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Hello,
I finished building my CODs and will be completing the IVY assembly by tomorrow. I have few questions on connecting the mono outputs to IVY. I will be using the RCA out from IVY to my amplifier.
1. Should I be using the passive I/V conversion on COD or let IVY do the conversion.
2. For the mono connection: (1 is COD-Left and 2 is COD-Right)
L1+ & R1- to IVY L+
L1- & R1+ to IVY L-
L2+ & R2- to IVY R+
L2- & R2+ to IVY R-
3. In one of the emails Russ metioned using 2 IVY modules. In that case will I be seeing any difference since I will be using the RCA outs.
Any other suggestions on this configuration will be helpful.
Thanks
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1) use the jumpers and omit the resistors as stated in the COD manual.
2) wire like this:
LDAC:L+ and R- to IVY L+
LDAC:L- and R+ to IVY L-
RDAC:R+ and L- to IVY R+
RDAC:R- and L+ to IVY R-
Everything should work just fine. :)
I would use the resistor values as specified for stereo Buffalo since the current swing will be about the same.
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Rank: Advanced Member
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Thanks Russ. I will report back once I complete.
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Rank: Advanced Member
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Hello Russ,
I finished my dual mono COD with IVY last night. Everything turned on well and working. I Let it running for a few mins and the OPA1632s on IVY were hot.
I am using 1% resistors on IVY. Does this could be a problem for the over heating? I measured the 1% resistors and the values were
R13-R16 - 176 Ohms
R5-R12 - 382 Ohms
R1-R4 - 740 Ohms
2K2 resistors were 0.1%.
For the power supplies, I use a 2 placid singles (COD VA on one placid and rest all powered by another placid) and 1 bipolar (+/- 15v) for IVY.
The setup is
S/PDIF (8804) -> Metronome -> Dual CODs -> IVY - Single Out.
The temparature on the OPA1632s were not in the comfortable range. I will post some pics later today or tomorrow if you need to look at them.
Is it normal for the OPAs to get hot and should I put some heat sinks on top of them?
Thanks
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Rank: Administration
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It is perfectly normal for the OPA6132 to run hot. Don't worry over it. :) It has a very high bias current. See the datasheet for more info. If it is running normally and sounds good, then you are in fine shape. Edited by user Saturday, May 29, 2010 8:41:00 PM(UTC)
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Rank: Advanced Member
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Thanks Russ for the quick reply. I will case them and put up some pictures in the project gallery. Do you have any suggestions for cases which can fit my setup?
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Hello Russ,
I have a problem with Metronome ASRC. After few mins of running, the C4 capacitor is hot and the music gets distorted. It happened once and after that every time when I turn on the kit, the music is distorted and C4 gets hot. I can feel the heat on the back side of the board.
If I remove Metronome and directly connect the S/PDIF to COD, the sound is fine without any distortion.
What could be the problem here? Any pointers on debugging the issue will be helpful.
Thanks!
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Can you post a close-up photo of the Metronome?
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That cap is itself would not be causing the heat, it is likely heat coming from the regulator (IC3) which is close by. It sounds like there is a short or possibly a wiring problem. Pictures would definitely help.
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It also could be that the supply voltage into the metronome is too high.
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Rank: Advanced Member
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Hello Brian / Russ, Thanks for your replies. I did some checking on the board and here is what I found. Input Voltage - 7.2 volts Output of IC3 - 3.24 volts Voltage across C1/C2 - 3.24 volts Voltage across C4 - 7.2 volts Also as Russ mentioned, the heat was mostly around IC3 and L2 which I could sense on C4 as well. Attached is the close-up picture of metronome. Edited by user Monday, May 31, 2010 10:25:46 AM(UTC)
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I think it's just a warm Vreg. Try dropping the input voltage to 5-5.5V or so.
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Brian, I reduced the voltage to 5.5v and the metronome doesn't get hot that much. But the other problem where there is lot of static in music exists. Static or noise exist when I bypass the ASRC through the switch also. When I remove the metronome everything works well. I tried rerouting the cables / using shielded cable etc but the problem doesn't go away.
I had mounted the ASRC on top of the S/PDIF module. Please let me what could be the problem here?
Thanks
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Typically, that kind of noise it related to I2S routing proximity to power wires. Can you provide a picture of how have it routed?
Other, less likely causes could be a damaged component (vreg, cap, chip). You built this unit yourself, correct?
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Brian, I am attaching the pictures of my build and I built this myself. One thing I noticed was when I disable using the "Disable" jumper the audio is little better (with static still present) also touching the ASRC board varies the noise. Also the voltage output at Vreg is about 3.8 volts. I can try replacing the Vreg ( I have a spare, but others I need to order them, which I don't want to do unless we find out if any of the Caps or chip itself is damaged). S/PDIF and ASRC are stacked and both CODs are stacked. The wire I used is a 26SWG Shielded / Stranded cable as you can see from the picture. Thanks Edited by user Saturday, June 5, 2010 5:54:06 PM(UTC)
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Those supply and output wires are very long. It could be they are picking up noise.
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The disable jumper turns off the clock. Which makes the ASRC not work.
3.8V does not sound right at the VREG. :)
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Russ, thats what I thought about the VReg, I will try replacing the Vreg as I have one spare and then re-arrange the board to shorten the wires. Can I mount the ASRC upside down so that input and output wires don't cross each other. That way I place the COD sideways to shorten the wire.
Thanks
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It is possible the ASRC itself is damaged if it was seeing too high a voltage.
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Russ, as per SRC4192 Datasheet, the absolute maximum ratings for all the voltages are -0.3 to +4.0V. Also the ASRC would have been on for a maximum of 5 - 10 mins. Let me change the Vreg and see how it goes. On the question about mounting the Metronome upside down, do you see any problems? Edited by user Saturday, June 5, 2010 9:14:36 PM(UTC)
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