Decklink Studio, Mixer, Y cable?? PLEASE..

[Justin Strauber]

Exactly what mixer are you using? Usually mixers with stereo inputs like that are balanced TRS.

[Tony Ienco]

Thanks for the reply, it is a Yamaha MG82CX but every time I plug any of the Decklink output channels into 3/4 and 5/6 Left (Mono) Inputs, I get LOUD distortion. The only ones I don’t get that from is the dedicated Mono channels 1 and 2???

Tony

[Bob Zelin]

here is a picture of your mixer –
https://static.musiciansfriend.com/derivates/19/001/327/896/DV020_Jpg_Jumbo_630139_V.jpg

You CANNOT use the XLR inputs. You must use the TRS 1/4″ inputs.
The Mic inputs will distort. In addition, you can see that the top knob is called GAIN – this is the trim control for the inputs – this appears on almost every mixer in the world. Turn all of these knobs all the way down (fully counter clockwise) and you will have no problems.

The XLR inputs are for -60dBu microphones only. No line inputs.

Bob Zelin

[Tony Ienco]

I was NOT using the XLR inputs, I was using the LEFT Mono input, but the instructions Clearly state these are unbalanced and it doesn’t matter where the gain was it made no difference at all. It looks like I either need a new mixer with more balanced inputs or perhaps I will build up the Jaycar kits that convert Balanced to unbalanced.. Thanks for the help anyway.

Tony

[Bob Zelin]

your distortion problem has nothing to do with this. For what you are doing (Decklink TRS balanced out into Yamaha mixer TS mono input), this is NOT going to cause distortion. Your distortion is happening because your signal coming out of the Decklink (+4dBu analog for example) is distorting the analog input of the mixer.
Almost every analog mixer in the last 20 years from Mackie, Behringer, Soundcraft and Yamaha can handle a +4dBu input from a source. If your mixer is distorting on these LINE inputs, then something else is wrong.

Would you like me to read the manual for you ?

Bob Zelin

[Tony Ienco]

Well I cannot for the life of me see what else it could be? Even when I plug Channel 1 & 2 from the Declink into the Left mono line input, it distorts where as it works PERFECTLY in the first two mono inputs of the mixer?

I am not sure if you are being sarcastic about reading the manual for me? I have read it several times. If you could offer any other advice as to what it might be, I would be great full.

Thanks
Tony.

Tony

[Bob Zelin]

1) here is the manual –
https://www2.yamaha.co.jp/manual/pdf/pa/english/mixers/mg82cx_en_om.pdf

from page 8 of the manual –
Let’s take a look at one of the most commonly used units in
audio: the decibel (dB). If the smallest sound that can be heard
by the human ear is given an arbitrary value of 1, then the
loudest sound that can be heard is approximately 1,000,000
(one million) times louder. That’s too many digits to deal with
for practical calculations, and so the more appropriate
“decibel” (dB) unit was created for sound-related
measurements. In this system the difference between the
softest and loudest sounds that can be heard is 120 dB. This
is a non-linear scale, and a difference of 3 dB actually results
in a doubling or halving of the loudness.
You might encounter a number of different varieties of the dB:
dBu, dBV, dBM and others, but the dBu is the basic decibel
unit. In the case of dBu, “0 dBu” is specified as a signal level of
0.775 volts. For example, if a microphone’s output level is –40
dBu (0.00775 V), then to raise that level to 0 dBu (0.775 V) in
the mixer’s preamp stage requires that the signal be amplified
by 100 times.
A mixer may be required to handle signals at a wide range of levels, and it is necessary match input and output
levels as closely as possible. In most cases the “nominal” level for a mixer’s input and outputs is marked on the
panel or listed in the owner’s manual.

REPLY – so 0VU on this mixer is .775 VAC, and 0 coming out of the Blackmagic is about 1.26 VAC. So the “zero’s” will not match.

from Page 15 of the manual
Sound is faint,
distorted, or noisy.
❑ Are the channel GAIN controls, LEVEL controls, STEREO Master control set to
appropriate levels?
❑ Are two different instruments connected to the XLR-type and phone jacks, or to the
phone and RCA pin jacks on one channel? Please connect to only one of these
jacks on each channel.
❑ Is the input signal from the connected device set to an appropriate level?
❑ Are you applying the effects at an appropriate level?
❑ Are microphones connected to the MIC input jacks on channels 1 to 5/6?
❑ If you are using condenser microphones, is the PHANTOM +48 V switch turned ON?

REPLY –
from page 56 of the manual –
ST CH LINE
INPUT (CHs 3/4,
5/6)
–34 dB
10 kΩ 600 Ω
Lines
–46 dBu (3.88 mV) –34 dBu (15.5 mV) –14 dBu (155 mV) Phone jack
+10 dB – 2 dBu (0.615 V) +10 dBu (2.45 V) +30 dBu (24.5V) (unbalanced)

THIS MEANS THAT YOUR INPUT 5 + 6 can handle a 10dBu signal (2.45 V) without distortion. If you are getting distortion, it’s not because your mixer can’t handle it on inputs 5 + 6 – unless the input preamp is blown (broken).

Do you have something else (besides the blackmagic, like a professional VTR, like a Beta VTR with XLR outputs) that you can stick into inputs 5+6 to see if you get distortion ?

Bob Zelin

[Tony Ienco]

Yes thank you I have a DVCAM deck so I will take the audio out of that and try it in the 3/4, 5/6 inputs..

Didn’t think of that, quickly assumed the inputs were not balanced causing the distortion, since Blackmagic make such a point about using Balanced cables….

I will post back in a little while. Most helpful. Thank you.

Tony

[Bob Zelin]

Tony –
I have re=read your post. I am starting to believe that you have a problem with your inexpensive mixer. Any of these line inputs should be able to handle the BALANCED input – even the unbalanced ones. The only thing you are possibly doing wrong is your trim (gain) control – and you said that the gain control only affects the XLR input – so you probably have a problem with the mixer. Behringer makes terrific very inexpensive mixers, so you should try one of them to resolve your issues.

Bob Zelin

[Tony Ienco]

No, the gain does effect the 6.5mm BUT even with the gain turned down to about half of 1 (one) the distortion is do loud it is terrible. I have been looking at a Peavey mixer? I have read many reviews on the internet about the Beringer, none of them favourable, because I defiantly considered buying one 2 weeks ago..

Tony