Sennheisers HD650 and valve amp synergy

Lawrence001

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I've known it for a while, but after listening to planars and solid state amps for about a year I've dug out my HD650s again. With the SS amp there was something not quite right after the planars, but now I've swapped in one of my Eufonika OTL amps, they are sounding great and I remember why I liked them so much.

Just saying, for anyone who hasn't got on with the HD650s in the past, but never tried then with valves, do give them another chance, it's worth it.
 

JANDL100

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Recently I've become a big fan of valves in the signal chain for headphone amps.

I'm not sure I've ever listened to Sennheiser 600 series headphones.

The 700 I loved, the 598 I hated for its intrusive tonal colouration and claustrophobic sound.
That and the reviews of the 600 series sound quality - which manage to not appeal to me despite users' enthusiasm (and also my terrible luck with headphones recently*) rather restrain my curiosity.
I've developed the probably erroneous idea that a 6xx is just a somewhat more open sounding 598, which doesn't appeal at all.

And they look very open backed.
Do you get Grado levels of sound leakage? That would be an issue for me.

(* Beyerdynamic DT990 died in transit to new owner, Hifiman Deva developed fatal fault, Monolith M1060 lost in post, Feliks Echo amp valves DOA with new owner.
Just scads of £ down the drain, although hopefully I'll get my money back on the Monolith. It's not been a good few weeks at all! )
 
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lazycat

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And they look very open backed.
Do you get Grado levels of sound leakage? That would be an issue for me.
I was told they are very leaky - the ex got annoyed if he was watching the usual sh*te on TV and I wanted some music.

He was particularly fussy tho'. :LOL:
 
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DCS

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I got a new pair of Beyerdynamic 900 pro x and although open back they don’t appear to leak much.
 
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JANDL100

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Yes, some 'open backs' leak as if the drivers were pointing outwards (Grado, Philips X2HR) but others can be remarkably quiet. Weird.
 

Headcoat

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Very small margins imo. I can't say my HD6xx sound any better from OTL than SS. I guess it's one of those things some can hear and others can't.
 

Jazid

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It's a lot easier to make an otl amp that likes 300-600 ohm impedance than 20-40 ohm impedance. So many plusses and few minuses. Maybe this is related to your experience Jerry?
Valves and electrostats are such a sweet combo I'm surprised it isn't a commonplace DIY solution, c'mon guys, let's tweak. But not fry of course...
 
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JamieMcC

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OTL topology implementation, tube choice and component quality all effect sonics. The best are very good and there will also be some that are pants.

HD6xx are very enjoyable and do scale reasonably well. But they do have limitations in resolve and dynamics which can mask differences between upstream sources and amplification.
 

terryg1

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I've known it for a while, but after listening to planars and solid state amps for about a year I've dug out my HD650s again. With the SS amp there was something not quite right after the planars, but now I've swapped in one of my Eufonika OTL amps, they are sounding great and I remember why I liked them so much.

Just saying, for anyone who hasn't got on with the HD650s in the past, but never tried then with valves, do give them another chance, it's worth it.
Could be looking for recommendations on a Vavle headphone amp pm wellcome
 

Headcoat

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I've used the Senn HD6xx extensively with the Feliks Echo and Elise (both OTL and with various valves), and also with the Arcam rHead and headphone out from a NAD C368 (desperately under rated amp with an excellent headphone amp built in).

The HD6xx just didn't improve at all for me. Lots of people suggest they are meant to sound great with both the Feliks OTL amps I mention. My experience goes against that received wisdom.

My understanding is the issue with low impedance cans and OTL amps is the higher amp output impedance breaks the 8:1 output to input rule; which - if the headphones are of low impedance - can result in messed up frequency at the top and/or bottom on the headphones.

Most OTL amps are approx. 50ohms output. However, measurements suggest output impedance between 0 and 100ohms often makes no (or tiny) difference to many heapdhones e.g. the Audioquest Nighthawks fq graph doesn't change at all when the output impedance is altered.

Certainly that's my experience: that lower impedance cans, more often than not, are just fine on high output impedance OTL amps.
 

stokiebloke

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I've known it for a while, but after listening to planars and solid state amps for about a year I've dug out my HD650s again. With the SS amp there was something not quite right after the planars, but now I've swapped in one of my Eufonika OTL amps, they are sounding great and I remember why I liked them so much.

Just saying, for anyone who hasn't got on with the HD650s in the past, but never tried then with valves, do give them another chance, it's worth it.
I have yet to try an otl amp with my hd600s, you do see a lot of positive comments about the synergy between the two.

I used a Burson Soloist SL MK2 for a while to good effect with the 600s, easily driving them on low gain setting, it is a powerful amp.

But I tried a Beresford Caiman SEG dac and found I really liked the pairing with the 600s, particularly the extended bass. I run the DAC off a 12v lead acid battery.

I also have a pair of hd660s headphones, they are capable of greater resolution and detail than the 600s and I get amazing results using them with a little fiio dap, but somehow I still prefer the Beresford - hd600 combo.

I did try a Icon Audio HP8 valve headphone amplifier (transformer coupled) it stayed with me for one day and went straight back to the dealer, I found the background mains hum was completely unacceptable, not sure if that particular unit was atypical or if they are all like that.

I should say I use icon audio amplifiers in my main speaker system and absolutely love them.
 

Lawrence001

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I have yet to try an otl amp with my hd600s, you do see a lot of positive comments about the synergy between the two.

I used a Burson Soloist SL MK2 for a while to good effect with the 600s, easily driving them on low gain setting, it is a powerful amp.

But I tried a Beresford Caiman SEG dac and found I really liked the pairing with the 600s, particularly the extended bass. I run the DAC off a 12v lead acid battery.

I also have a pair of hd660s headphones, they are capable of greater resolution and detail than the 600s and I get amazing results using them with a little fiio dap, but somehow I still prefer the Beresford - hd600 combo.

I did try a Icon Audio HP8 valve headphone amplifier (transformer coupled) it stayed with me for one day and went straight back to the dealer, I found the background mains hum was completely unacceptable, not sure if that particular unit was atypical or if they are all like that.

I should say I use icon audio amplifiers in my main speaker system and absolutely love them.
My Eufonika amps are virtually silent I'm not aware icon audio would be any different, but I've noticed they can pick up hum from nearby cables and components
 

Lawrence001

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Could be looking for recommendations on a Vavle headphone amp pm wellcome
Depends on budget, I loved the Little dot MkIII and MkIVSE. If you can spend a bit more, Eufonika from Poland are great, that's what I use now.
 

stokiebloke

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My Eufonika amps are virtually silent I'm not aware icon audio would be any different, but I've noticed they can pick up hum from nearby cables and components
RFI can be a nuisance, I have a dimmer switch on the ceiling lights, interestingly a mm cartridge will pick up the noise generated by this switch, but a MC cartridge does not. Switch and turntable are about 5 feet apart.
The icon audio hp8 I tried hummed loudly when switched on, then it faded to a low but still audible hum after 30 seconds or so, which made me think it was a rectification issue within the amp. I assume this example must have been faulty in some way because I had tried another hp8 at a different dealer previously and that had no hum as I recall.
 

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