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Post by madmac on Oct 13, 2013 15:10:25 GMT
I just did
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Rabbit
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Post by Rabbit on Oct 13, 2013 15:32:31 GMT
Well done. I see your avatar is a double whammy too!!! Like a matched pair of tubes!! Welcome.
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Post by audiomanph on Nov 9, 2013 7:51:16 GMT
Interested in the mods that were described in this thread. Good job!
First, I want to make the EVO more flat so I was thinking of using the T50RP pads first since I have no experience in soldering or doing electrical mods. Will that be enough?
Second, if that does not "satisfy", I'm planning to doing the filter mod (good luck to me!) plus the velour pads. I'm thinking of using 68ohms and 39ohms. Is this correct?
With all of those mods, to what headphone/s is it comparable with?
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solderdude
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Post by solderdude on Nov 9, 2013 10:06:09 GMT
The filter can be external so you don't have to solder the parts inside and can even use bigger sized components.
The resistor in parallel with the capacitor can be 68 or 82 Ohms but most likely 68 Ohm will be preferred. The resistor in parallel with the inductor can be between 22 and 39 Ohm.
Best part of the external filter is you can easily experiment with resistor values and buy 4 small 100 Ohm potentiometers instead the resistors and 'dial-in' the compensation you want/prefer.
This is the beauty of an electronic solution over a 'mechanical' one where it has to be taken apart and changed and don't know what exactly changed and how much.
With the potmeters you can put the EVO on your head and adjust the pots while listening.
I can't really say what it compares to but SQ will be quite similar to the one with T50RP pads but slightly less bass.
IMO the EVO isn't a bad headphone for the price but personally prefer the old (modified) HD681 over the EVO as the old one is more forward, the EVO is more 'relaxed' though and non-fatiguing.
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Post by audiomanph on Nov 9, 2013 11:11:49 GMT
Thanks for the reply!
I see. I cannot seem to find the old HD681 version here in our country. It is probably sold out and ordering from another country will be really expensive. Hence, I'm going with the EVO.
Could you describe how the external filter can be achieved/done?
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solderdude
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Post by solderdude on Nov 9, 2013 12:52:34 GMT
I'll see if I can 'Paint' a picture in the near future.
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Post by audiomanph on Nov 9, 2013 13:10:39 GMT
Alright. Thanks!
Basically, I will need the following components: 4 resistors (2 68ohms, 2 39(or22)ohms) 2 inductors 2 10uF bipolar capacitors PCB/Prototype Board?
Is this correct? I have a feeling that I'm missing the input and output component (sorry do not know the term for them). Any recommended brand for the parts?
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solderdude
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Post by solderdude on Nov 9, 2013 16:26:50 GMT
These are 2 options, the above one with fixed resistors (where R1 = 68 Ohm and R2 is 39 Ohm (or lower version) and the bottom one is with small potmeters. The potmeters are more expensive though and it might be cheaper to buy a few values say 15, 22, 39 Ohm and see what you like. The same for R1 (100 Ohm, 68 Ohm, 56 Ohm). The resistors don't have to be more than 0.6W but should be above 0.3W. The electrolytic capacitor MUST be bipolar (or nonpolar) make sure they are not 'standard' polar capacitors (those with '+' or '-' on it). Non Polar caps DO have a long and short leg but these do not mark + or - but indicate which leg is connected to the outer cannister. This is NOT of importance in this case but might be in other applications. The inductors have to be max 2.7 Ohm in resistance, lower is better but the size and price increases. I am not a 'brand' type of person... The external filter could be made by cutting the short or long extension wire and incorporate it in there OR you can buy a socket and plug and connect it to that. PS. the components do not need to look like the drawn components but are likely to look like the drawn types.
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Post by audiomanph on Nov 10, 2013 12:02:00 GMT
Thanks for the diagram! It is really helpful. I will start looking for the parts now... will let you know the results. Thanks again!
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solderdude
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Post by solderdude on Nov 10, 2013 13:42:26 GMT
When you post the links to the components you selected I will check if they are the correct ones.
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Post by audiomanph on Nov 10, 2013 15:29:26 GMT
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solderdude
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Post by solderdude on Nov 10, 2013 16:22:14 GMT
Both inductors are fine. you need 2 and for one of them the MOQ is 5 the other can be sold by piece. In most cases RS-online has high shipping costs for small orders. If you cannot find 10uF bipolar or non polar (I can't find them on Philippines RS) you can use 22uF polar capacitors but need 4 of them (2 of them in anti-series per channel) philippines.rs-online.com/web/p/aluminium-capacitors/0571975/I could find this one: philippines.rs-online.com/web/p/aluminium-capacitors/7270486/but MOQ = 25 ! these potmeters can be used: philippines.rs-online.com/web/p/trimmer-resistors/5221151/6.3 mm connectors usually make better contact but which one you choose should be determined what sockets you are using. The headphones themselves use 3.5 so one 3.5 socket seems logical. If all your amps have 6.3 the plug could be 6.3 but you can also use 3.5 plug + adapter (one comes with the EVO) is probably most convenient.
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Post by audiomanph on Nov 11, 2013 0:36:13 GMT
Alright. Will check one more store to see if I can get an inductor. If not, I'll but them online. Surprisingly, their shipping/delivery is free.
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Post by audiomanph on Nov 11, 2013 10:35:32 GMT
Ordered the above items and two 3.5mm connector jacks. Delivery would be in 5-8 days. Can't wait!
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solderdude
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Post by solderdude on Nov 14, 2013 20:55:57 GMT
The new article 'Superlux HD681 replacement pad measurements' might be of interest to those who do not want to filter mod the HD681-EVO and do not have T50RP pads. It can be downloaded HERE, scroll down and click on the Superlux HD681 replacement pad measurements link !
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