10
2011-Aug
Measurements G.E. Review Template for DACs & AmplifiersNick Name: Golden Ears Registered Date: Aug 10, 2011, 22:31:04 IP ADRESS: *.56.123.5 Views: 11396
* How we measure (Phones, DAPs, Amplifiers)
* How to read measurements - Phones, DAPs, Amplifiers
* Frequency response & perceived sound
Note.
Please keep in mind that the following data are from a test unit reviewed by Golden Ears - the test unit is not necessarily a representative sample of the model being reviewed.
<amplifier>The internal mixer was configured so as to counteract the amplifier’s gain, which was set to 3 for this test.
1. Digital Input Test
1.1. XLR Input (AES/EBU)
<Insert Frequency Response Graph>
Sampling Frequency : 96kHz / Company Name - Model Name
<Insert RMAA Summary Table>
Test Mode : 24bit, 96kHz
<Insert RMAA Comparison Table>
Test Mode : 24bit, 44.1/96/192kHz
1.2. Coaxial Input (SPDIF)
<Insert Frequency Response Graph>
Sampling Frequency : 96kHz / Company Name - Model Name
<Insert RMAA Summary Table>
Test Mode : 24bit, 96kHz
<Insert RMAA Comparison Table>
Test Mode : 24bit, 44.1/96/192kHz
1.3. Optical Input (SPDIF)
<Insert Frequency Response Graph>
Sampling Frequency : 96kHz / Company Name - Model Name
<Insert RMAA Summary Table>
Test Mode : 24bit, 96kHz
<Insert RMAA Comparison Table>
Test Mode : 24bit, 44.1/96/192kHz
1.4. USB Input
<Insert Frequency Response Graph>
Sampling Frequency : 96kHz / Company Name - Model Name
<Insert RMAA Summary Table>
Test Mode : 24bit, 96kHz
<Insert RMAA Comparison Table>
Test Mode : 24bit, 44.1/96/192kHz
2. Analog Input Test
2.1. RCA Input
<Insert Frequency Response Graph>
Sampling Frequency : 96kHz / Company Name - Model Name
<Insert RMAA Summary Table>
Test Mode : 24bit, 96kHz
A given headphone output may accommodate many different headphones - in general, a smaller load impedance (on headphones) will lead to a larger sound, but at cost of accuracy in measurable data due to the increased current - this cost usually manifests in an increasingly weak bass and elevated crosstalk values as the load impedance decreases. The purpose of the tests to follow is to see how these values change as a function of impedance.
1. Headphone Output
<Insert Frequency Response Graph / R16 ~ R250>
R16:16Ω / R33:33Ω / R62:62Ω / R250:250Ω
Sampling Frequency : 44.1kHz / Company Name - Model Name
<Insert RMAA Summary Table / R16 ~ R250>
R16:16Ω / R33:33Ω / R62:62Ω / R250:250Ω
Test Mode : 24bit, 44.1kHz
A lower impedance is desirable on the headphone outputs of amplifiers. The output impedance is closely related to the damping factor, and is one of the most important parameters that determine headphones' performance - desktop amps tend to exhibit high impedance values, corresponding to poor performance.
* Interaction between output impedance and phones
<Insert Output Impedance Value Table>