Distorting noise from Emu 1820m

[S.F.Sorrow]

I have a problem with distorting noise coming from the right side (left side is fine) of all outputs on my Emu 1820m. The headphone output is also crackling. It's a fairly high frequency distortion coming from the tweeter on my monitors but the crackling seems to be caused mainly by sounds with lots of low frequency content. It's had to describe a sound but let's just say I first thought my speakers woofer was busted.

I might also mention that my phantom power went bad years ago. I know this is a common issue with the 1820m (I get the low frequency noise in channels A/B when engaging phantom power, like many others have also reported). I dunno if this has any significance but I thought I should mention it.

Does anyone have any idea what may cause this? It's a pretty old interface so perhaps it's time is up, I hope not cause I really like it.

I'll try my local repair guy tomorrow but I have a feeling he won't be thrilled to work on it. After all it would require installing it with drivers on a computer to actually test it. Or perhaps he will find something without having to do that. I dunno...

Any help will be appreciated!

Thanks!

[2N1305]

Hi,
well, the first thing that came to mind was: are you going into an input that can handle the level of the 1820m? But then you said that the left channel is working and the whole thing was obviously working before, so that isn't the problem.

The next thing I am thinking of is: solder joints. solder on electronic devices nowadays is really poor, and on connectors and receptacles, where the tension and wear and tear is higher than isolated components, the joints can become cracked. Inspect, or simply re-do the soldering on both RCA jacks (those are the outputs, right? I just looked on EMU's website and took a quick look at the device)

If this does not fix the problem, then maybe it's your cables. Other than that, did you accidentally switch the level output in the software?

I hope this helps,

2N1305

[oxide54]

EMU hmmmm

I have a classroom full of EMU devices and a classroom full of M-Audio devices. and the EMU one cack out all the time. the "Creative" (soundblaster) doesn't inspire me with confidence

[S.F.Sorrow]

I believe the RCAs are the turntable inputs. There are 3 pairs of jacks for line level outputs and they all distort (or to be presise, half of them distort, only the ones on the right, the left ones are ok). And the headphone output also distorts.

I did some more searching online and found that LOTS of people experience the problem with the phantom power and apparently it's caused by poor quality caps that only last a few years. My phantom power has been gone for several years now (I never used the pres in the 1820m so I never bothered to look into it). Can the distortion also be caused by bad caps?

[2N1305]

Originally Posted by S.F.Sorrow

I believe the RCAs are the turntable inputs. There are 3 pairs of jacks for line level outputs and they all distort (or to be presise, half of them distort, only the ones on the right, the left ones are ok). And the headphone output also distorts.

I did some more searching online and found that LOTS of people experience the problem with the phantom power and apparently it's caused by poor quality caps that only last a few years. My phantom power has been gone for several years now (I never used the pres in the 1820m so I never bothered to look into it). Can the distortion also be caused by bad caps?

No, most likely not. the capacitors for the 48V supply are independent from
the audio output's supply, at least they should be, and it would be a really weird design if EMU actually designed the thing such as to have the LEFT channel only on the same supply as the 48V. It just wouldn't make sense. But, I mean, it's not a big thing to change the caps, and see if it does fix the problem!
If you're handy with electronics you should be able to do this. If not then why don't you just return it to EMU?

[S.F.Sorrow]

Returning it to Emu is unfortunately not an option. The 1820m has been discontinued for years and the warranty has expired a long time ago. Besides, Emu support stinks. They seem to have the policy that it's the customers fault when their gear fails. Even when LOTS of customers report the exact same problem.

I just noticed something else. Some of the tracks I record has started to appear on screen as blank waveforms, just a straight line. The recorded sound is there and if I zoom in the waveform suddenly appears. But when I zoom back out it disappears again. It seems to affect all tracks randomly, about 1 out of 20 times. Very strange... This has never happened to me before. I guess it could be totally unrelated to the problems with the 1820m but seems a little too much of a coincidence that it started just after the mentioned distortion began.

Maybe it's time to say goodbye to my 1820m and get that RME/SSL Alpha Link combo that I've been thinking about. Still, why change something that works? I do like my 1820m a lot so maybe I'll let my repair guy change any suspicious looking caps (I would probably mess up horribly if I try it myself) and see what happens.

[2N1305]

Well, while that is a wise decisionhaving a professional technician change those capacitors (and look at the rest of the circuit), it is my belief that the problem is not in the EMU unit. At least not in anythign analog. As soon as you described that "waveform disappearing" thing I started to think that it's actually the software or your computer. After all it is the computer that interfaces with the 1820m to tell it what to do, am I right?

While the 1820m does indeed have a microcontroller (I doubt it's a microprocessor, not in something this small) and steers its own functions, it cannot change the way the software on your computer behaves. However the inverse might happen. Your computer can tell the 1820m what to do, example, mute the left side, change the attenuation (causing distortion), etc. So maybe, re-install the software. Sometimes windows updates can do strange things...

Is there a way to monitor with headphones directly on the 1820m? I mean without going through any other device?

2N1305

[S.F.Sorrow]

Yeah, there is a headphone output on the front of the 1820m. The distortion is there as well. And zero latency monitoring that shouldn't pass through anything else as far as I know. It's there as well. Anything that comes out of ANY left side output is distorted when it contains low frequencies (like a normal bass guitar). And I haven't updated anything on my pc lately. The pc is not online so no Windows updates.

As for the disappearing waveforms they may be unrelated to the 1820m after all. I just found some info online about the picture cache in Sonar that might explain that. I haven't had a chance to take a look at it yet. But then again, it might not be Sonar causing this.

I'll try reinstalling the drivers and see if it helps. Whatever happens there is still something wrong with my 1820m because the phantom power doesn't work. And that's well documented to be caused by bad caps.

However, I can live without the phantom power just as long as that distortion disappears.

Thanks for helping!

[2N1305]

Originally Posted by S.F.Sorrow

Yeah, there is a headphone output on the front of the 1820m. The distortion is there as well. And zero latency monitoring that shouldn't pass through anything else as far as I know. It's there as well. Anything that comes out of ANY left side output is distorted when it contains low frequencies (like a normal bass guitar). And I haven't updated anything on my pc lately. The pc is not online so no Windows updates.

Ah, well that explains well that it isn't the computer. I don'Tt know if that's fortunate or unfortunate. In any case the problem does indeed lie within the 1820m. But I stil highly doubt it's the capacitors. I mean, changing the capacitors (for the 48V) will not fix the left side audio problem, that's my electronically educated hypothesis.

Originally Posted by S.F.Sorrow

As for the disappearing waveforms they may be unrelated to the 1820m after all. I just found some info online about the picture cache in Sonar that might explain that. I haven't had a chance to take a look at it yet. But then again, it might not be Sonar causing this.

I'll try reinstalling the drivers and see if it helps. Whatever happens there is still something wrong with my 1820m because the phantom power doesn't work. And that's well documented to be caused by bad caps.

However, I can live without the phantom power just as long as that distortion disappears.

Thanks for helping!

That's the least I could think of, outside from hardware issues.

You're Welcome! (eh)

[PRH]

If the phantom caps were known to go bad, then there might be good reason to be suspicious of other electrolytics on board. Are there electrolytic coupling caps in the signal path?

Might be as well to verify your supply voltages for left and right signal paths.

If supply is drooping on the left, then you might expect earlier signal clipping compared with the right. Conjecture only, since I don't know the device in question.

[djsubject]

this thread should help on replacing CAPs that cause distortion on analogue outputs

EMU 1820M not working properly - Badcaps Forums

i also have non working phantom power, if i can track down what cap it is i can replace & fix that also

Subz