Headphone & Amp Impedance Questions? Find the answers here!

[Chris J]

Quote:

Oh yeah, but every OT hp amp I've seen has such taps routed through a rotary switch (Cayin, Woo, etc) so I figured it was safe to assume as global.

 
Oh,  I didn't know all those headphone amps have rotary switches.  my turn to be......

I seem to remember seeing a few cheaper one without taps?
I think Little Dot makes a few without taps?   Or have I imbibed too much Sarian Brandy?

 

[Chris J]

Quote:

I'll keep my eyes peeled for the "Headphone/Amp Impedance Matching For Dummies" on Amazon - I think I need this to be explained to me like a 6 year old....

 

 
Then you probably don't want to read this:  http://www.head-fi.org/a/headphone-impedance

 

[obobskivich]

Oh,  I didn't know all those headphone amps have rotary switches.  my turn to be......
I seem to remember seeing a few cheaper one without taps?
I think Little Dot makes a few without taps?   Or have I imbibed too much Sarian Brandy?

Those are OTL models afaik; they're fairly popular from what I've seen.

 

[proton007]

Any advantages/disadvantages of OTL ? From what I know, they're mostly for high impedance headphones.

 

[Chris J]

OTLs have a high output impedance so they work better with high impedance cans.
Output impedance ranges from approx. 60 to 100 ohms, which is really dictated by the output tube used.
Since they don't have output transformers, they are cheaper than tube amps with output transformers.
And since they don't have output transformers, theoretically they would have lower distortion and a wider bandwith than transformer coupled tube amps.

 

[obobskivich]

OTLs have a high output impedance so they work better with high impedance cans.
Output impedance ranges from approx. 60 to 100 ohms, which is really dictated by the output tube used.
Since they don't have output transformers, they are cheaper than tube amps with output transformers.
And since they don't have output transformers, theoretically they would have lower distortion and a wider bandwith than transformer coupled tube amps.

What he said.

From user reviews, they tend to be preferenced for higher impedance headphones (and honestly there's not a lot of high Z cans that I personally like, so I haven't ever tested this out for myself - most OTL amps are dangerous with one of my favorite cans).

 

[Chris J]

Another way to look at this is to say that it is a fairly cost effective way to get into tube amplification:
 
A high impedance 'phone with an OTL tube amp is cheaper than a low impedance 'phone with a transformer coupled tube amp.
Good output transformers are expensive!
 
OTOH: a good solid state amp with drive both low and high impedance cans with ease.
IEM guys seem to get into trouble with excessive gain and noise from poor amp matching, but that is another argument for another day.

 

[proton007]

So far the only OTL amp I've heard of is the crack OTL, but seems like its a fairly old design, when headphones were inefficient and high impedance.

 

[T.F.O.A]

Great threat, but since i don't have any science background... smokes coming out of my ears.

 

[proton007]

Quote:

Great thread, but since i don't have any science background... smokes coming out of my ears.

FTFY.
And thanks but I guess you do need a bit of maths/science to understand it.

 

[obobskivich]

So far the only OTL amp I've heard of is the crack OTL, but seems like its a fairly old design, when headphones were inefficient and high impedance.

As opposed to now when they're inefficient and low impedance?

 

[proton007]

Quote:

As opposed to know when they're inefficient and low impedance?

 
Well, nowadays it seems to be more like efficient and high/low impedance...

 

[obobskivich]

Well, nowadays it seems to be more like efficient and high/low impedance...

Aside from noticing my glaring spelling error (BAH!), I was making a jab at the orthodynamic products that've come about recently.

 

[proton007]

Quote:

Aside from noticing my glaring spelling error (BAH!), I was making a jab at the orthodynamic products that've come about recently.

 
Yeah, thats what I was thinking of, I couldn't find the word...or-tho-dy-namic

 

[Chris J]

Quote:

Aside from noticing my glaring spelling error (BAH!), I was making a jab at the orthodynamic products that've come about recently.

 
OK, as long as you weren't taking a dig at AKG Q701!