[nofacemonster]

After months of saving i finally managed to buy a Senheisser HD650 off the eBay. It is a slightly used one but i am so happy that i managed to buy it. It is not really the Senheisser HD650, it is called Massdrop HD6XX version to be precise and i read that it is the same thing. I am so excited and waiting patiently to get it shipped. While i was waiting few thoughts came to my mind since this is somewhere 300 Ohms and i don't think it will work with my laptop or phones earphone jack. Since my job involve travelling i thought of doing a bit of research and finding a cheap affordable headphone amp to power this so when i am away i can listen to it.

Any recommendations...?

At the moment i can't afford super expensive ones so start with the budget ones you know. I checked out few things on my own by searching the eBay and came across CMOY.

can CMOY drive the HD650?

 

[nordkapp]

I'd look at either the Schiit Vali 2 or Magni 3. The Vali 2 is really good for the price.

 

[buke9]

I doubt the Cmoy will drive them too well. 20 mW output is not very powerful. My iPad will get fairly loud with them but I do prefer a Bottlehead Crack or Massdrop Cavalli Tube Hybrid to get the best from them. I think a Fiio A5 would be something to look at for a portable not a problem with power and can run power hungry planars too. Had the E-12 years ago but didn’t have the 6xx’s or 650’s at the time but was a very capable amp with plenty of power.

 

[Natarian]

Get an Audioquest Dragonfly Black or Red. Red is more powerful but costs more. Sounds great and is super mobile (laptop, iPad, phone etc). Great for a traveler or someone in need of just a simple but great setup.

 

[buke9]

Have not heard the the Red on the amp side but only as a dac and it is very solid. The first time I heard the Focal Utopias was from a Amps and Sound Kenzie amp and a Dragonfly Red as a dac and could not fault it as it just was not in the way at all and do own a Kenzie amp now.

 

[nofacemonster]

So I will chop off the thought of buying a Cmoy for HD6XX.

Thank you all for the recommendations. I think I will check it with my laptop directly first before proceeding to buy a portable headphone amplifier because I have a feeling that it is powerful enough to drive them acceptably.

At home I have two receivers and a Chinese amp, I think one of them will drive it. My Yamaha receiver says it has some headphone out or 470 ohms. I have no idea what it means but wouldn't hurt to try them.

Yes! I have heard of schiit and their affordable yet great sounding amps and dacs but availability is a big issue plus eBay second hand units mostly ship with a stock 110v adaptor but my local electricity is 230v only so I need to get a good converter here.

Any idea about magni or Vali 1?

 

[Me x3]

At home I have two receivers and a Chinese amp, I think one of them will drive it. My Yamaha receiver says it has some headphone out or 470 ohms. I have no idea what it means but wouldn't hurt to try them.

That's the output impedance.
It will drive the HD650 but it will colour the sound boosting the mid-bass region and making it less precise.

 

[nofacemonster]

That's the output impedance.
It will drive the HD650 but it will colour the sound boosting the mid-bass region and making it less precise.

I may sound total stupid to you but why would it color the sound....? i can have all the EQ flat.... no bass boosts etc.

 

[nofacemonster]

https://www.headfonia.com/60-pack-of-awesome-jdslabs-cmoy/

Look at what this guy says. CMOY running HD650....????????????? damn! sounds like a great way to take it around. I am not sure how true this is so i post this link for you all to see. Thanks a lot!

 

[Me x3]

I may sound total stupid to you but why would it color the sound....? i can have all the EQ flat.... no bass boosts etc.

It's a relatively complex matter that requires some math to explain. High output impedance from the amplifier colours the sound in the shape of the headphone's impedance vs frecuency plot. Since HD650's impedance goes up in the mid bass (500 ohm or so) it gets a boost in this region of the spectrum. It's a consequence of low damping factor. That's why headphone amplifiers have much lower output impedance (120 ohm is high for some tube amps, while solidstate amps are typically close to 0 ohm)

 

[nofacemonster]

It's a relatively complex matter that requires some math to explain. High output impedance from the amplifier colours the sound in the shape of the headphone's impedance vs frecuency plot. Since HD650's impedance goes up in the mid bass (500 ohm or so) it gets a boost in this region of the spectrum. It's a consequence of low damping factor. That's why headphone amplifiers have much lower output impedance (120 ohm is high for some tube amps, while solidstate amps are typically close to 0 ohm)

With all do respect you can correct me if i am wrong sir.... here is another brainless question which just got stuck in my mind. Please read it as if it is written by a person who has no idea about this ohms stuff. According to what you said about i need to buy an amplifier that perfectly matches the headphones impedance. 300ohms, anything above this will color the sound. I have done a lot of search during past couple of days and it only gotten me lost even further. I even contacted JDSlabs and they said

"If the volume level of your HD650 is good enough for you while it is connected straight to your notebook, then that's all you need. An amplifier only does increase the volume of the sound and nothing more"

Then i kept seeing Schiit stacks and Objective 2 getting recommended over and over for the HD650.

I really don't know where to begin so i am thinking, i should wait till i get the HD650 in my hands and do some real life listening it and see. Maybe my good old little chinese tube amplifier could power it with its headphone jack.

Any recommendation are still welcome. Thanks a lot for all your help, i really appreciate it.

 

[Me x3]

The higher the output impedance of your amplifier the more it will colour the sound.
As the output impedance becomes smaller and smaller relative to the headphone's impedance, the sound becomes less and less coloured to a point where the magnitude of the colouration is so small that the amp can be considered perfectly neutral. As a simple rule it's adviceable to have an amplifier with an output impedance that's at least 6 times smaller than the headphone's impedance, for HD650 that means an amplifier with an output impedance below 50 Ohm although you can do just fine with an amp with 100 Ohm output impedance as the added colouration will be sublte. With an amp that has 470 Ohm on the other hand the effect is not that subtle and it's not a very good match at all (it will sound more or less ok but not as intended).

An amplifier is designed to increase driving power without distortion and allow the source to provide it's best sound quality.
Most amps also come with a precise volume control and also some other features that you might or might not want.

If I were you, I would pick a DAC/Amp or a quality DAP instead of just an amp.
The amplifier is just one link in the audio chain. You'll get the best sound quality with all your links are covered by quality components (Recordings - DAC - Amp - Headphone)
Pairing a great amplifier with a generic audio chip used as DAC on most laptops or smartphones won't make the amp or the headphones much justice.

You don't have to spend a lot, but you need all the links covered to get a very clean and precise sound.
The little FiiO E10K for instance is really cheap and gives you a good DAC and a good Amp section (low noise, good volume control, more power than most integrated chips) so you can have a good reference. You will be able to find superior and more expensive gear, such as adding the suggested FiiO A5 to the E10K, or going with a Schiit Modi 2 Uber / Magni 3 combo, to name just a few products that offer nice price/performance ratio. As always, the last bit of performance is the most expensive, so this game can become pricy if you decide to go much further from this gear. My current player X7 Mark II + AM2 Module is 799usd while FiiO E10K is 79usd, so you get the idea. You'll find Burson and Violectric for 1000 - 2000 usd, Schiit combos for 2000 - 4000 usd. You know...

If you don't want to break the bank you can stay in the very affordable range and you'll get very nice and enjoyable sound anyway.
Keep in mind different headphones can sound very different, while different DAC/Amps sound more alike in the big scheme of things.

 

[S3nsoryDeprivati0n]

With all do respect you can correct me if i am wrong sir.... here is another brainless question which just got stuck in my mind. Please read it as if it is written by a person who has no idea about this ohms stuff. According to what you said about i need to buy an amplifier that perfectly matches the headphones impedance. 300ohms, anything above this will color the sound. I have done a lot of search during past couple of days and it only gotten me lost even further. I even contacted JDSlabs and they said

"If the volume level of your HD650 is good enough for you while it is connected straight to your notebook, then that's all you need. An amplifier only does increase the volume of the sound and nothing more"

Then i kept seeing Schiit stacks and Objective 2 getting recommended over and over for the HD650.

I really don't know where to begin so i am thinking, i should wait till i get the HD650 in my hands and do some real life listening it and see. Maybe my good old little chinese tube amplifier could power it with its headphone jack.

Any recommendation are still welcome. Thanks a lot for all your help, i really appreciate it.

Here are some guidelines:
1) try to get the output impedance of any amp you use as low as possible while maintaining enough power to drive them at 300 ohm.
- For the HD650s, you should get the output impedance down to at least 37 ohm (less is better; i.e. Schiit Magni 3 is a miniscule 0.3 ohm!) This figure affects the way the music sounds.
2) get a headphone amp with enough power for the headphones you want
- You need 2.6 Vrms to drive the HD 650s to 110db. If you limit volume to a comfortable 80-90 db, then an amp with less might be suitable (but THD becomes a factor at some point in the equation; need to do more reading about that)

About soundcards in PCs:
If you do use your laptop, don't crank up the volume. Many sound cards have a 2 Vrms rating. Thats not enough for the HD 650s without distortion from the amp. Cards with 1 Vrms will be nasty. You will find that you need to keep turning up the volume, and amplify the distortion along with it. Sound cards that have a headphone amp on them will say so. The datasheets of headphone amps on soundcards say something like "optimized for 32 - 600 ohm", which is fine for most headphones. For example, take a look at the specs for the "Asus Strix SOAR" "Headphone Impedance: optimized for 16, 32 - 600 ohm".

Personally, you are better off with a DAC/AMP, one that has low output impedance, and minimum 3 Vrms. It will keep your HD650s working optimally for years, no distortion damage.

 

[megabigeye]

After months of saving i finally managed to buy a Senheisser HD650 off the eBay. It is a slightly used one but i am so happy that i managed to buy it. It is not really the Senheisser HD650, it is called Massdrop HD6XX version to be precise and i read that it is the same thing. I am so excited and waiting patiently to get it shipped. While i was waiting few thoughts came to my mind since this is somewhere 300 Ohms and i don't think it will work with my laptop or phones earphone jack. Since my job involve travelling i thought of doing a bit of research and finding a cheap affordable headphone amp to power this so when i am away i can listen to it.

Any recommendations...?

At the moment i can't afford super expensive ones so start with the budget ones you know. I checked out few things on my own by searching the eBay and came across CMOY.

can CMOY drive the HD650?

Hi there,
I have the CMoyBB from JDS Labs (same one that's reviewed in that Headfonia article) and it drives my HD 650 just fine. Maybe not the most resolving, etc., but I think it'd be absolutely perfect for a beginner amp.

To be honest (and I know this is going to fly in the face of everything that's been said in this thread), but you might, maybe, if you're lucky be able to use the HD 650 with your laptop of desktop PC with no amp. I used mine with my old Mac Mini before I got an amp an I was amazed at how good it sounded. I could hardly believe that it could get better... It does get better, though. Again, it's not going to be the most ideal setup, but it'll work till you can get together enough money to buy a better amp.

Also, I don't know why we're assuming that the headphone output on your receiver has a 470 Ohm output impedance. What headphone would that be able to drive? My guess is that it's able to drive headphones up to 470 Ohms. Anyway, for the time being that's neither here nor there. When you get your headphones in the mail, plug them into your receiver and see if you like the sound. Easy as that! Of course, start with a low volume and turn it off if it seems like something is going wrong. Same applies to trying it with any amp or your PC or phone.

I would agree with the others that if you're going to use the headphones with your phone that you should get a DAC/amp. Most phones aren't going to be able to drive a 300 Ohm load (well, there are some that will, but not many. LG and HTC flagships are the only ones that come to mind, but I haven't ever put much thought into it), and using just an amp is likely to make the whole thing sound worse rather than better. I can recommend the AudioQuest Dragonfly Red ($200), but can't speak to any others.

...Speaking of using them with your phone: you do realize that the HD 6XX are in no way portable, right? They're bulky and don't fold up, but most importantly they're open back and will let in all sound. Everybody will also be able to hear everything you're listening to as well. That being said, they're absolutely stellar for home listening (and there used to be a guy I'd see near my job that wore his HD 650s out and about, so it can be done, but...).

Happy listening!

PS-- as I was typing this I got a notification that somebody had replied to the HD 650/6XX thread... turns out that it was somebody talking about how good the 6XX sounds directly out of their laptop. What a coincidence!

 

[Me x3]

Also, I don't know why we're assuming that the headphone output on your receiver has a 470 Ohm output impedance. What headphone would that be able to drive? My guess is that it's able to drive headphones up to 470 Ohms.

We're not assuming.

I've measured the output impedance on my Yamaha integrated amplifier and also shared a few chats with people from Yamaha in the past.
The headphone jack is typically taped off from the speaker path so that's why you get the very high output impedance. In other words, there's no dedicated headphone amplifier but a cheaper solution, not intended to drive a particular headphone perfectly fine. It can work fine with some headphones like DT880, some sensitive planars, and a few more. It's less than ideal for many headphones, but still better than no jack at all. Higher end speaker amps from Yamaha include a dedicated headphone amplifier with considerably lower output impedance.