Whistle tone in Tentdac

jpfastre · 11th December 2006, 09:25 PM

I have a whistling tone of about 4 kHz with my TentDac.
Regulator U23 has a sinusoidal signal of 20mV pp and a period of 1.5 µsec.
Need help please.

janneman · 11th December 2006, 09:28 PM

Quote:

Originally posted by jpfastre
I have a whispling tone of about 4 kHz with myj TentDac.
Rengulator U23 has a sinusoidal signal of 20mV pp an d a period of 1.5 µsec.
Need help please.

Jan/Jeff/Jos did you try to contact Guido tent?

Jan Didden

jpfastre · 11th December 2006, 10:03 PM

I would write "whistle" and not "whisple"
Sorry.

SY · 11th December 2006, 10:09 PM

Quote:

Originally posted by jpfastre
I would write "whistle" and not "whisple"
Sorry.

Fixed.

Guido Tent · 12th December 2006, 05:45 PM

Quote:

Originally posted by jpfastre
I have a whistling tone of about 4 kHz with my TentDac.
Regulator U23 has a sinusoidal signal of 20mV pp and a period of 1.5 µsec.
Need help please.

Hi JP

The 1.5uS may stem with the speed of the phase comparator. U23 however feeds the reclocking logic.

Is the whistle tone audible at both channels ?

best

jpfastre · 13th December 2006, 01:40 AM

Quote:

Is the whistle tone audible at both channels

Yes the tone is in both channels.
I made a mistake with T=1.5 µSec, time base was set to x2.
T is 3 µSec.
The volume of the tone changes regulary and is lower when set to PAUZE and STOP. Loudest when playing music. I use the pcm1704 adapter, but changing this for a pcm1702 adapter from Linn has the same result.
I'll try to observe the results so I can give more to the point data.
Any recommandation what I have to test?
Kind regards.
JP

peranders · 13th December 2006, 05:52 AM

Have you tested an another signal source to rule out the DAC?

jpfastre · 13th December 2006, 09:25 PM

Quote:

Have you tested an another signal source to rule out the DAC?

I'll try it and report .
Thanks.
JP

jpfastre · 14th December 2006, 10:24 PM

Report: (att Guido and Peranders and others)

1 The tone comes from the RADIO input of my Quad 44 and not from the DAC. My mistake, I used Radio and not the CD input.
Maybe oscillation? All is n ormal with the tuner as source on this input.

2 The signal on the regulator U23 is a mystery for me. Can this affect the sound quality of the DAC?

3 The noise level on the direct output after the filter is about 8 mV pp. Measured with an old oscilloscope. Mostly hum and noise.
Is this value good? The noise is good detectable when playing loud and then the CD player set to PAUSE.

Help is welcome.
JP

Guido Tent · 15th December 2006, 07:36 AM

Quote:

Originally posted by jpfastre
Report: (att Guido and Peranders and others)

1 The tone comes from the RADIO input of my Quad 44 and not from the DAC. My mistake, I used Radio and not the CD input.
Maybe oscillation? All is n ormal with the tuner as source on this input.

2 The signal on the regulator U23 is a mystery for me. Can this affect the sound quality of the DAC?

3 The noise level on the direct output after the filter is about 8 mV pp. Measured with an old oscilloscope. Mostly hum and noise.
Is this value good? The noise is good detectable when playing loud and then the CD player set to PAUSE.

Help is welcome.
JP

Hi JP

2: I have no DAC available here curently, so cannot verify, but will do once my own DAC i back

best

11th December 2006, 09:25 PM	#1
jpfastre diyAudio Member Join Date: Mar 2005 Location: Tongeren	Whistle tone in Tentdac I have a whistling tone of about 4 kHz with my TentDac. Regulator U23 has a sinusoidal signal of 20mV pp and a period of 1.5 µsec. Need help please.

13th December 2006, 05:52 AM	#7
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Have you tested an another signal source to rule out the DAC? __________________ /Per-Anders (my first name) or P-A as my friends call me

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11th December 2006, 10:03 PM	#3
jpfastre diyAudio Member Join Date: Mar 2005 Location: Tongeren	I would write "whistle" and not "whisple" Sorry.

14th December 2006, 10:24 PM	#9
jpfastre diyAudio Member Join Date: Mar 2005 Location: Tongeren	Report: (att Guido and Peranders and others) 1 The tone comes from the RADIO input of my Quad 44 and not from the DAC. My mistake, I used Radio and not the CD input. Maybe oscillation? All is n ormal with the tuner as source on this input. 2 The signal on the regulator U23 is a mystery for me. Can this affect the sound quality of the DAC? 3 The noise level on the direct output after the filter is about 8 mV pp. Measured with an old oscilloscope. Mostly hum and noise. Is this value good? The noise is good detectable when playing loud and then the CD player set to PAUSE. Help is welcome. JP

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