# Latest **URL:** https://forum.quantasylum.com/latest.md [Latest](https://forum.quantasylum.com/latest.md) · [Categories](https://forum.quantasylum.com/categories.md) --- ## [Welcome to the QuantAsylum Forum](https://forum.quantasylum.com/t/welcome-to-the-quantasylum-forum/7)
**Author:** [@system](https://forum.quantasylum.com/u/system)\ **Replies:** 0\ **Last updated:** [December 5, 2019, 12:47am UTC](https://forum.quantasylum.com/t/welcome-to-the-quantasylum-forum/7 "2019-12-05T00:47:46Z")
The QuantAsylum Forum is a place to discuss QuantAsylum hardware and software. Have a question? Need support? Have an idea on how to streamline something? Want to share some measurements? This is the place. We’re using … --- ## [Rasberry pi 4b compatible?](https://forum.quantasylum.com/t/rasberry-pi-4b-compatible/2401)
**Author:** [@ctorre](https://forum.quantasylum.com/u/ctorre)\ **Replies:** 0\ **Last updated:** [September 24, 2026, 2:58pm UTC](https://forum.quantasylum.com/t/rasberry-pi-4b-compatible/2401 "2026-09-24T14:58:00Z")
Hi, Will this software run on a ras pi 4b (with OS Debian 13, “Trixie”? Also, I don’t like my pc providing 1A (5 vdc) via a UBS port. Can anyone recommend a powered USB hub that would be compatible with the QA403? Th… --- ## [QA40xPlot Thread](https://forum.quantasylum.com/t/qa40xplot-thread/1795)
**Author:** [@MarkZ](https://forum.quantasylum.com/u/MarkZ)\ **Replies:** 423\ **Last updated:** [September 24, 2026, 10:34am UTC](https://forum.quantasylum.com/t/qa40xplot-thread/1795 "2026-09-24T10:34:27Z")
Now that QA40xPlot is stable I wanted a thread for help/upgrade requests and focused discussion. If you missed the thread while I was writing it… The QA40xPlot application is an open source Windows program that provides… --- ## [QA404 and QA403 Update](https://forum.quantasylum.com/t/qa404-and-qa403-update/795)
**Author:** [@matt](https://forum.quantasylum.com/u/matt)\ **Replies:** 66\ **Last updated:** [September 23, 2026, 5:42pm UTC](https://forum.quantasylum.com/t/qa404-and-qa403-update/795 "2026-09-23T17:42:05Z")
A short update on what is happening with material shortages and QA404 and QA403. First, a graph over time of the % of TI’s portfolio that Digikey has in stock. This is focused on DCDC converters because throughout the sh… --- ## [macOS ampMeasure public beta](https://forum.quantasylum.com/t/macos-ampmeasure-public-beta/2387)
**Author:** [@davorin](https://forum.quantasylum.com/u/davorin)\ **Replies:** 8\ **Last updated:** [September 17, 2026, 5:36pm UTC](https://forum.quantasylum.com/t/macos-ampmeasure-public-beta/2387 "2026-09-17T17:36:53Z")
Hi all, I’ve been building a native macOS app for the QA403 over the past weeks and it’s now feature-complete enough for a beta: ampMeasure — spectrum/THD/THD+N analysis with per-harmonic readouts, SMPTE/DIN/CCIF IMD, f… --- ## [Pink Noise User Weighting](https://forum.quantasylum.com/t/pink-noise-user-weighting/2386)
**Author:** [@Rammis](https://forum.quantasylum.com/u/Rammis)\ **Replies:** 13\ **Last updated:** [September 15, 2026, 10:00pm UTC](https://forum.quantasylum.com/t/pink-noise-user-weighting/2386 "2026-09-15T22:00:54Z")
I’ve been trying to create a user weighting filter which corrects pink noise input to read as “flat” on the spectrum analyzer (I know white noise already does). This is so I can make the QA403 read as an audio RTA when u… --- ## [Wanted Quant Asylum dummy load](https://forum.quantasylum.com/t/wanted-quant-asylum-dummy-load/2397)
**Author:** [@Hector](https://forum.quantasylum.com/u/Hector)\ **Replies:** 0\ **Last updated:** [September 15, 2026, 5:38pm UTC](https://forum.quantasylum.com/t/wanted-quant-asylum-dummy-load/2397 "2026-09-15T17:38:08Z")
If anyone has a good working one and wish to sell I would be very interested. --- ## [ampMeasure 1.0 is now on the Mac App Store 🎉](https://forum.quantasylum.com/t/ampmeasure-1-0-is-now-on-the-mac-app-store/2396)
**Author:** [@davorin](https://forum.quantasylum.com/u/davorin)\ **Replies:** 0\ **Last updated:** [September 15, 2026, 3:24pm UTC](https://forum.quantasylum.com/t/ampmeasure-1-0-is-now-on-the-mac-app-store/2396 "2026-09-15T15:24:12Z")
Thanks to everyone who jumped on the TestFlight beta — your feedback shaped this release. For those just seeing this: ampMeasure is a native macOS app that drives the QA403 directly over USB — no Windows or virtualiza… --- ## [Driving DAC to be measured to full output](https://forum.quantasylum.com/t/driving-dac-to-be-measured-to-full-output/2394)
**Author:** [@sumitc](https://forum.quantasylum.com/u/sumitc)\ **Replies:** 3\ **Last updated:** [September 15, 2026, 2:57pm UTC](https://forum.quantasylum.com/t/driving-dac-to-be-measured-to-full-output/2394 "2026-09-15T14:57:23Z")
I am trying to measure a SMSL D400 DAC which is capable of outputting 5 Vrms. I would like to be able to drive the DAC to this max voltage and then step down from there to see the impact on SINAD. The DAC is connected … --- ## [Museum Audio Exhibit Testing Workflow Looking for Measurement Tips](https://forum.quantasylum.com/t/museum-audio-exhibit-testing-workflow-looking-for-measurement-tips/2388)
**Author:** [@borach](https://forum.quantasylum.com/u/borach)\ **Replies:** 0\ **Last updated:** [September 8, 2026, 4:05pm UTC](https://forum.quantasylum.com/t/museum-audio-exhibit-testing-workflow-looking-for-measurement-tips/2388 "2026-09-08T16:05:03Z")
Hi everyone, We’re working on upgrading several interactive audio exhibits in a children’s museum. The goal is to achieve consistent sound quality across speakers, headphone stations, and touchscreen kiosks before deplo… --- ## [Frequency response frequency](https://forum.quantasylum.com/t/frequency-response-frequency/2385)
**Author:** [@breedj](https://forum.quantasylum.com/u/breedj)\ **Replies:** 2\ **Last updated:** [September 7, 2026, 8:07pm UTC](https://forum.quantasylum.com/t/frequency-response-frequency/2385 "2026-09-07T20:07:35Z")
Hi, I am using the standard app quite some time and also build my own version some time ago. My version uses the API to do a EchoChirp. And I found that my amplifier was quite ok. But resently I started to build V2 of … --- ## [MCP Server for QA40x](https://forum.quantasylum.com/t/mcp-server-for-qa40x/2379)
**Author:** [@matt](https://forum.quantasylum.com/u/matt)\ **Replies:** 4\ **Last updated:** [August 20, 2026, 11:33pm UTC](https://forum.quantasylum.com/t/mcp-server-for-qa40x/2379 "2026-08-20T23:33:00Z")
I’ve been working on an MCP server for the QA40x software. MCP (Model Context Protocol) servers allow AIs such as ChatGPTs Codex and Claude Code to communicate with applications. But there’s also a discovery piece, where… --- ## [Python and QA40x](https://forum.quantasylum.com/t/python-and-qa40x/1464)
**Author:** [@matt](https://forum.quantasylum.com/u/matt)\ **Replies:** 13\ **Last updated:** [August 18, 2026, 3:37pm UTC](https://forum.quantasylum.com/t/python-and-qa40x/1464 "2026-08-18T15:37:31Z")
There are some Python classes I’m finishing that know how to use the calibration data inside the QA40x so that you can send/receive absolute values to/from the QA40x hardware. This will come in subsequent post. This post… --- ## [More precision in exported CSV files?](https://forum.quantasylum.com/t/more-precision-in-exported-csv-files/2374)
**Author:** [@iainfarq](https://forum.quantasylum.com/u/iainfarq)\ **Replies:** 1\ **Last updated:** [August 18, 2026, 3:35pm UTC](https://forum.quantasylum.com/t/more-precision-in-exported-csv-files/2374 "2026-08-18T15:35:44Z")
I’m currently running version 1.223, and I’m attempting to export trace data from graphtool to use elsewhere. It seems that all CSV files (at least the ones I’ve tried) limit values to 2 decimal places. Is this an actu… --- ## [QA403 measuring 76 SNR is loopback test?](https://forum.quantasylum.com/t/qa403-measuring-76-snr-is-loopback-test/2376)
**Author:** [@turambar517](https://forum.quantasylum.com/u/turambar517)\ **Replies:** 5\ **Last updated:** [August 18, 2026, 1:21am UTC](https://forum.quantasylum.com/t/qa403-measuring-76-snr-is-loopback-test/2376 "2026-08-18T01:21:02Z")
Hi all! I got my QA403 finally out of the box and am trying to get a good baseline on audio measurements. I have a BNC to BNC looped from L+ Out to L- IN and all the other 3 inputs blocked with shorting caps. I am just … --- ## [Phonalyzer for QA40x](https://forum.quantasylum.com/t/phonalyzer-for-qa40x/2343)
**Author:** [@Gerrittube](https://forum.quantasylum.com/u/Gerrittube)\ **Replies:** 17\ **Last updated:** [August 16, 2026, 6:47pm UTC](https://forum.quantasylum.com/t/phonalyzer-for-qa40x/2343 "2026-08-16T18:47:37Z")
Phonalyser is a free, open-source (AGPLv3) audio analyzer for Windows / Linux / macOS (soon), aimed at electrical audio-device measurement — no acoustic path — and specifically at the low-THD end where ordinary tools run… --- ## [Turntable cable test: cheap vs hifi](https://forum.quantasylum.com/t/turntable-cable-test-cheap-vs-hifi/2373)
**Author:** [@dlap56](https://forum.quantasylum.com/u/dlap56)\ **Replies:** 3\ **Last updated:** [August 14, 2026, 2:45am UTC](https://forum.quantasylum.com/t/turntable-cable-test-cheap-vs-hifi/2373 "2026-08-14T02:45:27Z")
What will be a simple test with q403 to compare good turntable cable vs cheap one. regards tks Dan --- ## [Channel muting when mirroring (QA403)](https://forum.quantasylum.com/t/channel-muting-when-mirroring-qa403/1310)
**Author:** [@yegolebi](https://forum.quantasylum.com/u/yegolebi)\ **Replies:** 7\ **Last updated:** [August 13, 2026, 2:38pm UTC](https://forum.quantasylum.com/t/channel-muting-when-mirroring-qa403/1310 "2026-08-13T14:38:49Z")
Does the generator channel mute setting also work with mirroring? maybe I am doing something wrong, but despite the mute setting both DAC channels generate the same signal… --- ## [Tractor Phase Measurement Test](https://forum.quantasylum.com/t/tractor-phase-measurement-test/1659)
**Author:** [@tkuzma](https://forum.quantasylum.com/u/tkuzma)\ **Replies:** 5\ **Last updated:** [August 12, 2026, 4:31pm UTC](https://forum.quantasylum.com/t/tractor-phase-measurement-test/1659 "2026-08-12T16:31:18Z")
Hey all, I’ve seen this topic come up before and I’ve run into several situations in production testing where I needed to measure the phase of of the DUT. Tractor never had this test, so I made my own. You can select th… --- ## [QA40x\_BareMetal](https://forum.quantasylum.com/t/qa40x-baremetal/769)
**Author:** [@matt](https://forum.quantasylum.com/u/matt)\ **Replies:** 7\ **Last updated:** [August 6, 2026, 12:11pm UTC](https://forum.quantasylum.com/t/qa40x-baremetal/769 "2026-08-06T12:11:47Z")
I’m not sure how useful this will be to most. But if you are working on a platform that isn’t supported and are able to write software, the code at the link below shows how to control the QA402, QA403 (and upcoming QA404… --- ## [Wow & flutter visualizer](https://forum.quantasylum.com/t/wow-flutter-visualizer/2333)
**Author:** [@Chicago](https://forum.quantasylum.com/u/Chicago)\ **Replies:** 10\ **Last updated:** [July 30, 2026, 2:29pm UTC](https://forum.quantasylum.com/t/wow-flutter-visualizer/2333 "2026-07-30T14:29:33Z")
Hi, I have a QA401 so older code 1.924. I have the W&F visualizer v0.83. I’m writing to verify this earlier version produces a valid measurement? I know it’s unweighted but the numbers I’m getting are actually better … --- ## [Noise and Root Hz (RtHz) Display Options](https://forum.quantasylum.com/t/noise-and-root-hz-rthz-display-options/152)
**Author:** [@matt](https://forum.quantasylum.com/u/matt)\ **Replies:** 3\ **Last updated:** [July 26, 2026, 7:06am UTC](https://forum.quantasylum.com/t/noise-and-root-hz-rthz-display-options/152 "2026-07-26T07:06:55Z")
This is an elaboration for a question sent to support since it’s easier to post graphics here: You often hear people talking about the “noise floor” of their measurement. And when the report it, they kind of eyeball the… --- ## [QA402/403 I2S expansion specifications](https://forum.quantasylum.com/t/qa402-403-i2s-expansion-specifications/612)
**Author:** [@audio-dav](https://forum.quantasylum.com/u/audio-dav)\ **Replies:** 8\ **Last updated:** [July 25, 2026, 3:59pm UTC](https://forum.quantasylum.com/t/qa402-403-i2s-expansion-specifications/612 "2026-07-25T15:59:23Z")
Hi, I have the pin-out of the expansion header, but couldn’t find the documentation for the pins in the header, i.e. max speed, io-levels etc. Also, would it be possible to add support for TDM8 and TDM16? Thx David --- ## [Unofficial open-source cross-platform tool for the QA402/QA403](https://forum.quantasylum.com/t/unofficial-open-source-cross-platform-tool-for-the-qa402-qa403/2331)
**Author:** [@raph29](https://forum.quantasylum.com/u/raph29)\ **Replies:** 11\ **Last updated:** [July 22, 2026, 9:55pm UTC](https://forum.quantasylum.com/t/unofficial-open-source-cross-platform-tool-for-the-qa402-qa403/2331 "2026-07-22T21:55:09Z")
Hi Matt, I’m a QA402 owner and I’ve built an unofficial, open-source desktop app to drive the QA402/QA403 from macOS/Linux/Windows — a from-scratch Rust + Tauri implementation of the USB protocol, with spectrum/scope/… --- ## [Revox B77 recording calibration](https://forum.quantasylum.com/t/revox-b77-recording-calibration/2338)
**Author:** [@Krypton95](https://forum.quantasylum.com/u/Krypton95)\ **Replies:** 6\ **Last updated:** [July 18, 2026, 10:56pm UTC](https://forum.quantasylum.com/t/revox-b77-recording-calibration/2338 "2026-07-18T22:56:56Z")
Hi everyone, Just sharing an interesting experience. While calibrating my Revox B77, I couldn’t find the usual bias peak, making the standard bias adjustment impossible. Instead, I monitored the frequency response in … --- ## [Continous measurements via REST API](https://forum.quantasylum.com/t/continous-measurements-via-rest-api/2342)
**Author:** [@tomiczeq](https://forum.quantasylum.com/u/tomiczeq)\ **Replies:** 0\ **Last updated:** [July 16, 2026, 10:45am UTC](https://forum.quantasylum.com/t/continous-measurements-via-rest-api/2342 "2026-07-16T10:45:43Z")
Hello. I am working with QA403 for capturing DUT output signal and using python for automated testing. I successfully used /AcquisitionAsync, /AcquisitionBusy and GET endpoints for acquiring some audio measurements. I… --- ## [QA403 Input and Output Impedance](https://forum.quantasylum.com/t/qa403-input-and-output-impedance/2340)
**Author:** [@BrandonS](https://forum.quantasylum.com/u/BrandonS)\ **Replies:** 1\ **Last updated:** [July 14, 2026, 11:53pm UTC](https://forum.quantasylum.com/t/qa403-input-and-output-impedance/2340 "2026-07-14T23:53:52Z")
I’ve been looking around, and I can’t find the spec for the QA403 Input and Output Impedance. Can someone provide it or point me in the right direction? --- ## [Interesting Problem (?) with PWR THD vs FREQ Automated Test](https://forum.quantasylum.com/t/interesting-problem-with-pwr-thd-vs-freq-automated-test/2334)
**Author:** [@VAR](https://forum.quantasylum.com/u/VAR)\ **Replies:** 8\ **Last updated:** [July 13, 2026, 2:31am UTC](https://forum.quantasylum.com/t/interesting-problem-with-pwr-thd-vs-freq-automated-test/2334 "2026-07-13T02:31:56Z")
I am doing some testing on a 1969 vintage Kenwood Receiver. Since it has pre out/main in jacks, I decided to test the amp by itself. The receiver is rated at 53w/8ohms at 0.5%THD. I was able to run a THD vs Pwr and Freq… --- ## [Any word on v2.0 software](https://forum.quantasylum.com/t/any-word-on-v2-0-software/2327)
**Author:** [@skipburrows](https://forum.quantasylum.com/u/skipburrows)\ **Replies:** 3\ **Last updated:** [July 7, 2026, 5:04pm UTC](https://forum.quantasylum.com/t/any-word-on-v2-0-software/2327 "2026-07-07T17:04:56Z")
Hey Mat, I was wondering if there’s been any further development on version 2.0 for the analyzing software. The feature set looked great but I haven’t seen any development in a while. Thanks. --- ## [QA401 noise floor](https://forum.quantasylum.com/t/qa401-noise-floor/2325)
**Author:** [@BeeElectronic](https://forum.quantasylum.com/u/BeeElectronic)\ **Replies:** 6\ **Last updated:** [July 7, 2026, 10:25am UTC](https://forum.quantasylum.com/t/qa401-noise-floor/2325 "2026-07-07T10:25:09Z")
Hello, I am a little worried with my QA401 noise floor when I do mesurment from an class D amplifier. I don’t use the QA401 so often and last time it what 2 or 3 years ago for an home made class D amplifier. Back then,… [Next page](https://forum.quantasylum.com/latest.md?page=1)