2 Channel Tube Amp and Sub Connection

[Bob B]

OK ...I am new...so start laughing!
I need some help to see if what I want to do is possible.
I have a two channel tube amp (no line out) and I am attempting to put together the following 2.1 system.
2- 8ohm passive bookshelf speakers
1- powered sub woofer..
Is it possible to power my passive speakers and still get a signal to my subwoofer.
I have a link to show photos for the back of my amp and the back of my sub.
http://farm9.staticflickr.com/8425/7675982556_060aee5d7c_h.jpg
Hopefully I am not being fool and somehow this is possible. If I have to add a device to make this happen I am not opposed to that.
Thanks. (be easy on me!!!!)
--bob

 

[Osvaldo de Banfield]

Usually the sub bass output is a signal generated adding resistively both left and right signals, and passing it though a low pass filter in order to maintain only bass notes, say, below 100Hz. It isn't difficult as you can see.

 

[Bob B]

Connections

LIke I said ...I am new...nothing is obvious to me. LOL.
I need a step by step ...this is what you need to do discussion.
Learning my ABC's here.

 

[TheGimp]

The powered sub woofer has a built in adjustable low pass filter. All you need to do is drive it from the output of your amp. The Sub has both left and right inputs which are internally buffered and mixed before the low pass filter. You will have to connect the output of your amp to the L&R inputs of the sub and may need to use resistor dividers to compensate for the signal level.

The rub is that if you don't have a high pass filter in your amp to compensate for the sub woofer, you may end up with excessive bass.

You will just have to play with it.

 

[Bob B]

yo Gimp...I am slow with this. If you looked at my photo of the back on the amp...I only have one left and right RCA input on the subwoofer. You must be very specific about wires or I will misunderstand. I am connecting the 8ohm left and right outputs and the grounds to my book shelf speakers. Can you tell me specifically (each wire from the amp what it connects to and the sub what it connects to. It is not clear to me.
Also...someone told me that I could take my headphone jack and use that ...put in a male connector to the jack and run a split (left and right RCA) and plug that into the two RCA inputs on the sub. Does that sound correct?????
Thanks for the help.
-BB

 

[richie00boy]

If you have a headphone jack and RCA inputs on the sub, it would be better to use that way as long as plugging in the headphones does not disconnect the speakers! I wouldn't recommend connecting to the speaker outputs on a valve amp because their bass response tends to be a bit poor.

 

[Bob B]

Thanks Richie Boy....I think I have the solution..I feel so Duh. I have been thinking of this backward. (this is not my strong area...LOL)..I think I can just put my signal in to the input RCA jacks on the SubWoofer and then run the left and right output from my SubWoofer (see photos) to one of the inputs on my amp. That is the best way..NO? If I do that ...is there a preferred input on the amp that I should use??????
Thanks everyone....

 

[richie00boy]

Yes that would work well. Any input on the amp will do.

 

[Bob B]

Thanks for confirming....You made my evening! I am so unsure of myself with this endeavor...I do not want to fry anything.