A2D
Moderator: Joe Malone
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Re: A2D
Also, won't I have to attenuate the signal at some point so the converter doesn't clip?
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Re: A2D
You imagine correctlyThanks 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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if you want a exact input level to equal 0dBFS a 3 resistor pad can be added in between the XLR and Yellow , Blue wires. Just need to let me know the level you end up having to put in to hit 0dBFS.
Most common setup is +18dBu = 0dBFS for pro A/D, Next most common setup is +22dBu = 0dBFS. A pad would be added hit either of these exactly.
Joe ![Smile :-)](./images/smilies/icon_smile.gif)
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Re: A2D
Thank you Joe, sounds great. Just two more question: Will this configuration work well with balanced as well as unbalanced sources? Also, how much DC on the input can the transformer handle?
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Re: A2D
Yes balanced in or unbalanced in doesn't matter as it is a floating transformer input so does not care. You should never have DC on the input as almost everything is capacitive coupled output and any DC servo outs will not have more than a few mV so will not matter.living sounds wrote:Thank you Joe, sounds great. Just two more question: Will this configuration work well with balanced as well as unbalanced sources? Also, how much DC on the input can the transformer handle?
Joe ![Smile :-)](./images/smilies/icon_smile.gif)
JLM Audio
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Re: A2D
Thanks Joe! I'll report back when I've got the JLM14 installed.
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Re: A2D
I was always fascinated with this project, and hated to see that it wasn't issued as a kit. Were any components removed from the A/D board, or did the signal go through all the input circuitry before the A/D chip?
Thanks
Craig
Thanks
Craig
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Re: A2D
A row of caps were removed to allow the input transformer to feed direct into the A/D chip. A2D PCB is no longer available unfortunatelycraigmorris74 wrote:I was always fascinated with this project, and hated to see that it wasn't issued as a kit. Were any components removed from the A/D board, or did the signal go through all the input circuitry before the A/D chip?
Thanks
Craig
Joe ![Smile :-)](./images/smilies/icon_smile.gif)
JLM Audio
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Re: A2D
Thanks for the reply Joe. Interesting stuff!
I have an old SM Pro Audio ADAT board, and would love try hooking up a couple of JLM14's to it and see what it sounded like.
I have an old SM Pro Audio ADAT board, and would love try hooking up a couple of JLM14's to it and see what it sounded like.
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Re: A2D
If you can take a large clear in focus photo of the top and bottom of the SM Pro PCB I am sure I can draw the mod on there for you to try.craigmorris74 wrote:Thanks for the reply Joe. Interesting stuff!
I have an old SM Pro Audio ADAT board, and would love try hooking up a couple of JLM14's to it and see what it sounded like.
If made a huge difference.
Joe ![Smile :-)](./images/smilies/icon_smile.gif)
JLM Audio
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Re: A2D
Hey Joe,
Thanks again for your reply. I've attached photos of the top and the bottom of the board, as clear as I could get of the analog sections, and the schematic.
Thanks,
Craig
Thanks again for your reply. I've attached photos of the top and the bottom of the board, as clear as I could get of the analog sections, and the schematic.
Thanks,
Craig
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Re: A2D
EDITcraigmorris74 wrote:Hey Joe,
Thanks again for your reply. I've attached photos of the top and the bottom of the board, as clear as I could get of the analog sections, and the schematic.
Thanks,
Craig
We removed all 150R feeding 10uF and 9.53k resistors feeding opamp inputs and added wire under pcb between 10pin socket pin 1 to 4 and 7 to 10 going to each A/D input 1 to 8 via the 10uF just to make it easy to unplug the pcb.
JLM14 backwards giving -12dB loss so in front of the transformer we used a U pad made with 3 x 1k resistors to yellow and blue to give +18dBu input clip level. Green wires to 0v pin 5&6 on 10pin connector. Red wires in series with 120R or 220R to form filter with cap on A/D input.
Joe ![Smile :-)](./images/smilies/icon_smile.gif)
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Re: A2D
Hi Joe,
I finally got around to wiring the converter up like what I thought you described in the previous post. I think I made a mistake, because all I'm getting is a high pitched distorted splat if I hit something like a drum, otherwise no signal is going through at all. I removed the 10uF capacitor right before the converter-is that causing the problem?
Thanks,
Craig
I finally got around to wiring the converter up like what I thought you described in the previous post. I think I made a mistake, because all I'm getting is a high pitched distorted splat if I hit something like a drum, otherwise no signal is going through at all. I removed the 10uF capacitor right before the converter-is that causing the problem?
Thanks,
Craig
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Re: A2D
Never mind, put the capacitor back in and it's working. sounds great!. Comparable to my UA 2192.craigmorris74 wrote: ↑Fri Apr 02, 2021 2:05 pmHi Joe,
I finally got around to wiring the converter up like what I thought you described in the previous post. I think I made a mistake, because all I'm getting is a high pitched distorted splat if I hit something like a drum, otherwise no signal is going through at all. I removed the 10uF capacitor right before the converter-is that causing the problem?
Thanks,
Craig
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Re: A2D
Hi Craig cool great to hear you got it working. Yes needs 10uF cap as input is at about 1.8vdc. Great to hear you like the sound of it ![Smile :-)](./images/smilies/icon_smile.gif)
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Joe ![Smile :-)](./images/smilies/icon_smile.gif)
JLM Audio
Capturing Audio without Injury
![Smile :-)](./images/smilies/icon_smile.gif)
JLM Audio
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