Remote controlled A/B sound test switch for amps, speakers and sources like CD, DACs

I have build my self a new remote controlled test switch for A/B comparison of amps and sources.

I had such a switch for many years, to do tests while modifying all kind of audio gear. I dislike just doing modifications and have no way to make (more or less) objective listening tests.
So I put one reverence or un-modified part on one side and the "tuned" one on the other. Then I switch between them without any delay and listen.
If you have to change wires, this is not as effective as just turn a switch to really do A/B testing.

Because today many amps are bridged, I decided to build a new switch unit, also more comfortable and universal than the old one, that used a wired remote switch.

One side switches two amps to one pair of speakers or with one amp between two sets of speakers.
Because relay contacts wear out when switched under load, they are doubled. Not elegant, but a good way to keep resistance down.

The other side can be used to compare sources like CD players or DAC´s, or just to match levels while comparing A/B on the other side.

On the RCA side the ground is switched with the signal to prevent ground noise from different sources.

By using cheap offers from eBay and AliExpress I was able to realize this for roughly 30 US$.

Parts are:

Remote control 12V
4-way relay board
8-way relay board
6 double speaker binding posts
6 RCA sockets
1.5 A voltage regulator
some wires
a used case


I will just post pictures from single parts to finished unit. If you work very pedantic, like me, be prepared to spent a whole day on it. All these wires are really time consuming.

PS still have to add some LED to show the state of the switchers.
 

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Last edited:

Sound41

Member
2012-05-19 5:08 pm
Nice execution. I'm interested in building something similar. My modified usage is for switching 2-4 vintage receivers to a set of speakers for A/B/C/D type source evaluation and general listening across my different receivers (Marantz, Sansui, Yamaha etc...), turntables and reel to reels.
 
For me one very interesting use is to plug in a CD player on one end and a separate DAC, connected to the same players digital out.

Be aware! Can be a very bad eye opener, if you switch during a song.
Very important is to match levels very exactly if you do such testing.
A CD with a 1000Hz sine tone and a voltmeter at the output will get you straight.