Sub wiring question

[NuckingFuts]

I have a sub with a wire that has a single 'rca' type connector at the end but since my receiver is old it doesnt have a 'line level' port for a sub. How can I make my "speaker level" jacks on my receiver "line level" so I can plug my sub in?

Thanks in advance!

[michael_w]

Does the sub have high level imputs? As in speaker wire attachments. If so you can run wire from your receiver into the sub high level imputs then out to your main speakers. If the sub doesn't have high levels I'm not sure what to do. Hope that helps a little.... btw what is your sub?

[NuckingFuts]

Its a little 8" sealed Pinnacle sub that I picked up for virtually nothing. It sounds pretty damn good for its size to. There isnt any other jacks on the sub itself, only gain and polarity knobs.

Im thinking there's got to be a simple way like a converter box or something for guys with vintage amps who've run into the same problem.

[gatemplin]

You would need some sort of step down transformer but I have never heard of one for this purpose.
The only solution I can see is to use the pre amp outputs on the receiver if it has them or split the line level output of the source to the receiver and the sub. With the latter method you would have to manually adjust the volume on the sub.

[NuckingFuts]

Man, I was hopin this was a common problem and there was a simple solution.:(

[michael_w]

It might be more benifical for you to just buy a new subwoofer. This option sucks if you are not wanting to spend the money on a different speaker but it seems like the only other option is to do what gatemplin suggested which will be a pain in the arse having to constantly adjust the sub level according to the level of your speakers. Well maybe someone knows of something that might work.

[LittleCar_w/12s]

well.. there is a common solution to this, but it is usually for car audio... it's a little box that converts speaker level to signal level.. should work for you, cheap too. (I hate to say this...) Try a car shop :( Though even I hate most of them.

[okiepolkie]

Don't you have to have an external power source for the speaker level to in-line converter(12V for the car converter)?

Just a logistical question when you look for one.

[NuckingFuts]

I'll give it a try. Thanks for the tips!

[LittleCar_w/12s]

I think it's a standalone unit.. either a transformer inside or a resistor network, probably transformer though.

[Tour2ma]

NF,
I am sure you could join your receiver's Tape-outs together and run that combined signal to your sub. Only issue would be that since "Tape Outs" are fixed level outputs you would have to manually adjust the sub's volume any time you changed the receiver's.

[NuckingFuts]

I think I have an rca 2-into-1 adaptor for my digital 8track.....I'll let you know if it works tomorrow.

:D

[anonymouse]

By simply bridging the RCA outs of the pre section, which is what you will be doing with this Y adapter solution, you will likely run into several problems -
1) Its possible that the RCA outs are used as inputs to the power amp sections internally. If this is the case, you are effectively shorting the left and right channels together, resulting in a mono signal through your front speakers as well. Even if the coupling is not direct, you will likely introduce crosstalk between the channels
2) If the RCA outs are direct coupled to a preamp internally, you could damage the amp (although this is unlikely)

My suggestion would be to hook up the sub to just one of the channels. Not perfect, but a cheap solution till you upgrade. If you are handy with electronics, you could design a small summation circuit with an opamp that would sum the left and right channels.

[sowen010599]

Radio Shack has an adapter that takes speaker level outputs and converts them to a line-level signal. You just wire it in between your receiver and speakers. It is primarily for car-audio, so it requires 12v DC. Radio Shack can fix you up with a 12 volt AC/DC adapter.

[Tour2ma]

Originally posted by anonymouse
My suggestion would be to hook up the sub to just one of the channels. Not perfect, but a cheap solution till you upgrade. If you are handy with electronics, you could design a small summation circuit with an opamp that would sum the left and right channels.

Good cautions, anon...

I am used to models I have that bypass all pre-amp processing in creating a tape out feed, but "your results may vary" is a wise add-on...

[NuckingFuts]

Just wanted to get back to everyone and report that I found a solution to my sub problem.

Went to the local electronic store (Fry's electronics) were they sell car audio components. I found a "Hi/Lo line level adaptor for $10 and it works perfect. There is 2 sets of +/- jacks on one side and L/R RCA jacks on the other side essentially taking a speaker level input and reducing the signal to a line level output. The converter is passive so it does not need an external power source.

Hope this info can help someone else in the future:D

[okiepolkie]

How does it sound? When I used one in my car, it picked up a lot of interference(engine noise and such). Since you are in a house though, you probably won't have much of a problem.

Enjoy your new system.

[NuckingFuts]

Its not perfect but its good enough to get me by until I can spring for another receiver. I have to turn the sub's frequency way down cuz the higher frequencies reveal a very subtle hum. This is ok with me since I only want the sub hitting the lowest range of frequencies to compliment my mains.

There were higher end converters that ran as much as $100 which Im willing to bet would have higher quality electronics to eliminate any feedback.

Lets just say $10 is worth the experiment:D