Recipe: how to cook a best in class 2-ch pre-amp with a/d convertor?

[5thString]

Just to let you know.... I emailed Five Fish Studios today to ask about the usability of their PSU in Europe, and this is the answer:
"The power transformers work with European voltages. The
transformer primary windings can be wired in series (for 220V) or in
parallel for 110V operation."

I think that should answer some questions here.

[john_fromAustria]

How about using an old personal computer power supply? I think that should work? It's capabel of multiple power outputs. Maximum 12v tough, but I think this still should work?

Can anyone tell me if that could work?

[thermos]

Sorry if you've seen this, but I'm selling a racked up/ready to roll one in the classifieds.

[R'shonn]

Hey anybody know what to make of this? (from the classified section) are they saying that you can't use the a/d converters in the pcm4222evm unless you use a special master clock, and that the 4222 is only good for working as a master clock for improving an external a/d interface? for ex: If I used the 4222 out to spdif > aroura lynx card, does that mean that the 4222 is just clocking the lynx card, and that the a/d is still being done by the chipset on the lynx?

somebody give insight, I orderd mine at the begining of the month an still havent got it (backordered)

Originally Posted by Rochey

that clock input is not for wordclock.
It's for masterclock.22.5792MHz ±50ppm (or 24MHz)

Good luck generating that .

/Rochey

Originally Posted by thermos

Wow, really? Are you sure? I best be doing some reading.


Edit: here is what the literature says.

"An external clock source (EXT CLOCK), may be input at BNC connector J11 and is buffered by U19. The
buffer includes a tri-state output, so that it may be disabled when one of the crystal oscillators is used as
the master clock source. Buffer U19 is always operated from the +3.3V supply generated by voltage
regulator U22, and is tolerant to +5V input logic levels. The maximum external master clock frequency is
27.648MHz."

Also, heres the pdf if you feel like reading more.
http://focus.ti.com/lit/ug/sbau124/sbau124.pdf

Originally Posted by Rochey

so in other words, your racked version of the PCM4222 EVM can only be used as the clock master in the system. You'll also have to pin out the word clock the device creates.

Good luck.

/Rochey

[5thString]

Originally Posted by R'shonn

Hey anybody know what to make of this? (from the classified section) are they saying that you can't use the a/d converters in the pcm4222evm unless you use a special master clock, and that the 4222 is only good for working as a master clock for improving an external a/d interface? for ex: If I used the 4222 out to spdif > aroura lynx card, does that mean that the 4222 is just clocking the lynx card, and that the a/d is still being done by the chipset on the lynx?

somebody give insight, I orderd mine at the begining of the month an still havent got it (backordered)

Absolutely not! From what I understand, this discussion only points out the fact that the external clock connector on the 4222evm can only be used to output a masterclock, not to use an external clock to drive the 4222.

But the 4222 is indeed an AD converter in itself!

[Rochey]

The PCM4222's evm has 3 different clock sources.

- 24.567 MHz Crystal
- 22.5792 MHz Crystal
- EXternal Clock. (at similar frequencies)

This makes the EVM (in it's default setting) act as the clock master.

The Data (including the self generated clocks) will come out of the pcm4222 and then into the DIT4192 S/PDIF generator which will then transmit AES data out.

Depending on the interface to the PC that you're feeding this device into, the interface may have to synchronise itself to the incoming S/PDIF.

However, if your product (like the lynx, or the digi192 digital I/O box) has a sample rate converter, then you needn't worry about it.

Running an ADC from it's own clock source, and allowing it to be the clock master will allow it to perform at it's best.

thanks again

Rochey.

P.S - if you DO want to make the PCM4222 a slave, then you'll need an external PLL to create the higher clocks, and drive the EVM appropriately.

Again - The PCM4222 is an awsome ADC, however, it's EVM was never designed to be used as an end product.

[5thString]

Hey guys.

Now I have another question, maybe slightly off-topic but related anyway. What if I want to build a complete ADA box using the PCM42222? I mean, I can use the PCM42222EVM for the AD part allright. What about the DA side? Do you know of a best-in-class DA board, maybe in EVM format as well, that could complete the setup?

[R'shonn]

Did anyone ever come up with a way to implement input limiting?

[Radioman]

Originally Posted by R'shonn

Did anyone ever come up with a way to implement input limiting?

limiter example

[René Hatt]

Although there are parts of answers spread over some threads, I've still got questions regarding more than 2 channels, and hopefully we can post the answers all together here...

So, is it possible to have more than 2 channels of the PCM4222EVM simultanously? What difficulties exist? As far as I can tell, the main problem is clocking.

Is it possible to send the clock from one unit to another, daisychaining the WC (if possible without using an external PLL)? What problems do arise, and how to overcome them? Or, at least, is it possible to use only one PLL for all 8 channels?
How difficult is it to build and implement a PLL?

Thanks!

[Radioman]

Originally Posted by René Hatt

So, is it possible to have more than 2 channels of the PCM4222EVM simultanously?

Is it possible to send the clock from one unit to another, daisychaining the WC (if possible without using an external PLL)? What problems do arise, and how to overcome them? Or, at least, is it possible to use only one PLL for all 8 channels?

Yes, and any PLL isn't necessary, you have only to pick the quartz clock output of one board and connect it into all the other boards inputs.
Pin 3 of the 2 quartz blocks (or maybe better pin 4 of U20) of PCM4222EVM connected to the Ext clock of all the other boards, the other boards setted on the external clock and all the other clock switch (SW6, SW3 etc) on the same settings.
The main problem is that you have only AES/EBU output available, so you have 4 AES/EBU (for 8 channel) and you must use a receiver board / DAW capable to accept 4 AES/EBU instead an Adat or a TDIF 8-channel stream.

[René Hatt]

Originally Posted by Radioman

Yes, and any PLL isn't necessary, you have only to pick the quartz clock output of one board and connect it into all the other boards inputs.
Pin 3 of the 2 quartz blocks (or maybe better pin 4 of U20) of PCM4222EVM connected to the Ext clock of all the other boards, the other boards setted on the external clock and all the other clock switch (SW6, SW3 etc) on the same settings.
The main problem is that you have only AES/EBU output available, so you have 4 AES/EBU (for 8 channel) and you must use a receiver board / DAW capable to accept 4 AES/EBU instead an Adat or a TDIF 8-channel stream.

Hey Radioman, thank you very much! Sounds good! I hope this is stable enough, then it really sounds easy.

Is there a clock setting (for SW6, SW3 etc) that is preferable?

I've got a Lynx AES-16SRC, so AES is no problem for me.

[Radioman]

Originally Posted by René Hatt

Is there a clock setting (for SW6, SW3 etc) that is preferable?

I've got a Lynx AES-16SRC, so AES is no problem for me.

1) i don't know, you have to sets the switchs depending the sample rate and other options you prefer, and set all the switch in the same manner on all the boards, except the clock source, internally setted on the master board, and "external" on all the slave boards.
2) connect the WClock line to the AES16SRC WClock external input too, and set the system clock on this flux. If the sample rate it's the same for the 4222EVM and the rest of the system disable the SRC flag option to preserve the maximum audio quality.

[René Hatt]

Originally Posted by Radioman

1) i don't know, you have to sets the switchs depending the sample rate and other options you prefer, and set all the switch in the same manner on all the boards, except the clock source, internally setted on the master board, and "external" on all the slave boards.
2) connect the WClock line to the AES16SRC WClock external input too, and set the system clock on this flux. If the sample rate it's the same for the 4222EVM and the rest of the system disable the SRC flag option to preserve the maximum audio quality.

Thank you very much! It all seems clear to me, and I hope it will be even more so when I'm finally sitting in front of the board. ;-)

BTW, what do you say about its sound?

Best, René

[wertt]

so, to double check everything that i've read in these 2 posts:

1) all i need (parts-wise) to put together a working converter is the pcm4222evm from ti ($150) and the power supply kit (regulated correctly) and transformer kit from five fish ($80 total). i'll then need to assemble the power supply and solder the supply wires to the pcm4222evm, but that's about it (aside from putting them in a box), correct?
2) i'm not 100% clear on how the spdif out works. when working at 44.1/48khz, do both spdif outputs spit out the signal in stereo? does only one of the jacks work? does one jack put out left and one right?

initially i'll be using this with my rack of 7th circle pres and, if everything goes well, i'll invest in another pair of the five fish pres. either way, you can't beat a $250 a/d converter.

[Radioman]

Originally Posted by wertt

so, to double check everything that i've read in these 2 posts:

1) all i need (parts-wise) to put together a working converter is the pcm4222evm from ti ($150) and the power supply kit (regulated correctly) and transformer kit from five fish ($80 total). i'll then need to assemble the power supply and solder the supply wires to the pcm4222evm, but that's about it (aside from putting them in a box), correct?
2) i'm not 100% clear on how the spdif out works. when working at 44.1/48khz, do both spdif outputs spit out the signal in stereo? does only one of the jacks work? does one jack put out left and one right?

initially i'll be using this with my rack of 7th circle pres and, if everything goes well, i'll invest in another pair of the five fish pres. either way, you can't beat a $250 a/d converter.

1) Yes, but you can use other power supply kits too.
The 7th circle PS03 switching power supply gives you all the voltage you need (+30, -30, +48) so you have only to reduce and stabilise them from +-30 to +-15V to drive the PCM4222EVM, and 200 mA are not a big flow (only 3 W) so the PS03 could drive all the set.
You have only to use a LM317 LM337 pairs like they are used in the A12 J99 T15 modules, or draw the regolated supply directly from a 7th module working at +-15V. If you want to use fivefish kits you can buy only the 1848 without the transformer and without mounting the 48V line driving it with the DC voltages taken from the PS03.

2) taken from the PCM4222EVM user guide: "When Mono mode is disabled, both the left and right channels are output on both AES3 Output #1 and #2.

This allows for simultaneous balanced and unbalanced transmission of the AES3-encoded output data" so at 44 or 48 khz you can drive 2 AES/EBU and/or Spdif gears simultaneously.

For the future the 7th pre T15 is virtually the same of the SC-1 but use a quieter chip (THAT1512), have a better supply regulation (LM317 LM337 instead the zeners), greater electrolytic supply capacitors and costs less, so (imho) it's a better choice especially if you have a 7th circle audio rack already.

[owel]

The zeners on the SC-1 PCB are not used for PSU regulation, FYI.

Just because you see a zener on the PCB, doesn't mean that's what it's used for.

I'm not using an AC-DC switching PSU, so no need for 317/337 on the preamp board.

I'm using a LINEAR power supply. So my 317/337 regulators are on my PSU board kit. Take your pick on which is a quieter PSU... switching or linear.

You can substitute a 1512 chip (both 1510/1512 are compatible) but you'll have 6db less gain. I tried a 1512 and 1510 and to my ears, they both sound the same and have same noise. But the 1510 is 6db more gain. Either way, you can swap it with a 1512 or 1510... or even an INA217 (but don't do the latter... the THAT chips are better :)

[wertt]

thanks much!

unfortunately, my 7th circle rack is actually full and, after reminding myself what the innards look like, i don't think there's anyway i'll be able to mount the board inside. it's a very tight fit and i'd have to find a place to put the board and mount the spdif outs on the back, which is unlikely. also, doesn't the PCM4222EVM need +5V as well for the digital components?

i'm a very capable solderer (i built all 8 channels in my sca rack and did several for a friend) but have a limited functional understanding of electronics. if i wanted to build another pair of t15s to mount with the converter in a new chassis, could i use a second five fish power supply to power the preamps? if so, do both power supplies need a transformer?

forgive my ignorance...i'm still a beginner in the electronics world and am good at following directions but not much else.

[wertt]

thanks for the reply owel. i may do your kits anyway just for some diversity.

so a couple more questions:

this power supply was mentioned in the other post for supplying the converters:

IHTAA-16W

since it runs about $65, am i better off going this route for the converter supply vs. $80 for the five fish psu and transformer kit?

and now my super amateur question: presuming that i then build a five fish supply and preamps, what do i need to do to wire my converter's supply into the iec jack and switch for the preamps? i know...stupid. that's how little i know.

[Radioman]

Originally Posted by owel

The zeners on the SC-1 PCB are not used for PSU regulation, FYI.

Just because you see a zener on the PCB, doesn't mean that's what it's used for.

I'm not using an AC-DC switching PSU, so no need for 317/337 on the preamp board.

I'm using a LINEAR power supply. So my 317/337 regulators are on my PSU board kit. Take your pick on which is a quieter PSU... switching or linear.

While SCA lists all the schematic and BOM into every module page i've searched for the SC-1 schematic into the fivefish website and i haven't found them, so i can't imagine the zeners are not used for the supply. Anyway SCA T15 have a 317-337 pair into the PCB, and they can be used to drive a T15 pre + a PCM4222EVM

[owel]

Schematics and BOMs for all my kits are included in the kit package inside the box. Thanks.

[Saxophonus]

Hi guys,

I´m about to start building an AD using 4 PCM4222 EVM boards. They will be connected via AES to a lynx AES16 for 8 channels of hopefully great sound (it better be after all the effort!)

Good info found on this thread.

I was just wondering if Rene was able to build the converter as per this radioman suggestions.

Yes, and any PLL isn't necessary, you have only to pick the quartz clock output of one board and connect it into all the other boards inputs.
Pin 3 of the 2 quartz blocks (or maybe better pin 4 of U20) of PCM4222EVM connected to the Ext clock of all the other boards, the other boards setted on the external clock and all the other clock switch (SW6, SW3 etc) on the same settings.

Also, it be cool if people that has tackled something similar could chime in to give suggestions, specially regarding to what kind of precautions and type of cable used to connect the clock from board to board.

Thanks for the help!!

[René Hatt]

Originally Posted by Saxophonus

I was just wondering if Rene was able to build the converter as per this radioman suggestion´s.

We are still waiting for our boards to arrive here in Switzerland, so no experiences to share yet.

It would be much appreciated if you could share your experience with building your units, and especially how well the clocking works. And of course, how it sounds!

Thanks, and best wishes,
René

[Saxophonus]

Hi Rene,

Well, I will post all I can but this is a project which is still on hold...I have the boards but I have no time to get my hands on them. Also, before this one I have a couple other projects that are ahead on priority. It may well be that you start before me!! Let´s try to help each other!

Have you thought of a power supply for it (comercial or DIY?) Haven´t made up my mind yet myself but I think it´s an important bit.

Thanks!

[peterwild]

I got last week my PCM4222. I have lynx AES16, but does anyone know what would be suitable mobile AES or SPDIF card etc. I would like to do mobile 4 CH recorder. I allready have mini-pc and 7" touch screen those are working with 12 volt.

[René Hatt]

Originally Posted by Saxophonus

Hi Rene,

Well, I will post all I can but this is a project which is still on hold...I have the boards but I have no time to get my hands on them. Also, before this one I have a couple other projects that are ahead on priority. It may well be that you start before me!! Let´s try to help each other!

Have you thought of a power supply for it (comercial or DIY?) Haven´t made up my mind yet myself but I think it´s an important bit.

Thanks!

Still no board here...

I've got a PSU for my API 512c that I will use for this project, before deciding which way to go. It's from Power One, comes without a case, and as far as I know it even has 5V connections.

[René Hatt]

How difficult would it be to implement an AES to FW convertor? I've got a Lynx AES16-SRC, so I'm equipped, but for some of my DIY friends it would be nice to have FW.