A2D

Support for JLM Audio Kits

Moderator: Joe Malone

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mfdu
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Postby mfdu » Tue Aug 21, 2007 10:25 am

bring on 96k s/mux capability, that's what i reckon - i've been eying off the m-audio Profire Lightbridge as a replacement for my 002R, and 16 channels of 24/96 via s/mux would be so much more usable than the same on AES xlr's. . .

chris
mfdu
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Mick@ITC
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ADAT Vs AES

Postby Mick@ITC » Thu Sep 13, 2007 12:32 pm

Hi all

Being a novice in the technical side of this world, I would like to ask a question re ADAT lightpipe versus AES connection. Are there any pros and cons I should be aware of?. I have chosen to connect my converters via lightpipe to my computer interface. Is this the "best" (however we define that?) method or are there reasons to use AES connection over and above lightpipe? Also if someone can explain the ADAT sync connection I am finding on some equipment versus the fact that I am daisy chaining them together with word clock connection??
Thansk for your input.

Regards
Mick
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chrisp
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Postby chrisp » Fri Sep 14, 2007 10:05 am

Mick

While AES does have a multichannel fibre optic version, it is not typically found in audio gear except live staging applications to get sound around stadiums.

Most AES connections are copper wire with 3 pin XLR connections: they carry 2 channels of audio, compared to ADAT's 8. Both contain embedded timing signals, although most would say that AES is better in this regard. If devices are clocked externally via BNC wordclock or ADAT sync, this is less relevant.

While on ADAT sync, its simply a timing protocol (an alternative to BNC wordclock) with D plug connections - ADAT tape machines used it to stay in sync with one another, and some MotU interfaces also have them as a sync option. Its lost a lot of ground to wordclock, though, and if you don't currently use it I wouldn't try to implement it now. Stick with wordclock.

What is "best" is highly subjective - depends a lot on what you've got and how it all hangs together. Often necessity drives the answer - if you have more channels than your interface has analog inputs, you're going to have to use something, and that something is often digital.

Its easily to get swallowed in the technical mire, but clocking aside, the digital conversion and transport is unlikely to be the ruin of a recording. Look more at the quality and placement of your mics, and the quality of your preamps. The only real problem, as I've said, is clocking. The fact that you're using wordclock is a great start, but that means all your gear is sync'd to the one master clock. Just make sure its the best one you have, or if on doubt look at a dedicated external clock, such as an Apogee Big Ben.
Chris P
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I do lots of things. I believe eclectic skills are best.

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Mick@ITC
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Postby Mick@ITC » Tue Sep 18, 2007 1:33 pm

Excellent answer, you have helped me a lot, many thanks. The wordclock comments are what I have been "banking" on to date with my set-up. I'm wordclocking to the best I have based on price of the unit...!!! :lol: not the most scientific method but hey dont know how to measure clock quality. Anyway, I fully agree that there are many many more things I work on to get the quality of the recoding as high as possible but it is nice to know I have some of it under control... :wink:

Thansk again
Mick
Mick

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WWW.Grapevinestudios.com.au

chrisp
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Postby chrisp » Tue Sep 18, 2007 2:44 pm

You're welcome.
Chris P

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I do lots of things. I believe eclectic skills are best.

malfunction
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Postby malfunction » Wed Apr 09, 2008 7:15 am

So anything new regarding this AD?

Ausrock
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Postby Ausrock » Fri Apr 11, 2008 5:24 pm

Comments like this one from 12 months ago "worry" me.............."In fact theres no functional reason to use any analog gear any more......."

8)
Digital information lasts forever......................or maybe five years.

Whichever comes first.

conleycd
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Postby conleycd » Wed Jun 04, 2008 3:01 am

I would really love to see this kit available. Any sense of if it will happen? If not, I won't hold my breath and I'll look for something different.

Thanks guys for all the great kits that you do turn out.

CC

conleycd
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Re: A2D

Postby conleycd » Mon Dec 08, 2008 5:55 am

I'm still eager for this original kit (please let me have it) ... but on the "new card lines" I wonder if some of the Focusrite stuff might do the job here. I know it is a little more expensive but:

there's:

http://www.focusrite.com/products/isa/i ... d_isa_828/
http://www.focusrite.com/products/plati ... _adat_adc/
http://www.focusrite.com/products/plati ... _spec_adc/

http://www.focusrite.com/products/plati ... _le_codec/ - this one has a DA too.

Of course they would all need a little reverse engineering. I did look at the Lynx stuff but I think those cards are too dependent on the other guts that are inside the Lynx units.

CC

skipwave
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Re: A2D

Postby skipwave » Sat Feb 28, 2009 8:03 am

I'm interested in a kit as well. Just got an M-Audio Lightbridge to run PT M-powered at home.

living sounds
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Re: A2D

Postby living sounds » Wed Oct 01, 2014 9:54 pm

I'd very much like to replace the differential op amp on the input of my PCM4222EVM converter with a couple JLM14. Would this be possible? Schematic attached.

Thanks!
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Joe Malone
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Re: A2D

Postby Joe Malone » Wed Oct 08, 2014 1:34 pm

living sounds wrote:I'd very much like to replace the differential op amp on the input of my PCM4222EVM converter with a couple JLM14. Would this be possible? Schematic attached.

Thanks!


Yes remove R1, R2 C1, C2 and R3, R4 to isolate the opamp circuit.

wire JLM14 yellow to XLR pin 2
wire JLM14 blue to XLR pin 3
wire JLM14 red to TP6 VINR+ (PCM4222 pin 2)
wire JLM14 green to TP5 VINR- (PCM4222 pin 3)
wire JLM14 black to either VCOMR pin 48 (should solder to R23 end that connects to C64)
or wire JLM14 black to pin 6 of OPA227UA which is buffer version of VCOMR.

Black wire must go to one or the other as this gives the voltage potential to pin 2 & pin 3 of the PCM4222

If the frequency response has a high end bump in the response it could be C61 2.7nF but I think it will we fine with it still there.
Joe :-)
JLM Audio
Capturing Audio without Injury

living sounds
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Re: A2D

Postby living sounds » Wed Oct 15, 2014 8:55 pm

Joe Malone wrote:
Yes remove R1, R2 C1, C2 and R3, R4 to isolate the opamp circuit.

wire JLM14 yellow to XLR pin 2
wire JLM14 blue to XLR pin 3
wire JLM14 red to TP6 VINR+ (PCM4222 pin 2)
wire JLM14 green to TP5 VINR- (PCM4222 pin 3)
wire JLM14 black to either VCOMR pin 48 (should solder to R23 end that connects to C64)
or wire JLM14 black to pin 6 of OPA227UA which is buffer version of VCOMR.

Black wire must go to one or the other as this gives the voltage potential to pin 2 & pin 3 of the PCM4222

If the frequency response has a high end bump in the response it could be C61 2.7nF but I think it will we fine with it still there.


Thank you very much, Joe! To be honest, I was expecting something more complicated with resistors isolating the secondaries from the DC bias source and for termination. Is the JLM14 a gapped transformer? Is there a datasheet availible (couldn't find one online)? Thanks again.

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Joe Malone
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Re: A2D

Postby Joe Malone » Wed Oct 15, 2014 9:29 pm

living sounds wrote:
Joe Malone wrote:
Yes remove R1, R2 C1, C2 and R3, R4 to isolate the opamp circuit.

wire JLM14 yellow to XLR pin 2
wire JLM14 blue to XLR pin 3
wire JLM14 red to TP6 VINR+ (PCM4222 pin 2)
wire JLM14 green to TP5 VINR- (PCM4222 pin 3)
wire JLM14 black to either VCOMR pin 48 (should solder to R23 end that connects to C64)
or wire JLM14 black to pin 6 of OPA227UA which is buffer version of VCOMR.

Black wire must go to one or the other as this gives the voltage potential to pin 2 & pin 3 of the PCM4222

If the frequency response has a high end bump in the response it could be C61 2.7nF but I think it will we fine with it still there.


Thank you very much, Joe! To be honest, I was expecting something more complicated with resistors isolating the secondaries from the DC bias source and for termination. Is the JLM14 a gapped transformer? Is there a datasheet availible (couldn't find one online)? Thanks again.


Because the transformer has equal current from the centre tap there is no need for gapping as currents to each input cancel each other out.
Joe :-)

JLM Audio

Capturing Audio without Injury

living sounds
Posts: 27
Joined: Tue Jul 17, 2007 6:54 am

Re: A2D

Postby living sounds » Wed Oct 15, 2014 11:33 pm

Joe Malone wrote:
living sounds wrote:
Joe Malone wrote:
Yes remove R1, R2 C1, C2 and R3, R4 to isolate the opamp circuit.

wire JLM14 yellow to XLR pin 2
wire JLM14 blue to XLR pin 3
wire JLM14 red to TP6 VINR+ (PCM4222 pin 2)
wire JLM14 green to TP5 VINR- (PCM4222 pin 3)
wire JLM14 black to either VCOMR pin 48 (should solder to R23 end that connects to C64)
or wire JLM14 black to pin 6 of OPA227UA which is buffer version of VCOMR.

Black wire must go to one or the other as this gives the voltage potential to pin 2 & pin 3 of the PCM4222

If the frequency response has a high end bump in the response it could be C61 2.7nF but I think it will we fine with it still there.


Thank you very much, Joe! To be honest, I was expecting something more complicated with resistors isolating the secondaries from the DC bias source and for termination. Is the JLM14 a gapped transformer? Is there a datasheet availible (couldn't find one online)? Thanks again.


Because the transformer has equal current from the centre tap there is no need for gapping as currents to each input cancel each other out.


Thanks Joe! Is there a drawing of the JLM14 windings so I can understand the wiring? From your description I would imagine that yellow and blue are the primaries in a single winding, and red and green are two secondary windings with black the center tap?

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