[Gluegun]

WOOOOHHHHOOOOOOO!!!!!!!

Got a set of HD565, used, from a headwizer....and THEY SING!!!!

*is listening to them out of his sound blaster live*

WOohhhhooooooooo!!!!!!!

*kinda starts to wonder how they compare to those 2nd-highest-end Philips, and then clamps down on that thought*

 

[Xander]

Actually, my assumption based on a glimpse of the amps schematic turned out to be false. I found this out when I turned on the speakers alongside the headphones, and experienced zero drop in power available to the headphones. Most of all, the speakers still functioned in this mode.

I'll scan the schamtic some time, so you can take a look.. Upon closer inspection, it appears that the headphone section has it's own dedicated MOSFET amplifier.

I'd also like to mention, after listening again using the speaker terminals and the output imp increasing resistors, it still has the same sound traits, however the bass is a lot more sloppy then it was directly out of the headphone jack.

Nevertheless, I'm planning on buying a HeadRoom MAX sometime in the future. I'm convinced, though, that this amp delivers good sound for what its worth. Compared to my other amplifiers, whereas snare hits and the like dont even SOUND the same, so much of the signal is lost.

 

[Xander]

And stop second guessing my judgment and equipment.

If the bass were that sloppy out of the headphone jack, I would've atmediatly noticed after a few seconds, and decided not to use the receiver to drive my headphones at all...

On the other hand, a raw, plain and simple mosfet power amplifier designed to drive high impedances is a _good_ thing. I can see now, why Sansui decided to create a dedicated amp for the headphones, although it doesnt offer much power. Because of the way things sounded off of the speaker terminals, it's obvious why they did it.

I had to hold the wires with my hand on my XLR jack, so my evaluation was anything but lengthly. Sorry about that. :/

I just hope you dont judge the equipment because of it's age and reason for creation (to be a good amplituner) like most people are. I think theres a general assumption that if it's not a dedicated headphone amp, then it must not sound as good as it could. On most receivers, this may be true. Unless it has a dedicated mosfet headphone amp of it's own.

 

[Xander]

WRONG AGAIN

Ok, no more quick glances.

It's driven directly from the speaker power amp section, using a few resistors. However, it's not completely clear as to what it's doing. The circuit it uses to match the headphone impedance to the speaker outputs, is a lot different then the one I used from HeadWize.

There IS however, a large decrease in bass resolution with the HeadWize resistor configuration, but for some reason there isnt with the internal one inside the Sansui amp. Later on, I'm going to copy the circuit in the Sansui and use it directly on the speaker outputs, and see if the bass is ill defined or not.

Maybe somehow the way the Sansui matches the impedances, the demping factor isnt severely harmed? Also, before I assumed that the headphones would cause the output to drop and the speakers to remain undriveable because of the power consumption. How this circuit works is somewhat clear now, so this isnt entirely true. I would've assumed though, that the Sansui would switch off the speakers as soon as the headphones were connected.

 

[Tim D]

I've had experience with quite a few jacks from integrated amps/receivers and the like. The use of dropping resistors is not a novel new design that would ever be certified as being a "dedicated" design for headphones. Also the fact that plugging in headphones and not hearing any sort of response or feedback from speakers is not special either.

MANY if not all receiver jack designs are taken from the speaker outputs with added resistors. This is not new or special. If the product boasts a true dedicated headphone amplifier that is seperate or different, the product would definitely boast it. Another way is if they have some transformer after the speaker outputs.

I can drive my AKG501 from my Audiosource speaker amp as well and not notice a huge bass bloat...but this is not the case with something like HD600's.

Damping factor is definitely harmed...it is wheter or not the headphones in question complain much or not. For example the Sennheiser HD600 frequency response graphs were probably done with the MAX...if you hook up something that was even a little higher in output impedance, the midbass which is already slightly elevated probably gets more sloppy. The highs which are already laidback probably become more so.

Higher output impedance is no big deal...it just depends on the headphone. Also depending on the headphone, most people might not hear that big a difference in damping factor in the first place. *Most* headphone diapghrams don't really have the same qualities of large speaker woofers that they absolutely need high damping factors. If damping factor was supreme, and higher output impedance is always bad, than there is no reason why the Melos SHA-1 has a higher output impedance jack. Or reason for Jan's Corda to have a higher output impedance jack. Or reason for the Creek OBH-11 SE to have varied higher output impedance jacks. Or for the original MGHead designs to sport high/low impedance switch (for some reason it seems most people didn't notice a difference on this one). Only Headroom seems really bent on keeping with low impedance...and the HD600 is one of their favorites. Course high damping is one of those amplifier/speaker "ideals", but not everything is ideal I suppose.

 

[Audio-Me]

Given that you have an adequate source to drive the Sennheiser HD600s, my take is that they sound more real than any other set I have ever heard. The slight coloration gives added warmth and also brings the sound to life. No need for details, it is what it is: a clear rich sound producer that gives drama to the source.

Otherwise, get something else!

 

[Xander]

Quote:

Originally posted by Tim D I've had experience with quite a few jacks from integrated amps/receivers and the like. The use of dropping resistors is not a novel new design that would ever be certified as being a "dedicated" design for headphones. Also the fact that plugging in headphones and not hearing any sort of response or feedback from speakers is not special either. MANY if not all receiver jack designs are taken from the speaker outputs with added resistors. This is not new or special. If the product boasts a true dedicated headphone amplifier that is seperate or different, the product would definitely boast it. Another way is if they have some transformer after the speaker outputs. I can drive my AKG501 from my Audiosource speaker amp as well and not notice a huge bass bloat...but this is not the case with something like HD600's. Damping factor is definitely harmed...it is wheter or not the headphones in question complain much or not.

I see what your saying. The impedance increasing circuit in the Sansui however, differs from the one that I used from HeadWize. I don't know which formulas to use to calculate the damping factor based on the speaker impedance / output impedance, do you? This would help me figure out why the bass is so different one way, as to how it is out of the headphone jack. I suspect that the damping factor may already be low, the HeadWize circuit may cause it to be even lower, resulting in somewhat sloppier bass then using the Sansui internal impedance matching circuit.

 

[lini]

Xander: Be a man, Arthur Puty! (= post the bloody schematic!

)

Grinnings from Munich!

Manfred / lini

 

[andrzejpw]

So far, I love my hd580s. Use em with a cmoy.

 

[Gluegun]

*Likes how his HD565's sound straight out of his SL-CT470, and out of his SBLive! X-Gamer, and out of his Total Airhead, and out of his Dad's DVD Player, and his Dad's Sony reciever, and his sony minisystem, and his other no-name minisystem, and his dad's Sony portable CD player, and his Dad's Sony Walkman, and his older Panasonic, etc. etc. etc.*

 

[Xander]

Quote:

Originally posted by lini Xander: Be a man, Arthur Puty! (= post the bloody schematic! ) Grinnings from Munich! Manfred / lini

I'm workin' on it lini! I can't find a serial cable, OR the damn power supply. Havent used it since I moved.

 

[Xander]

Actually, it may take more talent then I have.. I wonder if theres a place I can go to have large things scanned and put on a disk. The schematic is so large, I stuck it on my wall like a poster.

 

[ken36]

Very informative. Thanks.

 

[franci2105]

Anyone tried leather pads on the 565? Impressions? Something like this

https://a.aliexpress.com/_uWBOgT

 

[MrGoat]

Thread necromancy