Cheap balanced amp?
Feb 14, 2014 at 11:23 PM Post #46 of 63
No I did not just compare the RSA lightning to the Shadow I also compared it to the RSA Protector which is now a four year old model. The easiest way to answer this for me was when I compare the single output from the Protector to the balanced output. I much prefer the balanced output for the reasons I stated.


Then the balanced output of the protector is better than its single ended output, which isn't really a surprise given that it is designed as a balanced amp.  Your previous statements imply balanced > single ended period though.
 
 Originally Posted by Chris J /img/forum/go_quote.gif


Kinda weird statement there.........
confused_face_2.gif


What are you getting at.
It only accepts SE inputs?

 
Yes, the super 7 only accepts SE inputs.  The DNA tube amps are similar in that they are a SE design, but he also makes them with balanced outputs (which have an actual balanced output, not just to be there in place of an adapter).  Sonically there are not really any benefits to this, it is more of a convenience.  The super 7 sounds the same whether I use the single ended jack or balanced jack, but you just get the noise rejection properties when using the balanced jack with a balanced headphone, which has no real benefit given that we are usually running only a couple of meters of cable for our headphones.
 
Feb 14, 2014 at 11:33 PM Post #47 of 63
Then the balanced output of the protector is better than its single ended output, which isn't really a surprise given that it is designed as a balanced amp.  Your previous statements imply balanced > single ended period though.


Yes, the super 7 only accepts SE inputs.  The DNA tube amps are similar in that they are a SE design, but he also makes them with balanced outputs (which have an actual balanced output, not just to be there in place of an adapter).  Sonically there are not really any benefits to this, it is more of a convenience.  The super 7 sounds the same whether I use the single ended jack or balanced jack, but you just get the noise rejection properties when using the balanced jack with a balanced headphone, which has no real benefit given that we are usually running only a couple of meters of cable for our headphones.


OK......a tube amp with a balanced output transformer......

Yeah, if some mathematical genius went through all the math, I would wager that common mode noise rejection is not, practically speaking, a benefit of a balanced output power amp over a single ended power amp.
A headphone amp with a balanced input really only rejects significant amounts of common mode noise if the input is built to extremely tight tolerances AND the cable is balanced AND the source of the output is truly balanced,
I.e. The source has a balanced output impedance.
 
Feb 15, 2014 at 10:22 AM Post #50 of 63
What about the TEAC UD-501? It has dual 3-pin XLR outputs, has USB input for the Macbook, and costs $849, which is less than the OP said he could spend.


Looks like a nice piece of gear,

Edit:!
Doesn't seem to have balanced headphone output jacks......:redface:
 
Feb 15, 2014 at 10:40 AM Post #51 of 63
Feb 15, 2014 at 11:10 AM Post #52 of 63
Off topic:
Do people find the Fostex T50RP hard to drive?

The specs must be BS.
The specs make it sound as hard to drive as a pair of Beyers DT880 32 Ohm version.
 
Feb 15, 2014 at 11:13 AM Post #53 of 63
I'm not against balanced gear as all my headphones have balanced cables but you cannot say balanced amplification is better than single-ended amplification, it's just not true.


BTW,
I agree with that.
 
Feb 15, 2014 at 11:17 AM Post #54 of 63
In the example below you have a long cable (speaker cable) running out of a metal box with 120 or 240 volts inside (the amplifier). If the speaker cable becomes electrified due to a loose wire or amplifier damage with no ground the speaker cable stays live and could cause electrocution.

For anyone reading this thread,
In layman's terms,
This is one of the numerous reasons why you should not cut the third pin off an AC power cord.
It's for safety, as Rob points out, if the case gets electrified (electrically live), the third pin on the AC cable helps prevent you from getting an electrical shock from the case ( the enclosure).

5 posts in a row....I gotta quit posting.
 
Feb 15, 2014 at 11:35 AM Post #55 of 63
Off topic:
Do people find the Fostex T50RP hard to drive?

The specs must be BS.
The specs make it sound as hard to drive as a pair of Beyers DT880 32 Ohm version.

 
I have a pair with the basic modifications which make them less sensitive and they take much more power than my HE-500s and K240 Studios.
 
Feb 15, 2014 at 11:50 AM Post #56 of 63
I would guess it really depends on how much noise there is to be reduced by balanced circuits in the first place. Assuming  the amp architecture allows a comparison  with a single ended design..
I am sure you are well aware of my comments and can tell a balanced circuit from one that isn't.  I have read that some balanced circuits are not truly balanced. Personally I am not knowledgeable  enough to determine what is or is not truly balanced.  If  there is a single ended "pseudo balance" then obviously there should be no benefit.
It does make me wonder however , why many amp designers build balanced amps if there is nothing to be gained in doing so.
 
Feb 15, 2014 at 12:48 PM Post #57 of 63
 It does make me wonder however , why many amp designers build balanced amps if there is nothing to be gained in doing so.

 
Balanced push-pull or differential amplification is more efficient than single-ended amplification and benefits from common mode noise rejection. The downside is balanced amplification suffers from crossover distortion. Balanced amplification uses two amplifiers, one for the positive side of the audio wave, and one for the negative side of the audio wave. Every time the audio signal goes from positive to negative and negative to positive it passes through an area of amplifier overlap and 'crosses over' to the other amplifier. This transition can induce distortion into the audio signal.
 
Single-ended Class A amplifiers do not suffer from crossover distortion and have the potential to deliver the most faithful amplified audio signal (High Fidelity or Hi Fi for you old guys). The choice of amplifier topology is based on many design factors and is heavily influenced by what the potential customer wants. The current 'fad' in headphone amplifiers is for amps with balanced input, amplification and output.
 
Feb 15, 2014 at 7:41 PM Post #59 of 63
LOL all I wanted were some suggestions. I guess y'all hijacked my thread :wink_face:


Uh, yeah.
Looks like we got waaaay off topic which a pile of technical rambling.
Oddly enough, originally I got into this thread because I am looking for a cheap balanced amp (meaning something cheaper than $1,000 USD).
Way cheaper than a $1,000
Looks like we all got turned around......:confused_face_2:
 
Feb 15, 2014 at 8:09 PM Post #60 of 63
@Chris J

Yes I noticed my suggestion got immediately buried. :wink:


Anyway I did look up the Little Dot stuff (www.littledot.net) and it is the MKVII+ not the MKV that is balanced and has 1/4 TRS as well. It is $400 + ship. The MKVI+ is $770 + ship and the MKVIIISE is $839 + ship.

The MKVII+ is solid state the others are tube.

MK%208%20SE_1.jpg


The MKVI+ now has the 1/4 on the front like the MKVIIISE pictured above.
 

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