It is balanced or not?
After working on and rebuilding an XDA-2 DAC and looking at the XDA-1, my only answer would be "maybe?". I see two 2134 op amps after the fully differential AD1955 DAC chip. This suggests that the opa2134 op amps are working in fully balanced differential mode for the I/V section. After that, it goes straight to the discrete analog output stage. It is difficult to tell if this discrete analog stage is fully differential/balanced, but I would only assume so. This is different than the XDA-2 dac, which has the same two opa2134 I/V op amps, but then goes through another single opa2134 op amp which acts as a low-pass filter and downgrades this to "single-ended". Then the XLR outputs have their own set of opa2134 which convert the single-ended analog back to differential. The XDA-2 is not "fully differential" from end-to-end, but the XDA-1 DAC might be. |
@joser9616 - One point. Just because they are "studio amplifiers" does not mean they are fully balanced. The analog input stage of the amp may be balanced, but the amplifier itself is single-ended. You can tell because the amp can be bridged-mono to double the power output. You would not be able to do this on a balanced/differential amplifier. In actuality, pretty much all studio equipment is not fully balanced. "XLR balanced" was developed as a way to transfer analog signals between equipment devices, sometimes a very long distance (50-100+ feet). In almost all cases I have seen, the XLR input on a studio equipment will always convert to single-ended analog internally for purposes of volume / equalizer / mixing / etc. Then, on the output, it will convert back to "balanced XLR". |
Please people, which of these two amps have better audio quality? thanks: http://www.ti.com/product/MC33078 it is inside a JBL Professional MSC1Studio Monitors Controller http://www.ti.com/product/OPA2134 it is inside of a Emotiva DAC Preamp XDA-1 thanks. |
The op amp is a factor in sound quality, but it's never the full story. You also need to look at power supply, etc. The fact that the JBL uses a switching wal-wart power supply is an indicator of poor sound quality. The JBL is meant as a cheap mixer / room correction unit. I believe the Emotiva would have highly superior sound quality, especially since it has a fully discrete output stage. |
@auxinput I fond it here: http://bee.mif.pg.gda.pl/ciasteczkowypotwor/SM_scena/Crown/D75%20Service%20Manual%20%20-1.pdf it is just as you were saying, but please tell me, it is better to use it as a stereo then? thanks. |
Running the sound through the JBL MSC1 is definitely going to degrade the sound quality of the Emotiva DAC, but if that's all you have, that's what you are gonna have to use. Is the amp better to use as stereo? Generally speaking, yes. It really depends on the speakers and if they drop below 8 ohms, but usually stereo amps do not perform as well in bridged mode. Generally, a dedicated balanced/differential amp will have power from both the +(RED) and -(BLACK) speaker posts. In this situation, you cannot bridge amp channels because they are already, in a sense, bridged. The service manual does not give a complete schematic, but if you look at page 6-3, you can see the Output Stage schematic. On the right side of the schematic you can see the output connected to one speaker binding post. The other speaker binding post is shunted directly to ground, so this is a single ended amp (even though the input stage is balanced). |
Too many sources and amps are really SE main circuitry with opamps on the input or output to make them pseudo balanced (xlr) just to suck in the xlr freaks. In these cases stick with SE, and you bypass these opamps (best opamp is no opamp). You only need balanced (xlr) if your running 10mts of interconnect through bad surroundings with lots of rf emitting equipment. Cheers George |
@auxinput: Well, I think the best way that the Crown D-75 can sound is in stereo, because each amplifier has its connection balanced or unbalanced and is not divided for 2 amps, as it is on page 6-1 of the service manual; in My opinion, the best way they can sound is to put them both in stereo and connect the right speaker on channel 2 of one of them and the left speaker on channel 1 on the other, both in stereo, so each internal amp has its conection. what did you think? thanks :-) |
@auxinput Hi, I think I have something better than the Emotiva in my house and I did not know it, it's the Roland Mobile UA, it's a USB Audio Interface for headphones and it can also be used balanced to studio monitors: https://www.roland.com/global/products/mobile_ua/, it has this inside, amps:http://www.ti.com/product/TPA6120A2/description, DAC:https://www.akm.com/akm/en/product/datasheet1/?partno=AK4414EQ, and I think this works as pre amps: http://www.ti.com/lit/ds/sbos484a/sbos484a.pdf did you think this is better? thanks. |
@auxinput Hello, I'll be extremely honest, the Roland Mobile UA sounds a lot more detailed, with all types of music, Jazz, Rock, Classical Rock, Classical music, everything sounds better, it's a bit more on the treble side, but not in a way that offends or dislikes. congrats to all the fathers, have a good day. |
The Texas Instruments OPA1642 works as Low Pass Filter FET-input opamps and it is used in high end receivers and the Texas Instruments TPA6120A2 works as Output buffers and they are high fidelity amps used in high end USB interfaces for headphones, it works balanced and you can conect it to an amp, believe me, more detailed sound. |
