bi-amping

[izeek]

so i know this subject has been beaten to death.
ftf of it i am trying bi-amp with 1 amp for bass and one for mid/hi.
after hooking it all up, i now have a hum. probably a ground loop, maybe. dunno.
the hum is from the amp for the woofers.
comments pleeease.

 

[Vini darko]

Hi sorry to ask. Did you remove the jumpers on the speaker binding posts?
Next question. How is your system wired together from preamp to speakers? (It's important for identifying possible issues).

 

[izeek]

jumpers are removed.
preamp to amp1 and amp 1 line out thru to amp2.

 

[DonH56]

What make and model preamp and amplifiers?
Which amp is the woofer amp, 1 or 2?
If you swap amps, so preamp to amp2 and amp2 to amp1, does it still hum?
Where is the crossover? Can you try a Y-cable or adapter instead (assumes there is no line-level crossover in amp1)?

 

[Katji]

Try starting the normal way - pre-amplifier output/s to each amplifier.

 

[izeek]

jbl sdp3-pre
2-audiosource model 3
amp1 bass
amp2 mid/hi
amps have line out thrus

 

[izeek]

Try starting the normal way - pre-amplifier output/s to each amplifier.

gonna do that today soon as the store opens.

 

[izeek]

Try starting the normal way - pre-amplifier output/s to each amplifier.

ok if i use rca y adapters?

 

[Katji]

Yes, if pre-amp outputs limited, that's the way to go.

 

[izeek]

thanks, mang. rolling out the door now.

 

[abdo123]

How are you doing the crossover, at the digital level or the analog level?

 

[Vini darko]

Agree with @DonH56 suggestions. I would favor the Y splitter approch too.

 

[izeek]

Try starting the normal way - pre-amplifier output/s to each amplifier.

thank you, very much. that solved the problem.
something is different. the vocals got sharper.
all the music seems a bit more present.
i know, i know. all in my head.lol.

 

[izeek]

minidsp and umik on the way.
and i said i wasnt. sheesh.

 

[Katji]

At the end, your head matters too. ...My head understands better (I think) when I see separate line from pre-amp to amps.
...Then miniDSP/frequency division makes it better, the "picture in my head."

 

[levimax]

minidsp and umik on the way.
and i said i wasnt. sheesh.

Here is an article that explains bi-amping quite well https://sound-au.com/bi-amp.htm If you really want to get the full benefit you might want to consider active crossovers and by passing the ones in your speakers.

 

[izeek]

Here is an article that explains bi-amping quite well https://sound-au.com/bi-amp.htm If you really want to get the full benefit you might want to consider active crossovers and by passing the ones in your speakers.

great read. yea, maybe passive b-amping is a moderate improvement. im good with that for the moment.
this is a journey.

 

[AudioJester]

What speakers? How much power do they require?
I get the impression that with many speakers with multiple binding posts it all connects to the same input on the passive crossover?

 

[Vini darko]

What speakers? How much power do they require?
I get the impression that with many speakers with multiple binding posts it all connects to the same input on the passive crossover?

That's not been the case in my limited experience. Consider that were it the case, it would short the amplifers.

 

[DonH56]

From a very old article I wrote on passive bi-amping:

The top shows the speaker with high and low sections connected, driven by a single amplifier (E1), equivalent to shorting the binding posts. The top shows the speaker's networks driven independently (two amps, E2 and E3, shorting straps removed).

HTH - Don