XPA 100s and a Polk Sub.... HOW do I wire it?

[klyph]

Ok, so I'm trying to wire a Polk PSW505 subwoofer to 2 XPA-100 monoblocks by speaker level, and I need to know the proper way to do it so I won't mess up my amp/sub. Do I connect the speaker - wires to the amp's - or not? If I do, do I connect them together to only one amp? Or do I ground them to the chassis?

Any help would be appreciated.

[Gary Cook]

The Polk PSW505 is self powered (built in amp), so it just needs a pre amp output level for its input. If you have a processor then I'd suggest using the LFE output.

Cheers
Gary

[klyph]

It's for a stereo setup without pre-outs so it has to be speaker level. My question is specifically about the minus (-) speaker level inputs/outputs. How should those be connected since I'm using monoblocks?

[knucklehead]

You can use your preamp output RCA jacks directly to the sub's line level inputs. You'll need a 'y' connector to split the signal from the preamp to the amps so the sub also has a signal. In any case you'll need to adjust your sub for gain and frequency crossover for the sub. Your speakers will still be getting the full range audio signal. Then simply wire the speakers directly from the amps as normal.

You should list at least the equipment (preamp is unknown to us) involved so it does not take 5 additional posts to discover the audio gear you are working with. It makes things easier - usually.

[klyph]

The preamp is a Nightshade Audio Beacon II tube preamp>2 Emotiva XPA-100> Spatial Audio M4 speakers. I thought splitting with Y cables would degrade the sound.

[wiskers]

If you look at the back of UPA100's they have 2 speaker connections. connect one set to left/right speakers and the other set to your sub. set your crossover on the sub.

[Axis]

klyph
Here is the Manual for Polk PSW505. This sub has the speaker level inputs for use with Polk satellite speaker systems.

ec1.images-amazon.com/media/i3d/01/A/man-migrate/MANUAL000033226.pdf

Here is what you posted about your system.

"It's for a stereo setup without pre-outs so it has to be speaker level. My question is specifically about the minus (-) speaker level inputs/outputs. How should those be connected since I'm using monoblocks?"

"The preamp is a Nightshade Audio Beacon II tube preamp>2 Emotiva XPA-100> Spatial Audio M4 speakers. I thought splitting with Y cables would degrade the sound."


I searched and these were the only specs I could find on your preamp.

Nightshade Beacon 2
Frequency Response: 10-30,000hz
Output impedance: 100 ohms
Inputs: 2 (standard config.)
Outputs: 1 (standard config)
Tubes: 6SN7 x 2, any variety*
Dimensions: 17x10x5 inches @ 10lbs

Your preamp has one one left output and one right output. You are using one left and one right RCA line level interconnect to go to each of your XPA-100 mono amplifiers. Each amplifier has only one RCA un-balanced input but two left and two right speaker terminals that are the same channel.

This from the Emotiva XPA-100 manual.

"Two pairs of binding posts are provided to facilitate bi-wiring.
Note: Both pairs of speaker terminals carry the same signal. Two pairs of terminals
are provided to facilitate bi-wiring."

One XPA-100 supplies one left channel to one Spatial Audio M4 speaker and One XPA-100 supplies one right channel to one Spatial Audio M4 speaker.


Here comes the Polk PSW505 subwoofer. This is from the manual for your Polk PSW505 subwoofer.

H O O K - U P M E T H O D # 3 ( F I G U R E 9 )
This method is for use with electronics featuring “PRE OUT” jacks—and may be used as a secondary hook up method for use with compact
satellite speakers such as Polk RM Series. Connect the left and right preamp output from your electronics to the left and right LINE LEVEL input
of the subwoofer. This may require use of RCA “Y” cables (not supplied) to hookup both the subwoofer and your power amplifier. When using
method #3, it is necessary to adjust the settings on your preamp/processor as follows: Front speakers = LARGE; Subwoofer = “OFF” or “NO.”

If you notice it says to use a "Y" cable to connect from your preamp to both the amplifier and subwoofer. Also if you noticed the forum users with over 3000 post here recommended you use a "Y" cable.

It will be ok.

Warning !!!!! : Dot not use the single LFE input of the subwoofer. This input bypasses the subwoofer’s variable low pass filter and relies on the filter built into your electronics. Your preamp has no Low Pass filter and you want to use the Volume, Low Pass and Phase switch controls on your subwoofer.


Here is the thing. You only really need to feed one channel of the RCA line level output from your Nightshade Beacon 2 out to the subwoofer. I have been looking at the back of preamps for 50 years and cant count the times when I would see "For Mono Output Use Left Channel". Your Polk PSW505 subwoofer has both left and right RCA line level inputs so you can use a "Y" cable from both RCA preamp outputs and go to both RCA inputs on the subwoofer if you want to. I will not try to explain the difference other than your subwoofer is mono and only the left channel is needed for it to work properly.


Please don't try to use your speaker outputs on your XPA-100 amps with that sub and your speakers. You can do it but your asking for a whole host of issues that is just not necessary.

Get one short "Y" adapter cable. It should be a single male that you insert into the female left RCA output of your preamp and have two female ends. Connect one RCA interconnect to one of the female ends to go to the RCA input of the XPA-100 you use for the left channel. Connect another RCA interconnect to the other female end to go to the left input channel of the Polk PSW505 subwoofer.

Cheers

PS Gary Cook and knucklehead know there stuff and if you need anymore advice and they offer, take it !

[Axis]

Jan 28, 2016 23:14:27 GMT -5 wiskers said:

If you look at the back of UPA100's they have 2 speaker connections. connect one set to left/right speakers and the other set to your sub. set your crossover on the sub.

This is wrong. He has two XPA-100 mono amps. Both of the two speaker connections on the XPA-100 are the same channel and you would never connect the speaker wires from a single channel mono amp to both your left and right speakers ! He needs to go line level from his preamp to the sub. Using a single positive and negative speaker output from a single mono amp to a speaker and a subwoofer at the same time is not advised.

[Axis]

klyph , this looks like a great system you have. Are these the speakers you have ? I think this is a pic of the Nightshade Beacon 3.

www.digitalaudioreview.net/2015/10/rmaf-2015-waking-up-joe-public-with-the-spatial-m4/

[klyph]

Jan 29, 2016 2:08:27 GMT -5 Axis said:

klyph , this looks like a great system you have. Are these the speakers you have ? I think this is a pic of the Nightshade Beacon 3.

www.digitalaudioreview.net/2015/10/rmaf-2015-waking-up-joe-public-with-the-spatial-m4/

Thanks everyone for the help! I have some Y splitters so I'll go that route. And yes, those are the speakers I have. I just got them a few days ago (They are replacing a pair of Zu Omen's). Some of the best speakers I've ever heard..... except when it comes to "electronic" low bass (Hip-Hop and such). That's why I'm adding the subwoofer. It's something I already had from a previous setup. I'm thinking about trading it for a sealed Elemental Designs sub I used to have that I gave to a relative, because his setup is more for movies and he's not as "picky" as me. My preamp looks just like that except it uses 2 tubes instead of 3.

[geebo]

Speaker outputs from the amp the the Speaker inputs of the sub. Then Speaker outputs of the sub to the speakers. Adjust the crossover as desired.

From the manual:

RECOMMENDED HOOK-UP METHOD FOR “ SATELLITE ” SYSTEMS
SUCH AS POLK RM SERIES SPEAKERS
(FIGURES 6 & 7)
Connect the left and right front speaker outputs of your receiver or amplifier to the speaker level inputs of the powered subwoofer using
speaker wire.
Then, connect the left and right front satellite speakers using speaker wire from the speaker level outputs from the powered subwoofer.
If it is more convenient, parallel wire the subwoofer and front satellites from your receiver.

[wiskers]

Jan 29, 2016 1:03:08 GMT -5 Axis said:

Jan 28, 2016 23:14:27 GMT -5 wiskers said:

If you look at the back of UPA100's they have 2 speaker connections. connect one set to left/right speakers and the other set to your sub. set your crossover on the sub.

This is wrong. He has two XPA-100 mono amps. Both of the two speaker connections on the XPA-100 are the same channel and you would never connect the speaker wires from a single channel mono amp to both your left and right speakers ! He needs to go line level from his preamp to the sub. Using a single positive and negative speaker output from a single mono amp to a speaker and a subwoofer at the same time is not advised.

Not what I meant..... 2 xpa100's connect left speaker to xpa100 and left to sub. Connect right speaker to other xpa100 and connect sub. It works fine I had the xpa100's and connect my system that way,

[Axis]

Using a single mono RCA output is the best way to get the signal from the preamp to both the mono amplifiers and to the subwoofer.
The output level from the preamp to the amplifiers and to the subwoofer will match each other as the volume control on the preamp is raised and lowered.

Not the LFE (Unfiltered) input but the left and right line level inputs use the subwoofers phase switch, volume control and low pass filter with the signal from the preamp.


The speaker level inputs use the signal from an amplifier and convert it into a smaller signal for the internal amplifier of the subwoofer to use. The subwoofers phase switch, volume control and low pass filter are used with that signal.

The same high level speaker signal passes through to the high level speaker outputs. From everything I have read on this subwoofer it does not have a high pass crossover that effects speakers connected to the high level outputs.

Both methods will provide a signal to the amplifiers, the speakers and the subwoofer.

If you have a receiver that does not have a preamp output or subwoofer output but only a high level amplified signal that is controlled by the internal preamp of the receiver then you would use the subwoofers high level inputs.

You would connect one left speaker wire to the left high level input of the subwoofer. You would connect one right speaker wire to the right high level input of the subwoofer. You would connect a left speaker to the left high level output on the subwoofer. You would connect a right speaker to the right high level output on the subwoofer. You would use the controls on the subwoofer to control the subwoofer but not the speakers.


When you have a separate preamp from the amplifiers you can use that line level output from the preamp that normally goes directly to the amplifier and spit it so you can share it with the amplifier on the subwoofer. You only need the left channel (mono) signal line level output connected to the left line level input on the subwoofer.

If you Google this subject you will read many use the speaker level inputs on this subwoofer. Many say that it sounds better or the level is better. There are reasons why both methods are used. You can use either method and may see different results doing so.

I am glad we had this time together and if you do not agree with me I am ok with that.

Be carful with all those speaker wire connections. Make sure you do not have them crossed and they are in phase. Watch your step. You could trip on all those speaker wires or interconnects. Safe Audio please. Always use eye protection when stripping your wire ends. Do not run with scissors and wash your hands after your done.

Have a nice day !