AKG K7XX Tube Amplifier/DAC Advice

Hello Everyone,
I ordered the Massdrop AKG K7XX phones and would really appreciate advise and recommendations for a tube amplifier and DAC purchase.
First I want to say this is a VERY GOOD forum community. I am glad I joined. I am 64 and have become obsessed in the past month trying to educate myself about this new hobby.
Let me backup and give some background information. I am currently using a Windows 10 PC. I listen to music mostly through Spotify or JRiver Media Center. I use an Audioquest USB Jitterbug filter (recommended on this site) that connects to a Schiit Modi2 DAC. From there I use 10’ of good quality RCA cables going to a stereo receiver and KEF Q100 speakers.
I mostly enjoy jazz from the 40’s and 50’s, pop from the 60’s and 70’s and acoustical music in general. I am wanting a wide pinpoint spacious soundstage with clear uncongested mids and highs. through headphones. I am not interested in excessive bass response. I read reviews that AKG phones can meet my criteria. I thought a tube amp could add a little more warmth to the music.
My budget is $300.00. I can continue using the Schiit DAC for the external receiver/speakers and focus on a USB input amp/dac exclusively for headphones. I would prefer an all in one usb input amp/dac because I am thinking additional RCA connection cables between separate units would not have as clean of a sound. However, I am flexible.
It is very important to have an amp that will not output sound to my bookshelf speakers when I have the phones plugged in. Also, I want a dac that will have higher capabilities down the road when I focus on listening to better quality media files.
Nothing is set in stone. Please offer suggestions about an amp and dac that would be a good match for the AKG phones and other phones down the road. My headphone experience is very limited and I respect the advice here more so than Amazon reviews!
THANKS,
John

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First, given the impedance of the K7XX you’re going to want to stick to either tube-hybrid amps or a tube amp that has an output transformer.

The K7XX cannot be driven balanced so you’ll also want to stick to a single-ended amplifier (otherwise you’re either paying more than you need to for circuitry you won’t be using or you’ll be getting lower-quality parts than an equivalent single-ended design could manage for the same price).

The only competent all-in-one DAC/amp that uses tubes (it’s a tube-hybrid) and that comes in around $300 (it’s $320) that I know of is the Massdrop/Drop x Cavalli Tube Hybrid w/ built-in Grace SDAC. There may be others, but I can’t think of any off the top of my head.

Otherwise …

To do a DAC and a tube-amp for a total $300 is going to be a bit of a challenge.

The DAC part is the easiest to tackle … either a Schiit Modi 3 (which would be my choice to pair with the K7XX) or the Massdrop/Drop x Grace SDAC.

The amp part is harder … I cannot name a single pure-tube amplifier that I would recommend for $200 (doesn’t mean there aren’t any, just that I’ve not crossed paths with one). That means tube-hybrids - all of which will have less of a “tube sound” than pure tube-amps.

But, for tube-hybrids within your budget, that actually have a reasonable element of “tube sound”, I am partial to the Schiit Vali 2. The others that I’m aware of will break your budget unless purchased used.

It’s a bit hard to follow your requirements … so one thing I note is that after you talk about having a dedicated all-in-one for your headphones, it also sounds like you want to use it as a source/pre-amp for your speakers. The Vali 2 will fulfill that criteria, but the Cavalli Tube Hybrid I mentioned above does not have pre-outs, so it wouldn’t.

You also talk about the DAC having “higher capabilities” down the road. Pretty much all modern DACs can support high-resolution files, including the two I suggested above (of which the Schiit will go to 24/192, the Grace to 24/96). If you want DSD support you’ll need to look at other products. If you want MQA support, you’ll need to up your budget or compromise on the overall quality of the DAC.

Finally, I wouldn’t worry about having a separate DAC/amp and using RCA cables to connect them. You’re only going to need something maybe 6" to a 1’ long, and you’re not going to be able to tell the difference between that and some cheap internal wire with this stuff anyway.

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I second @Torq suggestion about Schiit Modi 3 plus Vali 2 . I own that combo and love it. I use them with HD800 , HD6xx and Focal Clear. Months ago I was able to use the AKG Q701 for a couple of weeks whit Modi/Vali and was awesome !!
If you wait for them to be on B-Stock, you’ll paid $190 plus shipping( that was my case), but you won’t be able to returned if you don’t like them, regular price is $250 for both.

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Also, if you do order a Modi 3/Vali 2 combination, order yourself a set of the Schiit PYST 6" RCA cables as well. Makes for a very clean little stack with no excess cabling.

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Another idea and now I’m probably suggesting crazy stuff, is the Ifi Nano iDSD Black Label. Is a $200 DAC/AMP . Is portable which is a plus and sound great. I own it and once I connected to the Vali and use it only as a DAC , I din’t hear any difference in quality, but a lot in power. That combo will cost you $350 or $300 with a B-Stock Vali and you’ll have the flexibility of moving around with just the IFI since is dac/amp. I don’t know the impedance of yours headphones, but it drives my 300 ohms very good ( is not Vali 2, but it works).

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Hi Torq,
Thanks for your speedy and competant reply.
I think it was one of your post that recommended the Jitterbug filter, so thanks!
Sorry for the confusion in my post.
I am thinking a tube/hybrid amp and have decided to run the headphones in a separate dedicated usb path from my pc. The current Schiit dac will be exclusively for the receiver/speaker setup. Based on your recommendations, I am starting to lean toward the Schiit dac and amplifier with a short RCA connection.
I am still open to other ideas and suggestions. I am also open to alternative ideas that I haven’t considered.

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I love my NiBL! It is EDC for me. It lives in my backpack =) I keep an adapter cable 3.5 -> RCA with it in case I want to use it as a DAC only, plus the adapters needed to pair with my phone/iPad. It pairs well with everything I’ve thrown at it so far, plus it has that sweet iematch port for my Andromedas.

Outside of that I think @Torq gave the best advice, I had the MCTH and really enjoyed it, I also really liked the Modi3 (gave it to my brother with the JDS Atom amp and a pair of M1060s modded). I haven’t heard the Vali2 but @Torq hasn’t led me astray so far in suggestions (astray in that my preference didn’t match his suggestion :wink: )

Let us know what you decide on and give a quick impression! =0)

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Nothing “crazy” about that, as long as you’re going to either actually use it as a portable unit and also want both DSD and MQA support (neither are relevant with Spotify, of course).

Otherwise, as a pure-DAC, the Modi 3 out performs it for half the price.

Remember there’s more to how well an amplifier drives a headphone than it’s impedance. You need to consider the sensitivity of the headphone as well. Otherwise all you can tell is whether the headphone is more voltage or more current hungry.

For example, the HD650 need double the voltage, but half the current of the K7XX for the same output level. And amps all have different voltage and current limits - it’s very possible to run into one with a lower-impedance headphone that isn’t a problem with a higher-impedance one!

Not that I expect the iDSD Nano BL would have an issue with the K7XX in this case.

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Hello Everyone,
THANKS FOR ALL THE SUGGESTIONS!
I had to run some errands today and when I got home, the AKG K7XX package arrived in the mail!
My wife would say I was like a kid in a candy store. Since I haven’t ordered the amp and dac, I plugged them into the receiver and am playing FM radio through them.
I haven’t listened yet. I told my wife she could listen first because she is so agreeable and enthusiastic about my endeavors. (Now if she will just get off the phone and come into our cozy music/computer/library room.) As if I knew what I am talking about, I told her about a required break-in period and the need for a dac and amplifier. She has already approved the purchase. All the joking aside, we are both excited because we have both rekindled our enjoyment of good music.
Anyway, I am persuaded by the Modi 3/Vaali 2 and Schiit PYST 6" RCA cables setup.
Torq, Hansel and Darthpool, thanks for your comments and suggestions.!
I look forward to many more discussions.
John

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Your welcome , please let us know how it ends !!

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Hey Everyone.
Thanks for your help.
I am listening to my new phones as I type. It seems in the past couple hours, the soundstage has become a little bit more “airy”.
I just took the plunge and ordered the Modi 3/Vali 2 combo and a patch cord. I also picked up a few used vinyl albums out having fun this afternoon. I haven’t listened to vinyl in 35 years. Maybe there will be a turntable obsession in the near future.
John

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The AKG K7XX (and other K series, as well as the Q701) have a reputation for needing burn-in. Now, ether it’s a mental adjustment on the part of the listener or an actual electro-mechanical thing, I can’t say (I lean towards the former), but it’s an often reported phenomenon with the K7XX.

Enjoy!

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Really late to reply here but in the future you might want to look at amps from Garage 1217, tube/hybrid amps that have adjustable output impedances so they can be tuned to much better match your K7XX or any other future headphone that you might like to try along with doing tube rolling and it can use most, if not all the tubes from the Vali2 so your investment in tubes for the Vali2 will not be wasted.

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David,
I have spent over a month, day and night reading reviews and articles about phones, amps and dacs.
Now, my thoughts are turning to tube rolling.

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I would suggest first spending a few hundred hours listening to your incoming Vali 2, with it’s stock tube, before you start looking at other tubes.

If it is your first amp with tubes, then you’ll want that time to get accustomed to how break-in with tubes works. And with tubes this is as much, perhaps more, about mechanical settling with the tube, as parts expand and contract through normal thermal cycling and the noises they make that are environmentally audible (i.e. not through the headphones, but just in your ambient environment).

There will be “tings” and “pings” and other mechanical noises that lessen over time. And there may be whistles and burps and noise, here and there, as the tube settles which can take as much as a couple of hundred hours to fully go away (and with tubes that are marginal, may never go away).

Beyond this …

Tube-hybrid amplifiers are generally much less affected by the tube in use than pure-tube amplifiers. So, the possible benefits (or differences, as most of the time “better” is going to be purely the product of personal preference) are a lot smaller than they are with pure-tube designs.

Don’t spend a lot on tubes for inexpensive amplifiers (you’re typically much better off investing that money in a better amplifier, especially at the budget end of the hobby). I’ve never personally heard a situation where doing so has taken an amplifier to “the next level”. Changes and improvements are generally small and often subtle.

Which isn’t to say “don’t tube roll”, just don’t go buying $100 rare tubes expecting them to turn a Vali 2 or an MCTH or a Sunrise into something like a Decware, EC or DNA amplifier.

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Welcome to the world of tube rolling, its a hard addiction to over come but hopefully you will find tubes that are quite different and find that 2-3 will keep you satisfied for a few years. For me the rabbit hole with tubes when quite deep, $2000+ deep with my Ember, Lyr2 and BH Crack, granted there are a few “spares” like 3 sets of Telefunken CCa’s, two WE421a’s, 3 5998’s and others.

I agree with what Torq said about spending $100 for a rare tube for the Vali2 since it will probably be a slight difference from the stock tube but you never know, good luck and keep us posted on your impressions.

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Hello Again,
I have some good news!
The Schiit Amp and DAC was set up last night I spent a couple hours fiddling with options in JRMC and guess what.
The set up sounds great!
My first impression was how precise, airy and deep the soundstage was on the external KEF speakers.
The headphones are crystal clear with a beautiful and precise soundstage.
One thing I like is all I have to do to switch between the speakers and phones is connect or unconnect the headphone plug. I am a little concerned about the amp running with medium power when I play speakers.
Any advice?
John

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Nice one. I bet you enjoyed a few hours fiddling. I love when after trying to get something going just as you like it all ends well any you can lay back and enjoy.

I bet it sounded great once set up.

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Great!! You’ll love them even more in a few day.

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You need a new habit.
Turn the amp volume all the way down before plugging/unplugging your headphone.
Particularly with music playing. Some headphone amps can experience catastrophic failure unless this is done.
That won’t happen with the Vali but… at least your neighbors won’t complain.

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