How would I integrate a subwoofer with a Nuforce DDA-100 - AVS Forum
Forum Jump: 
 
Thread Tools
post #1 of 10 Old 01-22-2013, 08:39 PM - Thread Starter
Newbie
 
reedermw's Avatar
 
Join Date: Jan 2007
Posts: 12
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I had intended on running a parallel speaker cable from the speaker posts of a Nuforce DDA-100 to the high level inputs of an Outlaw Audio LFM EX-1 sub but it's my understanding that the digital amps don't ground the negative speaker terminal but rather the "float" meaning that both positive and negative terminals are active. I believe that most class-d amps do this. I read elsewhere that hooking up the outputs to a high level input of a sub can short or otherwise damage the main amp. What has been your experience with digital amps in this regard? Do the folks here connect to a sub via the high level inputs? If so, are there any caveats or other info you can share?
reedermw is offline  
Sponsored Links
Advertisement
 
post #2 of 10 Old 01-24-2013, 05:09 PM
Newbie
 
wherearewenow's Avatar
 
Join Date: Jan 2013
Location: Ireland
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
This guy Stephen Stone did it http://www.audiocircle.com/index.php?topic=112761.msg1171402#msg1171402 but he doesn't mention which sub he used.

I chickened out and just ordered an ex-demo REL R-218 (class D amp) which I intend to connect to the DDA-100 using the supplied speakon connector which has 3 wires on the amp side, 2 you connect to the R & L + terminals and 1 you connect (ground) to either - terminal. I'll let you know in a week or so if I've blown myself up.
wherearewenow is offline  
post #3 of 10 Old 01-25-2013, 06:15 AM
AVS Special Member
 
mnilan's Avatar
 
Join Date: Jun 2002
Location: Central NY
Posts: 2,111
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
wherearewenow:
Yes, I'm interested in what you think of the setup as a whole. The DDA 100 is an interesting piece of gear...
Mike

mnilan
mnilan is offline  
post #4 of 10 Old 01-25-2013, 06:21 AM
AVS Addicted Member
 
arnyk's Avatar
 
Join Date: Oct 2002
Location: Grosse Pointe Woods, MI
Posts: 13,827
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 392 Post(s)
Liked: 1035
Quote:
Originally Posted by reedermw View Post

I had intended on running a parallel speaker cable from the speaker posts of a Nuforce DDA-100 to the high level inputs of an Outlaw Audio LFM EX-1 sub but it's my understanding that the digital amps don't ground the negative speaker terminal but rather the "float" meaning that both positive and negative terminals are active. I believe that most class-d amps do this.

Yes indeed!
Quote:
I read elsewhere that hooking up the outputs to a high level input of a sub can short or otherwise damage the main amp.

That would depend on how they implment in high level inputs of the sub.
Quote:
What has been your experience with digital amps in this regard? Do the folks here connect to a sub via the high level inputs? If so, are there any caveats or other info you can share?

More to the point, using a powered sub by driving its high level inputs is pretty backward, both technically and sonically, as compared to using an AVR that was designed all along for this kind of situation.

I would nominate this Nuforce DDA application as today's best example of a tail wagging a dog! ;-)
arnyk is online now  
post #5 of 10 Old 01-28-2013, 08:43 PM - Thread Starter
Newbie
 
reedermw's Avatar
 
Join Date: Jan 2007
Posts: 12
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I have the Outlaw Audio LFM-1 EX (rebranded HSU with a BASH amp). I contacted tech support and they claim that the high level speaker inputs handle these amps. So, I hooked it up, closed my eyes, and flicked on the power. Kaaboooommm!!! Just kidding. Nothing happened and it seems to work fine. Note that I only attached the left channel from the power amp to the left channel speaker-level input of the sub. My sub's speaker level inputs are designed for 100 - 200w so the DDA-100 produces a pretty attenuated input to the sub's amp. I had to double the volume of the sub to trim it up into the range of the mains.

The DDA-100 is a fun amp to listen to music on. It has great texture and detail especially through the mids. The location queues are also good as is the separation. The USB input isn't async however so it depends on how jitter free your source is. A lot of people are purchasing an async USB to SPDIF converter to remedy the situation. I think the USB input is engaging all the same. @ArnyK, I'm with you on the "tail wagging the dog". One review I read (The Absolute Sound) suggest buying a $1200 USB to SPDIF converter to go with this $550 amp and that's exactly what I thought.

Another option I considered was a speaker-level to line-level converter with an isolation transformer. These folks make a line-level isolation transformer (http://www.jensen-transformers.com/sub1rr.html) as a way to de-couple a sub from the main system. This might also help for with those sub's that lack speaker-level inputs. I have an inquiry into Jensen Transformers on the topic. I'll report back when I hear from them.

As for the sound of the DDA-100, it's very nice for music. Great texture and detail through the mids. Sound stage is reasonably deep and layered. Location queues are good. Music sounds very natural and authentic. Stringed instruments and vocals particularly seem to stand out more so than the other amps I've got. I wish they would build a model with a larger power supply as I felt the 4 ohm speakers I was using seemed somewhat current-starved. This effects bass performance primarily and had to be augmented with the sub to reinforce the bottom end. The under-representation of bass in the upper-bass and lower-mid section may perhaps be the reason for the increased texture and detail in the mids that seem to favor some types of music so well. In short, I wouldn't recommend this amp with 4 ohm speakers without a sub. If I had some high efficiency 8 ohm speakers that were close to full range, it might be great though without a sub.

This reminds me of the Ongaku that I spent some time with a while back. (Review here: http://www.stereophile.com/ces2009/ongaku_means_ecstasy/index.html) Specs on paper were bad. 3% of all the sound coming from this amp didn't match it's input but it sounded great. The DDA-100 is obviously not in the same league but I think it sounds good with music in my setup perhaps partially due to inappropriateness to my speakers in that it just reveals more midrange detail and texture as a result. The Ongaku on the other hand manged the VMPS speakers just fine and sounded great in spite of some pretty horrible looking numbers on the spec sheet.
reedermw is offline  
post #6 of 10 Old 01-29-2013, 03:50 AM
Newbie
 
wherearewenow's Avatar
 
Join Date: Jan 2013
Location: Ireland
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
Quote:
Originally Posted by reedermw View Post

INote that I only attached the left channel from the power amp to the left channel speaker-level input of the sub.

Why didn't you connect both channels? Obviously you're still connecting the mains to the DDA-100 and not using the LFM-1 Ex's speaker out connections? Is there some secret maths involved here?!!
Quote:
Originally Posted by mnilan View Post

Yes, I'm interested in what you think of the setup as a whole. The DDA 100 is an interesting piece of gear...Mike

Hi mnilan, yes I went with your input and ordered a REL. Have my spade connectors ready. Have my wattage monitor ready to make sure it's not overheating. Have my Sorbothane Hemisphere Rubber Bumper Non-Skid Feet ready (so I can put the DDA-100 and a lava lamp on top of it without them jumping around too much). Can't wait for it to arrive and give it a run. Will let you know my experience.
Quote:
Originally Posted by arnyk View Post

I would nominate this Nuforce DDA application as today's best example of a tail wagging a dog! ;-)

Woof, woof!
wherearewenow is offline  
post #7 of 10 Old 01-29-2013, 06:24 AM
AVS Special Member
 
mnilan's Avatar
 
Join Date: Jun 2002
Location: Central NY
Posts: 2,111
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
wherearewenow:
Cool. What speakers are you using? The Absolute Sound review mentioned speakers with at least 88 dB sensitivity... I am truly hoping you have a great experience! Good luck!
Mike

mnilan
mnilan is offline  
post #8 of 10 Old 01-29-2013, 06:35 AM - Thread Starter
Newbie
 
reedermw's Avatar
 
Join Date: Jan 2007
Posts: 12
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I paired the Nuforce DDA-100 with the smaller Magnepan MG12's in a second setup. Those speakers are about 83db efficient on a good day and it seemed to handle them ok. You're experience may depend more on your frequency based impedance curve. What speakers are you planning to try with it?
reedermw is offline  
post #9 of 10 Old 01-30-2013, 03:35 AM
Newbie
 
wherearewenow's Avatar
 
Join Date: Jan 2013
Location: Ireland
Posts: 8
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
I have Monitor Audio RX2s, which have a sensitivity of 90dB, and an impedance of 6 ohms. Can't find any detailed technical review of them so I don't know what the frequency-impedance curve is. I bought them as soon as I got the DDA-100 about 4 months ago. The main reason I got them (I had been looking at Monitor Audio BX2s) was for the 8" woofer - most other bookshelf speakers I looked at (around the €600 or less price range) seemed to have ~6.5" woofers - and I'd thought that with the 8" I'd get away with not having a subwoofer. Indeed I doubt originally that I'd've bought the DDA-100 had I known that one fine day I was going to need/want a subwoofer. So ordering the REL now is totally arse-about-faced. Can't say I've any real regrets though...so far....at least....
wherearewenow is offline  
post #10 of 10 Old 01-30-2013, 08:15 AM
AVS Special Member
 
mnilan's Avatar
 
Join Date: Jun 2002
Location: Central NY
Posts: 2,111
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Liked: 10
wherearewenow:
I think the Monitor Audio speakers along with the REL will be really nice. I think you will be pleased indeed. Let us know...
Mike

mnilan
mnilan is offline  
Reply 2 Channel Audio

User Tag List

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off