Giordano, you're right that it won't be optimal.. but its very conveniant 😉. I was thinking that the dc from the IC inputs pins would create a current flow through the secondary winding to saturate the transformer. I'm unsure how that DC situation will affect things. I think my safest bet is to connect 4+ in paralell on each channel to lower the output impedance. They are very inexpensive after all..
Hello,
So now the problem of driving comes 🙂
I'm using the balanced, no driving opamp version directly connected to a Focusrite Scarlett i2i balanced output with great success. Despite it is an IC, I found the sound of it together with the Focusrite to be well balanced with warmth and details.
On the other hand, for portable, I want to make a relative small, lightweight, unbalanced, but as good as I can make DAC+headphone amp.
On another thread I was looking for what currently available DAC chip to use, but I've got a great advice how to use still my favorite DAC, the AD1865 without the I2S reclock, interface etc. circuits, only with an XMOS input with 2 osc, than an FPGA to create the 18bit pcm signal for the AD1865. So, sorry for the sideways, now I want to interface an AD1865 to the TPA6120. I would use as less opamps as possible, but as I see I need minimum 2. One on the I/V output resistor after the AD1865, before volume control pot, but I need another one after the volume control pot.
How would you guys do it? What opamps would you use? I do not have experience with opamps since about 2007, when I "switched" to tubes. Obviously, on this circuit I will not use interstage transformer and tube amplification, but what is the best opamp and circuit I can use than?
The headphone would be a HD800S, so I rather go on the warm side.
Thanks!
JG
So now the problem of driving comes 🙂
I'm using the balanced, no driving opamp version directly connected to a Focusrite Scarlett i2i balanced output with great success. Despite it is an IC, I found the sound of it together with the Focusrite to be well balanced with warmth and details.
On the other hand, for portable, I want to make a relative small, lightweight, unbalanced, but as good as I can make DAC+headphone amp.
On another thread I was looking for what currently available DAC chip to use, but I've got a great advice how to use still my favorite DAC, the AD1865 without the I2S reclock, interface etc. circuits, only with an XMOS input with 2 osc, than an FPGA to create the 18bit pcm signal for the AD1865. So, sorry for the sideways, now I want to interface an AD1865 to the TPA6120. I would use as less opamps as possible, but as I see I need minimum 2. One on the I/V output resistor after the AD1865, before volume control pot, but I need another one after the volume control pot.
How would you guys do it? What opamps would you use? I do not have experience with opamps since about 2007, when I "switched" to tubes. Obviously, on this circuit I will not use interstage transformer and tube amplification, but what is the best opamp and circuit I can use than?
The headphone would be a HD800S, so I rather go on the warm side.
Thanks!
JG
Hello,
I can not translate it. Google translate only finds a few words. Please write in English.
Thanks!!
JG
I can not translate it. Google translate only finds a few words. Please write in English.
Thanks!!
JG
Translation. 🥷🥷🥷🥷🥷🥷🥷🥷🥷🥷🥷🥷
''Hi So here comes the driving question. I am using the balanced, no driving op-amp version connected directly to the Focusrite Scarlett i2i balanced output and have had great success. Even though it's an IC, I found it to be well balanced with the Focusrite's sound with warmth and detail. On the other hand, for portable, I want to make a relatively small, lightweight, unbalanced, but as good a DAC headphone amp as possible. On another thread, I was looking for currently available DAC chips, but I got a good suggestion how to use my favorite DAC, the AD1865, with no I2S relock, interface, etc. circuits, just one XMOS input and 2 osc, not FPGA to create 18bit pcm signal for AD1865. So, sorry for the sideways, now I want to connect the AD1865 to the TPA6120. I would use as few opamps as possible, but as I can see I need at least 2. An I after the AD1865''
''Hi So here comes the driving question. I am using the balanced, no driving op-amp version connected directly to the Focusrite Scarlett i2i balanced output and have had great success. Even though it's an IC, I found it to be well balanced with the Focusrite's sound with warmth and detail. On the other hand, for portable, I want to make a relatively small, lightweight, unbalanced, but as good a DAC headphone amp as possible. On another thread, I was looking for currently available DAC chips, but I got a good suggestion how to use my favorite DAC, the AD1865, with no I2S relock, interface, etc. circuits, just one XMOS input and 2 osc, not FPGA to create 18bit pcm signal for AD1865. So, sorry for the sideways, now I want to connect the AD1865 to the TPA6120. I would use as few opamps as possible, but as I can see I need at least 2. An I after the AD1865''
How to make a correct connection of single ended inputs to TPA6120 schematics in startpost of this topic ? I want to make dual input balanced + unbalanced amp. DRV134 or something else ?
upd, I've found another variant of input stage, but anyway the question is how to properly match it with differential input ?
upd, I've found another variant of input stage, but anyway the question is how to properly match it with differential input ?
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Hi,
Some time ago I've made a balanced version also, but is is basically 2x the same circuit.
JG
Some time ago I've made a balanced version also, but is is basically 2x the same circuit.
JG
Hi, it's clear to me, but the question is how to make dual input for that amplifier. For ex how to add correctly this input stage to your amp. I don't need any switches, just want to left one of inputs unconnected while using another.
Attachments
I do not understand what do you want. You want 2 different balanced signal source connected to the input and use either A or B source? Or, you want both in the same time, so mix it? Either way, if you leave both connected, you will mix. I do not know how to do with balanced signals. The circuit section you linked I do not understand. I see it makes balanced signal from unbalanced, but as I see that adds some amount of crosstalk ?? What is that pot? If there would be a dot here:
I would say it is just a volume pot, but there is no dot, so I guess it is some kind of effect.
So, if you want to mix two inputs, you could do easy on unbalanced side. You add a buffer on each input and a series resistor on each opamp output before you connect them together. I guess you can do that with balanced signals also, but someone else should answer that, I have no experience mixing balanced signals. Than, after connecting the input buffers together you can connect to your unbalanced to balanced circuit. On the other hand, if you do not need both in the same time, I would suggest to consider a switch. You add less opamps and you are not listening to the noise of both inputs.
If it is the balanced signal input what you mean dual input, than your circuit should work. but if you search for "line level unbalanced to balanced circuit", you will find more. Or, you could use an interstage transformer with middle tap. If my signal source would be unbalanced and I would really want to make a balanced headphone amp, I would look here for potential candidates: https://www.lundahltransformers.com/input-and-dc-free-line-output-application/
I did not use any on my balanced amp, because the signal source I've used is balanced (TC Electronic Konnekt 8). ... and even for that, I've dropped the TPA and other solid stage amps and use OTL headphone amp (unbalanced naturally).
JG
I would say it is just a volume pot, but there is no dot, so I guess it is some kind of effect.
So, if you want to mix two inputs, you could do easy on unbalanced side. You add a buffer on each input and a series resistor on each opamp output before you connect them together. I guess you can do that with balanced signals also, but someone else should answer that, I have no experience mixing balanced signals. Than, after connecting the input buffers together you can connect to your unbalanced to balanced circuit. On the other hand, if you do not need both in the same time, I would suggest to consider a switch. You add less opamps and you are not listening to the noise of both inputs.
If it is the balanced signal input what you mean dual input, than your circuit should work. but if you search for "line level unbalanced to balanced circuit", you will find more. Or, you could use an interstage transformer with middle tap. If my signal source would be unbalanced and I would really want to make a balanced headphone amp, I would look here for potential candidates: https://www.lundahltransformers.com/input-and-dc-free-line-output-application/
I did not use any on my balanced amp, because the signal source I've used is balanced (TC Electronic Konnekt 8). ... and even for that, I've dropped the TPA and other solid stage amps and use OTL headphone amp (unbalanced naturally).
JG
One more thing on still the TPA : the reason why I've dropped the balanced version of TPA... even before I've dropped the solid state amps: I found the power supply influence more the audio experience than if I make it balanced. When I've added a better power supply, the unbalanced TPA circuit outperformed to me the balanced one with simple LM317/337 psu. Then, I've added that power supply what is in the pdf I've attached above, it is a "Superreg" PSU and really good. I have better experience with that than batteries (which is really strange, but that is what I've preferred and I had lots of hours into it years ago).
On proper desktop amps I did not experience advantage of balanced amp (but that is just my experience). On small, tiny battery powered amps I do. I have a Qudelix 5k and I clearly prefer the balanced output, but I would guess the reason is the 1-2 Li Ion cell power. On the desktop circuits we run it from + - 15V or similar, plenty of headroom. .... IMHO
On proper desktop amps I did not experience advantage of balanced amp (but that is just my experience). On small, tiny battery powered amps I do. I have a Qudelix 5k and I clearly prefer the balanced output, but I would guess the reason is the 1-2 Li Ion cell power. On the desktop circuits we run it from + - 15V or similar, plenty of headroom. .... IMHO
I want to have both inputs (differential and single ended) with differential amplifier.
Should I do something like this (picture only for one channel) ?
Planned to make psu on TPS7A4701/TPS7A3301 or LT3045/LT3094