Sennheiser HD 800 Redux

[dsavitsk]

There is an argument that damping factors are grossly exaggerated anyhow. Link, citing the Audio Cyclopedia 2nd ed.

My experience says that a non-zero Zout is beneficial to most dynamic phones. For Grados, I like ~10-15 ohms of impedance, for Senns (the 650's anyhow) anything from about 4 to 30 ohms seems pretty good. Indeed, driving the 800's from a gm amp with a Zout of around 600 ohms worked really well (it also works well for Grados.)

As mentioned, the positive impedance seems to give some warmth and body to the mids. Indeed, this is a big part of the SET thing -- it has nothing to do with tubes being "tubey" (which they aren't), but rather has to do with a lower damping factor and lack of feedback being pleasing. It is a subjective preference, but at the end of the day, it is a subjective hobby.

[RudeWolf]

Still- most headphones don't employ crossover circuits, right? Damping factor has always been a source of mystery and confusion for me. I have a bad feeling that there's something fundamental that's lost in the simplification that allows to talk about damping as it's done in popular circles. As far as I know there is mechanical and electric damping, loads can be resistive, reactive and inductive that may or may not change at certain frequencies. And then there's people who like driving orthodynamics on a SET amp.

Go figure.

[spritzer]

I just made a short adapter cable with 120ohm resistors (Vishay metal film) inline for the Dynalo/HD800 combo. The volume difference makes A-B comparisons all but impossible but there is a clear change to the sound. Whether this is better or worse only time will tell...

[Tyll Hertsens]

FWIW, I cast my vote for low output impedances. Just seems to make more sense to me.

[spritzer]

I agree but half the fun of DIY is to try crazy shit. Only reason I'm building a "lovely cube" type amp...

[dsavitsk]

FWIW, I cast my vote for low output impedances. Just seems to make more sense to me.

Low Z makes sense when speakers are badly behaved -- as most commercial ones are. But, headphone impedance is really linear, so it is not that important. Try listening to a Lowther, or a Fostex full ranger with a low Z amp -- it is awful -- unlistenable. So, the argument here is that dynamic phones are basically like extremely good single driver speakers.

Tyll - I'll send you a gm type amp if you want to give it a try. Even KG liked it (though he says it isn't really a gm amp.)

[luvdunhill]

Best amps I have heard my Lowthers and Fostex are low impedance. I think the First Watt J2 is half an ohm.. plenty of people seem to agree, look at 6moons article for the J2 where a room of people compared the FW series and loved the F4 F5 and J2 the highest of which has 0.4 ohms.

Edited August 1, 2012 by luvdunhill

[Tyll Hertsens]

PM sent

[Tyll Hertsens]

I think the thing with higher output impedance amps you'll get more interaction with the headphones and you'll find "magic" combinations from time to time. But it's a hit or miss kind of thing, and for makers who want a significant number of sales, making amps with hit and miss results is a dangerous model.

If (when, hopefully) headphone jacks commonly have very low output impedances, the fucking Germans will be able to give up this stupid 120 Ohm impedance that requires them to fuck with their designs, and can build headphones under the assumption that their going to get electrical damping.

I betcha Beyer headphones generally suck almost entirely because of this assumed 120 Ohm output and their acoustic damping schemes in response.

/rant

[nikongod]

I think the thing with higher output impedance amps you'll get more interaction with the headphones and you'll find "magic" combinations from time to time. But it's a hit or miss kind of thing, and for makers who want a significant number of sales, making amps with hit and miss results is a dangerous model.

not at all.

Put a switch on the front dsavitsk/Donald North/Pete Millet style. Or use separate jacks like Jan Meier does.

With a SS or transformer coupled amp its not hard or significantly more expensive to accommodate many headphone "drive styles" with one amp.

If (when, hopefully) headphone jacks commonly have very low output impedances, the fucking Germans will be able to give up this stupid 120 Ohm impedance that requires them to fuck with their designs, and can build headphones under the assumption that their going to get electrical damping.

How do you know its not the other way around?

How do you know that its not EASIER for the headphone designers to design around a 120ohm output impedance, and they compromise their designs so that they don't sound like abject crap from 0-ohm outputs?

If/when DIYers/Objectivists drop the preconceived notion of how a headphone should be run the people designing the most complicated part of the system (the headphone) will have free reign to do their best.

Let the headphone designers steer the ship.

[mypasswordis]

I think Beyers just suck because they suck. I also think if headphone manufacturers used more science and less voodoo to design their headphones, there wouldn't have to be crazy amp designs suited for a particular esoteric driver or type of speaker that sound like crap on the majority of amplifiers. But I guess some people find that fun.

Was going to type out a long response but Firefox decided to go nuts on me so I had to restart. Basically I can see where Doug and others are coming from. From the viewpoint of a (former?) orthodynamic enthusiast, in which there needs to be a lot of damping involved, electrical damping is much preferred to acoustic damping. Less issues to deal with, and less fiddling around with felt and vents and whatnot. Granted, there still usually needs to be some form of acoustic damping, but less is better.

I wouldn't say the impedance of the HD800 is that linear, but it is better than crossovers which then can have phase issues, etc.

[spritzer]

I've tried to get the Senn engineers to open up about this but they just refused to answer. Very German of them too...

After a few hours the 120ohm adapter test has ended in utter failure. The sound was just too soft and bloated with it in place so while the top end bite was diminished a bit it also killed the near ESP bass these cans do so well.

[Tyll Hertsens]

Booyah!

[Tyll Hertsens]

BY the way, had a little chat with Doug, and wanted to say that my aversion to high output impedance amps does not include transconductance amps. That's quite a different beast and I think a very rational alternative approach. My favorite amp for K1000 was a First Watt amp, and to me it was a spectacular match up.

[cobra_verde]

Tyll, I've read mixed results about K1000 and FirstWatt F1. Do you recall which FirstWatt amp you liked K1000 with? (Long time lurker, first post, rip me a new one.)

[mypasswordis]

F1 with K1000 is not gm amp, it's just a poor voltage amplifier. F2 also isn't, and the others most definitely aren't.

[luvdunhill]

F1 with K1000 is not gm amp, it's just a poor voltage amplifier. F2 also isn't, and the others most definitely aren't.

agreed.

Also, the F1 and F1J have a high output impedance (and F2 and F2J).... so, it doesn't make sense to make an exception for them Tyll. My point is that It's the other ones that have low output impedance, aren't gm amps and sound awesome in the context above.

Also, here are some quotes to consider from the F1 owner's manual:

This is a very unusual amplifier that will not sound good with about 98% of

the loudspeakers on the market. It requires careful attention to

loudspeaker loading to get the best performance. The accompanying white

paper “Current Source Amplifiers and Full-Range High-Efficiency Drivers”

is required reading. This is a tinkerer’s amplifier, and experimental tool. If

you just want to be a consumer, then buy something else, otherwise be

prepared to patiently experiment with your system to get the best

performance.

It does not often work well with ordinary passive crossover networks – the

components and their locations tend to be reversed. It won’t break, but

probably won’t sound good

Edited August 3, 2012 by luvdunhill

[Tyll Hertsens]

Aleph 1? Not sure. I think it was a Volksamp version.

Edit: Just caught up on the last two posts. Oh well, guess I'm out of the loop on this one. It did sound damned good to me though.

Edited August 3, 2012 by Tyll Hertsens

[swt61]

Marc was dead on about the F5/K1000 combo. He recommended I build the F5 before he actually heard the combo IIRC, but was pretty sure it'd be the right amp for the K1000. As much as I love the b22, the F5 is the better match for the K1000. Now if it just didn't double my electric bill for the month.

[robm321]

I thought the F1/K-1000 had very good synergy. It seemed to control the drivers as good as any amp I've heard them with.

[nikongod]

I also think if headphone manufacturers used more science and less voodoo to design their headphones, there wouldn't have to be crazy amp designs suited for a particular esoteric driver or type of speaker that sound like crap on the majority of amplifiers. But I guess some people find that fun.

Hang on, are you speaking from the position of a headphone designer? No, cause you're not one so shut up. None of us to the best of my knowledge are. All any of us are doing is putting off-the-shelf drivers in a new enclosure or taking off the shelf headphones and designing amps around them. We find new sounds with this effort, but nobody here has designed an actual dynamic driver*.

The headphone designers have a really hard time of it. Its a wonder they can get anything done with having to work in BOTH electrical and mechanical fields. Let the headphone designers do their own thing, their job is already hard enough.

Lack of science? You are out of your fucking mind Straight up insane insulting headphone MFRs like that. The technology in the AKG "varimotion" drivers and how AKG solved the problems they set out to solve is amazing. The ring radiators senn is pushing are a freakish show of knowledge. Beyer is too busy hyping the retarded field strengths in the T1 drivers to talk about anything else, but what kind of shade-tree engineering went into just getting those magnets & coils set up? Ooh, yea, none. They use plenty of scientific methods even when you don't like the results.

The additional effort required to design an amplifier around a headphone with unusual (based on what standards?) drive requirements is a joke.

There are tons of amp designers on this board. Ask really quick how hard it is to make a headphone amp with 120ohms output impedance. Don't let them weasel their way out with the bitch response of "why would you want to" just ask how hard is it? The effort is nominal.

Sorry.

*Apologies to anyone who has actually designed a dynamic driver. If you think your job is easy enough to let amp designers tell you what to do I have a few things I could add.

[Dusty Chalk]

[Knuckledragger]

[nikongod]

I feel like I got the same response the last time I posted a long post from SLC. Maybe just a deja vu of a deja vu from last year.

[deepak]

I feel like I got the same response the last time I posted a long post from SLC. Maybe just a deja vu of a deja vu from last year.

I "liked" the post and was pretty much in full agreement with it. Even if I don't care for many of these products, I can appreciate the extraordinary amount of engineering that goes into them.