nad phono stage

reddish75 · 2nd June 2008, 10:13 PM

hi i have an old nad 3020 that im currently restoring, it was in very bad shape, its all going well appart from the phono stage when i apply a sinewave to it, it turns it into a square wave, having not really dealt with phonostages before i was wondering if this was correct because the trace on my friends oscilloscope is the same for left and right at the pre-amp output, its just that its a square wave!

any help would be appreciated

thanks
chris

leadbelly · 2nd June 2008, 10:16 PM

No it's not right, of course. What are the ranges for your input and output? Is your output range so low that it is clipping off the peaks?

adason · 2nd June 2008, 10:17 PM

may be you are clipping it heavily

djk · 3rd June 2008, 09:58 AM

Clipping?

For sure.

A phono input only handles a few mV (0.001V).

You also need an inverse RIAA filter to check response.

2nd June 2008, 10:13 PM	#1
reddish75 diyAudio Member Join Date: Aug 2006	nad phono stage hi i have an old nad 3020 that im currently restoring, it was in very bad shape, its all going well appart from the phono stage when i apply a sinewave to it, it turns it into a square wave, having not really dealt with phonostages before i was wondering if this was correct because the trace on my friends oscilloscope is the same for left and right at the pre-amp output, its just that its a square wave! any help would be appreciated thanks chris

2nd June 2008, 10:16 PM	#2
leadbelly diyAudio Member Join Date: Dec 2002 Location: Calgary, Alberta	No it's not right, of course. What are the ranges for your input and output? Is your output range so low that it is clipping off the peaks? __________________ Aerodynamics are for people who can't build engines. Enzo Ferrari

3rd June 2008, 09:58 AM	#4
djk diyAudio Member Join Date: Feb 2001 Location: USA	Clipping? For sure. A phono input only handles a few mV (0.001V). You also need an inverse RIAA filter to check response. __________________ Candidates for the Darwin Award should not read this author.

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2nd June 2008, 10:17 PM	#3
adason diyAudio Member Join Date: Nov 2004 Location: troll in US	may be you are clipping it heavily

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