We've sold *hundreds* of A1s and had essentially zero hums. It's not impossible to have a mechanical hum with these types of transformers, but we honestly haven't run into it. To be honest, I can't remember *any* instance of audible hum from these amps, but having sold so many, I'd assume there must be a case somewhere or another of one that hummed at least a little.

"essentially" "not possible with this type of transformer" "one that hummed just a little" just admit it...they hum. I spoke directly with tech service a yr or more ago and was told that "some" hum was acceptable.

Glad you like it. Are you bi-amping the fours? I ran mine 'regular' for a couple months and then purchased two a1's and an x2. Made a nice difference. Infact, if you don't have a huge room you could get away without using a sub as these go clean below 30 dipping into the upper 20's hz.

No I am not bi-amping the fours, as a matter of fact they are still being ran off a Marantz SR4001. However anytime they get played loud the display starts pulsing and the amp starts clipping, so next step will be a nice 3 or 5 channel amp. I did not notice any timbre difference between the fours and threeC. Also I am not using a sub at this time and for music the fours really work great! More power and I am sure they would be really pushing out some nice lows. Most likely not into the 18 inch sub woofer range but they still work great. Not a huge movie watcher so the big sub doesn't really overly imprtant to me, though they can be nice for music as well.

If you are comparing two speakers to each other that are not placed at the same height as each other, they are going to sound different, even if they are the same speaker. Unless you put the ThreeC at the same height as the Four, it is going to sound quite a bit different.

I have the Xd system and once in a while there would be a loud hum audible from my sitting position. Did quite a bit of troubleshooting and it turned out to be just loose xlr cables coming from the NHT PVC pro that I'm using for volume control.

I currently have a Sonos and a Sony DVP7000 (for CD playback) connected to a Cambridge Audio DACmagic. I am thinking of replacing the DVP with a SACD player. Any suggestions?

I thought that I had seen somewhere that the ThreeC had the same mid and tweeter that the Fours use. I am remembering wrong? Thought even the 6.5 driver was the same. Of course as has happened before and will happen again I am sure, I could be mistaken.

Has anyone used NHT speakers with an Emotiva amp?

The 3 and 4's have same drivers. Essentially a 4 is a 3 on top with a 10 woofer added on lower side. The 3c shares same drivers plus an additional midbass, minus the 10in, although the xover have slightly different points. Mine sound fantastic for movies and reallllly good for music. I would give the edge for movies concerning the system as a whole but I have been happy for a yr or so. Bi-amping the 4's made a great difference. It could be easily done if you have 2 extra amp channels that you are not using and put an x2 in the loop. I use 5 of my 7 channels availabe from my power amp to power the top end of 4's, center, and surrounds. As soon as I add a couple more spkrs I'll have the pwr for them with those 2 extra unused channels. I mentioned before that I use dual a1's/x2 for the 10's. I don't use the lfe option on x2 to send lfe signal to the 4's...just the low out. I send lfe from Controller straight to stand alone sub. I only have about 200 hrs on the whole deal...probably less on center/surrounds. Sound better than ever with time under their belt.

Has anyone used NHT speakers with an Emotiva amp?

I have not ...but, I'm trying to talk my buddy in to bringing over his Emo just for kicks. If/when I do so I'll surely post. Biamping my fours w/ a1's/x2 combo really free up my main amp to strut it's stuff since it only has to handle midbass drivers up. From all reports it should sound fantastic. My bud and myself noticed an immediate, audible difference when he added the Emo to his rig (Klipsch Heritage spkrs...khorns and Jubilees). The nht's should really like the power as they are on the low side of sensitivity and nominally 6ohm for many models.

If you are comparing two speakers to each other that are not placed at the same height as each other, they are going to sound different, even if they are the same speaker. Unless you put the ThreeC at the same height as the Four, it is going to sound quite a bit different.

I had this thought/assumption some time ago. Thanks. The center sits about 18in or so below the 4's top...so there is some distance difference there.

I currently have a Sonos and a Sony DVP7000 (for CD playback) connected to a Cambridge Audio DACmagic. I am thinking of replacing the DVP with a SACD player. Any suggestions?

How do you like the DACmagic? Been thinking about one of those to use with my Xds. I'm debating between that or saving up longer for a Benchmark DAC1.

Also, how do you like using the PVC with the Xd?

I like the DACmagic a lot as it greatly improves from what the Sonos offers and is reasonably priced. It has inputs for 3 digital sources and is small. Only drawback is the lack of a remote for switching sources but this is not a big deal to me. I also like using the PVC with the Xd. Combined with the DACmagic's multiple inputs, I avoid the need for a preamp, which saves money and eliminates one more thing to put in the signal path, but I can still switch sources and control the volume fairly easily. I am quite happy with this set up. In fact, I just got the SACD of the E.S.E. sessions from Blue Coast Records and I am blown away by how great the music is.

mnc, I would definitely be interested in knowing how you like the Emotiva amp paired with the NHTs. I think I've mentioned before that I have individual A1s powering everything and well 10 monoblock amps sounded like a good idea at the time, but.... So I would really like to know how the XPA-5 sounds with the NHTs. I'd need two of them but still that's 8 less power sources to consider.

Hey all - I have been interested in the classic line since it came out, but now am finally in a position to purchase. I am going for a semi-HT setup; I would love to go with the 4s, but most likely will go with the 3s and a 3c (and if possible 2s for the rear at this point).

Does anyone know if there is a place to get any kind of "package" deal? Or can these only be bought as individual/pairs? Thanks!

Hey all - I have been interested in the classic line since it came out, but now am finally in a position to purchase. I am going for a semi-HT setup; I would love to go with the 4s, but most likely will go with the 3s and a 3c (and if possible 2s for the rear at this point).

Does anyone know if there is a place to get any kind of "package" deal? Or can these only be bought as individual/pairs? Thanks!

I would call NHT directly and see if they can do anything for you.

Xd owners: What happens if I have two pre-amps, one single-ended/RCA and one balanced, plugged into the XdA?

Currently I use my receiver to drive the XdA via the RCA inputs. But I'd like to perhaps use a PVC Pro (likely driven by a DAC) to drive the XdA's balanced inputs, giving me a separate 2-channel setup. I'm wondering if this is possible.

mnc, I would definitely be interested in knowing how you like the Emotiva amp paired with the NHTs. I think I've mentioned before that I have individual A1s powering everything and well 10 monoblock amps sounded like a good idea at the time, but.... So I would really like to know how the XPA-5 sounds with the NHTs. I'd need two of them but still that's 8 less power sources to consider.

You have 10 a1's...? So you just come out of prepro to an a1 and then on to a spkr or pair of binding posts? geez. How do you utilize 10 channels of pwr. 4 for mains, 2 for cntr, 2 for side, 2 for rear...oh...that is ten. Wow. Yea, I would say downsize with a xpa5 for the upper 4's, center, and surr. Use two a1's on the 10in woofers. Basically same setup as mine. Later add an xpa2 for the mains and switch the other channels of the xpa5 to pwr rear surr for a 7ch setup. BTW...my budd has the xpa3 so it should be comparable to the 5. I'll see if we could do a session while over the holidays coming up soon.

[QUOTE=Tim916;17439228]I would call NHT directly and see if they can do anything for you.[/QUOT

As suggested or call AV logic or Audio advisor to see what they have left. As I understand Nht are going internet/factory direct. Got my 4's for a grand shipped...3c for 2 forty shipped. I don't think you will get them that cheap...but you can find very competitive places to do so. Pm and I'll give pointers as we are not supposed to discuss prices...I think:confused:

You have 10 a1's...? So you just come out of prepro to an a1 and then on to a spkr or pair of binding posts? geez. How do you utilize 10 channels of pwr. 4 for mains, 2 for cntr, 2 for side, 2 for rear...oh...that is ten. Wow. Yea, I would say downsize with a xpa5 for the upper 4's, center, and surr. Use two a1's on the 10in woofers. Basically same setup as mine. Later add an xpa2 for the mains and switch the other channels of the xpa5 to pwr rear surr for a 7ch setup. BTW...my budd has the xpa3 so it should be comparable to the 5. I'll see if we could do a session while over the holidays coming up soon.

Well not exactly; I'm running a 5.1 system. I have two pairs of T5s (1 pair for the front and 1 pair for the rears), a M5 for the center and a subwoofer. So each M5 gets an A1 and each B1 gets an A1. I was thinking that I could use an XPA-5 for the for front 3 M5s and front B5s. Then I could use another XPA-5 for the rear 2 M5s and rear B5s. But I do have one caveat, the back pair of T5s are not hooked up at the moment because I don't have space for them in the room (but will soon) so at this point I'm just considering simplifying my setup with fewer amps.

Please let me know what you think of your friends XPA-3 and the NHTs.

Matt,

The optical connection between the Mac and the receiver will break any ground loops at that interface.

I would still remove the RCA to RCA cables and replace them with the NHT supplied RCA to XLR cables. If you need to extend the RCA to XLR cables, don't extend the RCA end. Get an XLR to XLR cable to extend them.

Jack,

I tried the RCA to XLR cables. I believe they decreased the noise by about half (subjectively), although it was still audible. But I think the improvement was enough that I'll order a pair of XLR cables to extend the RCA to XLR so I can use them permanently.

I did notice that when I powered the receiver off, the noise went away (the XdA was left fully powered up). The Xd, receiver, Mac mini/Drobo hard drive array, etc. are all part of a home theater system, so it's conceivable there's another path for the ground loop to form.

If you have any ideas on how to eliminate the noise entirely, I'd be glad to hear them. But the RCA to XLR suggestion helps and is much appreciated.

Oh, one more question: is there anything special about the RCA to XLR cables included with the system, or would any such cable (e.g. this (http://www.monoprice.com/products/product.asp?c_id=102&cp_id=10244&cs_id=1024404&p_id=4777&seq=1&format=2)) do the trick?

EDIT: Never mind on this one. Found Jack's answer elsewhere in the thread where he states most of the converters are not built correctly, so use the NHT ones with an XLR extension.

[QUOTE=mattwardfh;17440796]Xd owners: What happens if I have two pre-amps, one single-ended/RCA and one balanced, plugged into the XdA?

I would like to know if this is possible also, but instead of 2 preamps, can I have a DAC's RCA out plugged into the XdA's RCA inputs and balanced outs from a SACD player going into XdA's balanced inputs.

Anyone tried this?

I would like to know if this is possible also, but instead of 2 preamps, can I have a DAC's RCA out plugged into the XdA's RCA inputs and balanced outs from a SACD player going into XdA's balanced inputs.

Anyone tried this?

You can use a DAC or CD player in place of a pre-amp if it has volume controls; that shouldn't be any different from what I'm trying to do.

Can I still get replacement drivers from NHT?

Well not exactly; I'm running a 5.1 system. I have two pairs of T5s (1 pair for the front and 1 pair for the rears), a M5 for the center and a subwoofer. So each M5 gets an A1 and each B1 gets an A1. I was thinking that I could use an XPA-5 for the for front 3 M5s and front B5s. Then I could use another XPA-5 for the rear 2 M5s and rear B5s. But I do have one caveat, the back pair of T5s are not hooked up at the moment because I don't have space for them in the room (but will soon) so at this point I'm just considering simplifying my setup with fewer amps.

Please let me know what you think of your friends XPA-3 and the NHTs.

Ok. Used the xpa3 with my 4's. Can't tell you if I had trick or treaters or not. Could not hear the doorbell :) They liked the extra muscle...spkrs that is. All seriousness aside, the tonal quality did not change but rather seemed faster. Faster attack and decay which made for a tighter sound. I hooked up the jumpers and ran it full range stereo mode with signal coming from oppo cdp through my nht Controller. I let speaker wizard feature do the auto setup some time ago so all settings remained. I bumped up the bass via tone to plus 2 and left treble at my usual plus 2 from flat. This works with my living room as it has cushioned furniture, heavy drapes, and carpet. I then jacked in the x2/a1/a1 combo again. It was time to crank it up. These speakers really surprise me and others. They get louder without changing tonally. I can get it to -10db or -6db and it's loud but does not hurt your ears. It's just jamming. Listening selections included some Steely Dan, Porcupine Tree, Diane Krall, General Public, Seal, Jeff Beck, Pat Metheny(The Way Up), A Perfect Circle, and Cab (fusion jazz), Madonna. I use select songs for attributes that I am very familiar with. Mind you, not everything sounds good but passable. Very dependent on recording/artist. These volumes are for 'show-off' purposes only and are not typical. My pwr amp is a Boston 7200...Sherwood/Outlaw clone that Boston tweaked and rebadged. It weighs 80lbs and is rock solid in sound quality. I have no desire at present time to switch out as I practically stole it. I can tell you the xtra horsepwr sped-up an tightened things a bit. For the price/quality/cust serv of the Emo stuff...it's a no brainer really. I would imagine a xpa5 doing the c4's well and a xpa2...well, of course as it's one of their best. Best of luck in your decision/s. Remember, you do get 30 days trial but have to foot the return shpng cost.

mnnc, many thanks for testing the XPA-3 with your 4s! I might have to get an XPA-5 and see how I like it; I forgot about the 30 days return policy.
When you mention that not everything sounds good which is dependent on the recording, do the recordings sound the same with your normal amp, just the XPA-3 allows you to run the 4s louder?

PlainFan...yes. If recording is so-so on my amp it was same on Emo. I can play loud w/ my amp as well. With the extra pwr the emo seemed to have more control over the spkrs. My focus was on the 4's ability to go loud without sounding different. Some spkrs sound different at diff volume levels. The nht's sound the same at low volumes to me as they do at higher volumes...just louder...not different in tone/sound. I typically listen somewhere in the -30's/-20's db so it's not cranking but it's not lounge level either. Mind you...I'm using an ok cdp...just ok/good. I guess with a nicer cdp like a rega, cambridge, or denon it may sound better. I got my cdp prev owned for a song and it's versatile handling my multi-ch music quite well. I could go on and on about adding better source components but you get the idea. The nht/emo combo would be a smashing start or upgrade for an a/v rig. When you consider quality/price ratio it would be quite difficult to top. I'm content as my dream spkrs are the tol revels...one day. Just a quick story. Last summer/08...I visited some hi-end 'salons'. Listened to some Wilson/Classe combo Vandersteen, B&W, etc. This stuff is expensive. I was not impressed. Either the rooms were not good or the setup was off. I don't know, but my buddy and I looked at each other and agreed my rig sounded better. He has Khorns and Mac. You know the kind of sound levels that stuff can produce. It's all subjective. Let me/us know what transpires and post impressions.

That is exactly what I gathered while reading your post. I agree the T5s sound the same regardless of volume for me as well. I will definitely post my findings if I decide to go with the emotiva amps. I'm actually on the preorder list for their UMC-1 so when or if I go ahead with that purchase I'll post my findings with the UMC-1/NHT combo as well. I've just become the owner of the M60 Pro system which is heading my direction. I got it at a very good deal so I'm pretty interested in finally hearing for myself the system that received so many great reviews.
If you get a chance listen to Sonus Faber as well. A friend in the home theater business sells Sonus Faber, Macintosh, Arcam and REL gear. He demoed for me the low end Sonus Faber bookshelf speakers with Macintosh electronics and the low end REL sub all fed by Blu Ray. WOW, you get the chance to hear the Sonus Faber speakers do so. Of course I was tempted but I'm so pleased with my NHTs that trading up was never a serious consideration. :D

That is exactly what I gathered while reading your post. I agree the T5s sound the same regardless of volume for me as well. I will definitely post my findings if I decide to go with the emotiva amps. I'm actually on the preorder list for their UMC-1 so when or if I go ahead with that purchase I'll post my findings with the UMC-1/NHT combo as well. I've just become the owner of the M60 Pro system which is heading my direction. I got it at a very good deal so I'm pretty interested in finally hearing for myself the system that received so many great reviews.
If you get a chance listen to Sonus Faber as well. A friend in the home theater business sells Sonus Faber, Macintosh, Arcam and REL gear. He demoed for me the low end Sonus Faber bookshelf speakers with Macintosh electronics and the low end REL sub all fed by Blu Ray. WOW, you get the chance to hear the Sonus Faber speakers do so. Of course I was tempted but I'm so pleased with my NHTs that trading up was never a serious consideration. :D

I own an M-60 system as well (I use the XdW subs, did you get the S-80s?) and it is unbelievable for the price I paid. However, be warned that it is a different animal than a Sonus Faber. Sonus speakers tend to be on the warm/lush side of neutral whereas the M-60 was designed to be as neutral as possible.

I got the S-80 with the package. I'm not expecting Sonus Faber sound; just mentioned it to mnnc to give them a listen if the opportunity presents itself.

What do you think of the M-60 system? Are you running dual Xdw subs? What are you using for a switching source? I've started looking but have no clue what might be good to mate with the Xda.

I got the S-80 with the package. I'm not expecting Sonus Faber sound; just mentioned it to mnnc to give them a listen if the opportunity presents itself.

What do you think of the M-60 system? Are you running dual Xdw subs? What are you using for a switching source? I've started looking but have no clue what might be good to mate with the Xda.

I am using dual XdW subs with mine. The system is spectacular. Read the reviews of the standard Xd system, but remove the caveat expressed by most of those reviewers that the Xd is a little lean in the 100-200hz region (it is), and that's what you are going to have with the M-60 system.

It is remarkably clean sounding at high volumes in comparison to most hifi speakers of similar size. In fact, you have to be careful because you won't realize how loud you are playing it until a neighbor/wife/landlord lets you know about it.

Hi guys, ive had my classic 3 system for about 5 months now and im absolutely in love with them. I have the classic 3 center and classic 2's for surrounds.

Right now im poweing them off a yamaha rx-v661. They sound escellent to say the least. But i have a bit of cash to spend so im wondering if i should buy an amp for them.

Im not looking for output as i have a very small room 10x15x8 and i sit about 7 ft away from the 3's. I want punchier bass, bigger soundstage, more seperation and detail.

How much wattage should i be going for?

Right now im looking at the emotiva xpa-3, and 5. ANd the UPA-7 as well

is 200 watts wasted heat for my room? (in terms of amplifier size)
For those not familiar the xpa 3 and 5 are 200 wpc and the upa7 is 125.

Tim, thanks for the input. The system will be here about Thursday so I'll post after some evaluation time (might be dangerous when I compare it back to my T5 based theater).

What do you use as a source for the Xda?

RedMed427, the NHTs like power. I have 250 watt amps powering mine and the difference is very noticable when I left the receiver for separate amps.

RedMed427, the NHTs like power. I have 250 watt amps powering mine and the difference is very noticable when I left the receiver for separate amps.



Well i would assume that they would sound alot better with a dedicated amp. My question is if i would notice, or even need the extra 75 watts, or possibly better construction... not too mention higher price.

Im really considering the UPA-7 atm.

Redmed...xpa5 for now...add xpa2 later for 7ch. It would lift things to a new height. Do you use a sub? A good 10 incher from the likes of svs or hsu would be great in your room

Tim, thanks for the input. The system will be here about Thursday so I'll post after some evaluation time (might be dangerous when I compare it back to my T5 based theater).

What do you use as a source for the Xda?

RedMed427, the NHTs like power. I have 250 watt amps powering mine and the difference is very noticable when I left the receiver for separate amps.

The XdA likes a balanced input, but if your preamp or processor does not have balanced out the next best thing is to use the NHT supplied RCA to XLR cables.

I am using a Denon 3808 and it seems to work pretty well, but I have not tried anything else with them, nor do I plan to anytime soon.

Well, I made an impulse buy and got 2 Xds.
I even overpaid for them (should have bought them from Jack (http://www.avsforum.com/avs-vb/showthread.php?t=1125860)). :o

I don't know what I was thinking (okay, I was thinking "fun project"... :D ), but now I need to figure out a good use for them.

The first thing will be to read over this thread to figure out what to do about the crossovers without forking the dough for an XdA.
I got confused with the specs mentioning of a crossover at 1kHz, but now understand that there's no crossover whatsoever in the speaker. :(
The reason for not going the XdA route is because I want to possibly reuse the XO and amp for another project (if ever).

As far as crossover, so far, I have the Behringer ULTRADRIVE PRO DCX2496 in mind.
Any opinion on it?
How close does it come to the XO of the XdA?

Anybody has a picture of the back of the Xd?

My current plan is to the NHT RCA to XLR cables which is why I'm asking what people are using with the XdA boxes.

Does anyone know how long the A1/X1 delay before going into stand-by is supposed to be? I need to figure out if there is a phantom signal that is causing them to wait 20-30 minutes. They are driven by a pre-amp that is also in stand-by, not off.

My X1 stays on for about 15-20 minutes before shutting down. I manually turn the A1 off by the switch in the back but I think it too has about a 15-20 minute delay.

So I've got the M60 system set up but unfortunately the NHT supplied RCA to XLR cables weren't included. I have a very distinctive hum in the playback so I'm pretty sure I need them. I've emailed the seller but need to start looking for alternatives. I'm trying to find the posts the discussed this topic, but can I use other RCA to XLR alternatives? I checked NHT's website but do not want to fork out the $125 per cable they are asking!

It didn't take me long to answer my own question. Found the reference on the previous page to Jack saying that the NHT supplied RCA to XLR cables is the way to go. So any suggestions if the previous owners don't have the cables...?

So I've got the M60 system set up but unfortunately the NHT supplied RCA to XLR cables weren't included. I have a very distinctive hum in the playback so I'm pretty sure I need them. I've emailed the seller but need to start looking for alternatives. I'm trying to find the posts the discussed this topic, but can I use other RCA to XLR alternatives? I checked NHT's website but do not want to fork out the $125 per cable they are asking!

It didn't take me long to answer my own question. Found the reference on the previous page to Jack saying that the NHT supplied RCA to XLR cables is the way to go. So any suggestions if the previous owners don't have the cables...?

Hum... I hope other XLR to RCA cables can be used.
Either that or I have just wasted a small amount of money buying cables from Lynx (http://www.lynxstudio.com/product_detail.asp?i=46).

Update:

Got up this morning and decided to try plugging my Creative Labs Zen MP3 player into the XdA just to see if that eliminated the noise. Good news, all the interference/noise from last night is gone! Unfortunately that confirms that a.) I need the RCA to XLR cables and b.) my receiver passes a lot of noise/interference to the XdA. Still need help!

I've been listening to different tracks through the MP3 player. So far, my observation is WOW, I didn't think MP3s were supposed to sound this good! I encode at VBR but still it is shocking. Again, I need the other cables so I can listen to music from the original CD, SACD, BD, etc... Completely understand the people that post about turning the system up loud. It just plays so clear and easy that you find yoursefl enjoying the music bumping the volume up every few minutes...

Again, still need help getting the NHT supplied RCA to XLR cables...

The hum is from grounding issues with the XLR to RCA cables.
A lot of manufacturers did not follow the proper specs in making these cables.

XLR is a balanced type cable and RCA is unbalanced.
So, XLR to RCA is balanced to unbalanced, which requires proper pin conversion.
Once I get my cables from Lynx, I will let you know.

Otherwise, just call NHT for the original cables.

I purchased a U2 sub system a while back and I am having some issues with the X1. The unit has to be totally cranked to get any volume to the amp. Then some time if you pause for a while and restart it will blast and over drive the amp. I am at a crossroads with the unit and realize the subs must have the proper eq to be of use. Any possibilities of a loose wire on the inside? I have some skills with a soldiering iron if I could fix it myself.

Thanks in advance.

Could it be the device sending the signal to the X1? Are you using a receiver or pre/pro? How do you have the X1 setup?

I have tryed it with a multitude of processors and configurations. Emo, Onkyo, Halcro. Currently I am trying the simplest configurations let the processor handle the xover and just use the x1 for eq and some volume control. I have tryed the sub amp on the left and the rt sub out but currently it is on the rt. I have tryed the sub in on the sub in and rt in and currently it is on the sub in connection of the x1.

Are you using the U2s as subwoofers (LFE signal) or as subwoofers for low end extension of "small" speakers?

Currently I have all the speakers crossed over in the AVR at 80hz and added to the lfe channel and that is what I am feeding the x1. Called method #3 in the manual?

Does anyone know how long the A1/X1 delay before going into stand-by is supposed to be? I need to figure out if there is a phantom signal that is causing them to wait 20-30 minutes. They are driven by a pre-amp that is also in stand-by, not off.

My dual A1's/X2 combo stay on for 15-20 mins after no signal. Manual states this time interval as well.

This seems to be the biggest NHT thread around, so hopefully my question is appropriate.

I have a pair of NHT ST-4s. I bought them about 7 years ago, and am quite fond of them when they have enough juice to run. I'm looking to step up to a surround sound system and I suppose I have three options:
1) Buy 5.1 additional speakers and leave the NHT's for stereo (not likely due to space)
2) Get rid of the NHT's and buy 5.1 speakers.
3) Buy 3.1 additional speakers to compliment the NHT's.

I like option 3 the best from a financial point of view, however, I'm not sure what I could match with the ST-4's for center/surround. Any thoughts?

The hum is from grounding issues with the XLR to RCA cables.
A lot of manufacturers did not follow the proper specs in making these cables.

XLR is a balanced type cable and RCA is unbalanced.
So, XLR to RCA is balanced to unbalanced, which requires proper pin conversion.
Once I get my cables from Lynx, I will let you know.

Otherwise, just call NHT for the original cables.

To follow up, the Lynx cables were a bust as they don't conform to specs.

This is how the proper cables should be wired (make sure any XLR to RCA cable you buy is wired this way):
http://www.speakerrepair.com/ebaypics/xe-wiring.jpg

There is no such thing as a balanced RCA connection with a single connector, yet many cable makers wire the -ve to the RCA ground leaving the connection ungrounded (hence the hums). :eek:

A balanced RCA connection should be an XLR to two RCAs.
http://www.mediacollege.com/audio/connection/images/XLR-2xRCA.jpg

Here is a good read: http://www.mediacollege.com/audio/connection/xlr-rca-1.html

So, I have now ordered these: http://www.speakerrepair.com/mm5/merchant.mvc?Screen=PROD&Store_Code=genem&Product_Code=37-372&Category_Code=

Spectrum,

The XLR inputs on the XdA require a male connector - the ones you provided a link to have female XLR connectors.

Spectrum,

The XLR inputs on the XdA require a male connector - the ones you provided a link to have female XLR connectors.

I know.
Nonetheless, I am using the behringer DCX 2496, which needs both male XLR for input and female XLR for output.
For the short term, I am using the DCX with a set of NHT Power 2 amps.
The NHT amps are just too neutral (borderline sterile), and you need a nice pre-pro to give them some flavor.

Back on the cable subject, note that the Lynx XLR to S/PDIF cables seem to be properly built (mainly because a digital signal does not need/cannot be balanced).
So, buy those if you need XLR to S/PDIF cables, but don't buy their XLR to RCA cables.

The previous owner is checking to see if they can get the cables for me. I'm going to reveal my ignorance here but how do I hook two RCA cables up to a single output?

There is a lot of misinformation in the last 10 or so posts about connecting balanced and unbalanced interfaces to each other. There is no single cable that works for all XLR to RCA applications or RCA to XLR applications. Why this is so requires quite long explanations, that I don't have the time or desire to type out. You can find everything you need on the Jensen Transformers website tech section. Click on the paper link in the first post of the link below.

http://www.avsforum.com/avs-vb/showthread.php?p=16128643&highlight=balanced#post16128643

The previous owner was able to get their hands on a pair of the NHT RCA to XLR cables and will be shipping them to me. :D

The NHT amps are just too neutral (borderline sterile), and you need a nice pre-pro to give them some flavor.Now, if you stop a minute you have to realize that's completely a matter of personal preference. One person's "too neutral" is just accurate and clean for most people, and your "flavor" might be euphonic or it might be just too much for some.

I've always enjoyed the neutral or revealing nature of the NHT speakers and electronics.

There is a lot of misinformation in the last 10 or so posts about connecting balanced and unbalanced interfaces to each other. There is no single cable that works for all XLR to RCA applications or RCA to XLR applications. Why this is so requires quite long explanations, that I don't have the time or desire to type out. You can find everything you need on the Jensen Transformers website tech section. Click on the paper link in the first post of the link below.

http://www.avsforum.com/avs-vb/showthread.php?p=16128643&highlight=balanced#post16128643

I wouldn't call it misinformation but rather a potential for partial information.
Devices like the DCX2496 will detect, based on the cable, whether to output a balanced or unbalanced signal.
In the case of unbalanced signal, the wrong cable will create grounding issues; hence, people complaining of "hums".

All information posted was based on having the proper cables for such device.
Clearly, no cable will transform a balanced signal into an unbalanced one.

In the context of what we are trying to do in this thread, a cable that grounds properly to an RCA ground is the only type we care for.

FYI, the GLS cables I ordered worked like a charm.
I even opened them up, and they are properly wired.

Now, if you stop a minute you have to realize that's completely a matter of personal preference. One person's "too neutral" is just accurate and clean for most people, and your "flavor" might be euphonic or it might be just too much for some.
Everything in this forum is a matter of personal preference.

I do not want to get into a long drawn out discussion on signal transmission and electrical engineering, so I'll just show one example in this thread of misinformation.

Post #8551 above has a schematic for connecting the balanced output of one device to the unbalanced input of another device. Above the schematic is says "This is how the proper cables should be wired (make sure any XLR to RCA cable you buy is wired this way):"

When you wire the cable this way, if the output of the balanced device has one opamp driving each phase, then you are shorting the output of the - opamp to ground. Some balanced equipment has very high output impedance to keep this from blowing up the opamp. Some equipment has cross coupled outputs to keep this shorted condition from causing damage. Some equipment will have a much reduced output level drive when one phase is driving a short. Without knowing exactly how the output stages of your balanced equipment is designed, you can't know whether shorting the negative phase is safe to do or not.

The important thing to see here is that there is no reason to ever wire a cable this way. There is no advantage to it, and a lot of potential downside. It doesn't affect the ground loop behavior of the system. It doesn't decrease the noise level. With some type of output driver ICs, it can increase the maximum output level, but this is really a disadvantage, because it adds just as much noise as it adds in maximum output capability.

Interesting.
I am not shocked at the fact that the wiring can be application specific.
However and for general purposes, one would think (given the fact that RCA is only two wires) that there would be a clear standard going from XLR to RCA.

My assumption here is again that the output device is capable of auto-sensing and thereby capable of switching its output from balanced to unbalanced.
If that's not the case, then I can foresee the need for a transformer type device to do the proper conversion from balanced to unbalanced.

Can you tell us how the NHT supplied XLR to RCA cables are wired and what the behavior of the XdA is based on the type of cable being used (XLR-XLR vs XLR-RCA)?

Thanks.

Jack...or anyone,

I've have a VT3 HT system with 4 VR-3's for the surrounds. I'm getting a new processor and am going to try out some of the new "DSX" speaker configurations. Assuming VR-3's are pretty hard to find, if I take the Back Surround VR-3s and put them up front, what would be a good back surround replacement that mesh well with my side surround and front speakers?

Regards,
John

what is too neutral?

The safest way to wire an XLR output to an RCA input is this:

Pin 1 of the XLR goes to the shield of the RCA.
Pin 2 of the XLR goes to the center conductor of the RCA.
Pin 3 of the XLR goes no where.

This configuration connects the signal grounds of the balanced and the unbalanced devices together. If the power grounds of these devices are also connected together, normally through a grounded AC power cord, then you will almost definitely have a ground loop and the associated buzz from the 60Hz harmonics. Even if one of the devices does not have a grounded AC power cord, you can still have a ground loop due to the interwinding capacitance of the power supply transformer in one or both of the devices. Since this capacitance forms a low pass filter, the ground loop will only allow the very high harmonics of the 60Hz power supply to flow in the ground loop. This will make the resulting noise sound very buzzy.

If the cable configuration above has ground loop noise, I would try this:

Pin 1 of the XLR goes no where.
Pin 2 of the XLR goes to the center conductor of the RCA.
Pin 3 of the XLR goes to the shield of the RCA.

In this configuration there is no signal ground connection between the devices. There must be a power ground connection between the AC power cords of the two devices. If there isn't, you will have horrible buzz and distortion. You will be massively clipping the input of the RCA device since there is no ground reference for the voltage that is being applied to its inputs. Normally if one of these devices is battery powered, you would never want to use this cable configuration because there would be no ground connection between the devices.

To connect the output of an unbalanced RCA device to the input of a balanced XLR device:

The RCA center conductor goes down one of the conductors to pin 2 of the XLR.
The RCA shield goes down the other conductor to pin 3 of the XLR.
The RCA shield also goes down the cable shield to pin 1 of the XLR.

Note that this configuration require a two conductor cable plus a shield. This is where many manufacturers blow it. They use a single conductor cable with a shield and just jumper pin1 and pin3 of the XLR together. This always results in some degree of more noise. If the cables were ideal and had zero resistance, there would be no increase in noise.

When there are ground currents circulating in a loop and the ground current flows between the signal grounds of the two devices, the noise from this ground current ends up as part of the signal at the receive end when you use a single conductor cable. When you use a two conductor cable, the ground loop current flows only in the shield and therefore doesn't modulate the current flowing into the - XLR input, so it doesn't end up as part of the signal in the receive device.

This ideal RCA to XLR cable is shown in figure 2.1 of the following document:

http://www.jensen-transformers.com/an/an003.pdf

This document also discusses several of the other issues I brought up here. It is the very short simple version in the discussion on balanced and unbalanced interfaces. The same section of the Jensen website has much longer articles that go much more in depth. I strongly recommended reading them if you have any interest in this subject. Start with the long ones as they explain the underlying physics.

The NHT supplied RCA to XLR cables are wired following figure 2.1 in the Jensen paper linked above. The NHT XdA is somewhat more susceptible to high frequency ground loop noise because of the switching power supply. The switching power supply has more primary to secondary coupling capacitance than a good traditional transformer. With a switching power supply, switching amplifiers, two DSP processors and a couple of microcontrollers, there are plenty of high frequency sources around to induce noise in any ground loop. This is why we included the RCA to XLR cables so that the user would be using the balanced inputs which are much less affected by ground loop problems. They aren't always needed. Whether they are needed or not depends on your preamp, the other equipment connected to the preamp and the EMI environment the system is in.

John,

I know of several people with VR-3s for sale. Contact me by PM for info.

Jack, is it absolutely critical to mount or at least place the L5 against a wall? The sound quality will be compromised if I place it say 12 inches away from the wall?

@Jack

Thanks for the enlightenment... much appreciated. :)

If you place the L5 12" away from the wall, there will be a large dip in the frequency response around 300Hz.

At this distance away from the wall, you would probably be better off using an M5.