Topic: stereo to mono question

[rustyns]

Hello Gurus,

Would this connection work? My old sub amp had a L+R switch. This new one does not. I tried using only 1 RCA but I was losing half of the signal for some songs.

Main amp has no tape/aux/line/sub out. Sub amp has no speaker level inputs.

TIA

[JojoD818]

pwede pero 10Kohms ain't enough for good channel separation for your amp's left and right channel, 47Kohms to 100Kohms is what you should use but you'll attenuate a lot of the original signal.

a simple transistor "summing amp" or better yet, an opamp based one should work wonders.


 

[rustyns]

pwede pero 10Kohms ain't enough for good channel separation for your amp's left and right channel, 47Kohms to 100Kohms is what you should use but you'll attenuate a lot of the original signal.

a simple transistor "summing amp" or better yet, an opamp based one should work wonders.


 

Thanks sa reply sir Jojo. So mas ok dito ang active na circuit. Kapag 47Kohms ba ang ginamit dyan sa passive na connections, ilang db ang mawawala?

[JojoD818]

Thanks sa reply sir Jojo. So mas ok dito ang active na circuit. Kapag 47Kohms ba ang ginamit dyan sa passive na connections, ilang db ang mawawala?

The best talaga ang active circuit for your application since you will be combining 2 channels into 1 but still you want to be able to use the original 2 channels. Magiging mono pati fronts mo. 

Here is a simple solution (sorry pic came from net)...



If you make values of R₁, R₂, and R_f (feedback resistor) all 100K, V_out = V₁ + V₂

Using 100K resistors should isolate your left and right signals from each other and minimize crosstalk.

All you need is a single general purpose opamp for this and a +/-12Vdc (preferably regulated) power supply and tofu-tofu na...

Beware though that the signal is inverted (we used the inverting input of the opamp), if your sub has a phase adjustment then there shouldn't be any problem.

O labas na ang panghinang at gawin na yan!

Good Luck po!

[rustyns]

Mukhang kulang ang free time ko para gawin yan sa ngayon Tiis muna siguro ako sa kulang ng kalahati ang signal. Iwe-weigh ko din ang ibang options ko (gawing 2 ang subs, ipagawa yung luma kong integ amp na may L+R switch)

Tnx

[qguy]

may headphone out ba yung amp.. pwede yun

[rustyns]

Tnx nga pala sa mga replies. Ang ginawa ko na lang - gumamit ako ng active crossover na may mono switch. Crossover setting is at 60hz

[rustyns]

Sorry, reviving an old thread.

Sir Jojo, would something like this work? opamp TL072 and resistors all 100k. Power +-15v regulated.

Thanks in advance

The best talaga ang active circuit for your application since you will be combining 2 channels into 1 but still you want to be able to use the original 2 channels. Magiging mono pati fronts mo. 

Here is a simple solution (sorry pic came from net)...



If you make values of R₁, R₂, and R_f (feedback resistor) all 100K, V_out = V₁ + V₂

Using 100K resistors should isolate your left and right signals from each other and minimize crosstalk.

All you need is a single general purpose opamp for this and a +/-12Vdc (preferably regulated) power supply and tofu-tofu na...

Beware though that the signal is inverted (we used the inverting input of the opamp), if your sub has a phase adjustment then there shouldn't be any problem.

O labas na ang panghinang at gawin na yan!

Good Luck po!