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AKG K-702

Printed From: Graham Slee at Hifi System Components
Category: Headphone Audio
Forum Name: High Fidelity Headphone User
Forum Description: Technical Q&A, hints and tips
URL: https://www.hifisystemcomponents.com/forum/forum_posts.asp?TID=4057
Printed Date: 01 Jun 2020 at 3:15am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: AKG K-702
Posted By: Chris Firth
Subject: AKG K-702
Date Posted: 28 Oct 2016 at 7:41pm
My latest headphones are AKG K-702s, and I'm reet gruntled wi'em (Northern speak for properly pleased with them).
They've been thrashed with signal going through them for a week, and they've lost their initial slightly uptight quality, to blossom into a remarkably lucid and engaging transducer.

With them I get what I liked about the Sennheiser HD-650, but with a wonderfully open top end.
The HD-650 has a wonderful midband, but fell down for me with the treble performance - they're just too cuddly and rolled off in my opinion.
The K-702s just sing out clearly and accurately, and high harmonics from acoustic guitars are beautifully rendered (my reference point is a Martin DCPA5, which sees regular sofa action).

Something I'd like to dispel is the myth that the AKG K-702s don't do bass - they do, but you've got to work them hard and long to get them to loosen up, and once they loosen up they have you hooked.
From out of the box new they don't sound great, but put a good few hours on them with some taxing material.

They are a better headphone than the Superlux (they should be too, at five times the price), with greater control and precision. This is not to denigrate the Superlux - they are the headphone bargain, and they'll show many a headphone a clean set of heels.
It's just the AKG K-702 are more measured, and ultimately a better conduit for the music.

The K-702s also qualify for just about the most comfortable set of cans I have ever worn.

I am a very happy camper Big smile









Replies:
Posted By: Ash
Date Posted: 29 Oct 2016 at 10:10am
I've never used this headphone but looking at its chamber/driver qualities, I can understand why Graham once said they (the K701, which is the same design with a different colour scheme and no detachable cable) almost matched the sound of the HD800 at times (in terms of stereo imaging anyway). The K-702 has quite a large driver diameter compared to the vintage Senns from my old thread so the transducer moves more air.


Posted By: Fatmangolf
Date Posted: 29 Oct 2016 at 9:46pm
Thanks Ash and Chris, the loosening up is clearly very good advice to get the most from the design.


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Jon

Open mind and ears, whilst owning GSP Genera, Accession, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.


Posted By: Graham Slee
Date Posted: 30 Oct 2016 at 7:14am
Forum graft (choose your own definition!) gave the K701 cult status.

The forums also killed the HD250II.

Both had a poor initial sound which lasted weeks and probably resulted in much densistry. Wink

The K701 (IMO) vastly improved given time and a sound-thrashing, but still grains of high frequency distortion remain. I can only assume its creator developed them with a K1000 (specialised) 10 watt power amp.

Over the years I have driven headphones with numerous amplifier configurations, including the output of power amplifier voltage amplifiers, direct from power amplifiers meant for speakers, as well as my own headphone amps.

The earlier Sennheiser HD450 at 600 Ohms was equally happy being driven from a power amp direct, or via a IEC61938 120 ohms series resistance. So was the latter HD250II.

But the K701 was far more fussy. Near to zero Ohms drive suited it best making it unsuitable for just about any headphone jack.

Very much like the Grado's, developed with their own amplifier: these need the output impedance of the op-amp it used.

Why therefore would vast numbers of headphone fans want to buy (and virally promote) a headphone which required a specialised amp to drive it?

I finally nailed it with the ULDE, along with the Grado's.

I have never heard the K702. I trust the trace of HF distortion has been cured.


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Not simple enough for Google-Bot to understand...


Posted By: Ash
Date Posted: 30 Oct 2016 at 7:29pm
Graham, I think the K702 is exactly the same design as the K701, except the 702 is a different colour and has a detachable cable.

I have driven Senn HD540II, HD560II and HD800 each directly from Proprius power amps too. Obviously I set the Proprius dials low to suit the headphone impedance and sensitivity so that no hiss could be heard through them. If I recall correctly, HD540II and HD560II were used with Proprius dials at about 9 or 10 o'clock whereas HD800 was driven at 8 or 9 o'clock due to its higher sensitivity and increased ability to resolve low level hiss/noise. The HD250II would have been used at the same dial position as 540/560, as all three models have very similar characteristics and needs. I can use the K1000 at any dial position before 3 o'clock (I typically just set at 12 for ease). Beyond 3 o'clock, the impedance characteristics must be sub-optimal as low level hiss/noise can be heard through the K1000.

In my opinion, all of these headphones sounded just as good through the Proprius as they did through the Solo UL or ULDE. The headphone amp didn't seem to give these particular devices anything additional to what the power amps gave them, to my ears. No improvement could be heard from Solo. Maybe I'm just deaf but I think it's because the Proprius are so damn good that they can be used as either a high impedance or low sensitivity headphone amp and as a speaker amp, depending on the load characteristics of course.


Posted By: miT
Date Posted: 30 Oct 2016 at 7:29pm
I had the K701s for a long time at the start of my head-fi career and was pretty chuffed with them too, although I only ever used them through the Novo and then Solo II SRG + PSU1. It was recommended on a website with burn in times to let them go for 500hrs and I did this religiously from new. I also followed Graham's advice about keeping them physically warm during this period... I used them happily until I upgraded last year with a set of HD540IIs from Ash, but I shall stay on topic. Wink
In regards to the low frequencies, they are a tad "light" when compared to how everything else we are used to overblows it. I always found that the low-end was clearly audible for discerning ears and this allowed you to focus on the texture of the bass, something they reproduced very well.
The K702s are supposed to be very similar (if not the same from mixed reports) but if you like the sound they produce, they'll certainly give you an engaging listen. Thumbs Up
Contrary to what Graham said, I always found they were welcomed with mostly hatred on Head-Fi! But that reinforced their qualities to me as what do that lot know?? LOL


Posted By: Ash
Date Posted: 30 Oct 2016 at 7:43pm
It would be interesting to compare HD540II, K702 and HD800 side-by-side, to listen whether the perceived sound of the audio presentation definitely gets bigger as the driver diameter (therefore radiating area) is increased. I believe HD540II has a 36mm driver, K702 has 45mm driver and HD800 has 56mm driver. Although I'm not willing to spend any more money on headphones to find out. Don't want to have to report to HA (Headphones Anonymous) for falling off the wagon...


Posted By: miT
Date Posted: 30 Oct 2016 at 10:04pm
That it would be Ash. It's been a few months since I last did that with mine but from memory, K701s where airier than the HD540IIs. I don't really remember the HD800s apart from them grating my ears with certain types of music on a demo. I'm pretty sure they were extremely open, but they cheat a bit with the distanced, angled design of the driver.
Hifiman HE1000s though... You HAVE to listen to those! Mind-blown.


Posted By: Chris Firth
Date Posted: 31 Oct 2016 at 1:20pm
I just found this on Youtube, and it's rather appropriate - it shows AKG K-702s being made
https://www.youtube.com/watch?v=3LbsQRaQD6A" rel="nofollow - https://www.youtube.com/watch?v=3LbsQRaQD6A


Posted By: Chris Firth
Date Posted: 03 Nov 2016 at 11:20pm
The K-702s have been on soak for the second week, and during that time they come even more on song.
I'm currently playing Joan Armatrading's eponymous album, and Jerry Donohue's stinging, singing, mournful solo on the last track, "Tall In The Saddle" was beautifully rendered in all of it's sweet but savage glory.

The last few nights I've been listening to vinyl records, mainly through the AKGs, and I've enjoyed every minute of it.
It keeps the neighbours sweet, and the sounds can be breathtaking.



Posted By: Ash
Date Posted: 04 Nov 2016 at 3:06pm
Glad you're enjoying the K-702. Not sure whether they would be more "airy" in sound than the HD540II (probably be about the same if both properly set up before comparison) but I reckon they'd project a bigger stereo image size than the 540 because of the larger diameter driver, closer to that of the HD800. Maybe if Graham ever does another Roadshow in the future, I could have another listen.


Posted By: Humboldt
Date Posted: 05 May 2018 at 12:50pm
I am listening to the AKG 702 right now, amplified by the Bitzie. I can´t hear any traces of high frequency distortion, as Graham mentioned in an earlier post some years ago. In fact, in my opinion these cans are super. ( Compared to the Sennheiser HD600, which I also own, the Sennheiser sound is in my opinion kind of muffled.) The AKG is very dependent of the source material. Good recordings are just stunning with these cans, but the not so very good recordings out there are unmasked as poor without pardon. These recordings just need cans that mask the shortcomings. I think this is very much the case with most rock-recordings. For good recorded jazz or classical, few cans for the price beat these cans.  

There is no posts in this thread during last two years, but since then the Harman owned AKG has been sold to Samsung, and the Austrian headquarter in Vienna is shut down. The AKG 702 is made in Austria, and it can be found for a very good price. I think the future for these cans are uncertain. I would recommend anyone interested in these can´s to have a try withe these now, since they may be gone in a near future. My guess only, but I don´t think Samsung bought Harman because they felt a urging need to get into the high end audio industry.    


Posted By: morris_minor
Date Posted: 05 May 2018 at 2:24pm
That's interesting news, Pär - thanks for the "warning". Yes, I too doubt Samsung want to get into high end audio!

For anyone interested, "manufacturer refurbished units" are available for £84 https://www.scan.co.uk/products/akg-k702-headphones-manufacturer-refurbished" rel="nofollow - here . I am, er, tempted Embarrassed


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Bob

Majestic DAC/pre-amp
Accession MC/Enigma, Accession MM, Reflex M, Elevator EXP, Era Gold V
Solo ULDE, Novo, Lautus USB and digital, Libran balanced, CuSat50
2 x Proprius + Spatia/Spatia Links


Posted By: Chris Firth
Date Posted: 05 May 2018 at 2:49pm
Go for 'em Bob - mine are in regular use, and have seen off all comers around here.

The last cans to visit were Sennheiser HD-700s, and they were much better balanced sounding than the HD-650s I borrowed a few years ago.
They HD-700s still have that overly polite and shut in top end that the HD-650s have.
The K-702s properly tell you what's going on in the higher registers, and despite claims of them being bass light put in decent lower register performance too.

They're really easy to drive - I am currently monitoring a recording in progress on my Tascam DR-07MkII, and the Tascam powers my K-702s without any difficulty.

My son keeps pinching them too, so I might buy another pair, and those factory refurbs could be just the ticket.

You won't be disappointed - at around the cost of 3 Superlux HD681 Evos they're a bargain.


Posted By: morris_minor
Date Posted: 05 May 2018 at 4:25pm
I gave in to temptation, Chris. My main go-to cans are LCD-2s with HD650s on a second system. The Sennys are a bit like pipe 'n slippers - warm and comfy but lacking a bit in excitement! I'm not expecting Audeze levels of bass from the K702s but hopefully the balance will be good. 

And the Superlux were good - my son appropriated those, and the inner headband has broken and keeps needing to be taped up. I'll hide the K702s! LOL


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Bob

Majestic DAC/pre-amp
Accession MC/Enigma, Accession MM, Reflex M, Elevator EXP, Era Gold V
Solo ULDE, Novo, Lautus USB and digital, Libran balanced, CuSat50
2 x Proprius + Spatia/Spatia Links


Posted By: morris_minor
Date Posted: 08 May 2018 at 1:36pm
My K702s turned up this morning and sound remarkably good from the off. Being refurbed units I don't know how many hours they already have on them, but I'll burn 'em for a couple of days anyway. For £84 they seem to be tremendous value!

-------------
Bob

Majestic DAC/pre-amp
Accession MC/Enigma, Accession MM, Reflex M, Elevator EXP, Era Gold V
Solo ULDE, Novo, Lautus USB and digital, Libran balanced, CuSat50
2 x Proprius + Spatia/Spatia Links



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