Sennheiser HD 660S - Official Discussion

Sennheiser HD600 vs HD660s vs HD650 which headphones are best for you?

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I’ve never listened to the HD660s yet. But I do have and own the HD580 and HD600 (purchased between 1997 and 2000) and a HD650 purchased 7 years ago and a HD6xx from Drop and a HD580 Jubilee from Drop (150 ohm).

The way I choose which one to listen to is based on the quality of amplification I’m plugging the headphone in to. The 150 ohm Massdrop HD580 Jubilee sounds better than the 300 ohm Senns if I’m using a lower powered or lower quality amp in the $100-ish price range. Like a Schiit Magni, Cavalli Liquid Spark, PonoPlayer, USB dongle, computer laptop and such. With amps/sources like that the 150 ohm Drop HD580 Jubilee sounds better with better dynamics, better soundstage cohesion, better center image.

When I move up to an amp like the Cavalli Tube Hybrid the 300 ohm Senns like the HD600 and HD650 catch up and the 150 ohm HD580 Jubilee and 300 ohm Senns are more equal in sound quality.

But once you move on beyond amps like the Cavalli Tube Hybrid the sound qualities of the 150 ohm HD580 Jubilee hits a plateau and doesn’t improve with better amplification. While the 300 ohm HD600 and HD650 are hitting their stride and ready to get better and better with better amplification.

When I plug the 150 ohm HD580 Jubilee and 300 ohm HD650 in my Cavalli Liquid Glass the HD650 is just so much better. Better soundstage size, better center imaging, better tonality, better dynamics, better everything. Why would anyone even use the 150 ohm HD580 Jubilee with an amp like that? The 300 ohm Senns are just so much better.

The choice between using the 150 ohm Senns or the 300 ohm Senns is all about the quality of amplification and source. With $100-ish amps the 150 ohm HD580 Jubilee is better. The amps drive them better, soundstage is better, center imaging is better. With $200-ish to $250-ish amps you kind of hit parity where both can compete. With amps and sources above that point the 300 ohm Senns pull ahead and keep pulling ahead while the 150 ohm HD580 Jubilee stays at the same performance tier as it was with the $250-ish amp/source.

The 300 ohm Senns continue to scale with better amplification while the 150 ohm HD580 Jubilee hits its performance peak at around the $250-ish amp level.

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Purchased the singxer sa1 and it’s my favorite amp with thr 660s. Extremely smooth and velvety with great transparency. Like it better than Rebel combo.

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Rumor has it there’s a new “660S2” revision dropping imminently. 300 ohm impedance, better bass extension. $600. Color me intrigued… :thinking:

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The Singxer SA-1 tends to perform best with dynamic driver headphones.
The Rebel Audio RebelAmp tends to perform best with planar magnetic headphones.

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And yet, my Focal Elex sounds great on the Rebel (richness and dynamics)and somewhat dead ( poor dynamics and crispness) on my SA1. The SA1 seems to take all the character out of the sound of the Elex. Could it be Rebel prefers low impedance in general?

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My overly generalized theorems attempt to categorize what type of headphone tends to perform best on each amplifier. Only real life experience would actually reveal which headphones synergize best. I made the statement heavily influenced by the fact that I cannot name a planar magnetic headphone that does not excel with the RebelAmp.
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As for low impedance headphones, certainly planar magnetic headphones tend to rate as low impedance in general and support your thesis. I shall have to delve deeper into a variety of impedance rated dynamic driver headphones to determine correlations to performance yields and low impedance headphones on the RebelAmp.
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On another note, my Monoprice AMT headphone has a rated low impedance of 32 ohms, it performs slightly favorable on the Singxer SA-1 over the RebelAmp.

The RebelAmp is simply an excellent, overbuilt Class A amp. If you like the Class A sound then most headphones will likely sound great with it.

You read too much into @hottyson’s comment. I love the RebelAmp with my 300 ohm Sennheisers and 600 Ohm Beyerdynamic.

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I especially like the 660s with the Rebel. Gives much needed weight to the sound. Not that crazy with the 6xx pairing. Way too dark with 6xx.

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I was thinking about my HD 600 and HD 800S. Both lean bright so the warmish Rebel adds needed weight (plus I EQ the bass up too). I personally don’t like the 6XX on any solid state amp I’ve tried, as the mid bass comes across as excessive and forced. I do like the 6XX on some tube amps because they change it substantially.

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I also find the 6XX/650 a little too warm and dark with the RebelAmp; after EQ it’s better, but it has me considering selling the 650 and buying the 600.

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You all are crazy. I think the 6XX sounds amazing on the Rebel (currently paired with the Bifrost 2/64 which WOW). I do EQ it though; it sounds great without EQ but with EQ I like it better than a lot of more expensive things I have.

From what I understand the 6XX with EQ can be made to sound essentially the same as the 600 because they’re so similar, but I haven’t tried it myself.

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I mean, all of us audio enthusiasts are a bit crazy, yeah. :smiley:

Yeah, HD 650 sounds great with RebelAmp for sure, just a little too warm for my tastes. When using EQ though, it’s sounds better; same can be said for many headphones, though.

Tastes and individual HRTF are always going to play a role on the impressions we form, but at least we all agree that the HD 650 is an outstanding headphone; personally, I think the HD 6 series is the best value product(s) in audio.

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Pick your poison. All audio products have a character and you either find a way to work with them or move on. The rough differences to my ears:

  • HD 600: Limited bass volume and limited bass extension. Strong, smooth, and pleasant mid-range and vocals. A little bit too forward in the upper mids. Treble ranges from harsh and scratchy (noisy solid state amps) to controlled and semi-airy on balanced or a well-matched tube amp. It’s always a bit soft, fuzzy, and rounded in the highs and lows.

  • HD 6XX/650: In an apparent reaction to the limited bass of the 600, they boosted the mid bass to the extent possible. It still doesn’t go deep and can’t be forced to go deep with EQ either. The mids/vocals suffer versus the 600, per roughness, thinness, and grain. The treble has nowhere near the harshness potential of the 600, but thereby can suffer from the ‘veil’ of muddy treble. It becomes a different beast with the right tube amp, as non-technical, warmish and harmonics-crazy. I like that presentation better than on solid state. It’s a distinct, unique flavor.

  • HD 800S: No more bass than the 600 and sounds bit thin on a neutral solid state amp. It’s so wide/spacious that it’s almost as if the headphones are playing in a room next door. However, it comes alive when you add bass (Class A amp; EQ with max deep bass) and on tubes. Tubes thicken the timbre while preserving far better treble details and location information than either the 600 or 6XX.

My preferences: HD 800S on EQ and/or tubes > HD 600 on balanced > HD 6XX on tubes

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As usual, my ears are in 100% full agreement with generic’s ears on both of these.

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Posted my impressions today on youtube unfortunately not allowed to post them here.

All good, they are a step ahead and could very well be the 650 upgrade so many were waiting for and an upgrade to the of 660s. You can find those impressions on HeadFi.

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You’ve been spoken to multiple times about this in private. We ask for the bare minimum of participation in order for content creator’s to post their videos on this forum. Our forum is not a link dumping ground.

5 of your last 6 posts have just been links to videos over the last 3 months with one of them being a passive aggressive shot towards the mod team that has extended nothing but leniency around our forum rules.

We don’t care if you’re a store, a manufacturer, etc…

The rules are, you need to participate in the community in order to advertise your content.

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I hear ya all good, my contribution is the quality of the video and the impressions from the videos I create no different from the contributions I made when I was an affiliate for you which were allowed, only difference is it’s tied to a store that isn’t you.

It’s your website however and I understand you not wanting the video up but you have a strong enough following that it shouldn’t be an issue for others to see a different take, if they are going to buy from you they will and I am sure they do.

Again I hear ya though and will try to contribute to the forum in other ways. Although typing words on a forum can’t bring the same level of quality that a video I create can.

I think if you just provide some additional written commentary, like even some short form bullet points or quick thoughts on the subject of the video - something else in addition to the links - it would be fine. If it’s just links it becomes difficult to apply moderation rules evenly.

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I can totally do that and thank you for this explanation as it was never communicated to me like this, and that makes perfect sense. Thanks @Resolve