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HE-500, LCD2, D5000, DT770, SR80, on a speaker amp (Emotiva mini-X A-100) Project - Page 131

post #1951 of 3790
Quote:
Originally Posted by Shazb0t View Post



I also hear a very slight hiss with the emotiva mini-x and HE-500. From reading this entire thread I believe they all have a small noise floor, but that the people claiming they hear nothing either don't have as sensitive hearing or have not actively listened for it at 0 volume. It does get much louder towards 2 on the dial, but with a normal dac you shouldn't need the volume that high. That's my take on it for what it's worth.

Actually I am not interested in HE500 but HE-4 / HE-6 so with their ultra low sensitivity there sould be no sign of even small amount of hiss ...

 

Do you have any technical info about up to what power it stays in A class, max peak to peak voltage, distortion values at different power output ? (read somewhere about 80V p-p but don't know the source)


Edited by magicman - 10/18/13 at 12:04am
post #1952 of 3790
Quote:
Originally Posted by magicman View Post
 

Actually I am not interested in HE500 but HE-4 / HE-6 so with their ultra low sensitivity there sould be no sign of even small amount of hiss ...

 

Do you have any technical info about up to what power it stays in A class, max peak to peak voltage, distortion values at different power output ? (read somewhere about 80V p-p but don't know the source)


I suggest you use resistors on the output section of your amp. It's how I got rid of the very obvious hiss of my amp without affecting SQ.

post #1953 of 3790
Quote:
Originally Posted by robrob View Post
 

On a slightly related note, I added a Tripath TA2024 based amp card to my TEAC UD-H01 balanced DAC to drive my HE-500 headphones. The amp has lots of overhead, I listen at 9 - 10 o'clock position and it's dead silent at full volume. It sounds very good, even compared to the Schiit Mjolnir.

 

The how-to thread is here: http://www.head-fi.org/t/684169/tripath-ta2024-amp-board-as-balanced-headphone-amp-in-teac-ud-h01-dac

 

 

Geez you're handy

post #1954 of 3790

Could anyone with an A-100 comment on this question?  I just noticed for the first time last night.

 

Since I received the amp, I have mostly left it on to let it burn-in.  I turned it off last night and then back on about 30 minutes later.  I noticed that after I immediately turned it on and turned the volume pot, there was a very distinctive noise, like a 'whooshing' type of sound any time the volume pot was moved - up or down.  If it was stationary, that wasn't there.

 

I checked and it did it again this morning after being off overnight.

 

However, after about a minute or so of being on, this went away.

 

Does the amp just need a bit of time to warm up (capacitors get charged?) before turning the volume?  Or could some of the caps be failing?

 

I just picked this up so I'm getting concerned there may be a hardware issue with it.  Anyone with an A-100 that can test that out and let me know would be great!

 

Thanks

post #1955 of 3790
Quote:
Originally Posted by ohhgourami View Post
 


I suggest you use resistors on the output section of your amp. It's how I got rid of the very obvious hiss of my amp without affecting SQ.

He shouldn't have any hiss with the HE-4 or the HE-6..  

post #1956 of 3790
Quote:
Originally Posted by DaemonSire View Post
 

Could anyone with an A-100 comment on this question?  I just noticed for the first time last night.

 

Since I received the amp, I have mostly left it on to let it burn-in.  I turned it off last night and then back on about 30 minutes later.  I noticed that after I immediately turned it on and turned the volume pot, there was a very distinctive noise, like a 'whooshing' type of sound any time the volume pot was moved - up or down.  If it was stationary, that wasn't there.

 

I checked and it did it again this morning after being off overnight.

 

However, after about a minute or so of being on, this went away.

 

Does the amp just need a bit of time to warm up (capacitors get charged?) before turning the volume?  Or could some of the caps be failing?

 

I just picked this up so I'm getting concerned there may be a hardware issue with it.  Anyone with an A-100 that can test that out and let me know would be great!

 

Thanks

 

 

Take it back and get another one.  That's what I would do.

post #1957 of 3790
Quote:
Originally Posted by preproman View Post
 

 

 

Take it back and get another one.  That's what I would do.

 

I picked it up used on the forums here.  The warranty is transferable though.  Just really not wanting to spend a fortune shipping it down to TN from Canada...that is going to be pricey.

post #1958 of 3790
Quote:
Originally Posted by DaemonSire View Post
 

Could anyone with an A-100 comment on this question?  I just noticed for the first time last night.

 

Since I received the amp, I have mostly left it on to let it burn-in.  I turned it off last night and then back on about 30 minutes later.  I noticed that after I immediately turned it on and turned the volume pot, there was a very distinctive noise, like a 'whooshing' type of sound any time the volume pot was moved - up or down.  If it was stationary, that wasn't there.

 

I checked and it did it again this morning after being off overnight.

 

However, after about a minute or so of being on, this went away.

 

Does the amp just need a bit of time to warm up (capacitors get charged?) before turning the volume?  Or could some of the caps be failing?

 

I just picked this up so I'm getting concerned there may be a hardware issue with it.  Anyone with an A-100 that can test that out and let me know would be great!

 

Thanks

It's likely due to the quality of the potentiometer itself or potentially a faulty pot.  It's not easy to swap in a new/better one either unfortunately due to the design, but I'd recommend contacting Emotiva support regarding the issue.

post #1959 of 3790
Quote:
Originally Posted by DaemonSire View Post
 

Could anyone with an A-100 comment on this question?  I just noticed for the first time last night.

 

Since I received the amp, I have mostly left it on to let it burn-in.  I turned it off last night and then back on about 30 minutes later.  I noticed that after I immediately turned it on and turned the volume pot, there was a very distinctive noise, like a 'whooshing' type of sound any time the volume pot was moved - up or down.  If it was stationary, that wasn't there.

 

I checked and it did it again this morning after being off overnight.

 

However, after about a minute or so of being on, this went away.

 

Does the amp just need a bit of time to warm up (capacitors get charged?) before turning the volume?  Or could some of the caps be failing?

 

I just picked this up so I'm getting concerned there may be a hardware issue with it.  Anyone with an A-100 that can test that out and let me know would be great!

 

Thanks

 

Thanks sounds way odd to me. Better contact Emotiva and see if you can get a replacement.

post #1960 of 3790
Quote:
Originally Posted by ohhgourami View Post
 


I suggest you use resistors on the output section of your amp. It's how I got rid of the very obvious hiss of my amp without affecting SQ.

I am sure there will be no hiss with HE4/HE6 using a-100

 

your Krell is just overkill, too much power, too much gain, nothing strange you can hear some hiss

 

from some level of output power there are more cons than pros and amp should be carefully picked when connecting headphones to speaker amp directly, even these ultra low sensitive

 

a-100 has still nice power (especially for HE4), but great S/N ratio, very low distortion and many other factors (that's why I chose it + it's brand new unit, safe design)


Edited by magicman - 10/21/13 at 7:01am
post #1961 of 3790

The the piece itself I think might be digital.I'd contact emotiva and maybe they could just send you the part, but I don't think that's how they operate. 

post #1962 of 3790

Talked with Emotiva Support and they believe it is normal.  They said that they usually let their gear warm up for a minute or so.  The fact that this disappears after being turned on for a minute and doesn't happen during normal operation, they didn't seem to think it was an issue.

 

Still curious if other people's A-100's do this.  Pretty easy to check...have the unit off (for a period of time), have the HE500's connected, turn the unit on and as soon as you hear the "click" that the muting really has disengaged, move the volume pot.  Do you hear anything?  It is a constant noise so the level of volume doesn't affect it.

 

Thanks

post #1963 of 3790

Why is it you can't get speaker amps with switchable gain or something?

post #1964 of 3790
Quote:
Originally Posted by davidsh View Post
 

Why is it you can't get speaker amps with switchable gain or something?

 

Two reasons:

 

1) Impedance mismatch - With headphones, this tends to happen the most. Speakers and speaker amps are usually more in harmony

 

2) Pre-amp - Usually for stereo or even home theatre speaker rigs, there is typically a pre-amp involved somewhere in the chain, rather than a DAC line out to power amp. Emotiva is just a power amp.

post #1965 of 3790

yeah, actually putting some resistors on the amp's input is simply lowering its gain ...

 

I will let you know if my brand new unit acts the same (it will take some time to get to POLAND) but for me this is not normal behaviour, but don't know the implementation of the amp to tell

 

DaemonSire - this is why I never buy used stuff (especially when it's cheap like a-100), too many people have no idea how to use stuff and what is not good/safety for their equipment, but that's just me ... there is always a chance to get broken unit directly from the manufacturer but this is small chance ...


Edited by magicman - 10/18/13 at 10:00pm
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