A long time ago I knew the model of these devices, and even got access to their obscure datasheet. They're switches - - - electronic switches.
Below is the output section of the Topping E50 DAC - ES9068 and a bunch of OPA1612s. The 9068 is a bit of an odd chip and its datasheet is unavailable to the public. I investigated it, and it appears to have pins for feedback after the I/V section (if people are wondering why this looks a little strange)
To keep things simplest, we're focusing on the RCA output. Notice at the bottom, the op amp and the electronic switch above it.
You can see, the switch has two inputs and two outputs, made for stereo or single channel balanced.
The op amp is a 1612 - very nice op amp. I'm wondering why Topping didn't just put a relay on its output... Their headphone and pre amps with digital volume controls use a relay switched resistor network - obviously they've deemed them reliable enough. Seriously, how often do you switch on or off an output? You set it at the beginning and then you leave it. 99% of the time, that's what you do. Heck, there's an argument for there not even being a switch to turn the outputs on or off - especially when you're not going to use a relay, but an extremely obscure electronic switch! On a 1612!!!
I wish I saved the datasheet, or remembered where I saved it... I remember some of its specifications, though. THD+n was, at best, either -115dB or -110dB, and reduced to -105dB or -100dB when the load impedance dropped under a certain amount.
Topping, why? Why why why? Why didn't you use a relay? You have up to like 15 of them in series in the preamp sections of your resistor networked devices... You go through all the trouble to use 1612s, 1656s, ES9039Pros, AK4499EX, and at the end of it all... you put some 50c no-name electronic switch?
I know - the devices measure better than -100 to -115dB THD+n listed in the datasheet... But I'm a purist when it comes to audio... Anything unnecessary, in my opinion, should go. It's not just entry level devices which use these unfortunate things - my D90 III Sabres have them!!!
What I'm wondering is... What if - what if I bypass them by scuffing the PCB over the appropriate traces to jump the chip, and use some thin ribbon cable commonly used for signals to join them? And then severed those traces from either side of the chip, of course, effectively cutting the chip out of the design. The system would still have access to the chip, tell the chip to open or close. But its ins and outs would have nothing attached. And the output would have a direct path to the output from the 1612.
If I were to embark on this experiment, I do have an E50 that I could practice on.
Does anyone think there's any reason this shouldn't work? Aside from if I have bad soldering skills? (they're not bad lol)
Below is the output section of the Topping E50 DAC - ES9068 and a bunch of OPA1612s. The 9068 is a bit of an odd chip and its datasheet is unavailable to the public. I investigated it, and it appears to have pins for feedback after the I/V section (if people are wondering why this looks a little strange)
To keep things simplest, we're focusing on the RCA output. Notice at the bottom, the op amp and the electronic switch above it.
You can see, the switch has two inputs and two outputs, made for stereo or single channel balanced.
The op amp is a 1612 - very nice op amp. I'm wondering why Topping didn't just put a relay on its output... Their headphone and pre amps with digital volume controls use a relay switched resistor network - obviously they've deemed them reliable enough. Seriously, how often do you switch on or off an output? You set it at the beginning and then you leave it. 99% of the time, that's what you do. Heck, there's an argument for there not even being a switch to turn the outputs on or off - especially when you're not going to use a relay, but an extremely obscure electronic switch! On a 1612!!!
I wish I saved the datasheet, or remembered where I saved it... I remember some of its specifications, though. THD+n was, at best, either -115dB or -110dB, and reduced to -105dB or -100dB when the load impedance dropped under a certain amount.
Topping, why? Why why why? Why didn't you use a relay? You have up to like 15 of them in series in the preamp sections of your resistor networked devices... You go through all the trouble to use 1612s, 1656s, ES9039Pros, AK4499EX, and at the end of it all... you put some 50c no-name electronic switch?
I know - the devices measure better than -100 to -115dB THD+n listed in the datasheet... But I'm a purist when it comes to audio... Anything unnecessary, in my opinion, should go. It's not just entry level devices which use these unfortunate things - my D90 III Sabres have them!!!
What I'm wondering is... What if - what if I bypass them by scuffing the PCB over the appropriate traces to jump the chip, and use some thin ribbon cable commonly used for signals to join them? And then severed those traces from either side of the chip, of course, effectively cutting the chip out of the design. The system would still have access to the chip, tell the chip to open or close. But its ins and outs would have nothing attached. And the output would have a direct path to the output from the 1612.
If I were to embark on this experiment, I do have an E50 that I could practice on.
Does anyone think there's any reason this shouldn't work? Aside from if I have bad soldering skills? (they're not bad lol)
