subwoofer connection issue

[Qualitysound]

Hi All,

I'm using a yamaha mcr-b142 micro system and I found the bass is not sufficient to my taste..
So I purchased a used KODA sw800 sub yesterday.
I tried to connect yamaha system to sub through the speaker inputs of sub... (No RCA out in yamaha system )the sound was coming through the sub but, it was very low... so I increased the sound.. then the yamaha system turn off by it self..
Then I connect this sub to another player (which has RCA out) through RCA (Line level input) it worked fine.
what could be the reason behind yamaha system auto shutoff?
Also how to solve this issue?

Thanks

 

[tonitonitoni]

probably bridged output on yamaha so you shorted 2 outputs/to ground , altough unlikely

 

[Qualitysound]

well I just connected yamaha speaker output to sub's speaker level in... doubt there is a short circuit..
Im thinking of getting a rca level output through earphone jack..
but there is a issue.. because when I plugged earphone jack to earphone port sound will stop coming through speaker output..
I want to avoid this and make both earphone and speakers work simultaneously ...

Thanks All

 

[conanski]

Bottom line here is you cannot connect a sub to this system. When you connect the sub to the Yamaha speaker terminals the combined load trips the units protection circuitry.

And the speakers turn off when headphones are connected.. that is how it is designed to work and you can't over ride it.

 

[tonitonitoni]

he can connect only positive trough dc block capacitor to high input,and gnd from somewhere.and then it should work if it is bridged

 

[Qualitysound]

Thanks All....

Im thinking off getting a preamp out from yamaha system and connect it to sub..
will be getting help from a electronic repair shop?
what do you think?

 

[Qualitysound]

Any help...

how about using a hi to low converter jack to connect sub's rca input?

Thanks

 

[tonitonitoni]

you will do same thing with converter as you done wit just connecting highs, simplest and cheapest way is to connect it as on picture up if its bridged. but please take measurment from gnd of rca input to black output is there any voltage when operating?

 

[Qualitysound]

Hi All,

Managed to solve the problem through a high to low converter...
Thanks All for your help..

 

[sl1]

I have the same problem - want to connect a sub to this mini-wonder.
I tried hi-to-low converter, but this is not a good sounding solution.
Yamaha already outputs 1% THD since it has a digital switching amp, then you convert this to low level and amplify it back in a subwoofer amp and you get a pretty bad sounding bass.

So I opened up my yamaha and took a look at it, but I can't seem to find the input selector IC on the pcb - that's where I would steal the low-level signal that goes to the headphone amp.
Does anyone have any idea where it is? Or maybe anyone has a service manual for Yamaha MCR-B142?

Thanks!

 

[Qualitysound]

I have the same problem - want to connect a sub to this mini-wonder.
I tried hi-to-low converter, but this is not a good sounding solution.
Yamaha already outputs 1% THD since it has a digital switching amp, then you convert this to low level and amplify it back in a subwoofer amp and you get a pretty bad sounding bass.

So I opened up my yamaha and took a look at it, but I can't seem to find the input selector IC on the pcb - that's where I would steal the low-level signal that goes to the headphone amp.
Does anyone have any idea where it is? Or maybe anyone has a service manual for Yamaha MCR-B142?

Thanks!

check following link.

YAMAHA MCR-B043 MCR-B043D SM Service Manual download, schematics, eeprom, repair info for electronics experts

Although its not the exact thing, I cant seem to find any differences between two models.