Modding my 0404: Can someone please verify
Jan 29, 2006 at 12:33 AM Post #76 of 101
There you are
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Check the offset by sticking the multimeter probes on the output of each channel and ground, play some music. Measure for DC at the highest sensitivity setting on the meter. Check both channels this way.

People will have differing opinions on what is a safe level
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My first 0404 had about 2mv + 2mv with the LT1364, with an AD8620 I had 0.5mv + 0.8mv. My current 0404 is not so good, maybe because I have two browndogs in the link or lesser opamp, this one produces 5mv + 7mv. I was unsure at first, but I have run it like this for a year with an amp not equipped with DC blocking caps and there are no ill effects.

You should be ok under 5mv I think..anything under 2-3mv I wouldn't worry about. Try mesuring the output of some good and bad branded kit, I've seen a few things with a lot of offset.

If you run an amp with DC blocking caps later in the chain then you have no need to worry.

Obviously to be completely safe you should be at 0 and the only way there is with the caps in.

Don't rush with the cap changes, unless you are changing the output ones I doubt you'll hear much difference.
 
Jan 29, 2006 at 9:12 PM Post #77 of 101
Well i attached each probe of the multimeter to the bottom pins on each of the output caps and got a reading of 2.55. Im not sure what units those would be exactly as i had the multimeter on the 20 setting out of a possible 200,20,2000m, 200m. Am i doing at right, as i haven't used my multimeter in ages. This is with the caps still in place

With regard to replacing the caps, i have ordered OS-con to replace the (yellow from bigs diagram) 10uF/16V caps, a standard black gate 220uF/16v to replace the old single (red) 100uF/25V cap, and a 47uF/16V black gate to replace my single (purple) 47uF/16V cap. I also have an lt1364 here. What do you recommend i do first, regarding getting an accurate DC offset reading, then bypassing the output caps, and removing the output buffers??

Thanks
ad
 
Jan 29, 2006 at 11:29 PM Post #79 of 101
Ah iv given up. The solder doesnt want to flow between the legs of the caps, and always turns a dull colour. I guess this is caused by the solder not being silver solder ?

I checked the antex website, and the free stuff that maplins sent me isn't silver solder
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Jan 30, 2006 at 9:25 AM Post #80 of 101
Quote:

Originally Posted by adfinni
Ah iv given up. The solder doesnt want to flow between the legs of the caps, and always turns a dull colour. I guess this is caused by the solder not being silver solder ?

I checked the antex website, and the free stuff that maplins sent me isn't silver solder
mad.gif



Heh, it looks easy doesn't it
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Junk the solder they gave you. I've been using Antex silver solder for ages, thinking it was good but infact it is pretty bad. It has no lead and while that is normally a good thing, in this case it is not. Genuine lead free will not set as shiny as lead based solder, so don't worry about that. You need more heat for lead free too.

Try and get some lead based solder somewhere, it will flow much nicer. That said both my cards were done using Maplins silver solder :/
 
Feb 2, 2006 at 10:35 PM Post #81 of 101
Quote:

Originally Posted by Magsy
Heh, it looks easy doesn't it
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Junk the solder they gave you. I've been using Antex silver solder for ages, thinking it was good but infact it is pretty bad. It has no lead and while that is normally a good thing, in this case it is not. Genuine lead free will not set as shiny as lead based solder, so don't worry about that. You need more heat for lead free too.

Try and get some lead based solder somewhere, it will flow much nicer. That said both my cards were done using Maplins silver solder :/


cheers magsy. Il post back when ive finished bypassing the buffers and replaced the op-amp, during this weekend.

btw the DC offset i got with the bridged output caps was 1.41mv i think. Thta was on the standard setting on the multimeter, and the multimeter setting from highest to lowest go 1000 > 200 > 20 (one i used) > 2000m > 200m. How does that look, as i got no readings with the 2000m and 200m values, or the 1000 for that matter ?

cheers
 
Mar 5, 2006 at 9:31 PM Post #82 of 101
Quote:

Originally Posted by adfinni
cheers magsy. Il post back when ive finished bypassing the buffers and replaced the op-amp, during this weekend.

btw the DC offset i got with the bridged output caps was 1.41mv i think. Thta was on the standard setting on the multimeter, and the multimeter setting from highest to lowest go 1000 > 200 > 20 (one i used) > 2000m > 200m. How does that look, as i got no readings with the 2000m and 200m values, or the 1000 for that matter ?

cheers


sounds very reasonable; of course you have yet to remove output buffers (opamps), or change the opamp. going one step at a time and recording offset along the way is very good style.
 
Apr 17, 2006 at 5:15 AM Post #83 of 101
I have a question for u guys. Basically it's about the dangerous dc offset value. General question, does most marketed speaker sets amp have output coupling caps for eliminate the dc offset?
 
Apr 25, 2006 at 12:44 PM Post #85 of 101
Hi,


Has anyone modded the 0404 by just bypassing buffer output caps and buffer opamp? If so, what was the dc offset? Will there be much dc offset if you bridge the buffer opamp and caps than just bypassing caps alone?

Thanks for you help.
 
Apr 26, 2006 at 11:29 AM Post #86 of 101
Quote:

Originally Posted by blaine2323
Hi,


Has anyone modded the 0404 by just bypassing buffer output caps and buffer opamp? If so, what was the dc offset? Will there be much dc offset if you bridge the buffer opamp and caps than just bypassing caps alone?

Thanks for you help.


i've modded mine by just bypassing the output caps and buffer opamp. the DC offset measured is 225mV and 320mV. the value i measured is not the output from the 0404 itself. it's from 0404 to aego2 speakers. meaning i measured it at the satallite ports. i consulted alamaklor, and he said it's safe for a speaker sets to have less than 1V. and for headphones, less than 300mV. and yes. there is vast improvement on the bass and the soundstage. before i removed the caps and opamp, the bass seems like it's being "locked" at a certain frequency. now after modded, the bass sound much more "unlocked". satisfied.
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Apr 28, 2006 at 9:28 AM Post #87 of 101
Quote:

Originally Posted by katopunk
i've modded mine by just bypassing the output caps and buffer opamp. the DC offset measured is 225mV and 320mV. the value i measured is not the output from the 0404 itself. it's from 0404 to aego2 speakers. meaning i measured it at the satallite ports. i consulted alamaklor, and he said it's safe for a speaker sets to have less than 1V. and for headphones, less than 300mV. and yes. there is vast improvement on the bass and the soundstage. before i removed the caps and opamp, the bass seems like it's being "locked" at a certain frequency. now after modded, the bass sound much more "unlocked". satisfied.
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Thanks, but decided to get something better that i don't need to mod.

cheers
blaine
 
May 29, 2006 at 4:44 PM Post #88 of 101
Hi there,
I recently got my emu 0404 and found that my card has a different model number then one which image was posted for modding(model num:EM8850). My card has model number EM8852 and a bit different element topography. My question is can I mod my card same way as was discussed at this forum or it’s not applicable? If yes what the difference.
Thanks.
 
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