Marantz CD-7 audio output mod.

D.A.R.R.Y.L. · 17th January 2006, 08:29 PM

Hi All,
Having succesfully modified the output of my denon 2900 with two Mundorf Supreme Silver/oil 1µF's I am willing to try to mod the output of my Marantz CD-7 also.

The cd-7 already has a Tent XO2 with XO supply, but I love what the cap change on the denon did, so I am willing to try it on the cd-7.

Included are the schematics of the parts concerned with modding the output of the CD-7.
From the HDAM (Marantz opamps) the signal, we take left channel as a guide, passes through R718 and then through the Elna's I want to replace, through relay L702 and then straight to the XLR connector.

I can not remove the caps and replace them with a wire, as I measured 0,5volt DC over these caps. So they definitely serve a purpose as to remove the dc component.

I was handed a formula to calculate the actual value needed for the replace cap, dictated by the lower cutt-of freq needed (in the order of 5 Hz) and the input impedance of the amplifier connected.

For the denon 2900 I calculated that 1µF would suffice due to the extreem high impedance of my Electrocompaniet ECI-4 of 330 Kohm.

Can I do the same for my xlr connected CD-7 to the same amp, or should I be concerned with the dc component of 0,5 volt over the two 220µF caps? Will a 1µF (Mundorf Supreme Silver/oil) as a replacement be able to also remove this dc component? Or will any cap remove this component? Or is there a formula for which cap value removes what dc component?

Thanks a lot!!

jean-paul · 17th January 2006, 09:39 PM

Quote:

Originally posted by D.A.R.R.Y.L.
Will a 1µF (Mundorf Supreme Silver/oil) as a replacement be able to also remove this dc component?

Yes.

Quote:

Originally posted by D.A.R.R.Y.L.
Or will any cap remove this component?

Yes.Some have more leakage than others. Electrolytics are the worst for this purpose ( in general ).

Quote:

Originally posted by D.A.R.R.Y.L.
Or is there a formula for which cap value removes what dc component?

No.

Please do not forget R720 in your calculations for the correct value for the capacitor.

f=1/(2xPixRxC). This is the -3dB point. So 100k parallel with the amps 330k = 76,7 kOhm

1/ ( 2 x 3,14 x 76.000 x 1exp10-6 ) = 2 Herz

X.G. · 17th January 2006, 11:32 PM

hi, D.A.R.R.Y.L.

could you share me the schematic and PCB layout papers of CD7?

thanks a lot.my email box is jmxg007@tom.com

X.G.

D.A.R.R.Y.L. · 18th January 2006, 08:14 AM

Hi Tom,

Thanks for your advise Jean Paul!

It is 6mb in size, can your mailbox handle this?

jean-paul · 18th January 2006, 08:29 AM

My mailbox can handle that

D.A.R.R.Y.L. · 18th January 2006, 08:31 AM

And your e-mail is?

jean-paul · 18th January 2006, 08:40 AM

I have sent you a PM....

D.A.R.R.Y.L. · 18th January 2006, 10:29 AM

Jean Paul,

is there any danger in changing the output with regards to killing a HDAM?

jean-paul · 18th January 2006, 11:18 AM

Not really if you don't short things.

D.A.R.R.Y.L. · 18th January 2006, 07:17 PM

Ok thanks I will give it a go.

Regrads,
Ramon

17th January 2006, 08:29 PM	#1
D.A.R.R.Y.L. diyAudio Member Join Date: Mar 2002 Location: Haarlem	Marantz CD-7 audio output mod. Hi All, Having succesfully modified the output of my denon 2900 with two Mundorf Supreme Silver/oil 1µF's I am willing to try to mod the output of my Marantz CD-7 also. The cd-7 already has a Tent XO2 with XO supply, but I love what the cap change on the denon did, so I am willing to try it on the cd-7. Included are the schematics of the parts concerned with modding the output of the CD-7. From the HDAM (Marantz opamps) the signal, we take left channel as a guide, passes through R718 and then through the Elna's I want to replace, through relay L702 and then straight to the XLR connector. I can not remove the caps and replace them with a wire, as I measured 0,5volt DC over these caps. So they definitely serve a purpose as to remove the dc component. I was handed a formula to calculate the actual value needed for the replace cap, dictated by the lower cutt-of freq needed (in the order of 5 Hz) and the input impedance of the amplifier connected. For the denon 2900 I calculated that 1µF would suffice due to the extreem high impedance of my Electrocompaniet ECI-4 of 330 Kohm. Can I do the same for my xlr connected CD-7 to the same amp, or should I be concerned with the dc component of 0,5 volt over the two 220µF caps? Will a 1µF (Mundorf Supreme Silver/oil) as a replacement be able to also remove this dc component? Or will any cap remove this component? Or is there a formula for which cap value removes what dc component? Thanks a lot!! __________________ {Marantz CD-7 Guido Tent Clock ---> HMS Sestetto MKII XLR ---> Electrocompaniet ECI-4 ---> Kimber 8TC ---> Eros MKII DIY}

18th January 2006, 08:14 AM	#4
D.A.R.R.Y.L. diyAudio Member Join Date: Mar 2002 Location: Haarlem	Hi Tom, Thanks for your advise Jean Paul! It is 6mb in size, can your mailbox handle this? __________________ {Marantz CD-7 Guido Tent Clock ---> HMS Sestetto MKII XLR ---> Electrocompaniet ECI-4 ---> Kimber 8TC ---> Eros MKII DIY}

18th January 2006, 08:29 AM	#5
jean-paul diyAudio Moderator Emeritus Join Date: Sep 2002 Location: The Netherlands	My mailbox can handle that __________________ It's only audio

18th January 2006, 08:31 AM	#6
D.A.R.R.Y.L. diyAudio Member Join Date: Mar 2002 Location: Haarlem	And your e-mail is? __________________ {Marantz CD-7 Guido Tent Clock ---> HMS Sestetto MKII XLR ---> Electrocompaniet ECI-4 ---> Kimber 8TC ---> Eros MKII DIY}

18th January 2006, 08:40 AM	#7
jean-paul diyAudio Moderator Emeritus Join Date: Sep 2002 Location: The Netherlands	I have sent you a PM.... __________________ It's only audio


	Please consider donating to help us continue to serve you. Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving

17th January 2006, 11:32 PM	#3
X.G. diyAudio Member Join Date: Sep 2003 Location: GuangDong China	hi, D.A.R.R.Y.L. could you share me the schematic and PCB layout papers of CD7? thanks a lot.my email box is jmxg007@tom.com X.G.

18th January 2006, 10:29 AM	#8
D.A.R.R.Y.L. diyAudio Member Join Date: Mar 2002 Location: Haarlem	Jean Paul, is there any danger in changing the output with regards to killing a HDAM? __________________ {Marantz CD-7 Guido Tent Clock ---> HMS Sestetto MKII XLR ---> Electrocompaniet ECI-4 ---> Kimber 8TC ---> Eros MKII DIY}

18th January 2006, 11:18 AM	#9
jean-paul diyAudio Moderator Emeritus Join Date: Sep 2002 Location: The Netherlands	Not really if you don't short things. __________________ It's only audio

18th January 2006, 07:17 PM	#10
D.A.R.R.Y.L. diyAudio Member Join Date: Mar 2002 Location: Haarlem	Ok thanks I will give it a go. Regrads, Ramon __________________ {Marantz CD-7 Guido Tent Clock ---> HMS Sestetto MKII XLR ---> Electrocompaniet ECI-4 ---> Kimber 8TC ---> Eros MKII DIY}

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