Superlux HD-681 modifications

[XTRProf]

May 3, 2011 20:57:07 GMT anttirr said:

May 3, 2011 6:07:21 GMT anttirr said:

Hi all and thanks for questions.

I will try to make later today step by step guide for DIY velourpads! Hope that it will give you all answers

Ok. No DIY posts today. I made new pads to my friends Grado's but now i need some sleep. And pads are not so good as i wanted them to be. but i have all the screens / pics now available for use.

Good night. Later...

Go get some sleep and have some life. We must have a balanced life as my father always like to remind me.

[edv]

Hello.
I'm italian and I bought the Superlux HD-662. I would realize a filter type hd-681 for it.
The impedance of HD-662 is 32 Ohm and my target is a filter to mitigate -8dB at 6200Hz with Q=1.5. Someone can help me to establish right valours of components?
I would be grateful for your suggestions.
Thanks
Enrico
**Sorry for my language

[Deleted]

Hi Enrico,

Welcome on board..
You can use the HD681 filter but the resistors should be 47 Ohm
The 1uF caps should receive an extra cap in parallel of 330nF (so in total 1.33uF)
This should be a close approximation.
-3dB bandwidth 3.4 kHz - 11 kHz
-7.5dB @ 6.3kHz

[edv]

Thanks Solderdude,

If I understand this is the list of components (one channel):

R1= 47 Ohm
C1= 1.33 uF
L1= 470 uH
========
L3= 470 uH (?)
C3= 1 uF or 1.33 uF (?)
R3= 56 Ohm (?)

It's Correct?

[Deleted]

Change R3 to 47 Ohm too
c1 = C3 = 1.33nF (1uF // 330nF)
L1 = L3 = 470uH

[edv]

Ok now is all clear.
Thanks again

[vodka]

Well, I've made my own velour pads from pillow stuffing. I don't like the sound :S It's too harsh (the highs go berserk, lots of sibilance) and lacks bass... I must be doing something wrong... either the real AKG velour pads have something special to them that I'm missing (since the commentaries praise them), or these headphones just don't like DIY velour pads..

I've tried both plump and "normal" pads, the amount of stuffing doesn't change much the bad signature they have now.. I'm back on the stock pads until I find out what's wrong with these.. :s They are exactly the same size as the stock pads. They're only lacking the "flap" to attach them to the headphone itself, but that shouldn't affect sound quality. Maybe pillow stuffing is just plain bad as pad material?


Comfort wise they're excellent, the SR850 becomes a REALLY comfortable headphone.. but with this sound quality these pads are useless. Your guide'd be really helpful right now anttirr...

[Deleted]

loss off bass (and thus siblance/highs becoming more noticeable) is mostly caused by leakage.
The pads not fully closing off the ear.
This could also happen when the material used let's through too much air.

To try velour pads (before buying) I made my own by simply covering the original pads with velours cloth.

Also the AKG pads are plastic and there is some velours stuff 'sprayed' upon it.
I noticed it when wearing glasses, you can hear 'squeeks' when moving around.
Beyer pads (real velour) don't have that and heef different.

That might be the source of the problem.
Also ear/driver distance may be a problem.

[vodka]

Hmmm ear/driver distance is the same as with the stock pads I believe, these get compressed when the headphones are worn and then become as thin as the stock ones.

As you said, they're not isolating my ears enough... I think there must be something more that I can add to the pads' inside so that they become more isolating.. since pillow stuffing doesn't seem to be enough for that task. I thought about adding more "layers" of velour, but that wouldn't be enough I believe. I've got some thicker cloth around here, I'll try doing a multi layered design with pillow stuffing and clothing in between, using velour as the external material. I'll end fixing them up I suppose...

Ahh, that's cool, thanks for clearing up what's going on with the real AKG pads.


EDIT: I think I have fixed them, redone the pads with 4 layers of velour and a layer of what's called "pana" in spanish, according to google translator that's "corduroy", and the same amount of pillow stuffing. The resulting pad is a lot thicker than the pillow stuffing + 1 layer of velour, and doing A/B tests with this pad on one ear and the stock pad on the other, sound quality seems to be the same. I'll do the other one now and test both thick pads at the same time. Will report back later.

EDIT2: Well, made the other pad. Now sibilance is a lot more under control, but not as much as the stock pads. The same with bass, it's back! But the stock pads have some more "punch". But that extra little sibilance, to my ears, reveals more details than the stock pads. I think I like this new signature.. Now I have to sew the flaps so that I can attach the pads to the headphones. I'll see if I can make them more round and flat in the bottom so they isolate more.


EDIT3: nah, I'm done with this. Every time I go back to the stock pads, I end up preferring their sound more than these DIY pads. To top it off, they've already got some time on them, they aren't uncomfortable. I may just add some velour to them so they don't get sticky, but that's all..

[clausdk]

May 14, 2011 15:46:21 GMT vodka said:

Hmmm ear/driver distance is the same as with the stock pads I believe, these get compressed when the headphones are worn and then become as thin as the stock ones.

As you said, they're not isolating my ears enough... I think there must be something more that I can add to the pads' inside so that they become more isolating.. since pillow stuffing doesn't seem to be enough for that task. I thought about adding more "layers" of velour, but that wouldn't be enough I believe. I've got some thicker cloth around here, I'll try doing a multi layered design with pillow stuffing and clothing in between, using velour as the external material. I'll end fixing them up I suppose...

Ahh, that's cool, thanks for clearing up what's going on with the real AKG pads.


EDIT: I think I have fixed them, redone the pads with 4 layers of velour and a layer of what's called "pana" in spanish, according to google translator that's "corduroy", and the same amount of pillow stuffing. The resulting pad is a lot thicker than the pillow stuffing + 1 layer of velour, and doing A/B tests with this pad on one ear and the stock pad on the other, sound quality seems to be the same. I'll do the other one now and test both thick pads at the same time. Will report back later.

EDIT2: Well, made the other pad. Now sibilance is a lot more under control, but not as much as the stock pads. The same with bass, it's back! But the stock pads have some more "punch". But that extra little sibilance, to my ears, reveals more details than the stock pads. I think I like this new signature.. Now I have to sew the flaps so that I can attach the pads to the headphones. I'll see if I can make them more round and flat in the bottom so they isolate more.


EDIT3: nah, I'm done with this. Every time I go back to the stock pads, I end up preferring their sound more than these DIY pads. To top it off, they've already got some time on them, they aren't uncomfortable. I may just add some velour to them so they don't get sticky, but that's all..

Try using foam for your padding it is more airtight than what you are using now, this will make a huge difference in the sound..

the problem is that you are making an open champer between your ear and speaker, then your bass will go away, like a small radio in a big room, the more closed you have the champer the more bas you will get..

The further away from the ear you get the speaker the balance will tilt more and more to the higher notes and vice versa, closer more bass, as the champer gets smaller, like a small radio in a closet would seem to deliver more bass than it did in the big room before..

So give this an other go and see if it works..

[vodka]

Well, I've made a new pair of pads... this time I've used foam as you recommended me, and 3 layers of velour. It's a definite improvement over the pillow stuffing pads! They turned out the very same size as the stock pads.

I'm listening to them right now, the bass is there, has kick! I like it. But of course there's a liiiitle bit of sibilance that actually gives the sound more detail. But not as much as the pillow stuffed pads. It's not unbearable, yet too much for me... But these are definitely on the right track. I'll keep experimenting.

So I need some foam that's more airtight than this one I've used... I'll look for some. Lots of velour left to experiment

[davsarus]

This is going to be off the topic but I just joined this forum to give you a huge Thanks! Especially to Solderdude, PinkFloyd, Heliharris, Clausdk to name but a few. I spend more and more time in this forum lately. It is both addictive and informative. Thanks again for being so awesome mavens!

[clausdk]

May 22, 2011 18:14:08 GMT davsarus said:

This is going to be off the topic but I just joined this forum to give you a huge Thanks! Especially to Solderdude, PinkFloyd, Heliharris, Clausdk to name but a few. I spend more and more time in this forum lately. It is both addictive and informative. Thanks again for being so awesome mavens!

Welcome onboard and I hope you have plenty of good hours still to come..

[clausdk]

May 15, 2011 3:23:36 GMT vodka said:

Well, I've made a new pair of pads... this time I've used foam as you recommended me, and 3 layers of velour. It's a definite improvement over the pillow stuffing pads! They turned out the very same size as the stock pads.

I'm listening to them right now, the bass is there, has kick! I like it. But of course there's a liiiitle bit of sibilance that actually gives the sound more detail. But not as much as the pillow stuffed pads. It's not unbearable, yet too much for me... But these are definitely on the right track. I'll keep experimenting.

So I need some foam that's more airtight than this one I've used... I'll look for some. Lots of velour left to experiment

If you pillow stuffing is the synthtic wool type, you could take a smalle amount of it nad put it in the chamber behind the driver, this will tame the siblans a bit, it also brings the middletone a bit forward..

[edv]

Thanks to the suggestions of this forum I just completed one filter for an HD-662 and one for an HD-668B. The sound of HD-662 is now much more pleasant. The 668B filtered have less sibilance but it seems less detailed. For the 668B I assembled the filter in a small plastic box so that I can exclude it.
Below some pictures of HD-662. I could do better but this was my first experience and then OK so.

digilander.libero.it/edvito/1%20-%20HD-662.jpg
digilander.libero.it/edvito/2%20-%20HD-662.jpg
digilander.libero.it/edvito/3%20-%20HD-662.jpg
digilander.libero.it/edvito/4%20-%20HD-662.jpg

[Deleted]

the 668B filter can be adopted so you get some more treble extension but will (like the SR850) never have the extension of the HD681/662
effieciency will drop a few dB though..

[edv]

Thanks,

I have a little doubt because I have made this filter for HD668B:

c1= 150nF
C3 = 1uF
L1 = 3.3mH (12.5ohm)
L3 = 470uH
R1 = 100
R3 = 68


Re-reading this thread I found another filter for HD668B:

c1= 100nF
C3 = 680uF
L1 = 2.2mH
L3 = 470uH
R1 = 100
R3 = 68

Choose I the wrong filter?


Perhaps I was not well expressed but my comments on HD662 and HD668B were referring to their sound performance before and after mods.

HD662 with filter is less strident and, for my taste, has improved considerably. Today I will probably buy the HD662B but is not a problem because I will use the HD662 mainly to have better sound insulation during voice and acoustic recording.


On the other hand, the HD668 without filter does not sound bad. Compared to my K240Studio, has a lot more pressure on high frequency and increased presence at low frequencies. With filter the high frequencies are attenuated but at the same time seems to lose a little definition. The operating range of the filter seems to have a large Q.
Greetings

[Deleted]

the difference between the 2 filters is only the bandwidth and centrepoint of the peak that are slightly different, not the amount of attenuation.
the difference between the 2 filters is marginal.

The HD668 is rolled off in the highs and lows (like the SR850) and the peak in the highs gives the impression it has treble extension. If you take away that peak you take away the 'impression' of clarity but the roll-off in the highs is not masked anymore so it becomes more obvious.
You could add some parts in front of the filter to add the missing treble a bit and regain clarity but costs a few dB efficiency.

the 662 is more like a closed verion of the 681 and does have (exaggerated ?) low and high extension.

the B version is quite similar but simply has less bass extension (and thus sounds more controlled in the lows, more tight) it's just a lack of low extension and more towards 'the truth' as the non-b versionhas TOO much lows, which many people like, but not all of them)

The HD668B without filter sounds pretty neutral because of the comparatively less low extension, the rolled of highs extension, which is 'compensated' by the extra treble in the peak region.
might be best to use it witout the filter or adapt the filter more towards the second SR850 filter (but not the same values, they will have to be calculated)

[edv]

Thanks Solderdude,
if you have a little time available to show me how to change the filter of 668B, I would be very grateful to you. I don't want too much abuse of your availability.
Yours sincerely

[Deleted]

try this in series with the filter you already have:

solder in parallel: 330nF and 47 Ohm resistor (2x, 1 for each channel) and solder this parallel circuit in series with the wire coming from the ear pieces (so between the output of the existing filter and the ear piece)

See if this is more what you are looking for.

[edv]

Thanks again,
as soon as I find the components I'll try this modification and will keep you informed.

[aroundykooshball]

Hi there. I know this is a thread about the 681's and my question is for the 668b's but I know there's lots of knowledgeable people on this thread and people that have had both pairs of headphones. So if you could help me out anyway that'd be great.

I recently got a pair of HD-668b's. I haven't had them for 90 days and a few days ago when I was putting them on, one of the top wires cracked. Is that the wire inside that's showing OR is that another wire that has the wire inside of it? Is this something I can ignore or should I go ahead and get them changed?

img146.imageshack.us/img146/676/1003fm.jpg

img9.imageshack.us/img9/82/1002sl.jpg

img707.imageshack.us/img707/2074/1001pr.jpg

Attachments:

[vodka]

There's no problem with that! What cracked was the plastic shell covering that metal rod you see there. No harm's been done to the rod. It's just something cosmetic..

I broke those the same way on my SR850 right when I got them, while bending the rods since the pressure was too much. I don't even notice they're broken anymore...

[gritzcolin]

So no rings anymore I hate being late to the game. Are the filters still available to buy? I'd make em but probably would fail. Also what are you guys recabling them with?

[radchild]

Greetings everyone! I've been lurking on this forum for a while and decided to register and ask some questions if you don't mind. I recently bought HD668B and even though this thread is about the 681, I wanted to ask for an opinion on which cable to use for recabling and how to do it. I've been looking at LOOPS® A800 on ebay, but they are either too short or too long. The other one I'm looking at is van damme SP-OFC and UP-OFC. AFAIK, SP-OFC is better than UP-OFC?

Any other modding ideas are welcome.