the choice is ruled by the pcb op area layout. If the op areas are made for single channel, choose the op1655. If the pcb is made for dual channel op areas, pick the 1656. Read the BOMs if choosing a ready made diy project.
Also one of the numerous thread about I/V with operational amplifier : https://www.diyaudio.com/community/...i-v-conversion-dac.34324/page-25#post-7482644
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Current plank setup! Waiting on parts for vunces 861, 811, and pass d1. New audial usb to simultaneous sounds really good, especially with asio.
Do not hesitate to feed Pedja's USB with a C-Core. Have you tried one of his Aya yet ? (very good layout)
I’ll try it with a c-core. And I haven’t heard an aya. There’s one that I’ve been eyeing though.
Do you have any recommendation for if I should change the values of 811 IV for TDA1541a?
I plan to use dc offset from miro's board, which should yield +-2ma, along with the values that Vunce is using for AD1862 (+-1ma).
Do you think this will work well or should I make a change?
Do you have any recommendation for if I should change the values of 811 IV for TDA1541a?
I plan to use dc offset from miro's board, which should yield +-2ma, along with the values that Vunce is using for AD1862 (+-1ma).
Do you think this will work well or should I make a change?
@cibo I'm going to us an OPA1655 for the first pass build but will change to the above AD811 as soon as I get a good power supply built. I'm laying out a Jung/Didden SuperRegulator supply in KiCad right now.
NOW for the big question: In every op-amp based IV stage I see, the DAC current always goes to the '-' input of the op-amp. Does that mean that we are istening to an inverted signal? Or is it inverted coming out of the DAC so the inversion with that IV scheme cancels?
NOW for the big question: In every op-amp based IV stage I see, the DAC current always goes to the '-' input of the op-amp. Does that mean that we are istening to an inverted signal? Or is it inverted coming out of the DAC so the inversion with that IV scheme cancels?
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@cibo In the original Walt article for TDA1541 the value of R202 is 1.82K and C201 is 2nF.
Good luck with the build 😉
Although I know that it will be difficult to beat the AD811 in my DAC, I will try to do this at the weekend. It doesn't look bad in LTspice, the only question is how it sounds🙂
Good luck with the build 😉
Although I know that it will be difficult to beat the AD811 in my DAC, I will try to do this at the weekend. It doesn't look bad in LTspice, the only question is how it sounds🙂
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Yes, that's exactly like that because those chips are designed to work with active I/V with OPA.
And when we do a passive I/V with a resistor and add a tube gain stage, or some other gain stage, that stage should also reverse the phase.
I think it can be checked with an oscilloscope, a PC, an online generator and a sawtooth signal that the output is in phase.
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Another one ist alive!
Fed by RPi and Allo Kali. PSU2. Parts are pretty basic.
Unfortunately I forgot to order 2R2 for the PSU, so I had to parallel 5*12Ohms...
Thanks Miro!
Fed by RPi and Allo Kali. PSU2. Parts are pretty basic.
Unfortunately I forgot to order 2R2 for the PSU, so I had to parallel 5*12Ohms...
Thanks Miro!
Only just started reading my way through this thread (skipped to end to see latest updates/opinions, need to go through a ton of earlier posts though) so I'm no doubt missing some info, but is there any reason you went with 74HCT164M96 instead of 74HCT164D or 74AHCT164D?
Ahh ok, 7nS difference seems like nowt. I just didn't know if I missed in the thread that your version had become the recommended choice for any big particular reason. Thanks for getting back though
Hi guys,
I am using ad1862 chips. Although the analog section is specified -/+ 10-13V I am powering it with ultracaps -/+5V. It sounds great. Could anyone tell what is the possible downside of undervoltaging?
I am using ad1862 chips. Although the analog section is specified -/+ 10-13V I am powering it with ultracaps -/+5V. It sounds great. Could anyone tell what is the possible downside of undervoltaging?
@reg66 @audiosteve 74HCT164D or 74HCT164M96 or the faster 74AHCT164D - it does not affect the resulting sound quality, because the sound from AD1862 is generated after latch (LE signal) and this signal is not affected by these digital ICs - it is directly connected with AD1862, so you can use what you like 😊 ... the most used is classic 74HCT164D
@TioFrancotirador +-10V is considered as minimum for the internal voltage reference precision in AD1862, which guarantee the parameters specified in the datasheet. It will work with 5V, but the measurable parameters may be impaired negatively - even if it won't be audible because it can be reflected only on very low signals 😉