Subwoofer to stereo amp without pre-out

[hifipal4all]

Just use the tape out of the amp to connect to the sub. Any amp will have this

only downside is you cant control volume of sub from the amp. you need keep adjusting volume on sub

It's extremely inconvenient if you connect the subwoofer in this method because the tape out (rec out) is a fixed level output and everytime you have to adjust the subwoofer's volume control. Instead ....

It is good the connect the subwoofer either from speaker B to subwoofer's high level (speaker level) in (OR) if there is a preout, use a "Y" adapter and connect to subwoofer's line level in.

Cheers,
Ramesh

 

[flanker.r]

Yes it will ... Assuming that an amplifier's specification is 100+100 watts, then ....

1) If a single pair (only speaker A or B) is connected, then each speaker will be driven with 100 watts power.

2) If two pairs (speaker A & B) are connected then the output power will be distributed i.e. each speaker will be driven with 50 watts power.

Regards,
Ramesh

It never happens this way. When you connect the 'B' pair, it gets connected in parallel to the 'A'. This way impedance is halved. The amp will still deliver the same wattage (probably more) to the speakers this way now

Seen the warning on amps with 2 pairs of speaker binding posts that says '2 pairs- 8 ohms min' '1pair - 4 ohms min' ?

 

[hauntedhunter]

Little confusion here too

The subwoofer connected to the other channel will be an active sub,so will it draw any power from the amp?

Thanks.

 

[Bobby]

Little confusion here too

The subwoofer connected to the other channel will be an active sub,so will it draw any power from the amp?

Thanks.

Yes it will...

Since you are joining the subwoofer wires to the amp along with the speaker cables, it will throw current (same frequencies) to the sub also, but sub woofer has got its own cross over to detect the frequency range which is to be used.

 

[hauntedhunter]

It never happens this way. When you connect the 'B' pair, it gets connected in parallel to the 'A'. This way impedance is halved. The amp will still deliver the same wattage (probably more) to the speakers this way now

Seen the warning on amps with 2 pairs of speaker binding posts that says '2 pairs- 8 ohms min' '1pair - 4 ohms min' ?

So is there any issue in connecting the sub to say speaker B and main speakers to speaker A ?

What I need to take care of?

Thanks a ton for all the help from everyone

 

[Bobby]

There is no need to take care of such issue.. Connect i anywhere you want

 

[hauntedhunter]

Please don't get angry that I'm asking too many questions

This is the rear of the amp I wanna buy (CA 340A )

This is the rear of the sub

I plan to use Wharfedale 9.1 as my main speakers ( rear )

Can someone please explain me how I can connect these to have my 2.1 setup ?

Also will I be able to control the volume of the sub through the amp remote?

Need to match anything ?

Please help.Promise not to bug you guys a lot

 

[flanker.r]

Point 1: You cannot connect an active sub to Speaker B. Active sub need to be connected on line level high Z output. Speaker outputs are low Z and the signal is already amplified. if you connect an active sub to this you will be amplifying an already amplified signal. Not possible !

Point 2:Only way to integrate a sub with the amp you have got is to put in in the tape out. but this way you cannot control volume of sub with the remote or knob on the amp. If you need this facility (which I think you do), go for an amp with a second pre-out like the Nad C370 or C372. They feature a gain controlled pre-amp out

 

[hauntedhunter]

Thanks...

Now I'm totally confused as so many people suggested I can connect the active sub to speaker B

If I connect it to tape-out,is there any other issue ( matching,crossover etc. which I'm still trying to understand ),expect for that I need to manually adjust the volume of the sub?

Any idea on the price of NAD370 in India ?

Thanks again!

 

[dinyaar]

Nad C 370 is an old 120WPC integrated now replaced by C 372 which is a 150 WPC integrated which should be around 55 to 60K

 

[hauntedhunter]

My budget is around 12-13K INR for the amp and that's the main reason I'm trying to find out how I can connect an active sub to amp without a pre out as the cheapest amp I could find with a pre out is CA 540A V2 which is also beyond my budget

Please help audiophiles,I'm real confused here by opposite ideas

Thanks all!

 

[flanker.r]

The only other way to do it pull out the soldering gun and plug it in.

Get the service manual with circuit diagram of the amp, connect an RCA female plug to the preamp output, drill holes in the cabinet and fix the sockets . You will now have a separate pre-amp out for your amp to which you can connect a sub-woofer.

Note: This will definitely void the manufacturers warranty but this is a simple tweak you can do by yourself.

Second option is to get yourself a preamp and use the integrated amp as a power amp (by turning volume full and connecting all inputs to the pre and using only one input from pre). if the preamp has only one output, use a Y splitter to connect one section of each channel to the poweramp (intergated in this case) and the other to the active sub (of course this again needs to me made as a summed mono output before feeding to the sub)

 

[hauntedhunter]

Thanks for the info

 

[hauntedhunter]

Hi,
Usually Powered Subwoofers have a couple of various ways that they can be hooked up. Most will have Speaker connections, where you can run your Marantz Speaker Cables directly into the Sub, then out to your Main Speakers, and thus also then utilizing the Sub's crossover, so let's say anything above 80hz will run to your Main speakers (Some Subs even have adjustable X-Over Points to integrate the Sub-Main Speakers better)

This in most instances will do two things: One, it will free the strain of having your Main Speakers provide the lower frequencies, and two, wil also free you Amplifier-Reciever of having to provide the Wattage to reproduce these lower frequencies. Probably 80% (Guessing here) of your Reciever's wattage goes towards handling lower frequencies.


( source : hooking up bookshelf speakers with a subwoofer to a 2270? [Archive] - AudioKarma.org Home Audio Stereo Discussion Forums )

Someone throw some light please

 

[flanker.r]

This method of wiring is found on most subs these days but is not at all recommended.

If you wire it this way, you will be passing your audio signal through 2 cross overs (one in the sub and again through the one within your speakers). This will induce unpredictable phase changes in the audio signal and ruin the fidelity

Also the crossover within the sub is usually crappy. Do not follow this method. I think I have seen a couple of BOSE systems with this kind of setup. Its ok for a 'BOSE' system but not for a quality system aimed at high fidelity playback

 

[hauntedhunter]

Thanks

Seems I'm left only with 2 options :

1.Either use the rec out and live with adjusting the volume of the sub manually using it's volume knob

2.Buy an amp with a pre-out.

Am I correct in my understanding finally

(I don't think I can open the amp and do all the electronics things suggested )

Thanks

 

[Bobby]

I doubt if both the circuits works simultaneously (pre and integrated)
If you use pre out from an amp for subwoofer, it will cut off the integrated circuit line..

please ensure it.

 

[hauntedhunter]

Then how do you connect sub to even an amp with pre-out ?

 

[Bobby]

You will have to use Rec out for subwoofer and keep on adjusting the volume nob every time you plug in or buy an AVR instead of dedicated stereo amp.

 

[hauntedhunter]

keep on adjusting the volume nob every time you plug in

Every time you plug in ?? Or whenever u wanna change the volume of the sub ??