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Will resistors in series hurt signal quality in iems?

post #1 of 5
Thread Starter 

Hello,

Just received an iem back from reshelling where I asked for a larger resistor in path, and they seem to have added two more resistors inline to the one already in there so there is now a cluster of three resistors, I don't know what prompted this strange decision but wanted to ask your opinion as to how and if this would effect sound quality.

 

*edit:

Looking at it more closely, it appears that there are two resistors in series that go to singlearmature, and the old boxy resistor goes to the dual armature(single port)(don't know the value, it is yellow with a brownish strip at the end, reads 225e on it). The resistors in serie are butt-to-butt 20 ohms 5% tolerance

 

I believe they sound more veiled and bass heavy than they used to, but since they have new dampening, I can't really know what is the cause


Edited by AudioNoob - 5/8/13 at 11:30am
post #2 of 5
Quote:
Originally Posted by AudioNoob View Post

Hello,

Just received an iem back from reshelling where I asked for a larger resistor in path, and they seem to have added two more resistors inline to the one already in there so there is now a cluster of three resistors, I don't know what prompted this strange decision but wanted to ask your opinion as to how and if this would effect sound quality.

 

What difference did you hope to achieve by making this change?

 

Are the resistors in series, parallel, or some weird combination thereof? 

post #3 of 5
Thread Starter 

I asked for a higher value resistor because they were so low impedance that the correct volume would be between 1 and 2 (out of twenty) which one cannot set, and the low impedance made the hiss and static of the laptop (post amplification) audibly loud ( effecting a low total snr if you will).

 

Looking at it more closely, it appears that there are two resistors in series that go to singlearmature, and the old boxy resistor goes to the dual armature(single port)(don't know the value, it is yellow with a brownish strip at the end, reads 225e on it). The resistors in serie are butt-to-butt 20 ohms 5% tolerance


Edited by AudioNoob - 5/8/13 at 11:19am
post #4 of 5

There are  3 reasons 2 resistors are connected in series= -1-he didn't have the correct total value in one resistor-2-the voltage through them is very high=300V up and he only had -250V ones-3- he didn't have the correct wattage ones. A brown band at the end separate from the other colors= 1% tolerance. 225 doesn't tie up with yellow. Resistor color code = 0=black--1=brown--red=2--orange=3--yellow=4--green=5--blue=6--violet=7--grey=8--white=9. read from left to right. If you asked for an increase in resistance because you were hearing too much noise  and then complain of dullness you cant blame the unit that was converted its your laptop that's the problem. I would have done something about the laptop. You now have something that is not what you want sonically. I would reverse the changes and start again.

post #5 of 5
Quote:
Originally Posted by duncan1 View Post

I would reverse the changes and start again.

 

This sounds like good advice.

 

It's incorrect to assume that 'they were so low impedance that the correct volume would be...'

 

The volume level is related to the efficiency of the phones, and only indirectly to the impedance.

 

Try turning the laptop up full and put a passive attenuator (pot) between it and the phones. The noise (hiss) from the laptop is probably at a fixed level, and turning up the volume will improve the SNR. This is not absolutely certainly the case, but it's the first thing to try. Just put a 10k pot in between the laptop and the phones and control the volume with that. If the volume setting is very close to the end of the pot travel you can add an additional resistive divider. If you don't know how to do these things then ask.

 

It's better to describe the problem and ask for expert advice on how to fix it than to ask for what turned out to be an ineffectual modification on the basis of an incorrect assumption. You need to accept that you don't understand this subject very well.

 

w

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