How necessary is an amp for Sennheiser HD650?

[aandgquestion]

I have found a good deal on a set of HD650s, which are ordinarily out of my budget.

Originally I was set on HD550's, but saw some suggestions to rather get a used HD650.

The issue is, these are my first pair of proper headphones, and I would have no budget left for an amp or DAC at all.

I believe the HD650 needs an amp more than HD550.

It's confused more by the fact I have seen critiques of HD650 for being too dark sounding with rolled off treble and weak bass, plus not the best soundstage.

I wonder if it is better to go with the newer 550's.

So my questions are:

- Would an un-amped HD650 sound worse than an un-amped HD550?

- How do the two compare WITH an amp. Is the HD650 objectively better or is it not that simple?

Would appreciate any thoughts

 

[Mort]

How will you listen to either without an amp or DAC?

650 is better yes, but 550 is quite good.

 

[raindance]

What are you planning on using them with?

In my opinion they're rather warm sounding and a little too dark and rolled off for my older ears. My son, who is on his 20's and has more treble hearing, absolutely loves them.

I must say, he was on the fence for a while until I gave him my used Channel Islands Audio headphone amp - he says it makes a big difference over his computer soundcard's built in amp. YMMV.

 

[aandgquestion]

How will you listen to either without an amp or DAC?

650 is better yes, but 550 is quite good.

What are you planning on using them with?

In my opinion they're rather warm sounding and a little too dark and rolled off for my older ears. My son, who is on his 20's and has more treble hearing, absolutely loves them.

I must say, he was on the fence for a while until I gave him my used Channel Islands Audio headphone amp - he says it makes a big difference over his computer soundcard's built in amp. YMMV.

I will just be listening to music from my phone or laptop

 

[NTK]

Max output from phones and laptops are all over the place, and only a few are tested here and they are very dated. For example, the Pixel 4a maxed out at 0.3 V whereas the Samsung S8+ can output 1 V. An old HP Z Series laptop maxed out at 0.6 V. I think you'll want minimum 1 V for the HD 650 (which should give 103 dBSPL).

Current Macbooks should be able to output 3V for headphones with impedance >150 Ω.

Google Pixel 4a Smartphone Audio Review

This is a detailed measurements of the audio performance of the Pixel 4a smartphone. It was kindly purchased new by a member and drop shipped to me. It costs US $350. Being used to my Samsung S8+, the Pixel 4a looks decidedly small: Screen sharpness is much better than above as I left the...

www.audiosciencereview.com

Do You Need an External DAC/Headphone Amplifier?

A question is raised from time to time whether one needs an external DAC or headphone amplifier for desktop computer use. I thought I address that with a set of measurements in this article. There will be more to come because unfortunately, there is no one representative computer sound...

www.audiosciencereview.com

Review and measurements of MacBook Air (2024) headphone output

This is a review and measurements of the MacBook Air 2024 headphone output. It was prompted by a request from @DrSpan, as the little Mac has a very strong reputation as a headphone source. Here it is, measuring itself: Since 2021 Apple has supported impedance detection on the headphone...

www.audiosciencereview.com

I recommend getting a relatively inexpensive dongle such as:

Review of TRN Black Pearl: Portable USB DAC & Headphone Amp with 10-band PEQ

Important Update (8/16/25) WalkPlay/TTGK is another company reacting to the issue of DRE-induced distortion associated with the CS431xx chips! A new firmware release for the TRN Black Pearl changed a key parameter related to DRE operation. With this firmware installed, the Black Pearl does not...

www.audiosciencereview.com

 

[aandgquestion]

Max output from phones and laptops are all over the place, and only a few are tested here and they are very dated. For example, the Pixel 4a maxed out at 0.3 V whereas the Samsung S8+ can output 1 V. An old HP Z Series laptop maxed out at 0.6 V. I think you'll want minimum 1 V for the HD 650 (which should give 103 dBSPL).

Current Macbooks should be able to output 3V for headphones with impedance >150 Ω.

Google Pixel 4a Smartphone Audio Review

This is a detailed measurements of the audio performance of the Pixel 4a smartphone. It was kindly purchased new by a member and drop shipped to me. It costs US $350. Being used to my Samsung S8+, the Pixel 4a looks decidedly small: Screen sharpness is much better than above as I left the...

www.audiosciencereview.com

Do You Need an External DAC/Headphone Amplifier?

A question is raised from time to time whether one needs an external DAC or headphone amplifier for desktop computer use. I thought I address that with a set of measurements in this article. There will be more to come because unfortunately, there is no one representative computer sound...

www.audiosciencereview.com

Review and measurements of MacBook Air (2024) headphone output

This is a review and measurements of the MacBook Air 2024 headphone output. It was prompted by a request from @DrSpan, as the little Mac has a very strong reputation as a headphone source. Here it is, measuring itself: Since 2021 Apple has supported impedance detection on the headphone...

www.audiosciencereview.com

I recommend getting a relatively inexpensive dongle such as:

Review of TRN Black Pearl: Portable USB DAC & Headphone Amp with 10-band PEQ

Important Update (8/16/25) WalkPlay/TTGK is another company reacting to the issue of DRE-induced distortion associated with the CS431xx chips! A new firmware release for the TRN Black Pearl changed a key parameter related to DRE operation. With this firmware installed, the Black Pearl does not...

www.audiosciencereview.com

Thank you. Would you say that the HD650 with this amp you listed would be better than the HD550?

 

[Sebby]

Thank you. Would you say that the HD650 with this amp you listed would be better than the HD550

No. An HD550 is better than the HD650 and the HD600. Technology moves forward.
The HD550 is objectively better than the entire HD6xx line, even though I subjectively prefer the HD660s2 over all of them. The HD550 has better bass extension, better treble extension and the pinna gain is in the right place, unlike the HD600/650 where it’s slightly delayed compared to what the brain expects.
It also doesn’t have a compressed three-lobed soundstage

 

[aandgquestion]

Thanks. I actually bought the HD550 a few days ago. I've been slightly underwhelmed by them, not to say that they sound bad, but just that they don't 'wow' me in the same way my Kefine Delci AE iems have.

I've got myself an Amp/DAC (Fiio BTR) to see if that is the issue (previously have just been using my phone) if not then I think it may just be that open backs aren't for me!

 

[Sebby]

Thanks. I actually bought the HD550 a few days ago. I've been slightly underwhelmed by them, not to say that they sound bad, but just that they don't 'wow' me in the same way my Kefine Delci AE iems have.

I've got myself an Amp/DAC (Fiio BTR) to see if that is the issue (previously have just been using my phone) if not then I think it may just be that open backs aren't for me!

I get what you’re saying, but that’s normal. I often prefer IEMs for fun too.
Maybe you don’t like the HD550 because it’s too ‘neutral’ and therefore not very colored or exciting.
A neutral target bores me and doesn’t give me a wow effect.
A BTR15/17 is fine, but if you take a BTR11 you’ll struggle because it’s a high-impedance headphone with an impedance boost in the lows, so it’ll sound anemic.
If you held a gun to my head and I had to choose between IEMs and headphones, I’d pick the IEM

 

[aandgquestion]

I get what you’re saying, but that’s normal. I often prefer IEMs for fun too.
Maybe you don’t like the HD550 because it’s too ‘neutral’ and therefore not very colored or exciting.
A neutral target bores me and doesn’t give me a wow effect.
A BTR15/17 is fine, but if you take a BTR11 you’ll struggle because it’s a high-impedance headphone with an impedance boost in the lows, so it’ll sound anemic.
If you held a gun to my head and I had to choose between IEMs and headphones, I’d pick the IEM

It's a BTR13 - will that be OK? I can return if not.

Thanks

 

[Palladium]

All you need is a JM20 Max dongle.

 

[Tonton_ZEeD]

It's a BTR13 - will that be OK? I can return if not.

Thanks

Can you try it before returning it ?

 

[aandgquestion]

Can you try it before returning it ?

Yep. I just did a calculation for it though and it seems to be more than enough based on the HD550 having 110 sensitivity and 150 ohms, as the BTR13 has 220mW at 32ohms. Does that seem right?

 

[Sebby]

It's a BTR13 - will that be OK? I can return if not.

Thanks

BTR13 is perfect, especially considering that the HD550 is 320 ohms at 80 Hz

 

[Jameson Reid]

Un-amped, the HD650 will probably sound dull and underpowered compared to the HD550, but with a proper amp the HD650 pulls ahead with richer mids, better control, and a more natural sound. If you can’t budget an amp right now, the HD550 is the safer pick. The HD650 only makes sense if you plan to add an amp soon.

 

[aandgquestion]

BTR13 is perfect, especially considering that the HD550 is 320 ohms at 80 Hz

Hey just so say I got the BTR13, definitely noticed a difference right away BUT it also allows EQ, which I did using a Harman preset for HD550.

WOW what a difference that has made. Things suddenly have a lot more 'oomph' and overall it just sounds great.

Whereas before I felt the bass lacking I feel it's very nice and full. So much so that I would actually like to have an alternate EQ setting that is more 'analytical' maybe with slightly less bass thump, something that focuses on really clear mids and treble with as much soundstage and detail as possible. As I've not EQ'd before this I'm not sure how to go about that. Do you have any suggestions?

Thanks again for the help

 

[FireEmblem]

For everyone interested who's coming across this thread: If you've got an audio interface, an amp is not required. I compared a Swissonic amp for 160€ with my UR-22 interface side by side with the same tracks and spots, and there's absolutely no difference in sound. Except that the Swissonic was adding stuff to the music unfortunately (more reverb, wider stage beyond the point of what's actually present in the OG mix, noise 'artifacts' that occured because of the artificial extra tail that the Swissonic added), what an amp shouldn't do, but that's another topic.

 

[solderdude]

So my questions are:

- Would an un-amped HD650 sound worse than an un-amped HD550?

They sound different amped or not.

- How do the two compare WITH an amp. Is the HD650 objectively better or is it not that simple?

They sound different in the bass, warmth mids and treble. There is no 'better' just different

Would appreciate any thoughts

Those were my thoughts.

Whether or not you need an amplifier depends on how loud you want to play without hitting limits (clipping).
The HD550 plays 5dB louder at the same volume setting compared to the HD650...