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Old 15th August 2010, 11:54 PM   #2921
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Does the edit button go away after a while?

I checked my R-Core transformer, and the voltages are 18VAC and 10.6VAC.

Over the acceptable range.. but I don't see why the LM317's couldn't handle it.
In either case, the VREF voltages nearly matches the 10.6VAC, only DC.
so, it does seem to be the case that one of the regulators is malfunctioning.

The resistors on it are fine though.

I suppose I will contact gigawork now. I hope they compensate my shipping.
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Old 16th August 2010, 02:55 AM   #2922
pchw is offline pchw  United States
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It has a while, I think there are 2 set of AC inputs - one requires 0 - 9-ish VAC, and the other requires 13-0-13 center tapped VAC. Check the AC at the DAC's AC input. I believe the 13-0-13 is for the opamps, and the 0 - 9 is for the DAC. If what is supposed to be around 13-0-13, and you get 18-0-10, then it can be a wiring error or defective R-core. Did gigawork sell you the R-core? If so, did he provide any wiring diagram?
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Old 16th August 2010, 04:06 AM   #2923
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I guess I should've been more explicit.

Yes, It is an R-Core from gigawork.
I get 18 - 0 - 18 VAC
and 0 - 10.5 VAC

I have two really cheap multimeters and they both say about the same thing.

It seems pretty hard to screw up the wiring, but yeah there is documentation on the wiring.

Even with these higher voltages, it seems like the LM317's should be fine.
I looked at the datasheet, and they should be able to easily handle it... might get a bit hotter though.

Therefore, I don't think the higher VAC has anything to do with the malfunctioning regulator.
I am not going to replace the regulator myself, cause it won't be warranted if I screw it up.
I've contacted gigawork, and hopefully I'll get a response tonight.

Last edited by nullstring; 16th August 2010 at 04:10 AM.
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Old 16th August 2010, 04:23 AM   #2924
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I am going to reiterate the situation, because it seems like my information is all over the place and is confusing people.
  1. I received my DAC and hooked it up via USB.
    I was getting pops, clicks, and intermittent hissing.
    I messed with different opamps and DAC DIP settings, upsampling and non-upsampling
  2. pchw suggested I check my opamp voltage, and so I did. It was in normal range.
    I figured that if low opamp voltage could cause this, low DAC voltage could easily do the same thing. so I figured I would check that as well.
  3. I checked each of the Voltages of the DAC and found that VREF was way out of spec at ~10.5V's. (should be 5V) Others were perfectly fine.
  4. I checked the VAC of my transformer and found that the outputs were 0 - 10.5 and 18 - 0 - 18.
    [The R-Core is marked 9 - 0 - 9 and 15 - 0 - 15.]

    I don't think these voltages are related to my problem though. The LM317's should be fine with it.
  5. Because the VREF is about the same voltage 10.6VAC and 10.7V or so as the input voltage, I figured that there must be an issue with a regulator.
    I checked to make sure the resistors were correct, they were.
  6. I don't think there is anything else I can do but to contact gigawork and get a replacement.

Last edited by nullstring; 16th August 2010 at 04:36 AM.
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Old 16th August 2010, 07:54 AM   #2925
WDYSUN is offline WDYSUN  Italy
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Hello,

my usb input never worked (at any sample rate). Did you try what happens on the SPDIF input?

Best
Pietro
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Old 16th August 2010, 08:54 AM   #2926
repeet is offline repeet  Australia
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Hi, my transformer voltages are even higher.
19.9-0-19.9v brown and yellow wires
0-11.75v blue wires
252v~ input to primary (should be 240v in Australia)

I just put the high secondary voltage down to the high primary supply.

I am having problems with hum though. Not sure if this could be related.

Pete.
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Old 16th August 2010, 10:14 AM   #2927
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Quote:
Originally Posted by nullstring View Post
so, I decided to check the voltages of the DAC while I was at it.

VD, Digital Power - 3.33 - NORMAL
VA, Analog Power - 5.1 or so - NORMAL
VREF, Voltage Referance - 10.15V !!!!

Is that normal? The Datasheet for the DAC says it should be in the 5V range.

EDIT: so there is no way thats right, looking at the schematic.
I am thinking maybe my transformer is output 10V and that the regulator in charge of that is doing nothing at all.

how do I figure out which regulator it is?


Is it time to send it back?
According to the schematic, VA and VREF are fed from the same reg. If this is true they will measure the same. You can check the reg outputs by measuring across the 3 smaller caps next to the 3 5V regs.
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Old 16th August 2010, 12:48 PM   #2928
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Yeah, I just looked at the schematic, and all of those caps are connected to ground, so I should be able to measure across any of them.

I'll look at it after work tonight.

Thanks

Last edited by nullstring; 16th August 2010 at 12:51 PM.
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Old 16th August 2010, 01:26 PM   #2929
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Another thing that would be nice is if one of you with a CS4398 wouldn't mind checking the VREF of your own DAC.
It's possible that the regulator isn't under load enough to actually regulate anything (which in case it doesn't matter.., maybe?)

If there is anyone who wouldn't mind:
Check the voltage across pins 16 and 17. (VREF and REF_GND).
http://www.cirrus.com/en/pubs/proDat.../CS4398_F1.pdf page 6.

I'd really appreciate it.
Thanks.


PS-
I really hate that I can't edit my posts after 30 minutes.
I think I am going to become the king of double posts.
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Old 16th August 2010, 03:18 PM   #2930
WDYSUN is offline WDYSUN  Italy
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Default Lundhal connection

Hello Dears

today I got a new pair of Lundhal LL1690. I would like to connect them without any additional filtering... straight to dac!

I need some help, actually I am not sure I understood how to connect it. The trafo-01.jpg (attached pics) is the trafo's electrical schema, then trafo-02.jpg is the way I understood I should connect to the dac for right channel, say. Did I get it correct?

Best
Pietro
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File Type: jpg trafo-02.jpg (64.6 KB, 348 views)
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