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HE-500, LCD2, D5000, DT770, SR80, on a speaker amp (Emotiva mini-X A-100) Project - Page 186

post #2776 of 3790
Quote:
Originally Posted by Drsparis View Post


The noise floor went up? Due to a battery preamp? Is this with the preamp at max volume?


Before it's like a hiss starts after 12 o'clock. With Quickie, it's like a hum from 10 o'clock to 12 o'clock, and hum plus hiss after 12 o'clock. This is all Emotiva volume control. Quickie volume control doesn't affect it. I usually use preamp at 75% volume.


Edited by Sonido - 12/18/13 at 7:16am
post #2777 of 3790
Quote:
Originally Posted by Bilco View Post
 

I've had my HE-500 + Emotiva for about a week and have <30 hours on both.  I'm using my SoundBlaster zx as a DAC going straight into the Emotiva.   I've noticed that the sound is much more crisp and clear coming from the amp, but the bass seems to be much less present than when plugged directly into the sound card.  I am wondering if maybe it is because of the connections I am using for the amp to HE-500 bridge?

 

It's most likely due to the sound card's amplifier intentionally boosting the bass.

post #2778 of 3790

When I use the emotiva and compare it to my weaker focusrite I find the emotiva and modi to smooth things out a lot. Also it becomes less impactful and snappy with the bass not as tight. I am wondering if it is the emotiva or the modi.

post #2779 of 3790

After further research on preamp and amp impedance matching, I've discovered there's a 1:10 guideline. Some places go as far as to say 1:20. Others have said a bare minimum is 1:5 or 1:4 before you really start hearing problems. The general idea is it can cause changes to the frequency response curve. Usually the output impedance of the preamp is not static through out the frequencies, so certain frequencies could have a worse ratio, creating more of a roll off there. It seems a higher output impedance occurs mostly in bass, so it would cause a bass roll off. While this is a guideline, you really have to personally try the pairing to determine if it's alright. I personally don't find any problems with the 1:5 of Quickie+Emotiva. Since the Quickie is DIY, there are ways to better this ratio. I'll probably look into that in the future.

post #2780 of 3790
Quote:
Originally Posted by Bilco View Post
 

I've had my HE-500 + Emotiva for about a week and have <30 hours on both.  I'm using my SoundBlaster zx as a DAC going straight into the Emotiva.   I've noticed that the sound is much more crisp and clear coming from the amp, but the bass seems to be much less present than when plugged directly into the sound card.  I am wondering if maybe it is because of the connections I am using for the amp to HE-500 bridge?

 

I am using:http://www.amazon.com/gp/product/B0010D0HO0/ref=oh_details_o05_s00_i00?ie=UTF8&psc=1

 

and

 

http://www.amazon.com/gp/product/B004HJ5JPQ/ref=oh_details_o06_s00_i00?ie=UTF8&psc=1

 

to accomplish that job as spending 100 bucks on a custom made adapter cable with nearly an estimated month arrival time seemed absurd.

 

Could this be due to the loss of bass I noticing going from directly in the soundcard to the Emotiva?

 

I h ave a Schiit Lyr on the way, and if the base sounds better while retaining the crisp clear sound stage of the Emotiva brings, I think I am going to just return this amp.


If you aren't hearing enough bass, it's probably just the sound signature of the Emotiva. It has a very tight, clean bass. I don't the connectors could be responsible. If there were a problem with them, it would be a lot more obvious than bass presence (e.g. channel imbalance or crackling). 

post #2781 of 3790

My cables for direct connect to Emotiva without HE-Adapter just arrived. I only got to listen to it briefly as I had to go to work soon. First impressions are no immediate difference compared to HE-Adapter. Trying with Quickie yields the same result. There is a slightly higher noise floor as you can kinda hear some background buzzing when the music is not playing. Also the Emotiva knob is set to 8 o'clock instead. Overall I am relieved that the Quickie works just as well without the HE-Adapter. I'm glad I didn't spiel all this about the Quickie with a caveat that is requires the HE-Adapter to work to intended results.

 

Interestingly though, the banana plug end of the cable did not have a positive or negative labeled, only white and black wires. I didn't know which was positive or negative, but I heard it shouldn't harm anything if done backwards, just opposite phasing. The first time I plugged it in, it worked for 30 seconds before the Emotiva shut down with a blinking orange light. I measured the impedance and it was ~38 ohms. I plugged it back in the other way around, and no complaints since. I thought phasing should not cause any problems? Can we even tell which phase is the right one? I have more suspicion it was the cable having a short somewhere the way it was hanging in the other direction.

post #2782 of 3790
Same thing kinda happened to me when my he500 blew. Switched phase, yellow light. It might have something to do with the common ground
post #2783 of 3790
Quote:
Originally Posted by davidsh View Post

Same thing kinda happened to me when my he500 blew. Switched phase, yellow light. It might have something to do with the common ground
I didn't connect positive to positive like you did though, so the headphones didn't blow thankfully. Well everywhere I read said wrong phase won't damage the speakers at least, so my headphones would be fine. Still I don't get why phase is an issue with the amp.
post #2784 of 3790
Quote:
Originally Posted by Sonido View Post


I didn't connect positive to positive like you did though, so the headphones didn't blow thankfully. Well everywhere I read said wrong phase won't damage the speakers at least, so my headphones would be fine. Still I don't get why phase is an issue with the amp.

Phasing isn't the problem here. I assume your headphones are single-ended so if you connect the HE-Adapter + to - you're connecting the two + signals together in the headphone cable instead of combining the - as you normally would.

 

If you were using balanced headphones then I agree there shouldn't be a problem as long as you didn't connect both white connectors to one side and both black to the other.

 

Normally black connectors are -

 

If the HE-Adapter's speaker terminals aren't labeled you can use a multimeter's continuity function and make contact with the XLR pin 1 (the numbers are molded into the connector) and touch the HE's speaker terminals. Pin 1 is L+, Pin 2 is L-, 3 is R+ and 4 is R-. You may have to insert a metal pin or paper clip into the XLR pin hole to make contact.

 

You can also just play a test sound that identifies which speaker is which, you know the, "My voice should be coming from the left speaker," mp3.


Edited by robrob - 12/18/13 at 10:54am
post #2785 of 3790
Don't really understand what happened when my 500's blew anyway.
post #2786 of 3790
Ok I see now. Since the connection becomes TRS eventually, switching the +/- results in a common positive and separate grounds, thus shorting the amp. Because there's a path back to the amp, the headphones did not get damaged I guess. Weird thing was it worked for 30 seconds. Maybe that's just how long the amp could take it. Well I hope nothing got damaged, but after listening to it with the phase set correctly, everything sounded fine.

Ok I just drew out some circuits to make better sense of this, and yeah the headphones shouldn't be damaged as there's always a path from + to -. The + channels do get shorted at the TRS plug before the headphones, so it can harm the amp, but the Emotiva seems to have built in self shutdown protection mechanism. As for the sound I was hearing it's coming from the combined + channels so it's likely some weird mono combined sound going to both drivers. And the Emotiva could only stand the short for 30 seconds before the safety mechanism triggered.
Edited by Sonido - 12/18/13 at 12:36pm
post #2787 of 3790
Quote:
Originally Posted by Sonido View Post

Ok I see now. Since the connection becomes TRS eventually, switching the +/- results in a common positive and separate grounds, thus shorting the amp. Because there's a path back to the amp, the headphones did not get damaged I guess. Weird thing was it worked for 30 seconds. Maybe that's just how long the amp could take it. Well I hope nothing got damaged, but after listening to it with the phase set correctly, everything sounded fine.

Ok I just drew out some circuits to make better sense of this, and yeah the headphones shouldn't be damaged as there's always a path from + to -. The + channels do get shorted at the TRS plug before the headphones, so it can harm the amp, but the Emotiva seems to have built in self shutdown protection mechanism. As for the sound I was hearing it's coming from the combined + channels so it's likely some weird mono combined sound going to both drivers. And the Emotiva could only stand the short for 30 seconds before the safety mechanism triggered.

That is really impressive that any amp can handle a short for 30 seconds and shut down before damage to the amp occurs. Not all amp protection circuits can fully protect the amp or its outputs. Also the fuses did not blow. Mine came with two spare fuses. With other amps you may not be as lucky.

post #2788 of 3790
Quote:
Originally Posted by john57 View Post

That is really impressive that any amp can handle a short for 30 seconds and shut down before damage to the amp occurs. Not all amp protection circuits can fully protect the amp or its outputs. Also the fuses did not blow. Mine came with two spare fuses. With other amps you may not be as lucky.
Well to be fair, it's not a 100% short where all power was forced down the shorted path. Even though the + channels met, it still had the option of going down the grounds. Most of the current probably flowed to the grounds, but eventually the shared + point must have caused problems.
post #2789 of 3790
I guess a short means that there is a direct connection between at least 1 channel and ground.
I am still wondering how an amp can make a DC voltage differential apparently without being faulty as it must have happened with my he500 and the upa2
Edited by davidsh - 12/18/13 at 2:12pm
post #2790 of 3790
Quote:
Originally Posted by davidsh View Post

I guess a short means that there is a direct connection between at least 1 channel and ground.
In that case short is not the right word I'm using. There's no direct connection from + to -. Only a direct connection from the +'s to reach other before the headphone. I'll draw out a picture of the circuit when I get home.
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