why can't we use power amp to be head phone amp
Sep 26, 2003 at 5:02 AM Post #16 of 34
Yes, of course but not that way, please do not assume that everybody is an ignorant, that have something to learn from you, some people have heard a few amps also, you are not the only one, BTW take it easy and chill down, there is nothing personal, OK? And as I said before, I agree with you in some other points....
 
Sep 26, 2003 at 6:40 AM Post #17 of 34
Wow, this CD3k v HD600 argument wound up getting very personal didnt it
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Sep 26, 2003 at 4:26 PM Post #18 of 34
Quote:

Originally posted by pbirkett
Wow, this CD3k v HD600 argument wound up getting very personal didnt it
eek.gif


No there is nothing personal, but FYI in my case I have heard both, I'm entitled to my opinion, of course is not the only one, or wrtten on stone, but I don't know if others are, there is nothing personal, it could be on any other member post, I do not consder the OBH11 a reference amp to be use as a comaprison with nothing, but a similar cheapo samll amp, about the amp in question (OBH11), even though I do not have heard the Sony vintage, but others 150 vintages amps or more, built on the same quality, era, and maybe the same circuit inside, I was realated to audio for more than 20 years now, most of the time with vintage gear, Pioneer, Sony, Sansui, Technics, Teac, Akai, etc...of course I know how they sound, that BTW the Sony sound, in amps at least, is the less seductive of the bunch among them, I likethe TCK series of decks OTOH, specially TCK-4 ferrite head, oh...memories, where have all the old good times gone??? When people designed to last for 20 years or more....
 
Sep 27, 2003 at 3:31 AM Post #19 of 34
Quote:

Originally posted by Rameish
I was gonna try this with my EAR-834L toob Pre-Amp. But I din not dare try it for fear of damading something (amp or headphone).

How does it sound in your setup?


Actually, it sounds great. What is the output impedance of your EAR-834L? I think it needs to be lower than your headphones (rule of thumb), and be able to swing the necessary voltage.
 
Sep 27, 2003 at 8:48 PM Post #21 of 34
Getting back on topic, and I DON'T know beans about electronics - will admit that freely! But I got the bug a year or so ago to try running from speaker taps and I started with an old pair of V-6's that I wouldn't miss (too much). I dug up an old Radio Shack headphone extension cable and stripped it back to hard wire it into the speaker jacks, tapped into an Onkyo receiver and was blown away (the right way). This led me to experimenting with several other combos including ss and tube amps. When I tried my HD-600's connected directly to a pair of Bottlehead Para S.E.X. mono-blocks (3 wpc) with a Foreplay Pre I HIT IT! Kept me happy for over a year at work and got LOTS of comments from the cheapie boombox users! And the sound is still one of my references.
I now have a DIY 45 based direct heated SET built by a friend driving my Grado RS-1's and DAAAAMMMNNNNNN. But this same amp (1.5 wpc) won't run the Sennheiser's or my CD3K's at all without distorting. I don't know why it is partial to the Grado's but when I listen it's the last thing I am thinking about!
So, the rule of thumb is...idunno. Try it and if it works do it.

John
 
Sep 29, 2003 at 1:45 PM Post #22 of 34
Quote:

Originally posted by Hirsch
The R10 has a maximum power handling capability of 1 watt. I'd hesitate about throwing 100 watts at them. Might be nothing left but a pile of smoldering zelkova wood
tongue.gif

.


I don't think you could output 100w into an average headphone.A 100w amplifier will deliver about 30v rms to a normal load from 8ohm upwards at least. According to Ohms law a headphone at 300 ohms will only receive 3w at full volume, which of course is still much more than most can handle.
 
Sep 29, 2003 at 4:21 PM Post #23 of 34
One has to consider voltage and current. There are limits on both for any given amplifier.

Headphones like the grados are 32ohms, closer to that of speakers. So, a power amplifier is more likely to drive grados. If you hook up a Sennheiser at, say, 300 ohms, then it will draw less current (V=IR) and demand more voltage to get listenable sound levels. This could put the amplifier into clipping.

That is why transformers are used... they are impedance transformers, swapping voltage for current and vice versa. So, to drive the Sennheisers, you probably need a special transformer on the SET amp. If it already has one, make sure to try the highest output impedance tap. Even that may not be enough.
 
Sep 30, 2003 at 6:23 AM Post #24 of 34
Dusty Chalk,

No idea what the output impedence is on the EAR 834L. EAR only gives the "input sensitivity for 1 volts output = 200mv. Not much help. hmmm...
 
Sep 30, 2003 at 8:23 PM Post #25 of 34
Quote:

Originally posted by protos
I don't think you could output 100w into an average headphone.A 100w amplifier will deliver about 30v rms to a normal load from 8ohm upwards at least. According to Ohms law a headphone at 300 ohms will only receive 3w at full volume, which of course is still much more than most can handle.


The R10 is a low impedance headphone, around 32 ohm IIRC. It would not receive the full 100w, but would receive enough of it that I'd hesitate to attempt the experiment. My guess is that R10 drivers are not cheap
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Oct 2, 2003 at 3:47 PM Post #26 of 34
K1000 are designed to be driven by a power amp. They are 120 ohms. What could possible be the reason for not using the k501, for example, with the same power amp, apart from the risk of turming the volume pot of your pre too high? Wouldn't be the 120 ohms of the K501 just as much a burden for the amp as the 120 ohms of the k1000? Just wondering, don't pretend I know...
 
Oct 2, 2003 at 9:18 PM Post #27 of 34
As far as I am aware there are two reasons. (I'm pretty new to this stuff so correct me if I am mistaken)

1. The K1000 are VERY inefficient, they need more than twice the power of the K501 to reach 100db

2. The K1000 require a much higher voltage output from the amp.

A 'normal' power amp will output a grater voltage than a 'normal' headphone amp. This is why you can not use a normal headphone amp to drive them. The amount of Watts is not the critical thing with the K1000's
wink.gif


BTW, hi everyone I am new to this forum! Though I have been posting on www.sgheadphones.com for a little while now... Nice to meet you all!
 
Oct 6, 2003 at 5:11 AM Post #28 of 34
I didn't mean using a regular headphone amp for K1000, I meant using the speaker outputs of a regular power amp for k501 (with an adapter, but without adding a transformer - which would degrade the sound to a certain degree - ) Once again, apart from the risk of feeding them more than they can swallow by not turning the volumew pot low enough before, what could go wrong?
 
Oct 6, 2003 at 5:52 AM Post #29 of 34
Well, the problem is, you may not have enough control over the volume at the bottom end of the "swing" of the volume knob. (We're talking less than millimeters.) So you may want to at least put another preamp in front of it (everyone here has an extra preamp hanging around, don't they?).
 
Oct 6, 2003 at 6:36 AM Post #30 of 34
Quote:

Originally posted by Dusty Chalk
Well, the problem is, you may not have enough control over the volume at the bottom end of the "swing" of the volume knob. (We're talking less than millimeters.) So you may want to at least put another preamp in front of it (everyone here has an extra preamp hanging around, don't they?).


Unfortunately I have only one extra preamp :). I'll give it a shot and report back. Thanks Dusty.
 
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