E-MU 0404 usb 2.0 and some "artifacts peaks" on left channel - Page 4 - diyAudio
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Old 29th October 2012, 02:41 PM   #31
sidiy is offline sidiy  Canada
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Good news all over, I'm glad it worked.
Earthquake? I hear all is well, our friends in BC may have some stories for us.

I'll try next some improvements on CMRR, decoupling and I may even change some of the op-amps and 'lytics. But I'll need to raise a schematic and order some parts...don't wait for me.
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Old 29th October 2012, 03:52 PM   #32
lemon is offline lemon  Greece
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We use the emu like a measuring equipment (most of us).
Any improvement to better measuring characteristics are welcome!

I have another one emu0404 with power on problem. What you say, I open a new thread about this or describe the problem here?

Last edited by lemon; 29th October 2012 at 04:09 PM.
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Old 30th October 2012, 02:53 AM   #33
sidiy is offline sidiy  Canada
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I suppose that a new thread with the appropriate title is more likely to prompt an answer from someone who had a similar problem. But you can try here too.
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Old 30th October 2012, 11:55 AM   #34
lemon is offline lemon  Greece
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OK, I'll create a new thread about this.

Here my mod on emu, like sidiy way.
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Old 1st November 2012, 01:20 PM   #35
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Mod results:

Open loop:

left ch mod open loop.png

This is clear improvement over stock condition.

Left input referenced to -1dBFS with 1kHz sine by adjusting output, left output used:

1kHz left -1db0.png

Right input with cable moved from left input, same signal:

1kHz right -0db8 with left ref.png

From above results, left channel remains susceptible to signal.

Excellent mod! Thanks for the adventure.

I hope your talents are fruitful and otherwise well employed.

Regards,

Andrew
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Old 8th November 2012, 12:37 PM   #36
lemon is offline lemon  Greece
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What should I like as next mod for this emu?

1) Better input noise, over 30KHz
2) Multiturn output pot with better precision between the two channels.
3) Multiturn input pots (many times I have struggled too much to get a certain level (dBV) entry.
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Old 8th November 2012, 08:37 PM   #37
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Quote:
Originally Posted by lemon View Post
What should I like as next mod for this emu?

1) Better input noise, over 30KHz
2) Multiturn output pot with better precision between the two channels.
3) Multiturn input pots (many times I have struggled too much to get a certain level (dBV) entry.

Item 3 I have struggled with also.
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Old 9th November 2012, 04:53 PM   #38
sidiy is offline sidiy  Canada
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Agreed on number 3.
Currently we seem to have a "Pot2" for input and a "Pot9" for Headphones and Output level. The tapper for Pot2 seems to be custom made for EMU (they don't list a 02C, only a 05C).

Link: 11mm Rotary Potentiometers

Having the footprint and pinout we should try first to find something equivalent in multiturn,...but I'm not too optimistic. Other solutions imply some sort of mechanical hack...
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Old 10th November 2012, 11:54 AM   #39
lemon is offline lemon  Greece
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sidiy, like Alpha inputs pots I find the Bourns PTV Serie (20K, 20%, 50mW) but it is not a multiturn, it has the same Resistance Tolerance characteristics : 20%. None improvement from Alpha!

Another solution for pecisely input pots, but not dimensional equivalent, is the Vishay Spectrol Series (2W, 20K), 10 no of turns, linear, same axle diameter (6mm), with better Resistance Tolerance characteristics : 5%, Linearity tolerance 0.25%.
It would supported to the upper pcb with nut and connected with the under pcb by wires, but has only 3 pins not 4 like emu's.

Click the image to open in full size.

Equivalent to Vishay Spectrol is the ETI Systems MW22B-20K (MW22B-10-20K ETI Systems | Mouser)
Click the image to open in full size.
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Old 17th February 2013, 09:54 AM   #40
ghemml is offline ghemml  Singapore
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Quote:
Originally Posted by sidiy View Post
I forgot to post the results for dynamic range. Still some little gremlins bellow -132dB or so...at these levels it gets complicated, we need to consider shielding , I think.
There is also a 12k component that appeared on the right channel, or I'm seeing it only now because everything is cleaned around. (see it in the previous posts with SNR and THD too).

On the downside my mod degrades the crosstalk, it is now down 3-4dB at 20k (~ -84 dB absolute), because the new wiring hovers above the right channel over a length of 3/4 inch or so...I don't really mind.
But I had to inform you...
Sorry for digging this thread out, nut I like to find out if this mod will change the input impedance?

thanks
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