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Old 14th January 2012, 04:19 PM   #711
tvicol is offline tvicol  Romania
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Quote:
Originally Posted by Jempie View Post
it's the same board as you can buy from tibi.
turn the volume up, and disconnoct the source you will hear hum
Jempie,

There are two 0 ohm resistors on the board R42L and R42R.
These are connecting VC ground to VC power suppply ground.
Normally these resistors shouldn't be connected. However, we have provided them in case you want to make a single ground star for all power sources in your design.
If these resistor are not connected, than you should search for hum elsewhere, because in this case VC is completely isolated from any power supply.

Regards,
Tibi

Last edited by tvicol; 14th January 2012 at 04:23 PM.
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Old 21st January 2012, 09:54 PM   #712
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Hi Jempie,
Did you cure the hum problem ?
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Old 6th February 2012, 02:45 AM   #713
aditya is offline aditya  India
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Default pcb layout for TDA7439DS

hi
made this pcb for replacing my pga2311 ( vvvvvvvery sweet chip) card, since things are modular in my amp.. i can relace the processor, amp, power filters. so even my preamp is sort of modular...

anyways just posting the pic of the pcb... let me how to improve it more.. if possible..

yes i know i should have used mkt capz.... but .... i wanted to make it small and couldnt source all the cap in same chemical family in bombay market.. anyways.. did what i could
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Old 14th February 2012, 06:54 PM   #714
tvicol is offline tvicol  Romania
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For those who like to use avrdude, I have added a small how to:
http://vicol-audio.ro/img/volume-con...r_firmware.pdf

Also more documentation is available at vicol audio : r-2r volume controller

Regards,
Tibi
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Old 18th February 2012, 03:30 PM   #715
TBKK is offline TBKK  Germany
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Farmtech

According to the regular r2r schematic the resistors are

R30-R40
10k 2.5k 5.8k 15k 53k 390k
R31-R41
82k 47k 27k 16k 12k 10k

If you compare link Logarithmic Attenuator Calculator

The value are different

10k 8k2 5k6 3k9. I have the Same problem as jempie
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Old 19th February 2012, 06:53 AM   #716
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Hi
I did not make the electronic part of this only made some software (addons) for it
so better ask one that know more about R2R than I do
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Old 19th February 2012, 08:52 PM   #717
TBKK is offline TBKK  Germany
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I hate also that the volume at "0" is not really quit
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Old 22nd February 2012, 12:42 PM   #718
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TBKK,
use 7relais R/2R with "-127dB" at "0" volume level like i did
Or recalc R/2R for -127dB with 2dB step

Last edited by Pryanick; 22nd February 2012 at 12:46 PM.
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Old 23rd February 2012, 07:35 AM   #719
Jempie is offline Jempie  Indonesia
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Tbbk,

I have the same problems, clinking is
reduce thanks to Pryanick.

Will try now to recalculate the resistors
With steps of 1.5 dB or 2 dB
still is not easy to make it right
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Old 23rd February 2012, 08:11 AM   #720
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Jempie,
the only way to do it right is do it ones in a proper way
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