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Post by brunomarcs on Jun 19, 2020 10:46:54 GMT -5
I’ve had my DR 3 in my two channel setup powering Kappa 7’s for several months now without a problem. I recently purchased some Kappa 8’s and have used full range 8 tc speaker wires, upon listening for a week the amp has shut off once, when I reached the 11 o’clock position on my volume, I figured it wasn’t anything and it’s worked normal since. Bi- wired the speakers and they work great, once listening for an hour or so the amp shut off and the right side red led blinking non stop, turned it off on the back restarted, cranked up the volume then it shut off again this time with the left led blinking! Is there a way to check these speakers?
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Post by brunomarcs on Jun 20, 2020 5:52:31 GMT -5
So the amp goes into protection mode and is barely warm with a difficult load of the Kappa 8’s. Unbelievable.
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Post by creimes on Jun 20, 2020 6:53:05 GMT -5
Doesn't seem right I would make the call on Monday to Emotiva, I'm assuming you have sufficient wall power to the amp, as in not using a surge protector or anything, all my gear has two dedicated 15 amp services to it.
Chad
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Post by doc1963 on Jun 20, 2020 7:31:20 GMT -5
The woofers in those larger vintage Kappas regularly dive down into the 1-2 ohm load territory. Given that fact, I’m not surprised that any amp with modern built-in protection would go into the “self protect” mode. It’s doing exactly what it’s supposed to do.
If you like those speakers, you’ll also need a “high current” vintage amp that’s designed to handle difficult loads without today’s form of intelligent protection.
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Post by garbulky on Jun 20, 2020 7:52:09 GMT -5
The woofers in those larger vintage Kappas regularly dive down into the 1-2 ohm load territory. Given that fact, I’m not surprised that any amp with modern built-in protection would go into the “self protect” mode. It’s doing exactly what it’s supposed to do. If you like those speakers, you’ll also need a “high current” vintage amp that’s designed to handle difficult loads without today’s form of intelligent protection. That makes sense. The DR-3 is a fully balanced amp. Which means a load of 2 ohms, it sees as 1 ohm. A load of 1 ohm it sees as 0.5 ohms. Therefore even if it can handle a 4 ohm speaker (and it sees it as 2 ohms), it might trip at below 2 ohm impedances. |
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Post by doc1963 on Jun 20, 2020 8:26:45 GMT -5
The woofers in those larger vintage Kappas regularly dive down into the 1-2 ohm load territory. Given that fact, I’m not surprised that any amp with modern built-in protection would go into the “self protect” mode. It’s doing exactly what it’s supposed to do. If you like those speakers, you’ll also need a “high current” vintage amp that’s designed to handle difficult loads without today’s form of intelligent protection. That makes sense. The DR-3 is a fully balanced amp. Which means a load of 2 ohms, it sees as 1 ohm. A load of 1 ohm it sees as 0.5 ohms. Therefore even if it can handle a 4 ohm speaker (and it sees it as 2 ohms), it might trip at below 2 ohm impedances. I agree... In regards to the Kappa 8’s, I just found this statement from a site that I use as a reference for “vintage” gear. “ We would consider a rating of 8 or even 4 ohms for this speaker to be unrealistic; the impedance was typically 3 ohms or less over most of the audio range. We had no difficulty in driving it with several different amplifiers, but it is conceivable that some amplifiers would not take kindly to the load it presents.” You can find that entire review HEREBack in the day, I had a friend who had these speakers and they were indeed great. While I owned Polk Audio Monitor 10B’s, we both owned NAD 2200 power amps to drive them. Looking back, I now understand why he had some occasion problems with his amp, but I didn’t... |
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Post by brunomarcs on Jun 20, 2020 15:26:22 GMT -5
Yep, I have read that review on the 8’s and knew they dipped to 3 ohms. I’ve found others to have problem with these speakers. So the amp is doing what it should do. I’m mean it was barely warm the last time it went into protection, you have about 2 hrs till this happens!
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KeithL
Administrator 
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Post by KeithL on Jun 20, 2020 22:18:55 GMT -5
You've got it sort of right - but not exactly.
Because the XPA-DR is a fully balanced amplifier each of the two amplifier modules in each channel does see half of the load impedance. This is why, if you bridge two channels of an amp NOT designed to operate this way, you shouldn't run it into a 4 Ohm load.
HOWEVER, both the amplifier modules and the power supply in the XPA-DR amps have been modified specifically to work that way.
The XPA-DR modules are modified to operate at lower voltages, and higher currents, as appropriate for the lower load impedance... And the power supply in the XPA-DR amps is adjusted to deliver lower rails appropriate to drive those loads... (That's why you cannot put standard XPA modules in an XPA-DR chassis.)
So, separately, each of the modules in each channel of the XPA-DR is actually designed to run into 2 or 4 Ohms instead of 4 or 8 Ohms...
But, yes, the Infinity Kappas do pose a very difficult to drive load... and many would say an "unreasonable" load...
So it's not unreasonable to believe that a normal amp's short circuit protection might take action when asked to drive them at very high levels... All of our normal amplifiers are stable into a 2 Ohm load... and won't have any trouble driving a speaker that dips down to 2 Ohms at some points... However, they are really not designed to run continuously, at high levels, into what reasonably should be rated as "a 2 Ohm speaker". (An amp like our A-400Z, which actually is designed to run continuously into a 2 Ohm load, might he happier in that application.)
You are quite right that some vintage amps designed to handle really heavy loads may do the job quite well... However, I would be careful to avoid using an amplifier that isn't up to the task, AND lacks protection, because the result might be catastrophic failure. (And, if I was unsure, I would seriously consider some in-line speaker fuses....)
The woofers in those larger vintage Kappas regularly dive down into the 1-2 ohm load territory. Given that fact, I’m not surprised that any amp with modern built-in protection would go into the “self protect” mode. It’s doing exactly what it’s supposed to do. If you like those speakers, you’ll also need a “high current” vintage amp that’s designed to handle difficult loads without today’s form of intelligent protection. That makes sense. The DR-3 is a fully balanced amp. Which means a load of 2 ohms, it sees as 1 ohm. A load of 1 ohm it sees as 0.5 ohms. Therefore even if it can handle a 4 ohm speaker (and it sees it as 2 ohms), it might trip at below 2 ohm impedances. |
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Deleted
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Post by Deleted on Jun 20, 2020 23:45:05 GMT -5
Just saying [breaking my silence], I owned the DR3 for a few months and never experienced a shut down. And the speakers driven [Tekton Ulfberhts] were a 2.3 ohm load in the mid-bass region. Another Ulfberht owner shared the below chart. Makes me wonder whether this [my fellow Ulfberht owner's find] was the reason the Parasound [with a bigger transformer and higher current] results in better fidelity?  |
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Post by markc on Jun 21, 2020 5:34:24 GMT -5
I’ve had my DR 3 in my two channel setup powering Kappa 7’s for several months now without a problem. I recently purchased some Kappa 8’s and have used full range 8 tc speaker wires, upon listening for a week the amp has shut off once, when I reached the 11 o’clock position on my volume, I figured it wasn’t anything and it’s worked normal since. Bi- wired the speakers and they work great, once listening for an hour or so the amp shut off and the right side red led blinking non stop, turned it off on the back restarted, cranked up the volume then it shut off again this time with the left led blinking! Is there a way to check these speakers? I had a problem with the XMC-1 that plagued me for months (yes really!) every time I tried to crank up the volume. In the end I just accepted that -20dB was the highest I could go without the channel tripping out. It was just about loud enough for everything. Just about!... so I tolerated it. In the end I accidentally discovered the problem was an electrical short at the back of the speaker terminals on the amp and it ONLY tripped the amp when the volume went up, I would have thought that a short would have been a problem all of the time, but no, it was definitely voltage (volume) dependant, and the amp only tripped when volume got close to -20dB (and always during a high volume action sequence in my movie! Bomb explosion? - One of my XPA-5 would shut down!) My message is to check all cables and terminations for anything metallic that could be touching metallic contacts behind the amplifier (or speakers) or for any stray bits of frayed wire that could do it. Always best to look for simple things first. I would never have believed that an electrical short could cause an intermittent problem if I hadn't have suffered it. You having recently changed your speaker cables is possibly relevant, as you may have something in proximity to the speaker cable outlets that is causing a short that only reveals itself sometimes. My problem was these!  A few months before I changed bi-wire cables to bi-amp and bought these screw fix banana plugs to quickly and easily terminate the second end that I snipped out of the plug that had two wires going in to it. (It would have been a pain to get the cables out to crimp and solder some better plugs on). It all worked fine. However, at some point, the clearly visible exposed metal on the shaft of the plug was being shorted by the metallic casing of an HDMI plug that was going into a connector block behind the amplifier. |
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Post by daveczski65 on Jun 21, 2020 7:38:55 GMT -5
Would Monoblocks be a better fit for this situation?
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Post by brunomarcs on Jun 21, 2020 18:46:38 GMT -5
I find it Hard to believe that I put the amp into protection as I wasn’t driving it hard. The first time I used full range 8 tc’s and I had the speaker binding post jumped with spades made from a speaker manufacturer, and made sure everything was correct. I had figured it was an electrical issue on my end and didn’t give it a thought. Then when I ran the bi-wire using Rocket 44’s and again made sure everything was right. I also had the toggle on the back of the 8’s in extended mode, (didn’t mention that before). I’m also using some longer 8’ tributary rca’s of which I found that I could get a bad signal through them upon tightening into the back of the amp or preamp! I’m patiently awaiting my New schiit Freya plus to be delivered today or tomorrow and I have some pretty nice xlr’s Audioquest water to try out. But like I said, I would run the amp for a hour or so and not really rocking but it would get warm, then once I brought the volume up to around the 10 o’clock position it would trip the amp. Once You turn it off on the back and back on it was fine, turn the volume up and it would trip again, and since then I’ve only listened at low levels.
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Post by brunomarcs on Jun 21, 2020 19:00:30 GMT -5
Also I’m on a dedicated circuit don’t remember if it’s 15 or 20 amp breaker though, but I can tell you I used all 12 ga in my house and it was a pita.
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Post by brunomarcs on Jun 22, 2020 5:56:57 GMT -5
Would Monoblocks be a better fit for this situation? I had planned on buying the DR monoblocks once this amp goes back to it’s original purpose in HT mode. Folks suggest I purchase a commercial amp such as a Crown XLS 1502, I don’t see that happening! |
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Post by garbulky on Jun 22, 2020 12:33:51 GMT -5
I find it Hard to believe that I put the amp into protection as I wasn’t driving it hard. The first time I used full range 8 tc’s and I had the speaker binding post jumped with spades made from a speaker manufacturer, and made sure everything was correct. I had figured it was an electrical issue on my end and didn’t give it a thought. Then when I ran the bi-wire using Rocket 44’s and again made sure everything was right. I also had the toggle on the back of the 8’s in extended mode, (didn’t mention that before). I’m also using some longer 8’ tributary rca’s of which I found that I could get a bad signal through them upon tightening into the back of the amp or preamp! I’m patiently awaiting my New schiit Freya plus to be delivered today or tomorrow and I have some pretty nice xlr’s Audioquest water to try out. But like I said, I would run the amp for a hour or so and not really rocking but it would get warm, then once I brought the volume up to around the 10 o’clock position it would trip the amp. Once You turn it off on the back and back on it was fine, turn the volume up and it would trip again, and since then I’ve only listened at low levels. The protecvtion wasn't because you were driving it hard. It was because the circuit goes into shut down when it detects below a certain impedance and perhaps a minimal amount of current. Basically when it detects a very low impedance it thinks it's because of a short and shuts off to save the amp. So it's not that the low impedance made it provide more power than it could. It's just that's what it's set at. |
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