has plenty of gain for me. They would be used with mics exclusivly. I don't really understand how padding the input is going to take my output down. The output must be effected by the level controls right? They are input gain knobs right? They are not output trim knobs are they? They are not setup like any I am familiar with if so. Oh well. Thanks again.
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What exactly are the meters showing me? Input? Output? I have always assumed that the meters would be showing input gain and that level would be the same as the output.
The V3's level meters are true dBFS meters, i.e. they tell you the level of the signal -at- the V3's ADC (they measure the level in the digital realm), NOT the level of the signal outputting via analog.
I don't really understand how padding the input is going to take my output down. The output must be effected by the level controls right? They are input gain knobs right? They are not output trim knobs are they? They are not setup like any I am familiar with if so. Oh well. Thanks again.
The V3's stepped and variable trim gain definitely control the strength of signal via the analog outputs (in concert with the internal pads, if used). They also simultaneously control the level of the signal hitting the V3's ADC. But in your case, since you're not using the V3's ADC, you should ignore the V3's level meters outright and use the level meters on your ADC.
Not sure if that makes any more sense...
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Oh wow, thanks. That makes perfect sense. I now wonder why the ADC section can take a lot more gain that the analog. So I now have to ignore the meters on the V3 and only use the meters on my recorder.
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I just posted this in another thread.
http://taperssection.com/index.php/topic,77346.15.html
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here's a great thread over on tapeop that i enjoyed and may have some bearing to this conversation:
http://messageboard.tapeop.com/viewtopic.php?t=38430