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Speaker amps for headphones - Page 121

post #1801 of 3116

Here's a graphic of the "preferred" two resistor network applied to a single-ended headphone:

 

Single-Ended Headphone Network

Headphone_Resistor_Netwrok_Single-Ended_Preferred.jpg

The headphone cable's shield carries the combined common ground negative signal.

A 5 watt 6 ohm Resistor2 and 3 watt 2 ohm Resistor3 will work best for the vast majority of headphones and speaker amps. The resistors should be wirewound non-inductive and cost about $2 each at Mouser.com.


Edited by robrob - 12/6/13 at 11:16am
post #1802 of 3116

Looks good Rob. If I may be picky here, space those negative amp terminals a little more, it just looks weird being that close together lol. :tongue_smile: 

post #1803 of 3116
Quote:
 Do audiophiles argue with lawyers about the law?

 

Yep, when they're not up on new laws. These definitions we're arguing about have changed over the years. Back in the day you'd be right.

 

Quote:

 All Operational Amplifiers have single ended outputs.

 

Click on the Texas Instruments link I provided. The paper shows an op amp with differential outputs (things change).

 

Quote:
 The TI note probably shows 3 Op Amps in an Instrumentation Amplifier arrangement?
Can you send me a link?
I can't really comment on it if I can't see the topology.

 

The title of the Texas Instruments paper is a link. The paper has a graphic showing a single op amp with differential outputs.

 

Quote:
 A Single Ended Triode is called Single Ended because the amplifier topology is Single Ended.

 

Ding! Ding! Ding! We have a winner! That's what I've been trying to get across to you. "Single Ended" refers to amplifier topology and interconnects.

I say again, the term "single-ended" is currently used by the electronics industry and audiophiles to describe amplifier circuits and unbalanced interconnects. It's kind of like the word "sick" can now mean bad or good. I can't change that by saying, "No it doesn't! No it doesn't!"

 

Edited by robrob - 12/6/13 at 11:25am
post #1804 of 3116
Quote:
Originally Posted by brunk View Post
 

Hehe yep :D Plus I'll add, IMO, that it's really not needed in a Head-Fi rig unless you're listening inside a server room or something lol. Your cables are so short, little power needed, that all it does for you is maybe reduce audible crosstalk and lighten your wallet by a large amount if you're not careful :tongue_smile: 

 

But those big XLR connectors on the headphone cables look so cool--that alone is worth the extra coin :atsmile:

post #1805 of 3116

Ugh, I'm just going to step out of the definitions/semantics debate.

post #1806 of 3116
Quote:
Originally Posted by robrob View Post
 

Here's a graphic of the "preferred" two resistor network applied to a single-ended headphone:

 

Single-Ended Headphone Network

 

The headphone cable's shield carries the combined common ground negative signal.

A 5 watt 6 ohm Resistor2 and 3 watt 2 ohm Resistor3 will work best for the vast majority of headphones and speaker amps. The resistors should be wirewound non-inductive and cost about $2 each at Mouser.com.

 

p.s. it doesn't have to be a shield, it can simply be a third wire

post #1807 of 3116
of course it does not to be shielded , there is nothing we do that makes any sense regarding the original concept of this type of signal transmission . so the headphone industry has created a whole new concept and named it after something most have heard of. perfect

AL D
post #1808 of 3116
Quote:
Originally Posted by Armaegis View Post
 

 

p.s. it doesn't have to be a shield, it can simply be a third wire

 

Very true but pretty rare. I know they're out there but I've never seen an unshielded single-ended headphone cable.

post #1809 of 3116
Quote:
Originally Posted by robrob View Post
 

 

Click on the Texas Instruments link I provided. The paper shows an op amp with differential outputs (things change).

 

 

The title of the Texas Instruments paper is a link. The paper has a graphic showing a single op amp with differential outputs.

 

 

Ding! Ding! Ding! We have a winner! That's what I've been trying to get across to you. "Single Ended" refers to amplifier topology and interconnects.

I say again, the term "single-ended" is currently used by the electronics industry and audiophiles to describe amplifier circuits and unbalanced interconnects. It's kind of like the word "sick" can now mean bad or good. I can't change that by saying, "No it doesn't! No it doesn't!"

 

 

At this point, I'm not sure if you're just trolling.   :rolleyes:

 

And I'm not too sure what you think changed in the terminology.

And I'm not 100% sure what you are trying to get across anymore.

Not too sure when you think the term single ended changed it's definition?

Seriously, the first Op Amps used vacuum tubes.

The definition of an Op Amp has never changed.

The definition of a balanced line or push-pull has never changed, etc.

 

The TI paper discusses fully differential Op Amps, i.e. Op Amps e/w Inverting and Non-Inverting outputs. Very nice.

The TI paper shows an Instrumentation Amplifier with differential outputs. OK.  You've found an unusual Instrumentation Amplifier.

Very true. They exist.

And this is also true:   a typical Instrumentation Amplifier has only one output designed to drive an unbalanced transmission line or cable or load or whatever those young kids are calling it today

And a typical Op Amp has one output terminal, referenced to ground, the output transistors are typically a push-pull pair. 

Sure, you can find Op Amps with bridged outputs that can drive balanced lines, but they are atypical.

 

 

!


Edited by Chris J - 12/7/13 at 10:56am
post #1810 of 3116

Chris, I'm not sure either.

 

I thought you originally said the term "single-ended" only applied to input, transmission and output (interconnects). I disagreed and said it applies to both amplifier topology and interconnects and posted the TI paper link to back up my assertion.

 

I agree that the term "balanced amplifier" is an audiophile invention. Balanced and unbalanced (single-ended) has to do with interconnects.

 

Do we agree on this?


Edited by robrob - 12/6/13 at 2:01pm
post #1811 of 3116

Changing the topic slightly here....

 

I need some help in selecting a speaker switch box, so I can toggle between my speakers and HE-6. I understand many units have amp protection with resistors to keep the impedance at roughly 8 ohms if you decide to run both A and B speakers at the same time. Some have the option to disable it, which is what I want. However, I am reading that some affect sound regardless. Anyways, what is a good low-cost switch box that has defeatable protection, and separate grounds?

 

I am looking at this switch so far, but I don't really know if it has dedicated grounds or not.

http://www.outdoorspeakerdepot.com/ishipo4pasps.html

 

another option I'm looking at is the Niles SPS-4

http://www.nilesaudio.com/images/legacy/manuals/sps4man.pdf

 

However, is there a switch like these where you can also toggle between two different amplifiers? This would be really nice, so I could use my speakers/headphones from 2 different amps!

 

Thanks in advance :)

post #1812 of 3116
Quote:
Originally Posted by robrob View Post
 

Chris, I'm not sure either.

 

I thought you originally said the term "single-ended" only applied to input, transmission and output (interconnects). I disagreed and said it applies to both amplifier topology and interconnects and posted the TI paper link to back up my assertion.

 

I agree that the term "balanced amplifier" is an audiophile invention. Balanced and unbalanced (single-ended) has to do with interconnects.

 

Do we agree on this?

 

Hello Rob,

 

The light bulb in my head just came on.

Sorry, I fully agree, Single Ended certainly applies to amplifier topology, too.

Easy to see that your simple tube amp examples are single ended......The Classic Single Ended Triode you referred to.

 

It certainly gets ambiguous when you look at the output stage of a "typical" SS power amp.

Um,  it's single ended push-pull?

 

I agree, "balanced amplifier" gets ambiguous........................kind of a useless term without some type of explanation of topology.

It drives me to drink when someone asks "is the Acme Mark IV power amp balanced from input to output?"

The answer is: yes, it's perfectly balanced front to back, i.e. it has a perfect 50:50% weight ratio.

 

So, yes, we agree on this.

:beerchug:

 

Chris

 

Note to anyone else reading this now:

I will have drink (of my choice) for each of you tonight!

post #1813 of 3116
Quote:
Originally Posted by brunk View Post
 

Changing the topic slightly here....

 

I need some help in selecting a speaker switch box...........

Thanks in advance :)

 

I'm not too comfortable with you changing the subject right now.......

 

....................hey, just kidding......:o

post #1814 of 3116
Quote:
Originally Posted by Chris J View Post
 

 

I'm not too comfortable with you changing the subject right now.......

 

....................hey, just kidding......:o

Hehe, go have that drink man, it'll "balance" you out :tongue:

post #1815 of 3116

Sorry Chris and everyone else.

 

I think I'll have a beer too. :beerchug:

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