Amping for AKG Q701
Oct 1, 2012 at 1:32 PM Post #271 of 508
TomodachiF:


As you know, the K701/2s & Q701s require an Amp that can provide sufficient current and voltage, and a couple of pre gain settings are surely welcome to get close to the sweet spot of your match. The Q701 needs 3.2 Vrms, that's 4.5 volts peak; At 62 ohms, that's 72 mA of peak current. So the Q701s need a low output impedance and quite a bit of voltage and current. IMO, that's the equation you have to solve first. Once you got a list of the tube Amps that match those characteristics, you can make the money math. Saving a bit more and waiting to get something better always pays off.


Cheers!


This is quite frankly...insane. Way too much voltage. About ten times. You're over their max input by a decent bit too.

From Tyll's measurements, ~1.65mW/ch:90 dB SPL. That's around .3Vrms @ 60ohms. The 701 also are fairly stable, so the concern over low Zsource is somewhat misplaced as well.

From AKG's specifications, they're some 100-and-change dB/V (note V). Which means that .2-.4Vrms range is pretty on-target.

I lol'd @ the 336 dB point - that's a few million times the atmospheric limit of acoustic pressure (which is around 194 dB; 40 dB of gain is around 100x loudness, you're talking around 150 dB of gain on top of a sound louder than a volcano exploding - I think that's *almost* loud enough to properly enjoy KISS).
 
Oct 2, 2012 at 12:44 AM Post #272 of 508
Thanks guys
 
I guess a tube amp is not possible for the Q701. I currently have the O2 and I have to agree that it's a transparent amp which doesn't give the music any feel. I heard the Schiit Asgard is  musical from the Headfonia review. Is the Schiit Asgard a good amp for the Q701? Also how is the Matrix M-stage compared to the Asgard. Please recommend any amp under $400 that is musically(warm mids). Please don't give me any technical stuff, I'm only in high school.
 
Oct 2, 2012 at 1:04 AM Post #273 of 508
Quote:
Thanks guys
 
I guess a tube amp is not possible for the Q701. I currently have the O2 and I have to agree that it's a transparent amp which doesn't give the music any feel. I heard the Schiit Asgard is  musical from the Headfonia review. Is the Schiit Asgard a good amp for the Q701? Also how is the Matrix M-stage compared to the Asgard. Please recommend any amp under $400 that is musically(warm mids). Please don't give me any technical stuff, I'm only in high school.

 
I will have to disagree with that. A tube amplifier sounds very good with the Q701. Their warm sound really makes them more "comfortable" to the hears. If you don't like the O2, a tube amp would be something significantly different.
 
The M-stage has been the "recommended amp of the month" for the Q701 for a while. It should be a safe buy. It is also known as a "warm" amplifier, which could give you what you want. It's a reasonable price too.
 
Oct 2, 2012 at 1:22 AM Post #274 of 508
Many tube amps are fine for the 701, just rarely OTL types... but Hybrids and transformer coupled are just fine, as are a few OTL amps which are designed specifically for lower output impedance (but they are harder to track down). 
 
Oct 2, 2012 at 5:07 AM Post #275 of 508
Quote:
Many tube amps are fine for the 701, just rarely OTL types... but Hybrids and transformer coupled are just fine, as are a few OTL amps which are designed specifically for lower output impedance (but they are harder to track down). 

What would you recommend?
I know some hybrids such as the:
Bravo Audio Ocean
Hifiman EF5
Littledot 1+
 
Is there any more of these hybrid tubes amps in this range?
 
Oct 2, 2012 at 5:28 AM Post #276 of 508
Oct 2, 2012 at 9:14 PM Post #278 of 508
Quote:
Woo has some other OTCs that would work too, like the WA6. And many hybrids, as mentioned above, will work too. Just avoid the OTLs that will have issues with <60R or <120R and you should be fine.
smily_headphones1.gif

 
 
Quote:

Woo Audio tube are good but their too expensive. What do you guys think is the most musical hybrid amp under $400?
 
Oct 3, 2012 at 12:03 AM Post #279 of 508
Quote:
 
 
Woo Audio tube are good but their too expensive. What do you guys think is the most musical hybrid amp under $400?

 
Millet MiniMax. But it's DIY - kit is $230 (though I suspect you could get one built for less). The EHHA and Bijou are better, but nowhere near $400. 
 
If you were willing to stretch the budget slightly, I'd say the Bottlehead Smack OTC (which no longer appears in their catalog, of course) - but the SEX is quite good as well. 
 
I should add - if you are after tubey sound, on the average, the hybrids exhibit it least, followed by the OTC designs, and with the most, the OTL designs - though certainly there are exceptions, and to a certain extent, which tubes are used can affect this. 
 
Oct 3, 2012 at 3:41 AM Post #280 of 508
I hadn't even thought about using my LD I+ with my Qs....I may need to do that! 
 
BTW, if you upgrade the tubes on the I+, it's a really nice sounding amp. It's been a fantastic match for my Grados. My issue with the Qs centers on the highs, so hopefully the LD will tame that thing down a bit. 
 
Oct 3, 2012 at 6:38 AM Post #281 of 508
Quote:
I hadn't even thought about using my LD I+ with my Qs....I may need to do that! 
 
BTW, if you upgrade the tubes on the I+, it's a really nice sounding amp. It's been a fantastic match for my Grados. My issue with the Qs centers on the highs, so hopefully the LD will tame that thing down a bit. 

Please try the Q701 with the LD1+. I'm really interested in if the LD1+ can make the Q701s sound musical. Also what tubes do you have with your LD1+? I know the stock tubes is not that good, how is the WE408A upgrade??
 
Oct 3, 2012 at 3:32 PM Post #282 of 508
Quote:
Please try the Q701 with the LD1+. I'm really interested in if the LD1+ can make the Q701s sound musical. Also what tubes do you have with your LD1+? I know the stock tubes is not that good, how is the WE408A upgrade??

 
I definitely will and I'll let you know the results...I didn't want to roll with the stock tubes, so I put some AEG/Telefunkens in there...sounds great to my ears. I'll have a chance to get back home to the LD in the next couple of days for sure. I'm really interested in the results myself! 
 
Oct 3, 2012 at 8:33 PM Post #283 of 508
Hey guys...so I'm just spending some time initially with this pairing tonight, but so far the results weren't impressing. I really think the reason is because the only source I have here is my iPhone with the mini-to-RCA connector, and that's just not a good match for the LD. I'm going to run home later tonight or tomorrow and get my ALO LOD cable-to-RCA, which will at least bypass the cheapo op amp in the iPhone. I've always had good results with this cable. I"m also going to bring over my PURE I-20 dock and use it to bypass the iPod/iPhone entirely and allow the DAC in the PURE and possibly also my AudioEngine D1 handle those duties. 
 
Keep in mind that my baseline for these headphones is that I like them a LOT for movies and TV, but I don't really care for them with music. My main issues for music are a goofy top end and lack of bass extension. So far with just the iPhone and the mini-to-RCA jack (which I don't like to use with an external amp) has had mixed results. The overall sound is relatively flat, and I'd even go so far as to say the mids are thin. Oddly enough, however, the LD (Telefunked/AEG tubes) really does a nice job fleshing out the low end. This has some serious potential if I can get the mids to get a bit fuller and tame down the top end. I've had poor results using the headphone out of my iPhone into an external amp before, so I'm still hopeful this may be a nice pairing. The low end is certainly moving in the right direction, so that's good news. 
 
I'll report back more as I get more time to play around...as it stands now, Im confident that if I clean up the source then this may really be successful. 
 
Oct 3, 2012 at 9:54 PM Post #285 of 508
Sure thing...it drives me nuts, cause I really like the way the headphone out on the iPhone sounds when Im using ONLY that...but when I run that into another amp, it seems like the better quality amp amplifies the crappy aspects of the headphone out that are inaudible when using the iPhone by itself. When I run my DAC into the LD, it's clean as hell. That's why I'm hopeful this pairing will still be great. But the iPhone out jack is just terrible when it, itself, is amplified in turn. I don't know if you guys find that too or if it's just me, but it's really a lousy effect sometimes. 
 
the way I can usually tell is because when I hook things up this way, my better quality lossless files will actually sound worse than my lower quality MP3 or below quality tracks. When I have a clean signal path from the source into the amp inputs, the lossless tracks clearly sound better than my lesser quality tracks. I'll get this ironed out, though, and report back. I do really like what the tubes did for the low end, though...very nice sounding. 
 

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