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Gear / Technical Help => Recording Gear => Topic started by: fandelive on May 06, 2016, 11:16:22 AM

Title: Adding gain from both recorder and preamp question
Post by: fandelive on May 06, 2016, 11:16:22 AM
I'm the proud owner of a Tascam DR-2d and a CA-9100 Church Audio preamp.
I've read on another thread that the CA-9100 can add up to +20dB gain when cranked to the max.

On the other hand, I couldn't find any information on how much gain can be added from the Tascam recorder itself (mic-in and/or line-in) when starting from 0 and cranking up to 100.

I recorded two shows recently and the first one came out with very low levels while the second one came out slightly distorted.
I've changed the setups on both the Tascam and the CA preamp for the second recording, but not much enough to suspect I'd get such a gap in gain between the two.

Both concerts were pretty similar in SPLs (same venue, same spot, same sound engineer, same kind of music).

1st recording :
CA-9100 (gain @ ~11 o'clock) > Tascam DR-2d (line-in - levels @ 96/100). Peak at ~ -20dB

2nd recording :
CA-9100 (gain @ ~12 o'clock) > Tascam DR-2d (line-in - levels @ 100/100). Sound was slightly distorted at loudest parts...

So there's more than 20dB gap between the two setups for +4/100 gain on the Tascam and +1(hour) gain on the CA preamp.

How can this be possible ? Is the preamp multiplying instead of adding gain to the recorder value ?

Thanks !
Title: Re: Adding gain from both recorder and preamp question
Post by: beatkilla on May 06, 2016, 01:37:30 PM
Is there a clip light on the church pre?

If so next time adjust the pre until it clips than back off a bit,than set recorder levels after.
Title: Re: Adding gain from both recorder and preamp question
Post by: nulldogmas on May 06, 2016, 02:05:05 PM
When you say "slightly distorted," do you mean clipping? (I.e., actual peaks visible hitting 0 dB.) There are other things that could be causing distortion...
Title: Re: Adding gain from both recorder and preamp question
Post by: fandelive on May 06, 2016, 08:04:00 PM
Yes, it's clipping, sorry about the confusion.
Title: Re: Adding gain from both recorder and preamp question
Post by: nulldogmas on May 06, 2016, 11:33:54 PM
And probably a stupid question, but I have to ask since you didn't say: Same mics?
Title: Re: Adding gain from both recorder and preamp question
Post by: fandelive on May 07, 2016, 01:56:23 AM
Yes, same mics also. DPA4061's.
Title: Re: Adding gain from both recorder and preamp question
Post by: swordfish on May 07, 2016, 02:32:01 AM
IMO it has to do with the level of the PA system, maybe it was a lot higher during the second recording...as far as I know at 11:00 the CA 9100 adds 0db.

Just to expalin happenend to em at one of the last shows I recorded...set levels  to -6 during the opener which was pretty loud and ended up with the main act clicking in around -21....
Title: Re: Adding gain from both recorder and preamp question
Post by: vanark on May 07, 2016, 06:50:13 AM
Are you certain the cable was actually plugged in all the way? I had this happen once and finally figured out I had been recording from the internal mics.
Title: Re: Adding gain from both recorder and preamp question
Post by: fandelive on May 07, 2016, 09:34:59 AM
IMO it has to do with the level of the PA system, maybe it was a lot higher during the second recording...as far as I know at 11:00 the CA 9100 adds 0db.

So let's say you start adding gain from the CA-9100 at ~8:00 (7:00 is OFF position) and the maximum gain you can add is at 5:00 : what's the use of the positions between 8:00 and 11:00 if you only start to add gain after 11:00 ?


Are you certain the cable was actually plugged in all the way? I had this happen once and finally figured out I had been recording from the internal mics.

I'm certain. The recording has that boomy omnis feel.
Title: Re: Adding gain from both recorder and preamp question
Post by: vanark on May 07, 2016, 09:56:27 AM
IMO it has to do with the level of the PA system, maybe it was a lot higher during the second recording...as far as I know at 11:00 the CA 9100 adds 0db.

So let's say you start adding gain from the CA-9100 at ~8:00 (7:00 is OFF position) and the maximum gain you can add is at 5:00 : what's the use of the positions between 8:00 and 11:00 if you only start to add gain after 11:00 ?


No, that isn't how it works on the 9100. 11:00 is +0 dB. Anything before that is attenuating the signal, not adding to it. That is the use.
Title: Re: Adding gain from both recorder and preamp question
Post by: fandelive on May 07, 2016, 10:54:23 AM
No, that isn't how it works on the 9100. 11:00 is +0 dB. Anything before that is attenuating the signal, not adding to it. That is the use.

Ok, and I've read on a thread about the Tascam DR-2d that it's line-in unity gain was around 95-96/100 and that you should never go lower or the recording will sound brickwalled.
I was set at 96/100 on the Tascam and I assume I added ~0 to 1dB with my CA-9100 knob positionned between 11 and 12.

Can the preamp introduce brickwalling when adding gain or attenuating the signal ?? (because that's what happened to me last night. You can check that thread : http://taperssection.com/index.php?topic=177533.0 (http://taperssection.com/index.php?topic=177533.0))
What should I do to avoid that ? Get a battery box ?

Thanks,
-fandelive