I’ve recently experienced sensitivity to that range of frequencies as I’ve been recovering from the flu. As the congestion dissipates I find certain things a little too intense at times.
Kind of like an “Oh, man. That’s too bright” experience. For reference I’m 41.
Absolutely- the flu or not enough sleep can change our listening experiance dramatically.
A sidenote:
I was able to tame down the 1990 Pro Beyerpeak with Dekoni elite velours pads and some EQ.
I lost the 1990s wide stage and imaging got diffused
The last point is irritating to me- so again fatigue 
Will try the original “analytical” pads with a new EQ this weekend
I personally own the THX AAA 789 and am happy with it. This is pull-no-punches detail machine and it will not cover up flaws in the source or in your headphones. That’s fine by me.
Yes, depending on where you come from. I added a balanced cable to the 789 too, and immediately noticed a cleaner high end.
You can get compatible pads for $20 that will be superior to worn factory pads:
https://www.amazon.com/gp/product/B00TGCDG90/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1
Before making recommendations, what are your goals here? Just amplification that will make your 6xx’s sound better?
Please let us know:
1: Do you have other headphones that you would want to use with the amp?
2: Do you already have a DAC? If so, what kind?
3: Do you have a budget in mind?
4: How mobile do you expect to be?
Anything else you think would be helpful. Like what is your usual music source.
Yes, thanks for the question. 
My goal really is to find a sub 1k headphone, that’s an upgrade in sound to my HD650. I ended up getting the Focal Clear but unfortunately I found the to be fatiguing. Beyond that I don’t have a specific sound signature in mind, or one that I can express precisely.
When you say upgrade in sound what are you looking for from that upgrade? Bigger soundstage, more detail, more bass, better imaging etc?
Do you like DIY? Bottlehead Crack OTL AMP (Kit/DIY) - Official Thread
might be something you’d like. Note that it might not be ideal for all headphones.
Other amps to consider might be the Atom or the Liquid Spark, if you want to keep to a tight budget.
Do you have any way to listen to other headphones to learn what you like? In the under $750 range, you will find lots of good headphones that sound DIFFERENT than the HD-650. I have the 6XX and a Hifiman HE-560 also a Grado RS1e. In some ways they are better, but in other ways not. I use all three, and an old pair of STAX SR-5n that I think are also the equal and different.
The Grados have better soundstage. The Hifiman has nice bass and a very pleasing presentation, and is fast. The Stax are exceedingly fast and detailed, but are light on bass.
I think in the sub $1k price range, you get better phones than most people have ever heard, but you are still choosing among compromises.
Having some choices make things less fatiguing. THERE! back on topic.
I wish I could tell, I don’t have a ton of experience from my research I have heard all these terms but I don’t quite know what they mean. I imagine being able to tell the physical separation would be a good sound stage, but I don’t know if that enhances my experience. I am kind of following the strategy which I did when I first got into good quality headphones, i.e. find the headphones that are generally in the best under which worked perfectly for HD 650 (at the time it was coin toss between 600, and 650 and they happen to be selling at ± $25 so I decided to go with 650).
This time I ended up picking Focal Clear, but that didn’t work out. Turns out I can’t wear them for long without getting fatigued. Anyways, I ended up returning those, and now I’m looking for a better strategy. Perhaps some place I can demo before I got for the purchase.
Try this. Hold tight for a bit with your HD-650s. I think you will be pleased with the sound they have when adequately powered. Listen to that for a while. Take your time. You not only educate your ear, but sometimes things happen, good used equipment comes up, whatever.
Write a review of your amp choice. I don’t think we have a review or impression of the sound board you use. You’ll soon qualify for the community lending program, and you can consult with our illustrious leaders here about having them send you something else to listen to.
What is your source? Make sure that is clean also.
Hi there! The HD650’s are excellent headphones, I have one Grados, the HD58x ( on dale both of them right now), Elears, HD800, LCD i3 and HD6xx ( HD650) . Elears and HD800 always go with Sonarworks or some EQ, the Audeze and HD6xx are the only ones I feel sound perfect without any kind of EQ.
If you are also looking for an amp, maybe you should start with the amp. My true love for the HD6xx was when I move to a better amp ( smsl sp200) and I remember @pennstac mention something similar about his HD650 when he got the Lyr 3.
Give them a chance with a better amp!!
Which amp you have right now?
Though I’ve not personally heard it, I’ve often seen mentioned that the ZMF Aeolus is a genuine upgrade to the HD650 / 6XX while retaining the overall pleasantness of the presentation. You can find one sub $1000 either used or B Stock.
I use Google Play Music, I tried Tidal but with my setup I couldn’t tell much of a difference.
I do not have an amp I only use the Khadas Tone Board, but I’m now planning to get one (thinking of THX 789, Or Lyr3, per an earlier recommendation).
I agree with @pennstac get a proper amp and DAC for your 650’s first @S_P that makes a tremendous difference in sound quality then after you enjoy them for a while properly powered, I would look at the Anandas, maybe the fact they are Planar vs. the Clear you may actually find them less fatiguing. I personally love them and feel they were the biggest upgrade in sound to me from the 6XX. I started with the 650’s or 6XX and still love them and have them but my current go to for open back listening is the Anandas. Many people have compared them to the Focal Clears. Everyones ears are different.
If money were no object then of course I would go for something more expensive such as Hifiman Arya, the ZMF Verite or Aeolus or the Focal Utopia but I haven’t heard any of those, so I am basically basing this off of the info I have read online. I think a proper amp/dac first then maybe look at the Anandas if you are trying to stay at a more affordable price point, that worked for me, but once again everyone is different.
Edit: I would also add that @pennstac @Torq @Resolve @ProfFalkin @TylersEclectic @Hansel and many others On this forum are extremely knowledgeable and I trust their input. I am strictly commenting as a person that was in your exact shoes in September of last year minus the Focal Clears lol.
I agree with most of the above. If you’re just looking for different sound, focus on different headphones. If you want to improve the sound from you 650, a dedicated DAC + amp is highly suggested.
I would suggest a Modi + Vali 2 or Modi + Magni+ stack from Schiit for an inexpensive starting point for dedicated DAC Amp combos. It sounds good, synergizes with the 650 very well, and will power other headphones you get down the road as well. As for headphones, if you want to keep the same kind of sound as the 650 with just better overall everything, a preowned Aeolus is killer. You can drive it from just about anything, but it best when given the power it deserves.
Great call on the mini Schiit Stack, I wish I would have gone that route originally vs the way I went. I probably would have had I found this forum first.
I think that makes sense, at this time I’ll go for a dedicated AMP/DAC, and see what difference that makes with the 650s. Hopefully, will try to sample other headphones to see what sounds good to me instead of basing them entirely on reviews. Thanks everyone
I started with the Schiit basic stack and they worked very good with the headphones I mentioned before, but I move up and just give my wallet to my wife, just have in my future Lyr 3 and I’m thinking about Aeolus more and more everyday, they are suggested everywhere ( the ZMF’s)
Any way, if you decide to go for the small Schiit stack I have Modi 3 & Magni 3 ( from last march) that I’m planning to sell at any moment, just send me a text for more info if you want, but Schiit prices are very good and the new Magni(s) looks really awesome !!!
I agree with all the advice you’re being give. And you don’t honestly need to pay crazy money for good amplification. As already mentioned once you give the HD650 plenty of good power they can be hard to beat. You’d have to pay substantially more for a good upgrade. Good luck.
My worst Audio mistake years back, was when I had the HD600 and no good AMP, to decide wrong and change the very good hf vs the HD660s (mediocre)
First the quality DAC/Amp is now my followed plan for the last years and the future.
It makes no sense to spend money on a headphone you can not drive properly.
Something like a Rupert Neve RNHP hf-amp, the LYR3 or the Felikz Audio Echo, are sub 500 and not to analytical. - if that is your thing.
Or get a ifi xDSD and a balanced cable for the 650.
Add later a LYR3…
For headphones
I see the Ananda as very different headphone vs the HD 650 - however this Hifiman would be my personal upgrade path … than the Aeolus or the HEDDphone(complete different signature)?
… so many choices
