# Testing Many Channels

**URL:** <https://forum.quantasylum.com/t/testing-many-channels/602>\
**Category:** QA40x\
**Created:** [February 17, 2022, 8:34pm UTC](https://forum.quantasylum.com/t/testing-many-channels/602 "2022-02-17T20:34:22Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![Dave\_MacKinnon](https://avatars.discourse-cdn.com/v4/letter/d/eb9ed0/32.png) [@Dave\_MacKinnon](https://forum.quantasylum.com/u/Dave_MacKinnon)\
**Post date:** [February 17, 2022, 8:34pm UTC](https://forum.quantasylum.com/t/testing-many-channels/602/1 "2022-02-17T20:34:22Z")

</div>

I’ve been asked to test some five-channel car audio amplifiers for a client. I did this with my QA401 and QA402. I’ve since sold the 401 and plan on ordering a 403 next week when sales re-open.

Is there a way of running two QA40x sessions simultaneously so I can monitor the main and subwoofer channels?

---

<div class="post-metadata">

**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://forum.quantasylum.com/u/matt)\
**Post date:** [February 18, 2022, 7:59pm UTC](https://forum.quantasylum.com/t/testing-many-channels/602/2 "2022-02-18T19:59:58Z")

</div>

Hi @Dave_MacKinnon, I think the right way to do this is to have a single QA40x running, and then use a 6 to one switch of some kind that lets you look at each load separately. The aim with a 5.1 amp is to stress all the channels at the same time. But, you can run the same test 6 times and test a single channel each time. Or, you can run the test 3 times and treat each channel as part of a stereo pair.

If you could do the tests manually, you could have a switch that lets you pick the pairs you want to measure. Something like this rotary switch [HERE](https://www.digikey.com/en/products/detail/c-k/A30305RNZQK/3752157) would let you make a measurement, turn the switch, make another measurement, turn the switch, etc. But for every measurement, you have a lot in place for every channel. The switch is just picking which load you measure across.

A more automated approach is shown in the link below.

> **[Building a 6:1 Mux for 5.1 Testing](https://quantasylum.com/blogs/news/building-a-6-1-mux-for-5-1-testing)**
>
> When testing a 5.1 amplifier, it's desirable to perform the tests with all channels under load. The front-panel of the QA440 is shown below. It's a product (to be released in January or February 2022) that permits relay switching using standard

---

<div class="post-metadata">

**Author:** ![Dave\_MacKinnon](https://avatars.discourse-cdn.com/v4/letter/d/eb9ed0/32.png) [@Dave\_MacKinnon](https://forum.quantasylum.com/u/Dave_MacKinnon)\
**Post date:** [February 18, 2022, 9:43pm UTC](https://forum.quantasylum.com/t/testing-many-channels/602/3 "2022-02-18T21:43:15Z")

</div>

Thanks for the Reply Matt! Always appreciated.

I think the selector switch might work for the short term. I can monitor the sub channel on the Right and switch through checking the main channels on the left.

That QA440 would be gold for someone setting up automated testing on a multi-channel amp.

Also, will look into those ARCOL loads. Very Interesting!