How to connect powered subwoofer R-12SW to a stereo tube amp (2-channel) without sub output?

[JohnZ]

System Background info:

Main Speakers: Klipsch RP-150M

Integrated tube power amp: Reisong A12 

Subwoofer: Klipsch R-12SW

 

My problem is:

1. the integrated tube amp does not have sub output or pre out or LFE (only regular 2-channel 4 ohm and 8 ohm speakers outputs are available)
2. Klipsch subwoofer does not have high level inputs (only line level inputs are available)

 

My question is:

Is it possible to connect Klipsch sub to this tube amp without interfering the main speakers' performance and sound quality? I don't have a preamp. The tube amp has the preamp built-in. I plan to connect a cd/sacd stereo player to the amp input as the music source.

 

Thank you for any idea you may have! 

Edited November 30, 2021 by JohnZ

[jason str]

Not going to work. 

[CWOReilly]

You'd need a different sub. You cant hook that one to that amp.

[tromprof]

It can be done, and quite easily. I used this with my Yaqin tube amp, worked perfectly connecting to a Klipsch powered sub.

https://www.crutchfield.com/p_543ADP12/Russound-ADP-1-2-Speaker-level-to-Line-level-Adapter.html

[babadono]

Of course it can be done. Like @tromprof pointed out. I don't know how handy you are at soldering but you could make your own voltage divider. All you need are those 4 resistors shown in the crutchfield post above.

[JohnZ]

Thank you @babadono and @tromprof. This is great news! Is the speaker-level to line-level adapter just 4 resisters? I have some resisters in my drawer to make a voltage divider for less than $1 😀 plus connectors. How dare can they sell that for $40? LOL Thanks a lot! 

 

 

 

Edited December 3, 2021 by JohnZ

[babadono]

Well it has a nice sturdy form factor to it. But $40 is a little steep. If you can make something for a couple bucks that does the same thing and is sturdy enough that you don't have to F' with it all the time I so go for it.

[babadono]

Keep us posted how it goes......

[MikeJapan]

In the end, did this adapter work?  I have the same amp and same subwoofer.  If you would, please tell me how you set this up.  How did you mount the adapter?

[CECAA850]

If you only had one source you could Y the rcas.  One side to the amp and the other to the sub.

[MikeJapan]

I tried connecting my Klipsch subwoofer (R-12SW) to my Reisong A10 tube amp, basically the same setup as @JohnZ above, using a Russound ADP-1.2 Speaker-Level to Line-Level Interface.

 

I tried connecting an L/R RCA male to an L/R RCA male cable to the subwoofer L/R RCA female in port.  On the other end of the RCA cable, I plugged in the male end into the Russound ADP-1.2 Interface’s RCA L/R female in plug.  
 

I used 16-gauge speaker wire to connect to the 4-connector on the Russound Interface, and then connected the speaker wires to the back of the Reisong A10 amp using the only available banana plugs; I put the wires into the 4om banana plug ports.  
 

I got a little base response from the Klipsch subwoofer, but it was short lived.  
 

Could anyone please tell me what I’m doing wrong?

 

Thank you!

[Peter P.]

Could you have connected the speaker outputs of the amp to the Russound out of phase? If not,  maybe the Russound device itself was built incorrectly out of phase.

 

One possible test would be to REVERSE just one of the speaker level inputs to the Russound device and see what happens.

 

Did you forget to turn the sub on? Is the gain up? Are you sure the sub is working at all-have you tested it with another stereo?

[MikeJapan]

Hi @Peter P., 

 

Thank you for your quick response.  
 

To answer your questions:

 

1) I’m too novice to know what “in phase” or “out of phase” means, exactly.  

 

The Klipsch R-12SW subwoofer has a phase switch, and I toggled that switch while having the sub and speakers connected.  The sub thumped 2-3 times but did not respond to the music played.  
 

The Russound ADP-1.2 is brand new and is a quality build.  I suppose it may have been built incorrectly, but I have no way of determining that.

 

2) I will try your idea of reversing the inputs.  Thank you.

3) The sub is definitely plugged in and switched on.  And yeah, the gain is cranked to max.  Yes, the sub most definitely works; tried it with my solid state amp.

 

@Peter P. ,thank you again.  I’m going to fiddle with this a bit more.  If you don’t mind, I will send photos of the setup.  That way you can truly see what’s going on.

 

Mike 

 

 

 

 

 

[Peter P.]

13 minutes ago, MikeJapan said:

Hi @Peter P., 

 

Thank you for your quick response.  
 

To answer your questions:

 

1) I’m too novice to know what “in phase” or “out of phase” means, exactly. 

Out of Phase: When you connect one speaker to your amp, the "+" and "-" from the amp with connect to the "+" and "-" to one speaker. On the other speaker, the exact same connection should be made. That way, both woofers for instance, will move forward and backward in sync with each other. If you connect one speaker from the amp backwards, while one cone is moving out, the other is moving in, effectively reducing the bass output because the speakers are moving "out of phase" with respect to each other.

 

Your Phase Switch on your subwoofer works slightly differently. It causes the subwoofer to move "out of phase" with respect to your main speakers.

 

Since you're pretty confident the subwoofer itself is working correctly, I figured maybe you connected the speaker wires to the Russound out of phase with respect to the left channel vs. the right. The other option is the Russound is not built properly so perhaps you DID connect to the Russound correctly but the Russound is reversing one channel, causing some of that bass reduction I mention above. A simple test would be to reverse the wires of JUST ONE speaker connection to the Russound and see what happens.

[MikeJapan]

Hi again @Peter P.,

 

Thank you for your explanation of phase.  I’m an audiophile wannabe in training 😂 Seriously, it’s good to compile such knowledge.  
 

Guess what?!

 

I did it!  Everything is working now.  I simply fed the +/- wires that I connected to the Russound ADP 1.2 Interface into the holes in the back of the banana plug connectors on the back of the Reisong A10 tube amp.  There they share the same 8 ohm connectors with the banana plugs for the speakers.

 

As a bonus, I was able to run TWO powered subs!
I realized that the Klipsch (R-12SW) subwoofer is of course mono, so it only needs one of the Russound’s two RCA ports.  So, with the second RCA available, I plugged in my smaller Jamo S 808 subwoofer, and no surprise, both subs are throbbing away.  Playing with phase settings, and using the tricks you taught me, I’ll get this system in synch, in phase.  
 

It sounds so good already.  That Reisong amp, btw, is absolutely amazing for the price.  
 

Thank you again, @Peter P.

 

Attached is a photo of the way I have the Russound rigged up now.  I plan to encase it in a housing I bought for it, but have to modify.  
 

One more question @Peter P.: do you happen to know if what I’m doing (i.e. attaching multiple speakers to my amp’s limited connectors) is kosher?  Or is there a better way to manage my multiple connections?  In fact, I’m planning to run two more (Klipsch ceiling mounted) speakers to those two already  busy 8 ohm connectors on the back of the Reisong.

 

Much thanks,

Mike

[Peter P.]

That's kosher, and extremely common to connect the speakers and subwoofer in parallel. The Russound presents a high impedance to the the amp, so the amp barely "sees" the subwoofer, or both subwoofers in your case.

 

However, I think the proper thing to do would be to connect BOTH RCA cables to ONE subwoofer. Here's why: The left and right channel outputs to your speakers are stereo information, so it's possible each channel is carrying different information, including in the bass region. An LFE input on your subwoofer is expecting a SUMMED signal (left + right), but you're only feeding it one stereo channel.

 

So I think BOTH RCA's should connect to ONE subwoofer otherwise I'm not confident the subwoofer is reproducing the bass signal correctly.

[MikeJapan]

Hello @Peter P. Thank you for your input (pun intended).  It’s decadent to have two subwoofers, and ultimately unnecessary, so I’ll connect the Russound ADP 1.2 Interface as you suggested, using one subwoofer.  I’ll use the other one elsewhere in the house, on a different system.  
 

By the way, @Peter P., what is an LFE input?

 

Again, huge knowledge gaps I need to fill if I want to claim this to be my hobbie (audiophilia) Thanks in advance

 

[Peter P.]

LFE stands for "Low Frequency Effects". It's usually the LFE or subwoofer output connection on most A/V receivers. LFE are your explosions, crashing helicopters, and whatever else happens in movies!

[babadono]

On 1/10/2022 at 3:20 AM, MikeJapan said:

I tried connecting my Klipsch subwoofer (R-12SW) to my Reisong A10 tube amp, basically the same setup as @JohnZ above, using a Russound ADP-1.2 Speaker-Level to Line-Level Interface.

 

I tried connecting an L/R RCA male to an L/R RCA male cable to the subwoofer L/R RCA female in port.  On the other end of the RCA cable, I plugged in the male end into the Russound ADP-1.2 Interface’s RCA L/R female in plug.  
 

I used 16-gauge speaker wire to connect to the 4-connector on the Russound Interface, and then connected the speaker wires to the back of the Reisong A10 amp using the only available banana plugs; I put the wires into the 4om banana plug ports.  
 

I got a little base response from the Klipsch subwoofer, but it was short lived.  
 

Could anyone please tell me what I’m doing wrong?

 

Thank you!

 

On 1/10/2022 at 5:00 PM, MikeJapan said:

Hi again @Peter P.,

 

Thank you for your explanation of phase.  I’m an audiophile wannabe in training 😂 Seriously, it’s good to compile such knowledge.  
 

Guess what?!

 

I did it!  Everything is working now.  I simply fed the +/- wires that I connected to the Russound ADP 1.2 Interface into the holes in the back of the banana plug connectors on the back of the Reisong A10 tube amp.  There they share the same 8 ohm connectors with the banana plugs for the speakers.

 

As a bonus, I was able to run TWO powered subs!
I realized that the Klipsch (R-12SW) subwoofer is of course mono, so it only needs one of the Russound’s two RCA ports.  So, with the second RCA available, I plugged in my smaller Jamo S 808 subwoofer, and no surprise, both subs are throbbing away.  Playing with phase settings, and using the tricks you taught me, I’ll get this system in synch, in phase.  
 

It sounds so good already.  That Reisong amp, btw, is absolutely amazing for the price.  
 

Thank you again, @Peter P.

 

Attached is a photo of the way I have the Russound rigged up now.  I plan to encase it in a housing I bought for it, but have to modify.  
 

One more question @Peter P.: do you happen to know if what I’m doing (i.e. attaching multiple speakers to my amp’s limited connectors) is kosher?  Or is there a better way to manage my multiple connections?  In fact, I’m planning to run two more (Klipsch ceiling mounted) speakers to those two already  busy 8 ohm connectors on the back of the Reisong.

 

Much thanks,

Mike

So @MikeJapan the only thing you changed to make it go from low level/not working to good is move the speaker wire inputs of the Russound adapter over to the 8 ohm output taps on your amp from the 4 ohm taps?

[Peter P.]

It sounds like MikeJapan stuffed the bare speaker wire ends from the Russound into the banana plug receptacles on the amp. I doubt they would have made a good electrical contact, hence the lack of sound.

 

When that didn't work, I think he discovered he could unthread the banana plug connections and he found through holes in the shaft into which he threaded his speaker wires.

 

Hopefully he'll correct me if I'm wrong.