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Is Akg k702 really a power hungry headphone ??

ZolaIII

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#41
What headphones amp do use with it
As this is going to far let's try to take it simple. Those need a 1.6 - 2V out so the mobile phone - MB int one's with 1.1~1.4 V (1.2 V as declared) won't be quite enough. Probably best cheap DAC/AMP for those would still probably be a TempoTec Sonata HD Pro. If you can get the money and for your main purpose (gaming) try getting an SBX G6.
Best regards.
 

solderdude

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#42
I had a made in Austria set around 10 years ago which I used almost daily for 2ish years. I then finished uni and couldn't use them so I sold them a few years later, they were still working when I sold them.

Are the K712 pads different to the 65th anniversary pads?
I remember buying the k702 65th anniversary pads when the model just came out as I'd heard the earpads was the only difference between the two models, there was more bass with the anniversary pads.
K702 (stock) vs K702 with K712 pads (ignore the deeper dip around 4kHz):
 

samwell7

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#43
K702 (stock) vs K702 with K712 pads (ignore the deeper dip around 4kHz):
Thanks for that! I just had a look to try and send you some info on the 65th anniversary edition but it looks like it is no longer for sale (it had memory foam earpads which is pretty much the only difference I can remember).
I wasn't able to take measurements at the time but there was definitely a little more bass and a little better comfort using the 'anni' pads.

I'll have a deep-dive to see what the differences are/were, are the K712 pads memory foam?
 

solderdude

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#44
are the K712 pads memory foam?
Yes, slightly angled memory foam pads, same as K7XX pads so very likely the anni pads are also the K712 pads.

K712 vs K702 with K712 pads


The K7XX seems to be closest to the K702 with K712 pads but the K7XX having slightly more lows.
 

samwell7

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#45
Yes, slightly angled memory foam pads, same as K7XX pads so very likely the anni pads are also the K712 pads.

K712 vs K702 with K712 pads


The K7XX seems to be closest to the K702 with K712 pads but the K7XX having slightly more lows.
Awesome graphs, thanks for that -

Yeah it'd make sense for them to use the new (at the time) pads in some ongoing designs.

I found this (look at the top review, by gabrielnorena) where the user owns both the 65th anniversary edition and the K712, their description of the difference sort of matches your frequency response chart above for the k712 vs k702 with k712 pads: a little less bass for the annis vs the k712 and a little more tre le for the annis.

When my new K702s rock up if I'm not happy with the bass I'll probably end up ordering some K712 pads, maybe an amp first depending how it sounds from either my receiver's headphone out or the apple USB to 3.5mm dongle.

Thanks again for your graphs, they're very descriptive
 
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#46
It appears K702, K7xx, and K712 could be using the same driver but mechanically tuned differently?
It would be ironic if the cheaper K702 could be toned down to sound like K712, but not vice versa.

I have K702 and like the comfort and relative ease to drive, but they could be a tiny bit mellower....
 

Robbo99999

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#48
Do you mean the wires connecting to the rods ?
I have had quite a few Superlux 'AKG copies' with the same issues.
Chalked it down to cheap labour force not giving a crap about good solder joints or having the wrong soldering equipment.

I wonder if the older Austrian made ones also have these issues.
Yep, to the metal rods. There was just a little blop of solder holding the wires onto the posts, the wires weren't wrapped around the posts and the solder wasn't wicked into the wire.....I somehow managed to wind the wires around the posts and get some solder wicked into it too, feels very strong now, will see how long it will last, I think it's been nearly 2 yrs since I soldered the first wire, and they've not failed since.
 

solderdude

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#49
The problem with the rods (at least IME with Superlux) is that they do not solder that well because the heat spreads into the rods.
Heating it longer or hotter will melt the plastic. This makes them hard to solder.

The biggest downside for the AKG series, however, is the elastic bands. In all the older ones I had to replace them. I have no idea why they still use that method.
You have to open them up to replace the bands.
 

Robbo99999

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#50
The problem with the rods (at least IME with Superlux) is that they do not solder that well because the heat spreads into the rods.
Heating it longer or hotter will melt the plastic. This makes them hard to solder.

The biggest downside for the AKG series, however, is the elastic bands. In all the older ones I had to replace them. I have no idea why they still use that method.
You have to open them up to replace the bands.
I recently had another set of K702's arrive with me this week, in case they stop making them, I bought them in a sale, and you can immediately tell that the elastic has grown loose on my old K702's vs the new one. There's still life in the old set and they fit fine, but I hear that replacing the elastic is very fiddly.....not looked into that yet. My old set of K702's I bought in Nov 2015, and I've used them almost everyday for hours since then, so they've held up very well.

Yes, I was worried about those rods heating up, so did my best not to leave it on too long. One of the posts was really hard to get to with hardly any clearance to the plastic structure that sits around it on the edges, the soldering iron did make some contact with that and melt the plastic a bit, but seems no harm done, it's just part of the outer housing. I think it was a real baptism of soldering fire for me considering this was my first ever soldering job! I watched Youtube vids and practiced on some pieces of wire before doing it. I'll probably start using my new K702 more now (rather than the old one) to ensure that the solder fails sooner rather than later....the more years I leave between ever touching the soldering iron the more I forget how to do it! At the moment though my K702's aren't getting much use since my HE4XX arrived with me a couple of days ago.....the standard Harman curve didn't bring out the detail & tone I'm used to in say the 1-5kHz range, so for the first time ever in my headphone use I sketched a few new experimental modifications to the Harman Curve (essentially a 1-2dB boost from 1-5kHz) and it seems to match my flat reference speakers better on my listening test tracks. First time I've had to do that with a headphone, all the other ones in my sig sound spot on EQ'd to the Harman Curve. Yes, the HE4XX is growing on me as I'm learning more about it and it's abilities.

EDIT: I should find out what elastic I need to buy for the K702 in case I need to buy something specific that might become discontinued.
 

solderdude

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#51
I bought some elastic band in a crafts store. The kind where they sell sowing stuff etc. There are several thicknesses.
As you already operated on the AKG then it isn't that hard to replace the bands.
The stuff I used was slightly thicker than the original.
 

samwell7

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#52
Just to go back to the original topic, my new (made in China) K702s arrived today.
They sound similar, I think the lack of bumps on the headband have made them slightly less comfortable and they are easier to drive than I remember!

Using an Apple USB C to 3.5mm adaptor from my computer I only need the volume at around 11% for normal listening from Spotify (with volume normalisation turned off), this fits in line with powering them from my Panasonic receiver and I even get sufficient volume (no outside noise) when using the Apple USB C to 3.5mm adaptor from an Android phone, pretty sure the output is limited at either 0.5 or 0.05V from the android phone.

I'm going to say these are not a power hungry headphone, also from @solderdude's website, because the impedance curve is fairly flat the frequency response shouldn't be different if the headphone amp has high or low output impedance.

One thing about the K702 is they really challenge my notion on whether burn in exists or not (I don't really believe in it but the K702s seem to change a fair bit), I remember burning my old made in Austria set in for like 300 hours and it being smoother afterwards (in line with a lot of other forum posts I've seen for these cans) and it seems the same thing is happening over a day of listening today.

The first song I listened to on the K702 today was 4AM by Grimes and it was very harsh (almost like whatever the song was mixed on had a dip in the FR right where the K702 has a peak) I've taken notes on how it sounded and I'll revisit this in a week or two
 
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Robbo99999

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#53
Just to go back to the original topic, my new (made in China) K702s arrived today.
They sound similar, I think the lack of bumps on the headband have made them slightly less comfortable and they are easier to drive than I remember!

Using an Apple USB C to 3.5mm adaptor from my computer I only need the volume at around 11% for normal listening from Spotify (with volume normalisation turned off), this fits in line with powering them from my Panasonic receiver and I even get sufficient volume (no outside noise) when using the Apple USB C to 3.5mm adaptor from an Android phone, pretty sure the output is limited at either 0.5 or 0.05V from the android phone.

I'm going to say these are not a power hungry headphone, also from @solderdude's website, because the impedance curve is fairly flat the frequency response shouldn't be different if the headphone amp has high or low output impedance.

One thing about the K702 is they really challenge my notion on whether burn in exists or not (I don't really believe in it but the K702s seem to change a fair bit), I remember burning my old made in Austria set in for like 300 hours and it being smoother afterwards (in line with a lot of other forum posts I've seen for these cans) and it seems the same thing is happening over a day of listening today.

The first song I listened to on the K702 today was 4AM by Grimes and it was very harsh (almost like whatever the song was mixed on had a dip in the FR right where the K702 has a peak) I've taken notes on how it sounded and I'll revisit this in a week or two
I also generally don't believe in burn-in of headphones, and I think/thought burn-in was gonna be psychological burn-in, but I've had the same experience with the K702. I own 2 pairs now, the first pair back in 2015 before I knew about any audiophile stuff, and I found they sounded better after leaving playing (without wearing at loud volume) on my ipod for hours (did it overnight a few times)....but then I explained that could still be psychological when I thought about it recently. But then I bought my second set of K702 which arrived a couple of weeks ago, and I too found that they sounded a bit harsh.....this can be explained by comparing old pads vs new pads to a large extent.....however I did leave them playing overnight a number of times and I do think they sound smoother now than they did when comparing them again to my old K702 (I use a Harman EQ for all of my listening, so not stock, which tones them down too anyway). It does make me think there could be something to burning-in of the K702 in particular, but I don't really see why that should be the case......to be honest I can't be sure it's not placebo as we're talking relatively fine changes to the sound (in terms of my perceptions), so I think I have to be careful about making any steadfast conclusions from what I think I've experienced.

(both are headphones from China)
 

solderdude

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#54
From Rtings but Q701


AKG Q701 | Frequency Response | Click for a timelapse animation

AKG Q701 | Frequency Response - Normalized | Click for a timelapse animation

The frequency response of the remaining three headphones didn't show the amplitude fluctuation that was observed with the Q701, probably due to the different type of material used for their earpads. The changes in frequency response measured were too small to be audible and a lot smaller than the normal fluctuations in frequency response that happen due to changes in the position of the headphones between re-seats. Specifically, the HF5 showed virtually no fluctuations in their frequency response, which means that the test system (the dummy head, audio interface, and amp) was very stable over the duration of the test and performed very well and consistently.
 

Miha_Nick

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#55
Yes, tried/measured them both.
non angled pads different color.
More of the same really. The K612 was more 'neutral' to me than the K701/K702.
A little on the bass-shy side (like K701/K702)
Slightly less efficient than K702 and slightly less 'forward/open' sounding.
K612 vs K702



I suspect the differences between these 2 are caused by the difference in pads (angled versus not angled) but same foam material used.
which AKG (701,702,612,712,7XX) is the best soundstage?
rtings has no measurements 7XX and 612 but the 702 are mutch better than 701
712 shows more pinna interaction with lower accuracy
how about soundstage in 7XX?
 

solderdude

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#56
K7XX is very close, but not equal to, a K702 driver with K712 pads.
The pads make the difference so K7XX will be close to K712.
 
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#57
I want to move a step up my eyes was on Akg k702 especially their price now in uk usually under 150 $.
I recommend that you read another thread here on the forum called: What headphone (s) do you own?

Read post # 947 where Robbo99999 has posted EQ settings for the AKG 702. The settings are based on the Harman Curvan, and in my opinion it made a big difference for the better. Of course, this presupposes that you have a headphone amplifier that can drive the AKG 702.
 

samwell7

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#58
I also generally don't believe in burn-in of headphones, and I think/thought burn-in was gonna be psychological burn-in, but I've had the same experience with the K702. I own 2 pairs now, the first pair back in 2015 before I knew about any audiophile stuff, and I found they sounded better after leaving playing (without wearing at loud volume) on my ipod for hours (did it overnight a few times)....but then I explained that could still be psychological when I thought about it recently. But then I bought my second set of K702 which arrived a couple of weeks ago, and I too found that they sounded a bit harsh.....this can be explained by comparing old pads vs new pads to a large extent.....however I did leave them playing overnight a number of times and I do think they sound smoother now than they did when comparing them again to my old K702 (I use a Harman EQ for all of my listening, so not stock, which tones them down too anyway). It does make me think there could be something to burning-in of the K702 in particular, but I don't really see why that should be the case......to be honest I can't be sure it's not placebo as we're talking relatively fine changes to the sound (in terms of my perceptions), so I think I have to be careful about making any steadfast conclusions from what I think I've experienced.

(both are headphones from China)
Yeah, realistically the changes are probably tiny but it is interesting so many people have similar experiences with the K70X family of headphones regarding burn-in.

I've seen threads on GS discussing the burn-in which is interesting because it's a pro-audio site which is usually fairly objective
 

samwell7

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#59
From Rtings but Q701


AKG Q701 | Frequency Response | Click for a timelapse animation

AKG Q701 | Frequency Response - Normalized | Click for a timelapse animation

The frequency response of the remaining three headphones didn't show the amplitude fluctuation that was observed with the Q701, probably due to the different type of material used for their earpads. The changes in frequency response measured were too small to be audible and a lot smaller than the normal fluctuations in frequency response that happen due to changes in the position of the headphones between re-seats. Specifically, the HF5 showed virtually no fluctuations in their frequency response, which means that the test system (the dummy head, audio interface, and amp) was very stable over the duration of the test and performed very well and consistently.
That's some great data, thanks for sending that through, it's great how repeatable their test results are.
It's like Schrodinger's burn-in!
 

Robbo99999

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#60
I recommend that you read another thread here on the forum called: What headphone (s) do you own?

Read post # 947 where Robbo99999 has posted EQ settings for the AKG 702. The settings are based on the Harman Curvan, and in my opinion it made a big difference for the better. Of course, this presupposes that you have a headphone amplifier that can drive the AKG 702.
At the moment I'm a bit on the fence about that particular EQ I created that you're talking about at following link (https://www.audiosciencereview.com/.../what-headphone-s-do-you-own.4285/post-540609). Reason being I bought some new K702 couple of weeks ago and that EQ is on the harsh side for the new pads, I think it's a lot more acceptable on old pads (my old K702). If you have a new K702 I'd probably recommend you try the EQ I did based on Crinicle's measurements which can be found here:
https://www.audiosciencereview.com/...amir-to-measure-next.17117/page-2#post-556240
Note that in that post I linked above I say that it sounded terrible, that's because it was on old pads, but I also think my previous EQ (the one at the first link in this post I'm writing) is a tad heavy from 500Hz to just north of 1kHz, I don't think I should have boosted that dip, possibly a measurement anomaly...so I think I had brain burn-in to that EQ that was not quite accurate, hence me initially not liking the EQ based on Crinicle's measurements due to the obvious tonal differences. You could try either of those EQ's and see which you like best, the first one likely to be better with old pads, and possibly the second one with new pads. I'm gonna be sending my K702 to Oratory for measurement once Thomann have K702 pads back in stock, so that Oratory can measure old pads vs new pads on the K702.....I've been speaking with him on reddit, and he's kindly agreed to do that.....I think he's just really keen on measuring as many headphones as possible to grow his database, it's a great service to the headphone community.
 

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