XPA-2 Protect mode

SolidSqual

http://emotivalounge.proboards54.com/index.cgi?board=amps&action=display&thread=1882

mmadden28

GV#27 wrote: »

Is it only happenig on the right channel?Is that channel getting excessively hot in comparison to the other?If so switch the speakers to opposite sides and see if the problem fallows the right speaker.

No-at first I thought so, but that was just a coincidence. Its happened no the right, left and both. In the video with that song-its consistently on the left.

mmadden28

Early B. wrote: »

Try this -- swap out the interconnects to the amp. As you may know, the XPA-2 and XPA-5 are sensitive to cables for some reason.

That was my next step--removed the Cyrotweak Silver ICs and put the Monoprice premiums back in - no change at all-still fails at the same spot at the same level.

mmadden28

OK, ruled out the ICs (note I replace both sets, between the CDP and the ELP, as well as between the ELP and the XPA.

Well next I swapped the speakers out--I put a pair of RM7300s, not quite the level of the LSis, but they are 8 ohm rated 89dB speakers, and guess what:



Disregard the poor sounding audio-it was simply too loud for the camera. :eek::D:eek:

It doesn't put the amp into protect mode!! :rolleyes: not sure if I should be happy or not.. Somethign I should note though is I was able to increase the ELP volume a couple hairs more-still didn't cause a fault, but I started to see the red leds on the XPA-I never saw them before-only full out red leds-I suppose this provides warning when you're approaching the limits. It also sounded like I might be pushing the speakers to thier brink so I quickly turned it down.

So is that position (~10:00 o'clk) on the ELP a normal max position? What on earth could you run that would enable the ELP to turn it up more? I suppose its amp dependent??
Or is there something wrong with my LSi's? Or perhaps the XPA?

I think I'll call the Emotiva guys to get thier take--I may bring the LSIs and the ELP upstairs to my XPA-5 and see if the same thing happens there. If its an impedance issue I suppose it would happen there too right?

First though, to tackle the noise floor/hiss issues. Its probably too late for me to crank it up in the Family room.

mmadden28

nikolas812 wrote: »

...

Fyi. That was reference level when I had it. (75db)

According to what, an SPL meter?

I forgot mine - i left it at work

mmadden28

It's odd that with the RM7300s where it actually plays thru-
the level meter on the XPA doesn't peak at the spot where the LSI's crap out-not until the drums do you see the meter close to peaking. I suppose the level meter is not looking at the highs???

Face

It may be looking at the highs(peaks). The way the EMO is designed, wattage is doubled when impedance is halved.

Your RM7300's are 8 ohms, correct?

LSi9's are 4 ohm and dip down to 2 ohms.

mmadden28

Here's another interesting thing-unrelated to the XPA-2 protect mode issue (or is it?), but more with my noise issue (interference?)..With the Dodd on and unmuted, but with the CD stopped, everytime I snapped a pic with a flash I could hear the pops-like static. It got louder when I held the camera closer to the Dodd. I obviously can't take a video of that.

Face

Have you tried the other tubes yet?

mmadden28

Face wrote: »

Have you tried the other tubes yet?

Aside from two already tried, no. I'll be tring that to figure out he noide floor isssue

F1nut

I can't get the Dodd's volume much more than 50% before the XPA's protection mode kicks in (scares the crap out of me everytime ). Usually on the right channel. Normal listening can be had around 25-30%.
I also had this happen at least twice with an ipod as a source, but the Dodd was up at about 75% while the iPod was about 75% as well.

In general, most amps start to clip when the volume level on the pre hits around 12 noon. If the Dodd is a high gain pre then you're going to hit that wall before 12 noon.

75%??? That's just plain 'ole abuse.

Of course, it could just be that the amp doesn't have the balls that others do.



Edit: Sounds like you might have some microphonic tubes.

mmadden28

F1nut wrote: »

In general, most amps start to clip when the volume level on the pre hits around 12 noon. If the Dodd is a high gain pre then you're going to hit that wall before 12 noon.

75%??? That's just plain 'ole abuse.

Of course, it could just be that the amp doesn't have the balls that others do.



Edit: Sounds like you might have some microphonic tubes.

I hear ya--to clarify the 75% on the Dodd was when using the iPod. Based ont he volume differences betwen the Pio CD Player, and the iPod, I don't think the iPod puts out as high a signal as the Pio. thus it won't amplify as much????

fredv

There have been many helps so far. So, I will throw in my 2 cents.
The position of the of volume dial is not any kind of indication of the amp's output. There are
3 things in the equation:
1. Source output, most of the CD or DVD player has 2V RMS output. However, some recording are louder and some are lower. That's why sometimes we need to adjust the volume control to maintain certain sound level.
2. Most of the line level preamps accept 2V RMS input and amplify it. I don't have the specs of the ELP. Since everyone says it has a lot of gain, and based on most of the 2 tube topologies and the 6922 tubes, my guess is a minimum of 20X, probably high 20's. That is a lot!!!!!
3. The input sensitivity of the amp, most of the amps will need just 2V RMS to be in full power. Anything more than that will drive the amp in overload.

As you can see, when the ELP is at slightly over 1X amplification, it can deliver more than 2V RMS in the output (2V RMS input x 1.X > 2V RMS) which can push your XPA to full power!!! That's why you don't need to turn the volume knob a lot. I don't think the ipod can deliver 2V RMS output. That's why it can't drive the amp to full power. The visual of 25% or 75% is deceiving. What it really counts is how much is pumped into the amp. I can be wrong. The XPA probably can handle 2 ohm load but not sustain this load at full power.

I hope this will help.

george daniel

this may help,, but I think it gonna' take a call to Gary or the emotiva folks



http://www.polkaudio.com/forums/showthread.php?t=36517

nikolas812

mmadden28 wrote: »

According to what, an SPL meter?

I forgot mine - i left it at work

Yes.

I used a test tone CD and a SPL meter.


Now change those tubes!!!!! I forgot to tell you a couple pairs were microphonic. I just don't remember which ones.

I would suggest trying the Amperex's next. But its up to you. I know there not microphonic. Or shouldn't be anyway.


Nick

mmadden28

nikolas812 wrote: »

Yes.

I used a test tone CD and a SPL meter.


Now change those tubes!!!!! I forgot to tell you a couple pairs were microphonic. I just don't remember which ones.

I would suggest trying the Amperex's next. But its up to you. I know there not microphonic. Or shouldn't be anyway.


Nick

Microphonic?? Not sure what that is (yet)-would that explain why I hear the Flash of the camera? Or would that cause another issue? How do you determine if a tube is microphonic?

How far from the speakers should I take an SPL reading?

Face

http://en.wikipedia.org/wiki/Microphonics

nikolas812

mmadden28 wrote: »

Microphonic?? Not sure what that is (yet)-would that explain why I hear the Flash of the camera? Or would that cause another issue? How do you determine if a tube is microphonic?

How far from the speakers should I take an SPL reading?

I don't no if my advice is accurate. So take it for what its worth. But I would sit in my listing position when I took the reading.

As for microphoincs. That would explain the noise you here when you the flash goes off.

Its probably not recommended but you can tap on the tube when everything is turned on and you should hear some sort of feedback through your speakers. If you do the tubes are more than likely microphonic.

Try the Amperex tubes. They were one of my favorites.


Nick

mmadden28

george daniel wrote: »

this may help,, but I think it gonna' take a call to Gary or the emotiva folks



http://www.polkaudio.com/forums/showthread.php?t=36517

Not sure (I'm not ruling it out), that its related to the pre to amp connection--when I changed the speakers the amp didn't fault at the same exact settings (and even higher) when I used different speakers. Am I thinking right there? Or are you thinking about the background noice issue?

I stil have some more testing/swapping to do and I'm just about to call Emotiva-Been busy all day again-darn work keeps getting in the way :rolleyes:

mmadden28

fredv wrote: »

There have been many helps so far. So, I will throw in my 2 cents.
The position of the of volume dial is not any kind of indication of the amp's output. There are
3 things in the equation:
1. Source output, most of the CD or DVD player has 2V RMS output. However, some recording are louder and some are lower. That's why sometimes we need to adjust the volume control to maintain certain sound level.
2. Most of the line level preamps accept 2V RMS input and amplify it. I don't have the specs of the ELP. Since everyone says it has a lot of gain, and based on most of the 2 tube topologies and the 6922 tubes, my guess is a minimum of 20X, probably high 20's. That is a lot!!!!!
3. The input sensitivity of the amp, most of the amps will need just 2V RMS to be in full power. Anything more than that will drive the amp in overload.

As you can see, when the ELP is at slightly over 1X amplification, it can deliver more than 2V RMS in the output (2V RMS input x 1.X > 2V RMS) which can push your XPA to full power!!! That's why you don't need to turn the volume knob a lot. I don't think the ipod can deliver 2V RMS output. That's why it can't drive the amp to full power. The visual of 25% or 75% is deceiving. What it really counts is how much is pumped into the amp. I can be wrong. The XPA probably can handle 2 ohm load but not sustain this load at full power.

I hope this will help.

Good read thanks--It just doesn't sound like full power that should shut the amp down, but then again I'm not experienced enough to know what is-Odd thing is that I only changed the speakers (same cables, same pre, same source, same volume, and the amp didn't fault at the same pre level, I was actually able to increase the pre's output-so that should say something..Sounded much louder of course. Well I definately have to try this on more capable speakers (RTi12).
I'm leaning towards the impedance drop issue, but then again,...

Calling Emo now.....:D

Music Joe

http://www.soundstagemagazine.com/measurements/polkaudio_lsi9/

Look at the Impedance curve/Electrical phase junction, tough load for sure and the level those meters were showing - wow - 5 indicators per side is most I've seen in use and thats plenty loud for me, I'm still a newby on this amp though.

I can't find it but...there was discussion of XPA2's 2 0hm stability but it's not 2 ohm rated. The Emotiva forum talks about how will sag a/c line to deliver at 2 0hms.
Maybe those new XP1 monoblocks are in your future. Maybe 20 amp lines...just throwin' a couple of things out there and I sure hope you find your answer... it's a powerhouse of an amp.

SolidSqual

Maybe your amp is effed and you need to call Emotiva. There's no way a little Lsi9 is killin those amps, and doesn't break a sweat with a pair of Magnepan 3.6s. Oh by the way, I was in the room when I saw your Dodd go above half-way on my XPA-2 with a pair of Lsi9s. No Red Lights.

Time to start ruling out some major components.

mmadden28

I spoke to Lonnie today. I have some homework to do and get back to him, but so far he's thinking it could be a combination of things; the particular frequency that the violin note is hitting just might be causing the LSi9's impedance to dip real low, at the same time requiring the amp to draw more power from the wall, and possibly get starved- - Or something like that. It may have something to do with some of the protection circuitry watching the AC side as well as the line in side and both of them seeing a problem and shutting the amp down. Anyway, I have to try a couple things, specifically putting a resistor inline with the speakers to see if that eliminates the problem (at the same level). I have a couple other tests to do as well including some I already had on my plate (swapping amps, pres, etc).

mmadden28

Music Joe wrote: »

http://www.soundstagemagazine.com/measurements/polkaudio_lsi9/

Look at the Impedance curve/Electrical phase junction, tough load for sure and the level those meters were showing - wow - 5 indicators per side is most I've seen in use and thats plenty loud for me, I'm still a newby on this amp though.

I can't find it but...there was discussion of XPA2's 2 0hm stability but it's not 2 ohm rated. The Emotiva forum talks about how will sag a/c line to deliver at 2 0hms.
Maybe those new XP1 monoblocks are in your future. Maybe 20 amp lines...just throwin' a couple of things out there and I sure hope you find your answer... it's a powerhouse of an amp.

I think I know what discussion you're referring to. I'm sure I posted in that one-power related. i think thats the same one where it was mentioned that using a 240VAC ciruit would half the current requirements (this easing the AC wire gauge requirements).

Thanks for the link. Lonnie had asked if I could get something like that from Polk-this saves some time. One peice of homework checked off

mmadden28

SolidSqual wrote: »

Maybe your amp is effed and you need to call Emotiva. There's no way a little Lsi9 is killin those amps, and doesn't break a sweat with a pair of Magnepan 3.6s. Oh by the way, I was in the room when I saw your Dodd go above half-way on my XPA-2 with a pair of Lsi9s. No Red Lights.

Time to start ruling out some major components.

Another think learned in my discussion. The meter LEDs are actually tuned for an 8ohm load. So when using 4 ohm speakers the meters are not accurate. So when the lights are about half way-you're actually almost max.

WilliamM2

mmadden28 wrote: »

Another think learned in my discussion. The meter LEDs are actually tuned for an 8ohm load. So when using 4 ohm speakers the meters are not accurate. So when the lights are about half way-you're actually almost max.

That's odd. The amps I had with meters would go higher with a 4 ohm load. Which makes sense, since they are measuring output.

mmadden28

Well some more troubleshooting results so far:

I set the pre to the same level that caused the XPA to go into protect mode. Verified and reproduced the fault using the CD as a source with the same song. It's the left channel everytime with this song at this part.

I switched the channels into the pre (L is now R, and vice versa)
The fault followed/switched as well. So this tells me the Left speaker is not specifically to blame. Its the signal going out that channel into the amp.

Next test, I hooked the CD and Pre back up, but this time I set the CD options to set the speakers to small and to use a sub. There were no crossover freq options but the subwoofer was set to 80Hz not that I think that even made a difference-actually I don't think I even needed the sub hooked up.
With the Dodd at the same level that caused the fault last time, I played the CD again. this time it made it past the first big beat!! And I was actually able to push the Dodd at or just beyond the 12 oclock position. So this tells me the freq causing the fault is below whatever freq the Pio set the crossover (not sure what that freq is) since all those freqs would be sent to the sub. So that appears to put the LSi right into that low impedance area according to the chart referenced by Music Joe.

Next test, I put a resistor in line with the speakers, and the XPA no longer goes into fault. Lonnie will have to tell me what this means, but I think it means that the speakers impedance was dipping too low, triggering the fault. We'll see.

OK tried my iPod test again. Completely removed the Dodd pre, the Pio CD Player, and the interconnects from the equation.
Plugged the ipod directly into the amp-(as simple a config as you can get :rolleyes:) max volume on the iPod (and I do have the volume limited a bit as well)--I was able to reproduce the fault again. I'm not really sure why I wasn't able to do this before-maybe I didn't max the volume out?? So its not an issue with the pre output being too high or having too much gain, its not an issue with the ICs acting as AM antennas, its not an issue with a mismatch between the pre and the amp. It seems to simply be the impedance issue (again remains to be seen for sure).

One update, I said that the fault occurs at the time when the violin gears up thinking it was a higher frequency, however after getting my listening right-its actually at the same time as the first drum/bass beat, so its likely that lower freq, rather than the higher violin freq. But you might be able to see/hear that for yourself in the videos above.

Anyway-that just an update so far- I still need to reproduce this test with my other speakers, the Onkyo and the XPA-5, etc.-I'll do those in the morning.

Face

Time to unload it.

george daniel

^^^^^what he said^^^^^^

WilliamM2

The LSi's would only drop that low if that were the only frequency playing. That rarely happens in real music.

I think the XPA is defective.