Can I use Sansui AU-717 and Sansui AU-X901 for bi-amping?

and the point is not that it does nothing to what gets to the tweeter and what gets to the woofer BUT that
a full-range signal goes to both.

No, Bob, the full range signal is not going to the woofer and is not going to the tweeter. The tweeter signal still goes through the high pass filter and the woofer signal still goes through the low pass filter, just the same as with the jumpers in place and fed by a single amp. This is very clear in the illustrations I posted.

That the OP says it didn't sound right could mean many different things and be caused by several different reasons. But, one of those reasons isn't because full range signal is getting to the tweeter or to the woofer.
 
perhaps I should word it in a different way:

if anyone thinks sending two full-range signals to a KEF 105
with separated high and low inputs (not biwired) will work,
then
please give the OP the instructions so it does sound good.

he has the two amps, the KEFs, cables, and can do the test.

I am hoping that there's a solution - it would be pretty stupid
on my part to buying a pair of KEF 105s based on hearsay
and not tried.
 
Consulting the manual is always a good start.

105.png

The problem here is that one of the amps he uses is broken, and maybe it was failing at the time of the biamp experimentation contributing the bad sound.

Maybe one of the amps inverts polarity so while + and - may have been connected correctly, the signals themselves still were out of polarity. As well, it is unlikely the two different amps have the same gain - although with independent volume controls that can be managed. This is why with this form of biamping is recommended to use the same make and model of amps...so that those factors don't screw up the works for those that don't know how to identify and address those type of issues.

These caveats/considerations/potential "gotchas" about polarity and gain were mentioned earlier in the thread.
 
No, Bob, the full range signal is not going to the woofer and is not going to the tweeter. The tweeter signal still goes through the high pass filter and the low pass filter still goes through the low pass filter, just the same as with the jumpers in place and fed by a single amp. This is very clear in the illustrations I posted.

That the OP says it didn't sound right could mean many different things and be caused by several different reasons. But, one of those reasons isn't because full range signal is getting to the tweeter or to the woofer.

I get it - we are on different side of what the crossovers do, you maintain the unnecessary frequencies get dumped by the
internal speaker crossover sections and there is no difference, and I say that that unnecessary signal affects the speakers
response even if the crossover is in place.

I already gave my example. I have a mini-monitor for the highs and a big Polk for the bass using a crossover.
the treble sounds better on the mini-monitor with the crossover, and the bass sounds better with the crossover.

there's a bypass switch on the dahlquist so it's not a memory issue if cable/amp/connection switching is needed
its an immediate difference.

I attribute this to the mini-monitor only processing highs and not full range. and the Polks sound better processing
only the bass. each processes optimally instead of doing the whole thing.

I am not arguing about whether any speaker gets crossover processed - I don't recall saying any of that but
in my opinion, trying to get any speaker to perform well simultaneously at both ends is not as good as processing
the signal at its sweet spot.

the OP hasn't done anything that would make my assertions false, but he has the equipment and you have
the knowledge - pass it to him, prove that a fullrange signal to filtered high or low is not any different
than an active crossover.

then I'm in. I dump my two sets of speakers and I buy a KEF 105.

BUT please either try it and tell me what you did right, or what the Op needs to do to make it right,
but if you haven't done it then help him and me do it right.

prove to me speaker crossovers used properly will sound just as good as active crossover
(in spite of it being an extra perhaps even unnecessary extra part in the sound chain). I will
buy that KEF but not on speculation or lack of a proper test.

perhaps you have tried this with a different set of speakers with the same unlinkable crossover
I would entertain that speaker also, unless its uber $$$
 
the OP hasn't done anything that would make my assertions false, but he has the equipment and you have
the knowledge - pass it to him, prove that a fullrange signal to filtered high or low is not any different
than an active crossover.

You are confusing the situation with talk and theory of active crossover when that's not what the OP is doing.

What the OP is doing is a very common form of biamping, but that doesn't mean it's the same as biamping using active crossover before the amps and no crossovers in the speaker. Two completely different things with the same common name.
 
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well then, let's help the OP get there. he wants to bi-amp. there are, to make it simple, two ways,
eternal active/passive crossover, or use the KEF 105 method,

it didn't sound right. we post two different sets of why. I'd like to hear more about whether
it works (right now it doesn't), it works well (next step).

know you didn't say that but I has been misquoted here several times. Including this -
I mention full-range into a crossover as a reason. this works whether its method a or
method b.

let's get him to step b (works well or doesn't):

even if one amp is bad, you can still use two cables to each speaker (at low and high inputs)
it would be like paralleling speakers - with only one amp.

then if the cables are not reversed to each other they are either in phase/polarity
and can be tested simply with one (or two changes - in case the polarity of high/low are reversed)

anything else? perhaps in the future to not confuse anyone, I will leave out active
crossovers as being too confusing to the readers.
 
I will leave out active
crossovers as being too confusing to the readers.

Active crossover is not too confusing for the typical reader.

The confusion results when the OP is doing one thing but there is talk of something different.
 
even if one amp is bad, you can still use two cables to each speaker (at low and high inputs)
it would be like paralleling speakers - with only one amp.

That's not biamping though, that's just biwiring. Which is basically long jumpers going all the way back to the amp rather than short jumpers right at the speaker terminals.
 
then if the cables are not reversed to each other they are either in phase/polarity
and can be tested simply with one (or two changes - in case the polarity of high/low are reversed)

That's not necessarily true. The circuits of some amps or preamps invert the polarity of the signal going through them. So, simply connecting black to black and red to red isn't a guarantee of everything in correct polarity if you are using dissimilar amps or preamps.
 
As far as the OP using these two units to biamp, the very first thing that needs to be done is ensuring both amps are working normally. It's a dead end at step one if both amps are not working normally.
 
I am going to locate another Sansui B-2102 and try bi amping that way with the C-2102 pre. I think that will have a better result. Hopefully I can find one here soon.
 
@Bob , sorry, I don't know the specifics of your setup - this is James' thread and I'm replying to his situation.

However, I think we are now on the same path.

What you describe is a cross between passive bi-amping and active bi-amping. I'm not all that familiar with people doing it that way.

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image_preview


I understand what you mean regarding the potential benefits in keeping the original crossover in circuit. Unless you have very sophisticated electronic crossovers with sufficient 'tweakability' eg. DEQX, MiniDSP and others) it can be very difficult to get excellent sound from actively bi-amped speakers.

I know of a few boutique speaker manufacturers here in Australia who have tried going active with their speakers, and could never quite replicate the 'magic' of the old-school passive crossovers.

in my opinion, using crossovers for a long time, its that a full-range signal to a monitor (or a crossover supported tweeter
from a speaker that can separate its internal crossover into high and low section) and the same full range
signal to a bass/woofer speaker (with its still connected crossover but with or without its high section disabled
or bypassed) is not the same as a filtered treble signal to tweeter sections and a filtered bass signal to
a bass section.

the OP said it didn't sound right.

The issue I see with James' setup is that he is using two different amps with different gain profiles. This will make it very difficult to properly match the levels of the woofer and mid/tweeter at various volume levels without constant adjustment. It's less than ideal.
 
if both set of posts are still connected to a full crossover, then what's the point of
having a cross over, and specifically, having the labels split the highs and lows.

They are not still connected... I didn't say that (at least I hope I didn't!! hehe!)

When the jumpers between each pair of inputs are removed, the top inputs are connected to the section of the crossover which then divides the signal to the mid and tweeter, and the bottom inputs are connected to the section of the crossover which then connects to the woofer.

I think we may be batting for the same team, but speaking with a slightly different accent and are misunderstanding each other :)
 
I am going to locate another Sansui B-2102 and try bi amping that way with the C-2102 pre. I think that will have a better result. Hopefully I can find one here soon.

Implying two B-2102?

What is it you are trying to achieve by biamping?
 
there's an easy solution to this.

use one amp. use one cable to each speaker. this is baseline. I also assume you use the KEFs this way.

then use two cables to each channel. Bi-wire as it is called. make sure they're polarized
correctly (all positives connected - from amp to cables to posts. same for negatives)
using same amp. listen - better I would expect

lastly. turn amp off. leaving all amp/cable/speaker connections intact - remove the links.

and if the designers were correct as are the posters in this thread, then this should sound
the best.

and if it is, bi-amping at the speaker with a single amp and 4 cables is possible and is good.

I am sorry for any confusion I introduced. I thought about what I wrote ( I tend to overdo it
its a legacy of the work I used to do) and when I took short cuts, it got side tracked by
literal interpretations.

I am very curious about this as you might be able to tell from my previous posts. I generally
listen to experimental practice - what someone did. It drives my hobby.
 
Greater sound stage and clarity, because I like to listen to Jazz vocal pretty loud. Also I hear that the more power that you feed the Kef 105/3 the better it sounds.
 
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@jameswei

have you done this speaker-bi-amp test? I see you have the same equipment as the OP.

so, is your post about the sound quality in bi-amp mode?

if so, then the test is successful, it does work (I cannot believe no one has done this before)
and does sound better.

thanks for the input
 
Greater sound stage and clarity, because I like to listen to Jazz vocal pretty loud. Also I hear that the more power that you feed the Kef 105/3 the better it sounds.

A more powerful amp can provide more usable power to the speakers, but biamp in the manner you are pursuing does not...unless the amps themselves are more powerful than what you were previously using.
 
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