opEIGHT: What we know so far
90's throwback TMC High Voltage SE Headphone Amplifier using OPA1656
(mosconi-system.it AS 100.4 little broskies w/op-amp)
0.000004%(0.000000%) @1kHz 1VRMS 32R
0.000210%(0.000206%) @48kHz 1VRMS 32R
needs output Zobel RC+R||L
sub ONSemi BD140/BD139, adjust emitter R
model shows 5mV offset
note:
gain + phase very difficult to model in this configuration
use phase of harmonics for verification and freq distribution
model shows 5mV offset
90's throwback TMC High Voltage SE Headphone Amplifier using OPA1656
(mosconi-system.it AS 100.4 little broskies w/op-amp)
0.000004%(0.000000%) @1kHz 1VRMS 32R
0.000210%(0.000206%) @48kHz 1VRMS 32R
needs output Zobel RC+R||L
sub ONSemi BD140/BD139, adjust emitter R
model shows 5mV offset
note:
gain + phase very difficult to model in this configuration
use phase of harmonics for verification and freq distribution
model shows 5mV offset
Last edited:
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changes to R1/R2
back to the future fast
using 296-OPA1656ID-ND
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back to the future fast
using 296-OPA1656ID-ND
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opEIGHT.10
using OPA1642
added bootstrap (current sense)
lowered dissipation Q1/Q2 to ~160mW
total idle current 250mA for output stage
@4VRMS 48kHz
Total Harmonic Distortion: 0.004123%(0.004123%)
needs output Zobel RC+R||L
sub ONSemi BD140/BD139, adjust emitter R
model shows 10mV offset
1.6deg/20dB -3dB(~1.4MHz)
bom ~40euro at one unit (sans PCB)
platform for a discrete opamp?
EUVL??
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Attached Files
using OPA1642
added bootstrap (current sense)
lowered dissipation Q1/Q2 to ~160mW
total idle current 250mA for output stage
@4VRMS 48kHz
Total Harmonic Distortion: 0.004123%(0.004123%)
needs output Zobel RC+R||L
sub ONSemi BD140/BD139, adjust emitter R
model shows 10mV offset
1.6deg/20dB -3dB(~1.4MHz)
bom ~40euro at one unit (sans PCB)
platform for a discrete opamp?
EUVL??
<a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/"> <img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png" /></a> <br /> This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License</a>
Last edited:
opEIGHT.10 v.0 (using OPA1642)
added bootstrap (current sense)
* lowered dissipation further Q1/Q2 to ~120mW
* lowered total idle current further ~230mA total for 1 channel output stage (*balanced configuration - 2x pcb - 1 per channel)
* improved output damping circuit
Simulations are all Single Ended
@4VRMS 48kHz 32R
Total Harmonic Distortion: 0.004579%(0.004579%)
@4VRMS 48kHz 125R
Total Harmonic Distortion: 0.000768%(0.000768%)
* model shows 10mV offset
* ~1.4deg/24dB -3dB(~1.4MHz)
<a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/"> <img alt="Creative Commons License" style="border-width:0" src="https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png" /></a> <br /> This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License</a>
added bootstrap (current sense)
* lowered dissipation further Q1/Q2 to ~120mW
* lowered total idle current further ~230mA total for 1 channel output stage (*balanced configuration - 2x pcb - 1 per channel)
* improved output damping circuit
Simulations are all Single Ended
@4VRMS 48kHz 32R
Total Harmonic Distortion: 0.004579%(0.004579%)
@4VRMS 48kHz 125R
Total Harmonic Distortion: 0.000768%(0.000768%)
* model shows 10mV offset
* ~1.4deg/24dB -3dB(~1.4MHz)
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might I suggest the kaneda jfet preamp >
kaneda quasi push pull discrete opamp >
(in this article)
One Last Attempt at Discrete Opamp in DIP8 Footprint
opEIGHT.10 (lower gain v/i converter)
kaneda quasi push pull discrete opamp >
(in this article)
One Last Attempt at Discrete Opamp in DIP8 Footprint
opEIGHT.10 (lower gain v/i converter)
Still waiting for some useful explanation other than misery loves company
