How about building a 8in 8out line preamp with adat light pipe?

How about building a 8in 8out line preamp with adat light pipe? Is that a good idea?
Discrete differential buffer? or audio transformer?
Any good idea? or things that I need to be aware of?
Thanks!

what you are really talking about is an 8-channel analog to digital converter. that is the first and biggest (massive/huge) problem you need to solve. choosing between active input or transformer is a piece of cake in comparison.

Based on the type of questions you're asking, you should probably concentrate on making an simple preamp first.

Hum...... how simple is simple? a single 2N3904 transistor? I am talking about since we need to be stuck with the wavefront IC to do the adat optical is there anyway around it? or TCXO will help to lower the jitter? DC servo? I am not just building a 8ch ADC it should be a 8ch ADC and 8ch DAC at the same time, with digital bypass, I am thinking about when you are not using the adat interface options you can actually use it as a line preamp as well??  :

Adky said:

.....it should be a 8ch ADC and 8ch DAC at the same time, with digital bypass, I am thinking about when you are not using the adat interface options you can actually use it as a line preamp as well??  :

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Would that be the only reason for a DAC? If so, why not have direct  outs from the preamp?

If so I can add relay to switch between DAC out or Direct out, What about instrument DI input?

Is it like no matters how good the spec of the DAC or ADC chip I use , I am still running into the Wavefront bottle neck?

Adky said:

Is it like no matters how good the spec of the DAC or ADC chip I use , I am still running into the Wavefront bottle neck?

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Why use a DAC when you dont need it?

I sure do need the 8ch output for analog mixing......

If you're using wavefronr ics anyway, just buy a behringer ad8000 and mod the crap out of it. 8 I/o and adat I/o. Tada, just saved you a ton of time.

Without the wavefront 1401 you can still make adat lightpipe possible?

OK! My plan is using a discrete front end preamp with differential input to CS5981 to AL1401 with TCXO 2ppm crystal clock, DC servo power supply, how's about that? 8)

How do you plan to slave to another clock?

Also - you may find the costbenefit to be lower than expected on a converter.
I mean, you could hack a behringer box for not much more than it'd cost to make one.

Internal and external clock with BNC socket Use 89S52A, 74HCT4052, 74HC4040 this box will run up to 24bit 192K

Adky said:

Internal and external clock with BNC socket Use 89S52A, 74HCT4052, 74HC4040 this box will run up to 24bit 192K

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Unfortunately not over ADAT......
Unless you're designing a new lightpipe protocol ?

Oh man! I am stuck in the adat maze now! 4046? 74HC153?

Any suggestions? Anyone?

MADI

I believe the max with lightpipe is 24/96 using 2 lightpipe channels for 1 source.

gemini86 said:

If you're using wavefronr ics anyway, just buy a behringer ad8000 and mod the crap out of it. 8 I/o and adat I/o. Tada, just saved you a ton of time.

Click to expand...

The new ADA8000 have other chipsets (cirrus i believe). And there are some problems with "auto mute" and some delay at the beginning of ad conversion regarding this chips.

For the 1401 I can send out odd and even samples to make it 192K I think!.......hum.......... actually I dont need 192K maybe 96K will do!

Adky,

for 192kHz, you may as well use S/PDIF.

I don't understand your solution for generating MCK/BCK from LRCK(Wordclock). You have a processor and logic gates. You have not specified a PLL of any kind.

Best Regards

Rochey