We are awaiting from some minor comments from THAT around the 4315 limiter we will be using, then design the pcb and build the first prototype with the THAT parts.
Of course I'm looking forward to that to make final judgements and eventual changes.
THAT line & mic output stage
Re: THAT line & mic output stage
Output side looks good. You may want to re-instate their Ferrite beads.carlmart wrote:This is the circuit with mods applied: diodes moved back before the caps and pot taken away.
You need expert advice from THAT on the input side. Don't think 1606 allows even 47R, let alone 47R + 1n. BOTH inputs need LoZ to GND
Re: THAT line & mic output stage
Well, the ferrite beads are there. It's the semi-circles close to pins 2 and 3.
That filter was suggested, if I am not wrong on single supply implementation for the 1646, which was in fact using just one input.
Of course I'm asking THAT all these questions and many others I don't even mention here.
That filter was suggested, if I am not wrong on single supply implementation for the 1646, which was in fact using just one input.
Of course I'm asking THAT all these questions and many others I don't even mention here.
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Re: THAT line & mic output stage
OK, this how the output now looks and the way we will use it.
A very nice trick THAT support suggested, and we adapted on our design was to use the resistor divider inside THAT 4315, which we are using on our limiter, and buffer it to feed all Vref on that channel.
A very nice trick THAT support suggested, and we adapted on our design was to use the resistor divider inside THAT 4315, which we are using on our limiter, and buffer it to feed all Vref on that channel.
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Re: THAT line & mic output stage
What Recorders are your preamps most likely to feed? Brands & Model Numbers?
Re: THAT line & mic output stage
Probably any type, but mostly DSLR video cameras.
Why is that?
Why is that?
Re: THAT line & mic output stage
Just for a comparison with an existing product, now very popular, the Tascam DR-60D recorder, which also has unbalanced outputs.
Its maximum output line level is 10dBV, which is 3.16v RMS, which this preamp should exceed.
What do you think it might have problems with?
Its maximum output line level is 10dBV, which is 3.16v RMS, which this preamp should exceed.
What do you think it might have problems with?
Re: THAT line & mic output stage
To check this, we need to know the INPUT spec. for the DSLRs. Got any favourites?carlmart wrote:What do you think it might have problems with?
I detail this process in my MicBuilders LNprimer document.
Why do you need a MIC setting for output? Are there DSLRs with XLR (or other 3p balanced) inputs which are ONLY Mic level?
Re: THAT line & mic output stage
This not the first time I build a preamp for video cameras, and I simply followed THAT's guidelines.
I'm not sure if I will not find a camera that will not have mic level output, so I have to be prepared. And I will use the unit for balanced and unbalanced situations.
The output cable will determine that, as there will be a multi-pin interface. The customer will get the cable he needs for his camera.
For instance, on my Blackmagic Pocket I can select which I want, and it's unbalanced. The Blackmagic BMCC has balanced inputs, both mic and line level.
I need this unit to be flexible.
I'm not sure if I will not find a camera that will not have mic level output, so I have to be prepared. And I will use the unit for balanced and unbalanced situations.
The output cable will determine that, as there will be a multi-pin interface. The customer will get the cable he needs for his camera.
For instance, on my Blackmagic Pocket I can select which I want, and it's unbalanced. The Blackmagic BMCC has balanced inputs, both mic and line level.
I need this unit to be flexible.
Re: THAT line & mic output stage
This http://www.blackmagicdesign.com/au/prod ... techspecs/ just sayscarlmart wrote:For instance, on my Blackmagic Pocket I can select which I want, and it's unbalanced.
Analog Audio Input
1 x 3.5mm stereo audio
Got a better spec? eg Input Sens.
Are you supplying the special cable to go from your device to the Blackmagic Pocket? How will it be wired?
What's a BMCC? It's not on that websiteThe Blackmagic BMCC has balanced inputs, both mic and line level.