XPA-1 Binding post layout ????

mmadden28

I have a couple questions I wanted to run past the forum members here at Club Polk.

Check out the rear of the new Emotiva monoblock amp, the XPA-1.



Anybody have any thoughts on the way the binding post layout was designed?

First, does anybody have any idea why an amp designed as a monoblock amp would have multiple binding posts for each polarity? This has 2 + and 2 -. Is this standard at all on any other monoblock amps?. Here's a link to the user manual. Pages 12-14 discuss the hookup. I for one am confused by what the manual states, mainly because this is a Monoblock amp, and I always thought that a monoblock was meant for one speaker. Somebody please correct me if I am wrong or clarify why this might be.

Second, and of greater concern to me, is that the red (+) posts are on one side and the black (-) is on the other. They are about 13" apart. :eek:
So far none of the manufactured/pre-built speaker cables I have will work (this includes Zu Julian, AQ Bedrocks, AQ CV4.2's, MIT AVTs, MAC CuQ's, Zingo's Z-cables etc.). I am guessing this would be an issue with almost any commercially available terminated speaker cable (with the exception of made to order cables where the lead lengths can be rerequested.)
This is obviously not standard, but has this been done on any other amps anywhere? Any idea why?

Note: Just FYI, I also have a thread going at the Emotiva forum in case anybody wants to see any comments from that end.

comfortablycurt

I'm not an amp expert by any means, but I think it has the two pairs of binding posts for bi-wiring purposes. It's still just running one speaker per amp, but with wires going to both pairs of binding posts on the speaker.

Not sure why they're spaced so far apart like that...seems like a pretty stupid design to me. Like you said...I don't know of to many kinds of speaker wire that will accommodate that much of a gap. The wires would have to be custom made definitely...I'd like to know why they made it like that. Hopefully someone who's more informed will chime in.

george daniel

Other amp manufactures have the same config with their mono's,,EXCEPT, the ones that I have,the +&- are a tad closer together.Adcom mono's and Odyssey mono's have /offer two sets of binding posts, but they are much closer together.IIRC the binding posts on the Belles are similar(single set)

Hawkeye

That certainly is an unusual design:mad: I think it would be shame to have to split a higher end speaker wire to use these amps. Was the picture of the back available when you purchased these?

My amps have a total of 6 outputs: 2, 4 and 8 Ohms and any speaker wire can be used as manufactured.

Gordon

fbm211

I would suggest you go with a shotgun config like I have done.The only drawback is you would have to buy more speaker cables.And that is a strange design.My adcoms have 4 posts each but there all in the middle of the amps.

george daniel

Just recalled that the Belles were far apart,, but it was in pairs,, unlike the unit pictured. Not to derail,, but are the Emotiva's really as good as the Belles? I've never heard one,and would sppreciate/seek an unbiased opinion. Thanks--george:)

Face

That's **** backwards.

Mike Reeter

george daniel wrote: »

Just recalled that the Belles were far apart,, but it was in pairs,, unlike the unit pictured. Not to derail,, but are the Emotiva's really as good as the Belles? I've never heard one,and would sppreciate/seek an unbiased opinion. Thanks--george:)

george,Have you read something that compares Emo's to Belles?

I have been wondering myself as to the sound quality of these amps.

I know they must be the **** for HT,as there are several happy owners here.

Just curious as to how one would stack up in a 2-channel rig.

This is the one that's catching my eye http://emotiva.com/xpa2.shtm

Oh,sorry for the derail.

george daniel

Face wrote: »

That's **** backwards.

I've been called worse :)

george daniel

Mike Reeter wrote: »

george,Have you read something that compares Emo's to Belles?

I have been wondering myself as to the sound quality of these amps.

I know they must be the **** for HT,as there are several happy owners here.

Just curious as to how one would stack up in a 2-channel rig.

This is the one that's catching my eye http://emotiva.com/xpa2.shtm

Oh,sorry for the derail.

Someone here IIRC had a 350a ref and it was upstaged by one of the Emotiva's IIRC,,, I'll check and see if I can find the post/conversation.

Early B.

Mike Reeter wrote: »

george,Have you read something that compares Emo's to Belles?

I have been wondering myself as to the sound quality of these amps.

I know they must be the **** for HT,as there are several happy owners here.

Just curious as to how one would stack up in a 2-channel rig.

This is the one that's catching my eye http://emotiva.com/xpa2.shtm

I haven't heard the Belles, but I had an XPA-2 for a minute. It's flat out fantastic for any type of dynamic music (pop, rock, R&B, etc.) I recommend it highly, and for the price, it encapsulates the term, "no brainer." I listen mainly to jazz and light vocals, so the XPA-2 was replaced by a pair of kickass tube monos.:cool: In hindsight, the XPA-2 is the only component that I have ever regretted selling. It wouldn't upstage my monos, but I could use it elsewhere.

nikolas812

The only way to use factory terminated high end cables is to buy two pair. And Bi Wire the speakers. Remove the jumpers on the speakers first......... And this is probably what I would do in your situation.

Make sense?

Or you could have one pair custom made...


Its a stupid design IMO. But I think these are your only two options if you want to use something besides lamp cord as speaker cable.


I also don't understand why nobody from the Emotiva Staff has responded to your thread at Emo yet with an explanation???



Nick

mmadden28

nikolas812 wrote: »

The only way to use factory terminated high end cables is to buy two pair. And Bi Wire the speakers. Remove the jumpers on the speakers first......... And this is probably what I would do in your situation.

Make sense?

Or you could have one pair custom made...


Its a stupid design IMO. But I think these are your only two options if you want to use something besides lamp cord as speaker cable.


I also don't understand why nobody from the Emotiva Staff has responded to your thread at Emo yet with an explanation???



Nick

Still not fully understanding why there are two of each binding post to begin with, I'm not sure how that would hook up-what changes would happen, since it would be like hooking up two speakers then right?

I would think that if I were bi-amping I would remove the jumpers on the speakers, but leave them in place for bi-wiring in this case, no? (more actually shotgunning then bi-wiring)? I only say that since the manual almost makes the two posts to be separate circuits-not common, as would normally be the case when bi-wiring where normally both sets terminate at the same binding posts at the amp.

Its expensive enough for some higher end speaker cables, I can't see having to buy two sets them just because of this design. And then one set would have to be spades and on bananas, or use some kind of dual banana/staking banana adapter if both were bananas.

It sure does complicate matters-I'm not sure what I'll do, maybe make up some custom jobbers, hell maybe even rewire the binding posts internally. Or, most realistically, perhaps I could fashion some kind of extension jumper of sorts.

I suspect nobody from Emotiva has responded as its the weekend. For the most part though some of the responses were to use lamp cord and be done with it. :rolleyes:

nikolas812

Still not fully understanding why there are two of each binding post to begin with, I'm not sure how that would hook up-what changes would happen, since it would be like hooking up two speakers then right?

No.

It would be no different. You would just be losing the jumpers. The amp would still see one speaker.

They would only have to be terminated banana to banana. Nothing spacial.

Its really not that complicated. Your essentially Bi-wiring in a Bi-Amp configuration. Assuming both positives are on the same circuit and both negatives are on the same circuit.


Nick

mmadden28

nikolas812 wrote: »

...Assuming both positives are on the same circuit and both negatives are on the same circuit.


Nick

That's just it-I am not sure if they are or are not on the same circuit. Perhaps I'll meter it.

nikolas812

mmadden28 wrote: »

That's just it-I am not sure if they are or are not on the same circuit. Perhaps I'll meter it.

You would think they would have to be.

Its a damn mono block.



Meter it!!!




Nick

Hawkeye

I'm wondering if maybe one set of taps is a 4 Ohm and the other an 8? I just can't see why there would be multiple taps on a mono unless they were split 4/8 Ohm.

Gordon

nikolas812

The only thing I've seen 4 and 8ohm taps on is tube amps.


But I'm still a newb.... So take it for what its worth.








Nick

mmadden28

Hawkeye wrote: »

... Was the picture of the back available when you purchased these?
...

It was, but I didn't look at it that closely. I never even thought about why there were two sets of posts. I just assumed that the +/- would be reasonably next to each other-I never would have thought they would be separated so much. I have the XPA-5 and the XPA-2 as well, so I wouldn't have thought that such a radical design change would have been in order within the same series.

Hawkeye

I'm not newb nor am I know it all:D. My SS monos have 2,4 and 8 ohm taps and they can make a big difference on how hot they run and the quality of the signal. My speaks drop/rise to .75 ohm, almost a direct short or so I'm told. Tried running the speaks on the 2 Ohm tap and they sounded terrible.

Gordon

nikolas812

Your learn sumthin new every day.:D









Nick

mmadden28

Metered, they appear shorted. getting .2 ohms, but I'm getting .2 witht he leads directly shorted, so my meter may be off.
I opened the cover and visually at the circuit board they appear to be common. I'll get some pics ni a moment.

mmadden28

OK some pics:
Inside Neg Posts


Where the Neg Post's wires terminate on the circuit board-solder side.
They appear to be soldered together



Inside Pos posts
Note the Resistor and Cap



Where the Neg Post's wires terminate on the circuit board.


Where the Neg Post's wires terminate on the circuit board-solder side.
They appear to be soldered together

F1nut

The reason there are two posts per side is for bi-wiring.

+A to the top speaker posts.
+B to the bottom speaker posts.

Same for the - side.

Be sure to remove the jumpers.


Why they are so far apart? Could be that they expect you to use the kind of cable they used for the internal wire, which you should change as that stuff will oxidize over time. Or it could be that they simply adapted a stereo chassis for use as a mono block as a means to cut costs resulting in a big oops!

Emlyn

F1nut wrote: »

Why they are so far apart? Could be that they expect you to use the kind of cable they used for the internal wire, which you should change as that stuff will oxidize over time. Or it could be that they simply adapted a stereo chassis for use as a mono block as a means to cut costs resulting in a big oops!

Yep, it's a modified XPA-2. They wouldn't have saved much by removing the extra set of binding posts and many folks expect a monoblock or higher end two channel amp to have two sets--similar to why Polk and other manufacturers put two sets of binding posts on their speakers. A large part of it is just marketing.

Because of the layout of the XPA-2, the factory would have to run hookup wire from one side of the amp to the other to have positive and negative binding posts on one side for an XPA-1. As it is designed, it seems to be one among a series of shortcuts to keep costs down. Emotiva produces fine products, expecially for the price charged, but they don't work engineering miracles. Kimber 4TC or 8TC speaker wire or plain old speaker wire can be used without modification to connect speakers. I chuckled the first time I saw stranded copper hookup wire being used in the China manufactured amps. It's cheap, but it works.

mmadden28

Just for comparisons sake, heres a shot of the rears of the XPA-1 and XPA-2




Don't mind the pics-in reality the amps are the same size. Similarities, but a few differences as well (including post location). Probably just the rest of the design with some circuitry on the left and some on the right.

IMHO, it would have been better to save some costs on the extra binding posts, and put it into quality hookup wire and relocate the +/- binding posts together.