finding pre-amp outputs

chuck55 · 22nd September 2008, 07:14 PM

I'm trying to find the pre-amp for my Denon UD-M31.
I traced the amp outputs fom the back of the recv'r.
They are the 4 black and white wires at the bottom of the pic.

Going into the amp board is the ribbon cable and 5 wires colored black , red, orange ,blue. Is this the preamp input?
If so, how do I know which is the left right or ground wires?

Sorry my post was longer but internet erased my original.

chuck55 · 22nd September 2008, 07:27 PM

chuck55 · 22nd September 2008, 07:28 PM

chuck55 · 22nd September 2008, 07:31 PM

posted pic at you-tube under preamp since this computer cant process IMG

chuck55 · 22nd September 2008, 07:36 PM

or try my account at youtube.com
chuck123456789000000

gain · 22nd September 2008, 11:48 PM

the best way to do this imo is to get the schematic for the amp, find where the preamp connects to the input stage of the power amp(s) and tap it there. thats how i did it on a kenwood dolby 5.1 to extract the pre-outs for each of the six channels. just find the front-most component on the input stage of the PA (typically a coupling cap) and solder a wire right onto the leg or pcb trace for it. in my case i was able to quickly check my work by using a high impedance ear bud to listen to the preamp channel i had just tapped with the receiver in speaker-test mode.

chuck55 · 26th September 2008, 03:08 AM

Hi Gain,

But where do I get the schematic/ Denon won't give it out.

Still trying to upload photos [doesn't like IMG]

chuck55 · 26th September 2008, 03:12 AM

try youtube again.

I think I got an IMG this time

22nd September 2008, 07:14 PM	#1
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	finding pre-amp outputs I'm trying to find the pre-amp for my Denon UD-M31. I traced the amp outputs fom the back of the recv'r. They are the 4 black and white wires at the bottom of the pic. Going into the amp board is the ribbon cable and 5 wires colored black , red, orange ,blue. Is this the preamp input? If so, how do I know which is the left right or ground wires? Sorry my post was longer but internet erased my original.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Balanced outputs used as inverting & Non-inverting preamplier outputs	gni	Solid State	4	19th September 2008 03:25 AM
8V on outputs	dome406	Chip Amps	3	11th September 2005 03:16 PM
Fosgate outputs	clayton	Car Audio	2	23rd July 2004 02:14 AM
Selling outputs...	li_gangyi	Swap Meet	0	2nd September 2003 01:56 PM
how low is 'low DC' on SOZ outputs?	psarin	Pass Labs	8	8th March 2002 01:39 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	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

22nd September 2008, 07:27 PM	#2
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	<object width="425" height="350"> <param name="movie" value="http://www.youtube.com/v/2c6-odysKBc"> </param> <embed src="http://www.youtube.com/v/2c6-odysKBc" type="application/x-shockwave-flash" width="425" height="350"> </embed> </object>

22nd September 2008, 07:28 PM	#3
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	<object width="425" height="350"> <param name="movie" value="http://www.youtube.com/v/-y7W6CRwiB0"> </param> <embed src="http://www.youtube.com/v/-y7W6CRwiB0" type="application/x-shockwave-flash" width="425" height="350"> </embed> </object>

22nd September 2008, 07:31 PM	#4
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	posted pic at you-tube under preamp since this computer cant process IMG

22nd September 2008, 07:36 PM	#5
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	or try my account at youtube.com chuck123456789000000

22nd September 2008, 11:48 PM	#6
gain diyAudio Member Join Date: Apr 2008	the best way to do this imo is to get the schematic for the amp, find where the preamp connects to the input stage of the power amp(s) and tap it there. thats how i did it on a kenwood dolby 5.1 to extract the pre-outs for each of the six channels. just find the front-most component on the input stage of the PA (typically a coupling cap) and solder a wire right onto the leg or pcb trace for it. in my case i was able to quickly check my work by using a high impedance ear bud to listen to the preamp channel i had just tapped with the receiver in speaker-test mode.

26th September 2008, 03:08 AM	#7
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	Hi Gain, But where do I get the schematic/ Denon won't give it out. Still trying to upload photos [doesn't like IMG]

26th September 2008, 03:12 AM	#8
chuck55 diyAudio Member Join Date: Dec 2003 Location: New England	try youtube again. I think I got an IMG this time

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)