Blog categorized as Measurements

Check out this post for test setup and limitations.

ITU-R IMD is one way to measure intermodulation distortion. I am feeding the circuit with two test tones at -6 dBV, which will sum to 0 dBV. The test tones at 19 kHz and 20 kHz will produce a modulated signal at 1 kHz. The difference between the te...

Following up on the THD measurement of the Burson V6 Classic (which also shows the test setup and limitations), here's its frequency response.

Background

To see if the Burson V6 operational amplifiers are viable in the Muffsy Phono Preamp, I went ahead and bought the dual version of both the V6 Classic and V6 Vivid (*). They don't come cheap, about 20x the price of an OPA2134. Getting two of these instead of 40 OPAs for my kit stock was qui...

Measurements on their own are no good unless they can be seen in relation to something. Having established the measurements baseline, I want to get an idea on how the preferred OPA2134 performs.

I've been asked about how the Burson V6 discrete operational amplifiers would perform in the Muffsy Phono Preamp quite a few times. They don't seem to have many published measurements, so I thought I'd give it a go.

Wondering how the Muffsy MC Head Amp measures? Look below for the numbers.

• Topology: Dual mono
• Gain: 24.6 dB
• 0.3 mV input = 5 mV output
• 0.5 mV input = 8.5 mV output 
• Input impedance: 47 - 100 ohms, in four steps
• THD: < 0.1 % *)
• THD+N: < 0.6 % *)
• SNR:  71.8 dB, referenced to 0.5 mV input @ 1 kHz
• Frequen...

The signal to noise ratio (SNR) compares the level of the audio signal to the background noise. An SNR of at least 65 dB is what's needed to have a completely silent phono stage. The Muffsy Phono Preamp's SNR, with OPA2134, comes in at 79.46 dB as shown below.

The measurement of signal to noise ratio...

We've seen how the RIAA filter behaves with low and very low capacitor values. (See all simulation articles here) Now let's have a look at what happens if the capacitor values are higher than the recommended ones.

This is the Muffsy Phono Preamp with capacitor values that are 2.5% higher than specifi...

I wanted to know what happened to the Muffsy RIAA compliance if the capacitors were out of spec, and started with a plausible scenario where the capacitors were 3% below their stated values.

This time, lets see what happens if the capacitor values are extremely low. Let's say they're 10% below what ...

The RIAA equalization added to vinyl records can and do vary wildly, and you might rightfully say that a phono stage's RIAA compliance doesn't matter too much.

It's still a standard, and it should be one of the considerations when choosing a phono stage.

The Muffsy Phono Preamp uses Wima MKS2 capacito...