Can I add a line output to an amplifier?

[trvale]

I have the S5 electronics K12-M amp and I want to add a line out for a sub. I want to be able to control the output voltage. My problem is that I don't know where exactly a line output would go. I can't just use a tape out type can I? That would be easy to do, but then my sub volume wouldn't change along with my main volume. If I put it right after the volume pot, would that change some impedences? If anybody can explain to me where in the circuit this output should go, I would appreciate it. I will post the schematic as soon as I can find it, if that would help.

[Erik Mandaville]

TR:

Some CD players (don't know about the one you have...)have more than one output. Sometimes two fixed level outputs (full volume); and sometimes one variable out (with volume controlled via remote)in conjunction with another, fixed level output. Check to see what you have.

You could also use a Y-jack and split the signal from your source or preamp, OR add another output on the preamp in parallel with its original output.

If you have BOTH fixed and variable outs on your CD player, use the fixed outs with the S5 (which has its own volume control, I think), and the variable out with a sub.

However, if the sub has it's own amp and volume control, you could obviously use that to attenuate a full, line level signal.

Ironic! Most people using preamps are actually using them to reduce the gain, not raise it -- since the line outs from virtually every CD and DVD player now made is able to drive many amplifiers, especially sensitive, high impedance tube amps well into the clipping range and beyond.

We need some more info on this, though: Are you biamping? Does the sub you want to use have it's own amplifier? Can it accept BOTH line level and speaker level inputs (line level is usually better)?

What you want to do is easy and totally possible, but we just need to know the specifics about what is available to incorporate your idea.

Erik

[Erik Mandaville]

And yeah, you can start getting some impedance anomolies when combining components. We can work through this, though.

[NOSValves]

Does your sub have a volume control ? Is this amp is SS ?

[trvale]

I am actually using my computers Sound Blaster Audigy 2 as the source, not a CD player. It does however have a subwoofer output, but the volume from that output is really, really low. I have done some research on the internet on that subject and found that it is a common problem with my sound card with no solution. So I can't use that output. The subwoofer I am using, a REALLY cheap 100w 10" KLH model, does have both line level and speaker level inputs. Over time the speaker level inputs have stopped working. The line level still works great. It does have a volume control on the back of the sub, but it isn't easily accesible. And since I listen to music at wildly different volumes, I can't just set it and leave it. I don't have a preamp on this setup, and would like to have the sub and main volume controlled from the same volume pot on my amp. The only way that I can think that this would work would be to just splice two RCA jacks immediately after the pot. But I am worried this will cause some harm due to changes in impedances. Here is a link to the schematic. This seems like the simplest way, but if anybody else has any other ideas, please let me know.