Dual outputs from pre-amp. Adding sub.

[Anders76]

Hi
New here with a question


Im planing to use a pre-amp that have both XLR ( balanced ), and RCA out.
XLR is going to my poweramp, and I was planing to use the RCA out, to feed my SUB. That only offer rca mono input.
SO, for this reason I was planing to use a rca y-cable ( stereo to mono ), se pic.
Will this work? Or do I think wrong here??

( sorry for my badass paint skills and my bad English )..

Regards//Anders

 

[RayDunzl]

No.

You shouldn't combine two outputs with a simple Y cable.

Split one output to two inputs, generally safe.

Combine two outputs to one input without additional circuitry, I think "not advised".

You will be creating a "short circuit" between the channels.

 

[Anders76]

No.

You shouldn't combine two outputs with a simple Y cable.

Split one output to two inputs, safe.

Combine two outputs to one input without additional circuitry, I think "not advised".

Thanks for the reply.
Are they any products that use "additional circuitry", to do what im after? Like a "rca stereo to mono box" ?

 

[Anders76]

I found this.

https://www.rdlnet.com/product.php?page=164

 

[RayDunzl]

Are they any products that use "additional circuitry", to do what im after? Like a "rca stereo to mono box" ?

Try "stereo to mono summing adapter"

The minimal requirement is a couple of resistors, so the channels aren't shorted to each other,

 

[andreasmaaan]

I found this.

https://www.rdlnet.com/product.php?page=164

Presumably that's a similar circuit to the one Ray posted. Does your sub have a balanced input?

 

[andreasmaaan]

Actually, maybe you could tell us what make/model your preamp and sub are, @Anders76?

 

[Anders76]

Try "stereo to mono summing adapter"

The minimal requirement is a couple of resistors, so the channels aren't shorted to each other,

View attachment 107902

Thank you for this. Much appreciated.

 

[BDWoody]

Thanks for the reply.
Are they any products that use "additional circuitry", to do what im after? Like a "rca stereo to mono box" ?

There are summing circuits you can use to do that.

I also don't know how much info below whatever your crossover would be would be in both channels (I think a lot) , but in the mean time you could just hook up the R or L and you'd likely get much of the low frequency signal that is shared between both channels.

 

[Anders76]

Actually, maybe you could tell us what make/model your preamp and sub are, @Anders76?

Ofc sorry.

Preamp is Cambridge CXN .
Poweramp is Rotel RB1552 mkII
Sub is Audio Pro B2.27 ( a old sub ), highpass input on this sub sound bad/muddy. Much better sounds using rca mono in. Dont know if highpass is broken, or a flawed design. Otherwise I would have used that in this case

//Anders

 

[Anders76]

Presumably that's a similar circuit to the one Ray posted. Does your sub have a balanced input?

Im affraid not.

 

[Anders76]

There are summing circuits you can use to do that.

I also don't know how much info below whatever your crossover would be would be in both channels (I think a lot) , but in the mean time you could just hook up the R or L and you'd likely get much of the low frequency signal that is shared between both channels.

Thanks

I do not whant to cut the pre-out freq in this setup.
I whant fullrange to my speakers/poweramp/sub, and then I use the internal filter on the sub to adjust where it will operate, in my case around 60-65hz and down.

 

[RayDunzl]

in the mean time you could just hook up the R or L and you'd likely get much of the low frequency signal that is shared between both channels.

That would likely be fine.

"Most" popular music is likely already mono (same signal in both channels) in the lower bass.

Exceptions could be classical and jazz and even more, but running one channel will get you started. It might be enough, depending on what your sources are.


Example:

Michael Jackson Dangerous track 1 full and low passed at 80Hz (sub signal)

 

[andreasmaaan]

There are summing circuits you can use to do that.

I also don't know how much info below whatever your crossover would be would be in both channels (I think a lot) , but in the mean time you could just hook up the R or L and you'd likely get much of the low frequency signal that is shared between both channels.

+1

As a temporary solution, this will work for 90+% of recorded music. Less likely to work for classical, jazz and certain other genres of live recorded music.

I do not whant to cut the pre-out freq, I whant fullrange to my speakers, and then I use the filter on the sub .

You'd still have a full range signal. It would just be only one channel (either L or R). The reason it would work for most music is that most music already has mono bass anyway.

 

[Anders76]

+1

As a temporary solution, this will work for 90+% of recorded music. Less likely to work for classical, jazz and certain other genres of live recorded music.



You'd still have a full range signal. It would just be only one channel (either L or R). The reason it would work for most music is that most music already has mono bass anyway.

Got it.
I will use one of the L/R until i get a proper stereo to mono summing adapter .
Thanks guys

 

[andreasmaaan]

Got it.
I will use one of the L/R until i get a proper stereo to mono summing adapter .
Thanks guys

Nice

FWIW, if you listen to a lot of jazz, I suggest sending the R channel to the sub. Don't know why, but IME the bass and drums, which contain most of the low-frequency energy, are much more likely to be panned to the right in earlier stereo jazz recordings.

 

[Anders76]

Nice

FWIW, if you listen to a lot of jazz, I suggest sending the R channel to the sub. Don't know why, but IME the bass and drums, which contain most of the low-frequency energy, are much more likely to be panned to the right in earlier stereo jazz recordings.

I listen most to classical music, and film scores. Thanks for the tips

 

[Anders76]

I just order this. Hope it will do the job ok

https://www.amazon.com/MCM-Custom-5...=Stereo+to+Mono+Summing&qid=1611405477&sr=8-3

 

[andreasmaaan]

I just order this. Hope it will do the job ok

https://www.amazon.com/MCM-Custom-5...=Stereo+to+Mono+Summing&qid=1611405477&sr=8-3

This device seems to use a transformer rather than resistors. That's fine in terms of getting the job done, but cheap transformers are going to degarde the signal somewhat, perhaps even audibly. I'd look for a resistor-based circuit if I were you (and if it's not too late to cancel the order...)

 

[Anders76]

This device seems to use a transformer rather than resistors. That's fine in terms of getting the job done, but cheap transformers are going to degarde the signal somewhat, perhaps even audibly. I'd look for a resistor-based circuit if I were you (and if it's not too late to cancel the order...)

Thanks.. I get a resistor-based circuit adapter as well. That way I can do some testing

Regarding the resistor-based adapters. Will that lower the signal Volt to the sub? So I would probably need to crank up the sub volym vs only using a strait cable from the pre amp R channel ?