grado sr-125 recable. not what you think
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nikongod

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hello headfi.

i recabled my grado sr-125's this evening. i was prompted to do this by a burning desire to get the ballanced amp i designed working to its full standard. sadly, it has something shorted to ground somewhere i'l find it later...

anyways, the pictars. pictars for all.

grado sr-125's

wire (hand braded, pain in the arse) is small guage silver plated coper stranded wire. the blue stuff is canare starquad. the xlr plugs are neutrik, from lichtenstein. the signal travels through both the blue and white wires, and the "ground antenna" is the steel braded sleve. the ground antenna extends into the grado cups.

pluged into my ballanced amp

another pictar.

see folks, its not my sr-125's with just an aftermarket cable and my mbquart's pluged into the ballanced amp (the mbquarts were the "test phones") HAHA. pwned...

the innards of my ballanced amp

i made a thread about the ballanced amp, it shows the circuit i used (selected resistor values) and all that jazz.

now that i have taken my sr-125's out of comision for my other amps, i will have to build an adapter. being that i am not dumb, i setup the wires in the starquad so that they are (most importantly) in phase and i made sure to put the white wire on the same side of each driver. i heard someone somewhere say it mattered. worst it is is wasted effort, at best better sound.
 
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nikongod

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woot.

my amp apparently thought that my grado headphones lack impedance.

1 47.5 ohm resistor has been soldered to each side of the headphone, in the xlr connector. each headphone "looks" like 125ohms to the amp now.

the amp is happy, i am happy, and the headphones are happy.

ooh, i knocked out my headphone grills too. they are totally gone.
 
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jrockway

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A few questions for you...

First: how does the wiring work when you terminate the cable with an XLR plug? I only have two lugs to solder to on my headphones' drivers. Therefore I have the phones terminated in two 1/4" mono jacks. (This allows me to drive the headphones as though they were speakers.) Does this count as balanced
or is there something I'm missing? (That third pin should go to something, don't you think...)

Second: what's the cross-talk like between channels? I notice that on my 'phones wired as above there is some definite crosstalk (when I use my signal generator at a not-that-low voltage). I think there was probably more with the stock cable, but if I'm trying to eliminate it in my amps and I'd like to eliminate it in my `phones too... I suppose I could use to separate two-wire cables from each ear to the driver, but I like the cable only coming out of one side.

Third: does adding extra resistance (as you mention in your last post) to the setup change the sound? My rationale for rewiring my headphones with thicker wire was to reduce resistance (after reading some paper about the effect this has on speakers, I'll see if I can dig this up for you). I tested my `phones in series with a 10 ohm resistor and could notice a different sound quality (hard to describe, but apparent). As expected, the sound was a lot better after the rewire.

It would be a shame if after all your work rewiring your phones, you were losing sound quality due to the resistance issue... I would do some tests and convince myself that there's no effect
 
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RnB180

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I dont understand how you recabled your cables with star quad then teflon wire? did you splice something? I didnt fully understand your post, did you short the cable or the amp?

if its the cable, a continuity test is your friend

http://www.vandenhul.com/artpap/wiring.htm
 
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nikongod

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Quote:

Originally Posted by jrockway
A few questions for you...

First: how does the wiring work when you terminate the cable with an XLR plug? I only have two lugs to solder to on my headphones' drivers. Therefore I have the phones terminated in two 1/4" mono jacks. (This allows me to drive the headphones as though they were speakers.) Does this count as balanced
or is there something I'm missing? (That third pin should go to something, don't you think...)



the wires go like this: 1 wire from the negative side of the amp to the blue starquald wire this then goes on up to the headphone. 1 wire from the positive side of the amp to the white wire which also goes to the headphone. and 1 wire from the actual ground to function as a shield this is soldered to the shield of the starquad, whichi i un-wove about an inch of ands twisted into a suitable attachment bit. the link below shows an awsome picture.
Quote:

Second: what's the cross-talk like between channels? I notice that on my 'phones wired as above there is some definite crosstalk (when I use my signal generator at a not-that-low voltage). I think there was probably more with the stock cable, but if I'm trying to eliminate it in my amps and I'd like to eliminate it in my `phones too... I suppose I could use to separate two-wire cables from each ear to the driver, but I like the cable only coming out of one side.


i dont have the proper tools to check, but i assume that it is the crosstalk of the amplifyer circuit. VERY low indeed. the 2 drivers do not share a single wire except for the shield wire, which dosnt really cairy a signal anyways.
Quote:

Third: does adding extra resistance (as you mention in your last post) to the setup change the sound? My rationale for rewiring my headphones with thicker wire was to reduce resistance (after reading some paper about the effect this has on speakers, I'll see if I can dig this up for you). I tested my `phones in series with a 10 ohm resistor and could notice a different sound quality (hard to describe, but apparent). As expected, the sound was a lot better after the rewire.


adding esistance deffinatly did change the souond. i added the resistance just to stabalise the amp. the amp was deffinatly oscilationg/hissing LOUD without these extra resistors. adding more still would probably change the sound a bit again. i do like the osund on my non-ballanced grados when a 100ohm resistor is added. the diference thre is small but present.
Quote:

It would be a shame if after all your work rewiring your phones, you were losing sound quality due to the resistance issue... I would do some tests and convince myself that there's no effect


i doubt i am loosing quality from adding resistance. im pretty sure that it will have improved across the board, even when hooked up to a normal amp.
Quote:

Originally Posted by RnB180
I dont understand how you recabled your cables with star quad then teflon wire? did you splice something? I didnt fully understand your post, did you short the cable or the amp?

if its the cable, a continuity test is your friend

http://www.vandenhul.com/artpap/wiring.htm



yepp, i made a LOT of splices. it probably would have been "cleaner" to just braid 6 strands of the same wire together into a decent cable, but im lazy at times. actually at most times.

the short was in the amp. i didnt check well enough when i put in my xlr jacks, and made a solder bridge from output to something else. all fixed now. the cable was imho quite well made for something that was more or less made from parts on hand. every connection int he cable is soldered, shrink-wraped wire to wire, then the group of wires are shrink wraped, and then the whoile mess is further wraped. i also made a point of staggering the solder point so that they would lie flatter, and be less prone to shorting out.
 
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