Azazello wrote: ↑2023-03-13 21:44
lejonklou wrote: ↑2023-03-02 15:07
matthias wrote: ↑2023-03-02 07:36
I assume there is no input switch similar to Boazu?
No, it’s a mechanical switch on Superkikkin.
Is that better that no switch..? s
OK, so here's my take on this:
On Boazu there is, instead of switches on the inputs, what I call a mixer - it adds the four inputs together and plays the sum. I borrowed the idea from the legendary amp Au/Ra Z1, an odd and pretty great design by Jiri Janda, who is sadly no longer with us and his company Rational Audio seems to have disappeared as well. Z1 had a mixer on its inputs and you set the volume by turning a bent metal rod. I found it refreshingly simple to use.
The advantages of a mixer are:
+ It's convenient not to have to select inputs
+ With only one one source connected, the negative impact is zero so it sounds better than a switch
+ With two sources connected, it sounds about as good as a switch
The drawback of a mixer is:
- With many sources connected, the background noise of each starts to add up and will eventually impact musicality
On Sagatun there is a four-way electronic switch, so you need to select the input. Then I also added a single separate input that goes past the electronic switch (Single Source input) and a switch with which you can turn the four other inputs off.
The advantages of this 4+1 combination are:
+ If you have only one source, there's an optimal way to connect it (better than a switch)
+ If you have many sources, you connect them through an electronic switch that doesn't age or corrode
+ If you have many sources, there is no background noise that adds up and can impact musicality
The drawback of the 4+1 combination is:
- If you have many sources, you need to select which one to listen to (no convenience)
On Superkikkin, there are two inputs and not enough space for a third. The possible options for two inputs are: A mixer, an electronic switch, an electro-mechanical switch or a mechanical switch.
Initially I wanted to use the mixer, but there's a conflict in the design of Superkikkin that makes it inappropriate: Power consumption. That mixer adds power and will weigh down the power supply of Superkikkin, which makes it less musical. The same thing goes for an electronic or (in particular) electro-mechanical relay: The circuit of Superkikkin is optimally powered and preferably nothing more should be added that consumes power. The remaining option is a non-powered mechanical switch.
There also another reason to use a mechanical switch. It's probably common for people with two sources in their system to have one turntable and one digital source. Now if the phono preamp of the turntable source is Entity or SINGularity, those designs have a lot of gain. In contrast, my digital source Källa has lower gain. If these two sources (Entity/SINGularity and Källa) go into a mixer and you listen to the turntable, Källa adds almost no noise to the mix you're listening to. All fine there. But if you listen to Källa and turn up the volume, then the noise of Entity/SINGularity will become slightly noticeable. So for this particular combination, it's preferable to completely switch off the sound from the turntable. A Slipsik or Gaio phono stage has a gain that is closer to Källa, which makes them more suitable for the mixer used in Boazu (when combined with Källa).
The mechanical switch on Superkikkin needs to be manually flipped to listen to your second input. Assuming the second source is a turntable, you will still need to walk to the turntable, handle the record and put the stylus in the groove. Therefore I figured flipping a manual switch when playing vinyl wouldn't bother anyone.
The mechanical switch was chosen by listening to a lot of different models. Their impact on the music was surprisingly big and two models stood out from the rest: The cheapest one and the most expensive one. Both were really musical, but the cheapest one had a slightly odd tonal impact (sounded "grey") and as the contact points weren't gold plated and the housing not sealed, I strongly suspect that it would degrade with age. The most expensive one was sealed, gold plated and sounded
very close to not having any switch at all. That's the one I chose.