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Tube amp with low impedance Headphones

post #1 of 23
2/19/10 at 1:06pm
Thread Starter 
Is it a bad idea to use a Tube Amp with low impedance headphones? I currently have a Glow Audio Amp one, and I'm looking at purchasing the Audio Technica ATH-AD700 phones, that I believe only have 38 ohm impedance or so.
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post #2 of 23
2/19/10 at 1:17pm
There are a few out there that are doable such as the Woo WA6 or Mapletree Ear+HD (which I ordered and am waiting for) that will drive most impedances. OTL amps aren't the way to go. Look for a transformer coupled amp or one that has a low output impedance. Either that or look for hybrids.
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post #3 of 23
2/19/10 at 1:27pm
Quote:
Originally Posted by dongringo View Post
There are a few out there that are doable such as the Woo WA6 or Mapletree Ear+HD (which I ordered and am waiting for) that will drive most impedances. OTL amps aren't the way to go. Look for a transformer coupled amp or one that has a low output impedance. Either that or look for hybrids.
X2 on the WA6 or MAD ear+. I started this thread about OTL tube amps and low impedance headphones, and the consensus was that transformer-couple jobs (like the WA6 and Ear+) are the safer option. That isn't to say that some OTLs don't work nicely - some people find they work just fine - but TC tube amps can technically pander to low impedance better. I have heard of some OTL amps which actually output low impedance aswell - the Zana Deux being one of them (unless my memory is faulty). FWIW I am using a WA6 with some low-impedance cans (RS1i) and they sound brilliant together.
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post #4 of 23
2/19/10 at 4:41pm
Thread Starter 
I found these specs for my tube amp on their website. From this info, it seems I should be ok. What do you guys think though?

Amp One
SPECIFICATIONS
OUTPUT IMPEDANCE
Speakers: 4Ω~8Ω
Earphone: 32Ω~600Ω
OUTPUT POWER
5W×2 at 1KHz
Earphone: 600mW
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post #5 of 23
2/19/10 at 4:47pm
The 700's will be fine amped or unamped, so I would go for it, sit back and enjoy...

and in case no one has mentioned it yet, sorry about your wallet
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post #6 of 23
2/19/10 at 5:10pm
Thread Starter 
Oh, my wallet is already starting to feel the pain.. tube amps aren't cheap hehe.
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post #7 of 23
2/19/10 at 5:15pm
My transformer-coupled WA6 is fantastic with both low impedence and high impedence cans. Actually, they amp more of my low impedence stuff (RS1, K701, ESW10) than high impedence (HD650) currently.
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post #8 of 23
2/19/10 at 8:50pm
Quote:
Originally Posted by Hordsak View Post
Is it a bad idea to use a Tube Amp with low impedance headphones? I currently have a Glow Audio Amp one, and I'm looking at purchasing the Audio Technica ATH-AD700 phones, that I believe only have 38 ohm impedance or so.
The only problem with some amps with low impedance phones is noise,very much so if there sensitivity is up around 104 dB/mW.
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post #9 of 23
2/20/10 at 6:31am
Quote:
Originally Posted by dongringo View Post
Either that or look for hybrids.
Excuse me guys, are hybrid amps really good for low impedance headphones?
is WA6 a hybrid amp?
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post #10 of 23
2/20/10 at 10:02am
Quote:
Originally Posted by VALIENTE View Post
Excuse me guys, are hybrid amps really good for low impedance headphones?
is WA6 a hybrid amp?
The Woo WA6 is not a hybrid. It's 100% tubes including the rectifier. It's an excellent choice for both high and low impedance loads because it uses an output transformer which has both high and low impedance outputs

From what I hear, hybrid amps excel at driving low impedance loads. I'm not sure how well they do with high impedance's
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post #11 of 23
2/20/10 at 10:07am
Quote:
Originally Posted by VALIENTE View Post
Excuse me guys, are hybrid amps really good for low impedance headphones?
is WA6 a hybrid amp?
Yes, hybrid amps are considered a good match for low impedance headphones, as the solid state output stage can supply the amount of current favoured by low impedance designs. To clarify, a hybrid is a tube pre-stage with a solid stage output stage.

As for the WA6, it is not a hybrid amp, it is a pure tube design. Amps like WA6 make use of output transformers as a means of matching the output to either high or low impedances.
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post #12 of 23
9/29/10 at 7:37pm

Yes, I have a pair of Shure SRH-840s which are powerhogs but only run at 44ohms.  I have a Little Dot I+ hybrid and I've never heard my cans sound better.  I would definitely recommend a hybrid, but I too was wondering if I should upgrade to something like the LD III tube amp for better imaging, sq, etc.

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post #13 of 23
9/29/10 at 7:58pm

 

Quote:
Originally Posted by ford2 View Post

Quote:
Originally Posted by Hordsak View Post
Is it a bad idea to use a Tube Amp with low impedance headphones? I currently have a Glow Audio Amp one, and I'm looking at purchasing the Audio Technica ATH-AD700 phones, that I believe only have 38 ohm impedance or so.
The only problem with some amps with low impedance phones is noise,very much so if there sensitivity is up around 104 dB/mW.


I disagree with this, well I disagree that it is implicating that tube amps are inherently noisier than other types of amps. This is definitely not the case. Any amp can be noisy.

 

db/mw is a bad way to look at whether a particular thing will be noisy. There are quite a few high impedance headphones pushing close to 100db/mw after all... you have to have an especially speshul amp for someone to say that they are noisy. (A high gain SS amp with high impedance feedback/input impedance setting resistors should do just fine). db/mv is a better standard if you want to look at noise. 

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post #14 of 23
10/1/10 at 11:46am
Quote:
Originally Posted by dongringo View Post

There are a few out there that are doable such as the Woo WA6 or Mapletree Ear+HD (which I ordered and am waiting for) that will drive most impedances. OTL amps aren't the way to go. Look for a transformer coupled amp or one that has a low output impedance. Either that or look for hybrids.


That's what I learned, too.  However, my SinglePower MPX-3 Slam SE is doing a great job of driving my Audeze LCD-2s.

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post #15 of 23
10/1/10 at 2:15pm

What i have learn is that impedance matching is very important. If you have a tube amp like a Woo with high impedance and low impidance outputs wil work fine. I have notice a big difference in sound when I connect my D7000 in the low inpedance output compared to the high impedance output jack. Out of the high impedance output they just not sound right.

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