Maybe to do opAMPs on output - LT1469 in i-v and LT1122 in filter (and made on output small class A amplifier as optional)?
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Maybe to do opAMPs on output - LT1469 in i-v and LT1122 in filter (and made on output small class A amplifier as optional)?
Nice idea.
You can consider LT1363 in I/V and LME49990 in LPF.
Intense detail + virgin purity.
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I don't like LME49860 either, only LME49990 in high gain with LME49990 buffer, 4x total.
They say LT1363 sounds better in Class-A bias, I haven't tried that yet.
I will order LT1469 and LT1122 later.
PCB for AD1853+discrete (not my).
I draw 2 layers PCB for AD1853+opAMPs, then will draw 2 layers PCB for discrete output.
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Have a look at this schematic for a few ideas
http://www.diyaudio.com/forums/solid-state/255236-opamp-based-power-amp.html
Later in the thread, LTspice simulation achieves -160 dB!
http://www.diyaudio.com/forums/solid-state/255236-opamp-based-power-amp.html
Later in the thread, LTspice simulation achieves -160 dB!
Not enough information about the sound of discrete output: "the sound of discrete output differs from the traditional opAMPs" and all. Someone like - someone hates.
I will link you to a Swiss paper on discrete tomorrow or next day, on phone at the moment.
and now we rebuilding AD844 and LT1363 on discrete elements...
What?
!!I think, that Jean Hiraga's Le Monstre 8W will spread this AMP.
I want to build a DIY speaker amp, at the moment I only have "JLH", what do you think of Class-D? Which is the best?
I will link you to a Swiss paper on discrete tomorrow or next day, on phone at the moment.
aaaa, not understood.
What?
opAMP build on discrete elements : D
I want to build a DIY speaker amp, at the moment I only have "JLH", what do you think of Class-D? Which is the best?
Class D for car's subwoofer only. JLH much worse than Jean Hiraga's Le Monstre 8W and Super Class A 20/30W. I almost smashed JLH 1996 after made and heard Hiraga.
What does a current out DAC need?
Low Input resistance of the I/V (although a switched capacitor output stage as the AD1853 is not that sensitive, R2R DACS are much more picky). This impedance should be as flat as possible over a broad frequency range, as the DAC spits out, inherently, a high amount of HF components.
The shown discrete Output stage is NOT an OP Amp style stage, but common base open loop.
It has a low input impedance, which rises way later in the frequency band than a op amp I/V (which relies only to a high Loop gain, and it decreases quickly with rising frequency.
I suggest you to leave the discrete output stage as it is (at least from a topology view). You may look to increase the bias current through VT4-8, it gets better when their bias current is >> max current swing of AD1853 (AFAIR +/-3mA).
I'd bias them at least to 10mA.
Anyway, common base stages are the way to go for DAC I/V.
Low Input resistance of the I/V (although a switched capacitor output stage as the AD1853 is not that sensitive, R2R DACS are much more picky). This impedance should be as flat as possible over a broad frequency range, as the DAC spits out, inherently, a high amount of HF components.
The shown discrete Output stage is NOT an OP Amp style stage, but common base open loop.
It has a low input impedance, which rises way later in the frequency band than a op amp I/V (which relies only to a high Loop gain, and it decreases quickly with rising frequency.
I suggest you to leave the discrete output stage as it is (at least from a topology view). You may look to increase the bias current through VT4-8, it gets better when their bias current is >> max current swing of AD1853 (AFAIR +/-3mA).
I'd bias them at least to 10mA.
Anyway, common base stages are the way to go for DAC I/V.
How does the Hiraga sound?
Plus, from where did you purchase the Hiraga PCB? I have JLH 2001.
DAC will be not work on low impendance, 1 mA maximum output current. 10 mA bias can damage BJT (300 mW maximum).
I think too - build DAC with opAMPs (and to make discrete output for interest).
About R2R - do you have good scheme on PCM1702 (it's alone multibit, that I can to get in my city (PCM1702U-K))?
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