solderdude
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Post by solderdude on Dec 20, 2016 10:53:58 GMT
Most likely HD681-B's. The amount of bass from a regular HD681 would be MUCH more than HD212. Yep, those peaks will vanish. Make sure you create the filter in THIS article as it is better suited than the one I started out with (by ear) in the RG period. Use the 'Schematics for the HD681-B when using the headphone on equipment with an output resistance <10Ω :' circuit (second last in the article). When you do not want the amount of bass lowered then just leave outC5, C6, R5 and R6. As you are using it directly out of i-stuff you can use this simple filter.
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Post by ihack13 on Dec 20, 2016 13:16:12 GMT
Most likely HD681-B's. The amount of bass from a regular HD681 would be MUCH more than HD212. Yep, those peaks will vanish. Make sure you create the filter in THIS article as it is better suited than the one I started out with (by ear) in the RG period. Use the 'Schematics for the HD681-B when using the headphone on equipment with an output resistance <10Ω :' circuit (second last in the article). When you do not want the amount of bass lowered then just leave outC5, C6, R5 and R6. As you are using it directly out of i-stuff you can use this simple filter. Yes. I have been using the revisted pdf. I want to test this on a circuit first. With different settings, that I can switch between. I am trying to do it right. Can you take a look at this? Do I have to cut the line where a question mark is , with a switch? It seems I am shorting something there when I am bypassing the C5 + Resistor.
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solderdude
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Post by solderdude on Dec 20, 2016 16:36:20 GMT
R1, C1 and L1 only do something when the output resistance of the amplifier is well above 10 Ohm. I stuff is below that so these components are not needed. C5 and R5(6) are only needed when you find it has too much bass.
From your sound description the HD7 may be closer to the F version than the B version.
You can still use C5 and play with the value of R5. The higher the value is the less bass it will have. 0 Ohm thus is max bass level.
You could do without the left switch and connect the amp directly to C5. Then only use the upper switch and remove R6 and replace it with a short. Now when the upper switch is set to 'R6' the bass filter is off. When set to R5 the bass filter is active. Play with the value of R5 or use small potmeters of 50 or 100 Ohm
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Post by ihack13 on Dec 20, 2016 17:37:17 GMT
R1, C1 and L1 only do something when the output resistance of the amplifier is well above 10 Ohm. I stuff is below that so these components are not needed. C5 and R5(6) are only needed when you find it has too much bass. From your sound description the HD7 may be closer to the F version than the B version. You can still use C5 and play with the value of R5. The higher the value is the less bass it will have. 0 Ohm thus is max bass level. You could do without the left switch and connect the amp directly to C5. Then only use the upper switch and remove R6 and replace it with a short. Now when the upper switch is set to 'R6' the bass filter is off. When set to R5 the bass filter is active. Play with the value of R5 or use small potmeters of 50 or 100 Ohm Alright. I am not sure if I need the bass reduction then. I also dont want to confuse you. Because I have by all means not the knowledge that you have on this matter nor do I have a good analytical ear I think. At least I lack references. The Sennheiser HD 212 Pro are my only headphones that I can compare these too. And I realized it is very hard to compare sound, since you cannot remember it. It really depends on the songs that you are listening to. I dont know what your choice of analytical songs are, maybe you can share some information on good benchmarking songs. The thing is when I switch from the Sennheisers to the Presonus it doesnt sound crisp and on the spot. The quality is there but its like a slight dull layer on the sound. A bit more of echo and roomy sound. But then again when I listen to some turkish guy singing about his grief and sorrow and life with less instrumental sound (or more instrumental , doesnt matter) he voice is so clear and detailed and distinguishes itself from the instrumental. And this also makes these pair of headphones much better for lets say gaming and voicechat since you can hear the voices more clearly than on the sennheisers. Well whatever. Just for the sake of completeness , I might also include the bass filter then. Maybe it will remove the layer , I dont know. Will try and see. I have to add some potentiometers to the shopping cart now. I was looking for a suitable 3.5mm jack anyway. I will write back as soon as I am finished. This is the new schematics for now PS: I am not sure if the Macbook has low output resistance too. And besides I do not like Apple anymore and will switch to other brands like Xiaomi in the future. So it might be good to have the >10 ohm filter to be future proof. edit: Almost 10 € . Some stuff is duplicate like the big capacitors but still... www.mediafire.com/file/yy7j4hgu0tdcncv/Meine_Merkzettel.pdf
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solderdude
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Post by solderdude on Dec 20, 2016 19:53:02 GMT
The bass filter won't work properly as drawn above. And you don't need the switch when using a potmeter. The reason for this is that when you turn the potmeter to 0 Ohm you have bypassed the filter. And you can do another thing that may be of interest. You can replace R3 and R4 with pots as well. These pots you can make the filter even more effective (higher setting) to less effective (lower resistance setting). You can adjust it by ear (and sight when looking at the markings on the potmeter) to suit your taste.
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Post by ihack13 on Dec 20, 2016 20:48:21 GMT
Alright. Seeing how this is getting half as expensive as the headphones I think I will order the stuff from china and complete the external filter later when the stuff has arrived. Normally I dont have a problem with the price, but just defeats the purpose if you get overpriced electronic components that are half as expensive as the headphones.
For now I will only get the stuff for the high frequency fix from the local store and apply it directly on the headphones. So that is L3 , C3, R3 and L4, C4, R4.
Going to get the stuff on Thursday hopefully and then solder it in. So I can finally listen to music without getting headaches.
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solderdude
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Post by solderdude on Dec 21, 2016 10:03:10 GMT
Yep, that's really all that is needed in this case. Can always add the bass filter afterwards if so desired.
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Post by ihack13 on Dec 21, 2016 13:21:19 GMT
Also as it seems I will get a HD681 because I have a voucher left, which is about to expire. Effectively I get the HD 681 for 10 Euro. Too bad I wont have a need for the 662 Evo then. But at least I have a reference to test and a second headphone to modify. Besides, I dont have the materials right now to modify the Evo. I ran out of toilet paper
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Post by ihack13 on Mar 22, 2017 13:21:03 GMT
Not sure if I asked this. Do I really need big Resistors in terms of wattage? Or are 1/4W ok?
I had a hard time finding 0.6W resistors etc. If I remember your guide correctly.
edit: Just checked the guide again. Not sure why I was having a hard time. Basically you say that 1/4W Resistors are not enough and you should go with 0.4W at least. 0.6W max, because a bigger physical resistor could cause troubles in that little space? Did I understand that correctly?
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solderdude
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Post by solderdude on Mar 22, 2017 14:31:44 GMT
I use SFR16 sized resistors. These are spec'd as 0.4W and 0.6W. These are much smaller than the 'regular sized' SFR25 sized ones.
A power rating of 1/4W is already enough. Most current passes through the inductors so the resistors only have to dissipate a few mW.
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Post by ihack13 on Mar 22, 2017 16:38:26 GMT
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solderdude
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Post by solderdude on Mar 22, 2017 22:22:48 GMT
You will need 4 of these per channel because these are polar caps. Put 2 of these in antiseries (so with the - connected together) and put in parallel to that assembly 2 caps also in antiseries but with the + connected together.
This will create a 47uF bipolar capacitor.
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Post by ihack13 on Mar 23, 2017 8:50:50 GMT
wait. What?! I ordered these because they were labeled as bipolar.
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solderdude
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Post by solderdude on Mar 23, 2017 9:11:13 GMT
When they look exactly like the picture (blue with a white - marking strip) then these are polar. Also in the description there is no mentioning of it being bipolar. They are small so you can probably fit 4 of these in there ?
Bipolar caps usually are bigger in size anyway.
The configuration as mentioned above probably has better characteristics/performance than 1 bipolar cap.
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Post by ihack13 on Mar 23, 2017 9:24:34 GMT
Well I wanted to go for the best solution so I bought these. They were stated to be Bipolar as in this title www.aliexpress.com/item/10pcs-10uF-35V-ELNA-CE-BP-6x5mm-35V10uF-Bipolar-Audio-Capacitor/32787963773.htmlalso they are branded as CE- BPI think I had the datasheet once. Can't find it. Well I just tested one with my Multimeter and gives a reading of 49uF in just one direction. Since a bipolar capacitor acts like a back to back of 2 electrolytic capacitors + - - + it should have gave reading in both direction, hence bipolar , right? Some sellers mention that they are RB3 series. Not sure why they are labeled as CE-BP then. Cannot find CE-BP on any of ELNAs Datasheets anyways. www.elna.co.jp/en/capacitor/alumi/catalog/pdf/rb3_e_p96.pdfDoesnt make sense though, since the said voltage isnt available at that capacitance or dimensions. So these are simple polar low profile Aluminum Electrolyric Capacitors Alright. Seem to be Elna RC3 standard low profile capacitors.
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