[amb]

Btw, I prefer to call it "unbalanced" vs. "balanced". The term "single-ended" is overloaded and means different things depending on context. For example, "single-ended" also refers to an output stage topology within an amp channel (the opposite would be "push-pull"). You could build a balanced amp with amplifier channels having SE output stages. Confusing? Yup.

 

[Nebby]

I like "balanced" vs. "unbalanced" makes it somewhat clearer than mud

 

[fault151]

Right thanks for that, i understand it but better now. Well its just a case of which to go with? Part of me wants to try the full 4 channel version but that would mean i would need a balanced dac (which i haven't got, yet). The other means i could use it with my existing gear no problem.

I know this must be a very commonly asked question, but is there really a great deal of difference in the 4 channel and 3 channel sound?


Quote:

Originally Posted by amb /img/forum/go_quote.gif Sort of, but not really. In a 3-channel active-ground amp, the output ground is actively driven by an amplifier just like the stereo channels, but the ground amp does not swing voltage (only source/sink return load current). It allows you to get most of the benefits of balanced output without the need to modify the 3-wire headphone. It also does not require a balanced source to make full-use of its capabilities. See the "tech highlights" section at the β22 website for more detailed info.

 

[amb]

Quote:

Originally Posted by fault151 /img/forum/go_quote.gif I know this must be a very commonly asked question, but is there really a great deal of difference in the 4 channel and 3 channel sound?

You're going to get different answers from different people. Some might hear a big difference while others might hear a small difference, or none at all. I know this is a big hand-wave answer, but such is the nature of audiophilia. You just have to decide what's right for yourself.

 

[fault151]

Ha ha i thought that would be the respone. I wish i could hear the two before deciding one one option. I suppose for me its easier to make the 3channel as i dont need to mod other bits. Hmmm..... It's a tough one.


Quote:

Originally Posted by amb /img/forum/go_quote.gif You're going to get different answers from different people. Some might hear a big difference while others might hear a small difference, or none at all. I know this is a big hand-wave answer, but such is the nature of audiophilia. You just have to decide what's right for yourself.

 

[el_matt0]

where do you live? if your in any sort of major city i wouldnt be surprised if theres DIYers local to you who might have a 3 or 4 channel b22 to try. im in vancouver BC if it ever suits your fancy lol

 

[fault151]

Im in the UK. Thanks for the offer anyway. I think im just going to take the plunge and buy a kit and see how it goes. I'll practice making my cmoy first, then maybe attemp it when im a bit more confident.

Quote:

Originally Posted by el_matt0 /img/forum/go_quote.gif where do you live? if your in any sort of major city i wouldnt be surprised if theres DIYers local to you who might have a 3 or 4 channel b22 to try. im in vancouver BC if it ever suits your fancy lol

 

[vixr]

most of the wiring done...

 

[n_maher]

Ooooohhhhh, I bet that stepper sounds sweet.

 

[el_matt0]

bit of a balanced/SE conceptual problem i was having troubles wrapping my head around this morning. am im correct in thinking that, on a b22, you can run solely balanced inputs (2x XLR in), and from that, can run a balanced headphone output (using 4 boards) and a single ended headphone output (using 2 boards). dont know why i asked..lol thats how mine is setup, havent gotten it 100% working yet as im working on the casework at the moment, but to say the least - i HOPE thats a possible configuration. basically my "trip up" is that howcome no balanced to single ended conversion is needed in this case to drive the SE outputs? whereas if I was to run a set of single ended INPUTS into my b22 in addition to the balanced inputs, in order to drive a balanced pair of headphones from the single ended input, THEN id need some kind of converter inside the b22 right (SE to balanced)? are all my assumptions correct so far? ....basically in that you need a converter to go from SE to balanced, but in some senses, one isnt needed to go from balanced to SE (as i intend for mine to be setup)?

 

[naamanf]

When using balanced you have both a + and - for each channel(L/R). When using unbalanced(SE) you only need the + (or -) of each channel and ground. You don't need to do any conversion because you already have two boards that are amplifying the + (or -)signal.

You need to do conversion when using unbalanced on the input side because there is only + and ground.

 

[el_matt0]

lol, yea thanks thats all i needed, the obvious to be pointed out.

its early in the morning where i am- cut me slack. hehehe!

 

[el_matt0]

if im planning to place 2 sigma 22s and trafos in a separate enclosure, powering 4 beta 22 boards, do i need to run 12 conductors through my umbilical (3 for each board), or can i simply just run a 6 conductor umbilical, 3 from each of the s22s, and then use terminal strips or something to then "split" each of those 6 conductors in order to feed 4 b22 boards once in the amplifier board chassis. does that make sense/work?

 

[el_matt0]

just as a reminder, im running a 4 channel beta 22 with 1 set of balanced outputs on the front, and 2 1/4" single ended outputs (each driven by 2 boards). My question is, would it be possible to create one essentially "higher gain" S.E. output, ie so I could hypothetically say use IEMs on that output? would this be just a simple matter of putting a resistor in line with the L and R channels of that output? if so, any recommendations on what a good value/brand of resistor would be appropriate here? this is where I want to use something like a kiwame etc right?

 

[amb]

el_matt0, surely you meant "lower gain" for IEMs, right?

Resistors inline with the headphones are a way to reduce the effective gain, but it's got its share of problems.

First, the resistor forms a voltage divider with the headphone load, which is what causes the gain drop. But the headphone impedance is not perfectly flat, so the attenuation will not be uniform over the audio band, causing frequency response aberrations. Such aberrations are not a good thing if you want the amp to remain faithful to the input signal, but in some cases the frequency response change may "complement" a weakness in the headphones. It is my opinion that the amplifier is not the proper place to put such "fixes" for headphone deficiencies.

Second, placing series resistance with the headphone raises the amplifier's effective output impedance, as "seen" by the headphone. This results in a loss of damping factor. The β22 has extraordinarily low output impedance which gives it such commanding control over the headphone diaphragm, and such resistors will be detrimental to that quality. Some headphones that lack bass may actually sound "better" with high output impedance (the looser control imparts a false sense of increased bass), but again I question this as an appropriate thing to do.