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E1DA Cosmos APU - Teardown and personal thoughts and measurements

thin bLue

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Jul 29, 2019
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thin bLue

Active Member
Reviewer
Joined
Jul 29, 2019
Messages
267
Likes
775
hm, what about the knob gain control, just replace that for your switches? o_O
Knob with gain(range) selecter will be smart solutions.
->Wide range with No extremely sensitive knob

Topping's Headphone Amps are great examples!
 

oal

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Nice review. If you sell the Scaler, I will definitely buy it! Having said that, it would have been nice if the APU's 1kHz/10kHz notch switch were 1kHz/No-notch switch. I do not use 10kHz notch, however, the No-notch option will be useful for various measurements such as J-Test, multi-tone signal, etc. The APU can be used as an input buffer for the ADC. My primary issue with Cosmos ADC is low impedance, gain control is only secondly.
 
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pma

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My primary issue with Cosmos ADC is low impedance, gain control is only secondly.
Exactly. The race for lowest noise pushed the designers to offer low input impedance ADCs and preamps (Topping …). However, it is not practical at all. Cosmos ADC would need a high impedance, low noise input buffer (FET). This would be a real challenge for the designer. Anyone can use the low impedance BJT opamp. A good anti-alias input filter would be good as well.
 
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