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Post by moko on Dec 8, 2014 2:35:27 GMT -5
A push pull complementary output pair (npn pnp) is single ended. true for the connection. what you mean here is actually single differential not single ended amp because all class AB amps are push pull. www.circuitstoday.com/class-b-power-amplifiersactually 4. 2 of them are phase-inverted. yes, the differences may not audible for human ears but the measurements tell different stories. because hearing is not a duty for ears only but also for the brain, that's why people spend more money just to have balanced audio gears : just for the peace of mind. and because you seem into academic thing, this article may give you explanation of the advantage from balanced amplifier : www.ti.com/lit/an/sloa054d/sloa054d.pdf |
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Post by richardrc on Dec 8, 2014 4:46:18 GMT -5
A push pull complementary output pair (npn pnp) is single ended. true for the connection. what you mean here is actually single differential not single ended amp because all class AB amps are push pull. www.circuitstoday.com/class-b-power-amplifiersactually 4. 2 of them are phase-inverted. yes, the differences may not audible for human ears but the measurements tell different stories. because hearing is not a duty for ears only but also for the brain, that's why people spend more money just to have balanced audio gears : just for the peace of mind. and because you seem into academic thing, this article may give you explanation of the advantage from balanced amplifier : www.ti.com/lit/an/sloa054d/sloa054d.pdfHi, single ended is single ended be it an input or an output. I am not sure what you mean by single differential? Do you mean the input or the output? If the the front end happens to be a diff amp with one leg grounded or part of the negative feedback network it is still single ended. You can have a diff amp with single or balanced input or output in any combination. Go back and have another look at fig 15.16. It is all single ended, it is not a differential drive and it is push pull. I am not sure how I can explain it better? There are only two amp modules inside the XPA-1. How could there be four? Nothing is phase inverted except for the case of a single ended RCA connection. Remember the incoming balanced signal is already inverted, so no need to invert anything. How each of the pair of amps is configured internally is speculation BUT it can be single ended all the way even with diff amps and the outputs stage drive will most definitely be coherent as you do not want both outputs devices to be conducting simultaneously! If Emo used a circuit similar to one in the link I posted they could claim octodifferential in a balanced amplifier configuration! That would be pretty funny. If you have a really close look at the cct diagram you will see no signal inversions in the main signal path. Remember you get a phase inversion across the BC junction. |
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Post by moko on Dec 9, 2014 0:32:52 GMT -5
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Post by chipless on Mar 29, 2016 12:50:04 GMT -5
i think it's simple. single ended amp = single differential = unbalanced push pull amp = dual differential = balanced (IF using xlr connectors) 2 push pull amps = quad differential = fully balanced (emotiva)/pure balanced (ati)/true balanced (ps audio) but if you think to maintain balanced connection you need quad (4) differential per channel, think again. that means using emotiva gear to maintain balanced, you would need 8 (!) differential (4 for each channel) erc-3, 8 differential xsp-1 and 2 xpa-1 amps. or for less budget 8-gang audio-taper potentiometer control freak. that is not correct. now, if you ask KeithL or Lonnie this question : "do erc-3 and xsp-1 have 8 differential ?", then my humble guess the answer will be : "no, it has 4 differential. 2 for EACH channel."Little late to the party here, so please forgive me for reviving this thread. I currently own the XPA-1 and two XPA-1Ls to power my center speaker and left/right speakers respectively. I have an XMC-1 on the way, and I'm wondering if after implementing the XMC-1, I'll no longer be taking "advantage" of the "fully balanced" design of the XPA-1/L amps. I am guessing the XMC-1 is not "fully balanced", but can anyone confirm this? If it's not, what am I leaving on the table so-to-speak? I am guessing nothing audible, but I am simply curious. Thanks! |
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Post by garbulky on Mar 29, 2016 12:56:10 GMT -5
i think it's simple. single ended amp = single differential = unbalanced push pull amp = dual differential = balanced (IF using xlr connectors) 2 push pull amps = quad differential = fully balanced (emotiva)/pure balanced (ati)/true balanced (ps audio) but if you think to maintain balanced connection you need quad (4) differential per channel, think again. that means using emotiva gear to maintain balanced, you would need 8 (!) differential (4 for each channel) erc-3, 8 differential xsp-1 and 2 xpa-1 amps. or for less budget 8-gang audio-taper potentiometer control freak. that is not correct. now, if you ask KeithL or Lonnie this question : "do erc-3 and xsp-1 have 8 differential ?", then my humble guess the answer will be : "no, it has 4 differential. 2 for EACH channel."Little late to the party here, so please forgive me for reviving this thread. I currently own the XPA-1 and two XPA-1Ls to power my center speaker and left/right speakers respectively. I have an XMC-1 on the way, and I'm wondering if after implementing the XMC-1, I'll no longer be taking "advantage" of the "fully balanced" design of the XPA-1/L amps. I am guessing the XMC-1 is not "fully balanced", but can anyone confirm this? If it's not, what am I leaving on the table so-to-speak? I am guessing nothing audible, but I am simply curious. Thanks! XMC-1 is fully balanced on front left and right channels only. |
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Post by chipless on Mar 29, 2016 13:27:50 GMT -5
That's good to know, thanks for the info! So, how does that affect the center in terms of topography/SNR/etc?
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Post by garbulky on Mar 29, 2016 14:26:38 GMT -5
That's good to know, thanks for the info! So, how does that affect the center in terms of topography/SNR/etc? The center output is matched. It's just not fully balanced. |
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Post by goozoo on Mar 29, 2016 18:39:26 GMT -5
According to the Emotiva Products Page the XMC-1 using Balanced input to Balanced output has a SNR od 123db. In Unbalanced output to Unbalanced input it has a measured SNR of 114db. Can any of you speak to the differences, if any, that you hear when switching from Unbalanced connection to Balanced connections with the XMC-1. For instance, are you using the XPA-1 or XPA-1L with the XMC-1 now vs any other Emotiva amp or an unbalance amp from another manufacturer? A balanced connection has more voltage pushing through it and hence sounds louder. Because it is also balanced, you will get less hum over long runs. Everything else that everyone else is talking about here is more based on personal preference. I switched from RCA to XLR on my XMC-1 and love the added volume it brings to movies. When switching, go Monoprice and don't look back. |
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