Posts

Choosing appropriate phono preamplifer gain for a phono cartrage

Choosing the right phono gain is about amplifying the cartridge's tiny output voltage so it reaches approximately the same level as other line-level audio sources without overloading the phono stage or your preamp. The basic calculation Use this formula: Gain (dB) = 20 × log ⁡ 10 ( Desired output voltage Cartridge output voltage ) \text{Gain (dB)} = 20 \times \log_{10}\left(\frac{\text{Desired output voltage}}{\text{Cartridge output voltage}}\right) Where: Cartridge output voltage is the manufacturer's rated output (usually measured at 1 kHz, 5 cm/s). Desired output voltage is typically around 300–500 mV for a line-level input. Example 1: Moving Magnet (MM) Cartridge output: 5 mV Desired output: 500 mV 20 × log ⁡ 10 ( 500 / 5 ) = 20 × log ⁡ 10 ( 100 ) = 40  dB 20 \times \log_{10}(500/5) = 20 \times \log_{10}(100) = 40\ \text{dB} So a 40 dB phono gain is a good match. Example 2: High-output Moving Coil (HOMC) Cartridge output: 2.0 mV Desired output: 500 mV 20 ...
Post a Comment
Read more

How To Match Tonearm with Phono Cartridge

To match a tonearm with a phono cartridge, you're actually matching the tonearm's effective mass with the cartridge's compliance . The goal is to achieve a tonearm/cartridge resonance frequency between about 8 Hz and 12 Hz , which keeps it away from both record warps (typically below 6 Hz) and musical bass frequencies (above 20 Hz). Step 1: Gather the specifications You'll need: Tonearm effective mass (M) in grams (from the tonearm manufacturer) Cartridge weight (C) in grams Mounting hardware weight (H) (typically 0.5–1 g unless integrated) Dynamic compliance (D) of the cartridge in µm/mN (or "cu") Step 2: Use the resonance formula The commonly used formula is: f r = 159 ( M + C + H ) × D f_r = \frac{159}{\sqrt{(M + C + H)\times D}} ​ Where: f r f_r  = resonance frequency (Hz) M M M = effective tonearm mass (g) C C C = cartridge mass (g) H H H = screws/hardware mass (g) D D D = dynamic compliance (cu or µm/mN) Example: Sup...
Post a Comment
Read more

Rule of Thumb for Sizing Subwoofers

The addition and integration of subwoofers into a stereo system is one of the most misunderstood things in audio. To make life easier, i have developed a rule-of-thumb to help simplify things a bit. Begin by calculating the surface area of the woofers in your speakers. For those of you who are a bit rusty with middle school math,  A = π r².   For example, if we have a 6" woofer in each of the front (L/R) speakers, then A = 2 * 3.14 * 3 * 3 = 56.5 sq/in. If we have a pair of 8" woofers in each front speaker, then A = 4 * 3.14 * 4 * 4 = 200.9 sq/in.  The rough range for the ideal size of a subwoofer is between 1x and 2x the area of the front woofers.  Sticking with the example of 6" woofers, we would be looking for a subwoofer (or subwoofers) with an area of between 56.5 and 113 sq/in. We can convert area to diameter with the following formula: D=2 (sqrt(A/Pi)), which in this case works out to 8.5" to 12" Now that we have a rough range, let's try to narrow th...
Post a Comment
Read more

How much power do i need for my speakers?

I am often asked questions like "is this amp powerful enough for my speakers?" so i thought i would take a moment to write up a definitive answer.  To begin answering the question, it's important to know how loud you want your system to be at your listening position. This can be different for everyone, but using the THX reference level of 85db with 20db of headroom (max 105db) as a starting point is pretty safe.  https://www.thx.com/questions/what-is-the-reference-level/ Without getting into all the math... Doubling amplifier power boosts output by 3db. Using 2 speakers in a stereo setup will boost output by 3db. Positioning speakers close to a wall will boost output by around 3db positioning speakers in a corner will boost output by around 6db. And output will decrease by 6db for each doubling of distance between the listener and the speaker.  Its kind of a lot to remember, but fortunately there are tools, like this one that do all the work for you:  http://myhometh...
Post a Comment
Read more

Phono Overview

  “Affordable” Phono Preamplifier Review I always find it tough to start a new audio equipment review, partially because i find writing hard and partially because there is such a broad spectrum of needs, desires, and knowledge in this hobby. So… Bear with me, i'm going to try to make this particular review work for everyone, if a section is too rudimentary or doesn’t apply to you, skip it (or read it anyway, since i took the time to write it).  What’s needed to play a record?  In general, every two channel audio system requires a pair of speakers, an amplifier, a preamplifier, an audio source, and a bunch of wire to connect it all together.  Yea, i know, it sounds like a lot of stuff, but not to worry... There are plenty of products (such as the Sonos Amp, Bluesound PowerNode 2i, and Amazon Echo Link Amp) that house everything you need, with the exception of speakers, to listen to music via your favorite streaming service, in one small box.  Playing records (aka...
Post a Comment
Read more

Is there any point to an "entry level" vinyl playback system?

Is there any point to an "entry level" vinyl playback system? I recently ran ran across someone asking a this question, and it got me thinking... In a world where "entry level" digital playback is so damn good and so accessible, why would anyone go for an entry level vinyl playback system, which is both lower absolute quality and often significantly more expensive.  Let's start with a cost comparison: Streaming services range from free to about $20/month. Generally you get what you pay for in this arena, but even the free services are of reasonable quality and have catalog's consisting of millions of songs these days. The highest quality services, such as Tidal and Qobuz, cost a bit less than one new record per month.  Records range from about $3 for less desirable examples at used record stores, if you happen to have one in your town, to upwards of $100. On average you can expect to pay $20-$35 for a new record at Target, Walmart, or Amazon.   Streaming mus...
Post a Comment
Read more

Product Announcement: THX Onyx Portable AAA DAC/Headphone-Amp

Link to THX Press Release:  https://www.thx.com/blog/thx-launches-dacamp-thx-onyx/ Link to ASR Measurements:  https://www.audiosciencereview.com/forum/index.php?threads/thx-onyx-review-headphone-adapter.22223/ SAN FRANCISCO, April 7, 2021 —  THX Ltd., a world-class audio and video certification and technology company, today announced the global launch of its first consumer electronics device, THX Onyx™. Staying true to its mission to empower high fidelity for entertainment, the company unveiled THX Onyx with improvements over traditional DAC (Digital-to-Analog Converter) amplifiers by including THX AAA™ amplifier technology onboard to ensure lossless, pure sound that empowers listeners to hear content the way the artist intended. THX Onyx has both THX AAA and ESS Pro DAC chips inside, as well as MQA support, creating the best-in-class portable DAC/Amplifier solution on the market today at this price for powering wired headphones.       ...
Post a Comment
Read more