Sansui AU555 with Sub advice needed.

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griffbabe
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Sansui AU555 with Sub advice needed.

Post by griffbabe » 09 Dec 2019 13:00

Hello all,

Back with my second post here and looking to get some real clarity on this. I did spend a fair amount of googling for a definitive answer and found a couple of videos on youtube, but not yet found the assurance that what I want to try, won't do my system some damage.

I have an active sub kicking around not being used for anything and would like to see how this might enhance (or not) my system. The sub in question is a TAPCO SW10. It has RCA inputs and outputs as well as XLR, I was hoping to use the RCAs for convenience, its active with an input sensitivity knob.

From what I've so far read, the only way I could do this would be to insert it after the preamp stage of the Sansui, taking the left and right into the left and right RCAs on the sub. Currently the on the Sansui amp, the preamp and the amp stage are linked, so it seems to me that I would then have to take the RCA left and right OUT of the Tapco and feed this back to the amp element on the Sansui to complete that circuit once more.

There is part of me that thinks I could potentially damage something so after a double check from you, also wasn't sure I entirely understood the suggestion in the Sansui manual that if I do this, it renders some of the controls useless on the amp.

Perhaps if someone has been through this you can give me some confidence to go ahead.

Thanks,

jdjohn
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Re: Sansui AU555 with Sub advice needed.

Post by jdjohn » 09 Dec 2019 16:10

What does the manual for the Tapco sub say regarding the RCA outputs? Is it a direct pass-through, or is it influenced by settings on the sub (e.g., crossover point, gain/volume, etc.)? If it's direct pass-through, you should be okay.

billrog787
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Re: Sansui AU555 with Sub advice needed.

Post by billrog787 » 10 Dec 2019 23:28

I have done this, but with other components than the ones that you have with no problems or damage. The main thing is to ensure that the pre and power amp sections of your Sansui are unlinked, then hook up as you suggest. Suggest you turn down volume on Sansui and the sub before switch on, perhaps set crossover frequency on the sub to around 80 hz to start with. You will find that the volume and other controls on the Sansui pre-amp section work as normal, put on some music, bring up volume on Sansui and you should find your main speakers are going, then bring up sub volume to balance the sound. I’m sure you know this, but positioning of the sub is all important and very small movements of the sub can make a big difference to the sound, aim to get the sub and main speakers in phase with each other. Good luck. Bill.

griffbabe
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Re: Sansui AU555 with Sub advice needed.

Post by griffbabe » 11 Dec 2019 10:23

billrog787 wrote:
10 Dec 2019 23:28
I have done this, but with other components than the ones that you have with no problems or damage. The main thing is to ensure that the pre and power amp sections of your Sansui are unlinked, then hook up as you suggest. Suggest you turn down volume on Sansui and the sub before switch on, perhaps set crossover frequency on the sub to around 80 hz to start with. You will find that the volume and other controls on the Sansui pre-amp section work as normal, put on some music, bring up volume on Sansui and you should find your main speakers are going, then bring up sub volume to balance the sound. I’m sure you know this, but positioning of the sub is all important and very small movements of the sub can make a big difference to the sound, aim to get the sub and main speakers in phase with each other. Good luck. Bill.
Thanks Bill, plugged it in and it works. Maybe it is the quality of the TAPCO but my impressions are so far conflicted - the sub is obviously adding energy, but I'm losing the musicality of the S45s, might be some phasing issues that I'll explore a little more, however regardless of where I set the crossover or the level of the sub so far I'm missing the S45 sound. The sub goes down to 55hz, the S45s will go to 38Hz, ideally I'd tuck the sub in around 40hz just to make the 45s sound a bit bigger, but as is, the sub is making thing a little cheap sounding.

jdjohn
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Re: Sansui AU555 with Sub advice needed.

Post by jdjohn » 11 Dec 2019 15:55

If you have the sub on carpet, you might need to isolate it a bit by putting it on a big slab of something heavy, or using spikes. I assume you have the Beovox S45s on their stands. Subs can sound really muddy if not properly isolated.

billrog787
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Re: Sansui AU555 with Sub advice needed.

Post by billrog787 » 12 Dec 2019 03:25

That's a shame as the Sansui is such a nice sounding little amp IMO. You might have tried it already, but if you turn down the crossover frequency to it's lowest point, and the volume of the sub to it's lowest too on the Tapco, then listen to your S45s as full range as they can be with the sub in circuit but not making any sound, then if the sound quality is inferior to that of the original system without the sub in circuit, you will know that it's either the sub itself or the hookup wires/connectors that's causing the problem. Bill

griffbabe
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Re: Sansui AU555 with Sub advice needed.

Post by griffbabe » 12 Dec 2019 13:08

S45s are on stands and the sub was lifted off the ground, had another listen today, remain conflicted, the S45s are so well balanced even a touch of the sub seems to cheapen the sound, I might prefer running the sub via speaker B path, keep the S45s full range but blend the sub that way. I don’t think I can do this though without some high inputs on my sub. The Sansui -Olufsen seems a very sweet match, love it but it doesn’t really do loud as such, oh well!

paddypaws
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Re: Sansui AU555 with Sub advice needed.

Post by paddypaws » 12 Dec 2019 20:34

There are high level to line level conversion boxes around commonly used on car subs for little money. Personally I’d definitely want the S45s full range. Might be worth a try on the B speaker outs.
https://cpc.farnell.com/unbranded/fga-2 ... stallation

griffbabe
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Re: Sansui AU555 with Sub advice needed.

Post by griffbabe » 16 Dec 2019 10:03

paddypaws wrote:
12 Dec 2019 20:34
There are high level to line level conversion boxes around commonly used on car subs for little money. Personally I’d definitely want the S45s full range. Might be worth a try on the B speaker outs.
https://cpc.farnell.com/unbranded/fga-2 ... stallation
Just so I fully understand this product, you feed it from my speaker b outs and it allows me to use the RCA inputs on the TAPCO sub?

paddypaws
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Re: Sansui AU555 with Sub advice needed.

Post by paddypaws » 16 Dec 2019 16:15

Yes that’s right. As long as the sub has a frequency adjustment as most do, as you will be sending a full range signal to it.

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