Stereo to mono...

mcelaj · 15th May 2005, 12:24 AM

I tried hooking up the two outputs out of my gainclone into one speaker and it would distort (clip I guess). Is there a way to do this without causing the distortion, perhaps attenuate the signal? Perhaps the signals should be combined before it gets to the amplifier, or pre-amp (phono stage), which would entail putting together a monoblock, which I don't mind undertaking. Any help on a stereo to mono conversion would be most appreciatred.

anatech · 15th May 2005, 01:28 AM

Hi mcelaj,
You must be very careful about hooking amplifier outputs together. Normally this can not be done. When it can, the amp is either bridged or it's a tube amp and it may be in parallel. There is normally a switch to allow for this.

You almost let the magic smoke out of the box, and you wouldn't be the first to do this, this way.

-Chris

rabbitz · 15th May 2005, 12:51 PM

You have to do the mixing at line level prior to the power amp or bang and smoke.

Have a look here for a simple circuit using 2 resistors which I used on one amp with a switch to use stereo or mixed mono. Very handy also for sub inputs from line or speaker level but the speaker level has to be attenuated first with a voltage divider.

http://www.tkk.fi/Misc/Electronics/c...s/linesum.html

I'll add the speaker attenuation circuit as well.

http://www.tkk.fi/Misc/Electronics/c...r_to_line.html

mcelaj · 15th May 2005, 06:10 PM

Fortunately I didn't get the puff of smoke as I tried it from my gainclone into a Decware Radial speaker. Would have been a shame to lose them. Thanks for the response guys.

amt · 16th May 2005, 06:00 PM

So Rabbitz,

Are both these circuits essentially what are used in a sub plate amps?
Ive been thinking of building a sub amp, using an inexpensive car audio electronic xo. Would adding both circuits, allow for either speaker level signal use or line level, such as found on most all powered subs?

thx amt

BobEllis · 16th May 2005, 10:44 PM

does your circuit look something like the PA-100 in this app note? http://www.national.com/an/AN/AN-1192.pdf - the point when it comes top paralleling chip amps is to use a series reistance between the chip outputs. If the DC offset of each is significantly different you may want to consider a servo like that shown in the BPA200 circuit in the same note.

amplifierguru · 17th May 2005, 12:09 AM

Use 2 speakers! One amp per speaker - works for me. Or antiphase one for bridge if the speaker Z is high enough.

anatech · 17th May 2005, 01:15 AM

Right on amplifierguru. That's the best way since you now have lower voice coil temps. Efficiency goes up. Amps stay cooler and excursion may be lower.

-Chris

rabbitz · 17th May 2005, 01:30 PM

Quote:

Originally posted by amt
So Rabbitz,

Are both these circuits essentially what are used in a sub plate amps?
Ive been thinking of building a sub amp, using an inexpensive car audio electronic xo. Would adding both circuits, allow for either speaker level signal use or line level, such as found on most all powered subs?

thx amt

Basically it is all they use. Built a P101 sub amp with a sub processor which has an attenuation circuit and then a mixer. I've got it set up so I can use line or speaker level with a switch selecting either.

Stereo Speaker level> attenuation > mixer to mono> processor
or when switched
Stereo Line level> mixer to mono> processor (chosen by a jumper)
LFE> processor (chosen by a jumper)

amt · 17th May 2005, 03:45 PM

Excellent! I just so happen to have two P101 boards here and just waiting for Mosfets to arrive.

15th May 2005, 12:24 AM	#1
mcelaj diyAudio Member Join Date: Nov 2003 Location: N/A	Stereo to mono... I tried hooking up the two outputs out of my gainclone into one speaker and it would distort (clip I guess). Is there a way to do this without causing the distortion, perhaps attenuate the signal? Perhaps the signals should be combined before it gets to the amplifier, or pre-amp (phono stage), which would entail putting together a monoblock, which I don't mind undertaking. Any help on a stereo to mono conversion would be most appreciatred.

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15th May 2005, 01:28 AM	#2
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi mcelaj, You must be very careful about hooking amplifier outputs together. Normally this can not be done. When it can, the amp is either bridged or it's a tube amp and it may be in parallel. There is normally a switch to allow for this. You almost let the magic smoke out of the box, and you wouldn't be the first to do this, this way. -Chris

15th May 2005, 12:51 PM	#3
rabbitz diyAudio Member Join Date: Jul 2003 Location: Newcastle, Australia	You have to do the mixing at line level prior to the power amp or bang and smoke. Have a look here for a simple circuit using 2 resistors which I used on one amp with a switch to use stereo or mixed mono. Very handy also for sub inputs from line or speaker level but the speaker level has to be attenuated first with a voltage divider. http://www.tkk.fi/Misc/Electronics/c...s/linesum.html I'll add the speaker attenuation circuit as well. http://www.tkk.fi/Misc/Electronics/c...r_to_line.html

15th May 2005, 06:10 PM	#4
mcelaj diyAudio Member Join Date: Nov 2003 Location: N/A	Fortunately I didn't get the puff of smoke as I tried it from my gainclone into a Decware Radial speaker. Would have been a shame to lose them. Thanks for the response guys.

16th May 2005, 06:00 PM	#5
amt diyAudio Member Join Date: Feb 2003 Location: oregon	So Rabbitz, Are both these circuits essentially what are used in a sub plate amps? Ive been thinking of building a sub amp, using an inexpensive car audio electronic xo. Would adding both circuits, allow for either speaker level signal use or line level, such as found on most all powered subs? thx amt

16th May 2005, 10:44 PM	#6
BobEllis diyAudio Member Join Date: Sep 2003 Location: Upstate NY	does your circuit look something like the PA-100 in this app note? http://www.national.com/an/AN/AN-1192.pdf - the point when it comes top paralleling chip amps is to use a series reistance between the chip outputs. If the DC offset of each is significantly different you may want to consider a servo like that shown in the BPA200 circuit in the same note.

17th May 2005, 12:09 AM	#7
amplifierguru Account Disabled Join Date: Aug 2004 Location: Earth	Use 2 speakers! One amp per speaker - works for me. Or antiphase one for bridge if the speaker Z is high enough.

17th May 2005, 01:15 AM	#8
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Right on amplifierguru. That's the best way since you now have lower voice coil temps. Efficiency goes up. Amps stay cooler and excursion may be lower. -Chris

17th May 2005, 03:45 PM	#10
amt diyAudio Member Join Date: Feb 2003 Location: oregon	Excellent! I just so happen to have two P101 boards here and just waiting for Mosfets to arrive.

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