UPA-5 Disabling a couple or three channels

[2pt2]

I bought a UPA-5 to use as a two channel amp. At only $25 more (during the current sale) than the UPA-2, it has twice the transformer VAC and over twice the capacitance! If I understand the basics, this means I'll have plenty of dynamic headroom. ;D

Since I only plan to use two channels (for the immediate future, at least). I am wondering if I can unplug the other three modules without losing anything (except a little extra heat).

Also, is there an advantage to choosing any specific two amp sections for my "live" ones. For example, I would guess it might be good to run channels 1 & 5 to provide maximum distance between the two heat (and interference) sources.

I realize that I'm being anal, but why not?

[NorthStar]

Simply use two channels that's all, and it don't matter much which ones either.
- There is nothing to unplug; you'll get the full power from the transformer going to your two speakers.

* Are your Paradigm S-2 speakers bi-amplifiable?

[RightinLA]

Why don't you use four channels of the UPA-5 to biamp two channels?
That way you get max. headroom and take advantage of the amps capabilities.
.

[2pt2]

Oct 12, 2010 21:03:51 GMT -5 NorthStar said:

Simply use two channels that's all, and it don't matter much which ones either.
- There is nothing to unplug; you'll get the full power from the transformer going to your two speakers.

* Are your Paradigm S-2 speakers bi-amplifiable?

I know I don't have to unplug anything to use the two amps, but I also know that the amp puts out heat even when it gets no signal. Thus, it seems that the unused channel(s) (there will still be one if I bi-amp) will probably be putting out a bit of heat even though it is not in use.

The S-2's do have two sets of terminals, but I think everything runs through a common crossover.

[jlafrenz]

The amps run cool. You aren't going to have any real heat issues with unused channels.

[2pt2]

Oct 12, 2010 21:25:50 GMT -5 RightinLA said:

Why don't you use four channels of the UPA-5 to biamp two channels?
That way you get max. headroom and take advantage of the amps capabilities.
.

I'll give that a try.

So, the question remains if I bi-amp, should I use channels 1,2,4,&5 with three as the one to either idle or unplug?

[Lonnie]

Oct 12, 2010 21:55:19 GMT -5 2pt2 said:

Oct 12, 2010 21:03:51 GMT -5 NorthStar said:

Simply use two channels that's all, and it don't matter much which ones either.
- There is nothing to unplug; you'll get the full power from the transformer going to your two speakers.

* Are your Paradigm S-2 speakers bi-amplifiable?

I know I don't have to unplug anything to use the two amps, but I also know that the amp puts out heat even when it gets no signal. Thus, it seems that the unused channel(s) (there will still be one if I bi-amp) will probably be putting out a bit of heat even though it is not in use.

The S-2's do have two sets of terminals, but I think everything runs through a common crossover.

A couple of things I feel I should say as an official rep for Emotiva.

First, if you modify the amp by unplugging any of the modules it will void the warranty.

Next I really, really wouldn't recommend this course of action. I don't think you will like what the end results will be. i.e. you could get seriously hurt doing this, it could roast your speakers, etc.

At idle each module generates virtually no heat.

[2pt2]

Oct 12, 2010 22:01:46 GMT -5 jlafrenz said:

The amps run cool. You aren't going to have any real heat issues with unused channels.

Yeah, that is the anal part! Just the way I am. Assume I have OCD when it comes to these things (just ask my wife!).
But like I said, why not?

[Lonnie]

Oct 12, 2010 22:03:12 GMT -5 2pt2 said:

Oct 12, 2010 21:25:50 GMT -5 RightinLA said:

Why don't you use four channels of the UPA-5 to biamp two channels?
That way you get max. headroom and take advantage of the amps capabilities.
.

I'll give that a try.

So, the question remains if I bi-amp, should I use channels 1,2,4,&5 with three as the one to either idle or unplug?

It won't matter which channels you use. They are all gain matched and as for thermal disapation, not a problem.

[2pt2]

Oct 12, 2010 22:06:41 GMT -5 Lonnie said:

Oct 12, 2010 21:55:19 GMT -5 2pt2 said:

I know I don't have to unplug anything to use the two amps, but I also know that the amp puts out heat even when it gets no signal. Thus, it seems that the unused channel(s) (there will still be one if I bi-amp) will probably be putting out a bit of heat even though it is not in use.

The S-2's do have two sets of terminals, but I think everything runs through a common crossover.

A couple of things I feel I should say as an official rep for Emotiva.

First, if you modify the amp by unplugging any of the modules it will void the warranty.

Next I really, really wouldn't recommend this course of action. I don't think you will like what the end results will be. i.e. you could get seriously hurt doing this, it could roast your speakers, etc.

At idle each module generates virtually no heat.

Thanks for chiming in Lonnie. I guess that clinches it. I am certainly more anal about losing that great warranty than some extra heat.

What are your thoughts on using a UPA-5 as a 2 channel amp vs a UPA-2?

Thanks!

[strindl]

It would make sense to use the two channels on the outside. That way the amp modules in use are further apart as are their heat sinks.

[NorthStar]

Oct 13, 2010 0:13:39 GMT -5 strindl said:

It would make sense to use the two channels on the outside. That way the amp modules in use are further apart as are their heat sinks.

^ Hey, that makes great sense!

_________________

* But I think the OP can Bi-amp his Paradigm speakers (OP, just make sure you removed the copper bars from your speaker's binding posts); then only one channel will be idling (use it for the Center channel in the future).

OP, you mentioned the great deal you got from the UPA-5 over the UPA-2. So why asking if the UPA-2 would be preferable? This is a non-issue.
The UPA-5 is simply adding three more channels for only $25!
And with the UPA-2 you simply cannot bi-amp a pair of speakers as you can with the UPA-5.

~ The UPA-5 is a non-brainer in your case, period!

__________________________________________
__________________________________________

-> I bet if the UPA-5 was FREE, there will still be people asking if the UPA-2 would be more appropriate!

[2pt2]

Thanks for the help guys!

LOTR,
I have already bought the UPA-5, I was just wanting confirmation that even if used only as a stereo amp the extra transformer capacity and secondary capacitance of the UPA-5 would make for a more robust stereo amp than the already impressive UPA-2.
I understand and appreciate that bi-amping is a better solution yet; but still want to verify that the transformers and capacitors would all be available to feed the two channels being used.

I have read that the XPA-5 delivers more capability into two channels and I think the UPA-5 is the same but have not seen it stated explicitly.

Thanks!

[Deleted]

Well, here's my opinion although I see that Lonnie already stole my thunder (I'm sure he thought it just needed to be mentioned twice):

A couple of things I feel I should say as an official Emotiva Lounge member.

First, if you modify the amp by unplugging any of the modules it will void the warranty.

Next I really, really wouldn't recommend this course of action. I don't think you will like what the end results will be. i.e. you could get seriously hurt doing this, it could roast your speakers, etc.

At idle each module generates virtually no heat.

It won't matter which channels you use. They are all gain matched and as for thermal disapation, not a problem.

;D ;D ;D

[2pt2]

Oct 12, 2010 22:06:41 GMT -5 Lonnie said:

At idle each module generates virtually no heat.

Well I have been running my UPA-5 for a couple of days and although I didn't believe it, I must admit that if I run channels 1 & 2, I can not detect any heat on the channel 5 end (feeling with hand)!
Furthermore, the channels that are working only get warm.

This makes me wonder if something might be wrong with my XPA-2. It gets pretty darn hot playing the same speakers at the same volume. Is this right? It sure seems counter-intuitive to me!

[eusebio]

I also have a UPA-5 and have been trying to do some research to see if using 2 channels from this amp will double the power i am feeding to my center (CSi5). I've read that w/o removing the crossover all i would be doing is Bi-Wiring and not adding any power. is this incorrect?

[roflcatdown]

Nov 1, 2010 10:56:20 GMT -5 eusebio said:

I also have a UPA-5 and have been trying to do some research to see if using 2 channels from this amp will double the power i am feeding to my center (CSi5). I've read that w/o removing the crossover all i would be doing is Bi-Wiring and not adding any power. is this incorrect?

As far as I can tell Bi-wiring is basically a crummy marketing sham. Typically the bus bars on bi-amp capable speakers can be configured so that the speakers are in parallel or series.

You could bi-amp, but I guess the question I would ask is, "Why?" In home theater use you're not likely going to notice much difference unless you're playing at high volume really. Even then for the most part it is relegated to use for Vocals and Dialogue.

[strindl]

Oct 16, 2010 20:18:39 GMT -5 2pt2 said:

This makes me wonder if something might be wrong with my XPA-2. It gets pretty darn hot playing the same speakers at the same volume. Is this right? It sure seems counter-intuitive to me!

The XPA-2 has a higher power rating per channel as well as double the number of output transistors per channel vs the UPA-5. As a consequence, there will be more heat to dissipate.

I've got XPA-1's, an XPA-2 and an XPA-5 and of those amps, the XPA-5 runs the warmest

[michaeljhuman]

Nov 1, 2010 10:56:20 GMT -5 eusebio said:

I also have a UPA-5 and have been trying to do some research to see if using 2 channels from this amp will double the power i am feeding to my center (CSi5). I've read that w/o removing the crossover all i would be doing is Bi-Wiring and not adding any power. is this incorrect?

First off, you probably don't mean bi-wiring. you probably mean bi-amping.

I don't want to get into a long disertation on bi-amping. But when you bi-amp from an amp with a shared power supply for all amps, you may be power supply limited. Or not. But it could happen. You can be limited (amp is clipping), in one of three general ways -
* You hit the nominal supply voltage limit
* The power supply voltage drops under load (same problem as above, but the difference is that you are not bumping up against the normal voltage limit, you are bumping up against the power supply limitation)
* The amp's limiter circuits kick in, reducing voltage

Whether you biamp or not, these limits can apply. Does biamping with amps that share the same power supply give you more "room" before you clip? You could try it and see. I am skeptical, but I am not an engineer, either.

One more thing. You may have read that the high side of the speaker uses less power. So really it seems unlikely you would get a big gain.