Has someone tried these with 4 ohms speakers, at loud volume, full range. How much power do these have for 4 ohm loads. Do I need to go for a bigger trafo, caps and heat sinks.
The MyRef was designed for 8 ohm loads and +/- 32V rails. If you want to go with 4 ohm loads, the rail voltages will need to be restricted to +/- 28V. Distortion will also be higher, and odd-harmonic.
Can these be bridged internally with bigger trafo to get more power.
Nope, bridging is infeasible.
I see references to 1.2, 1.3, 1.3 premium and 1.4. Is 1.4 being the latest also the best. What upgrades are there in the premium kit as compared to the normal one. Are just the components better or the pcb is also different. There is a change in the input cap to make basic kit better, are there any other strategic component changes that will improve 1.3 basic, instead of going straight to premium. Whats the highest voltage i can go for in the trafo, also the largest possible caps i can put in the o/p. Are there any pictures of the populated boards for basic and premium kits.
They all employ the same functional schematic. The differences are mainly in the size and shapes of some components. The premium kits have higher grade components at many locations (Wima polypropylenes, Nichicon Muse and Rubycon Black Gates, more tightly matched resistor sets, fast/soft rectifiers, better zeners, etc.)
You can go with a standard kit or a bare PCB set and self-source your components, but there will be some difficulty in sourcing premium film caps and electrolytics locally.
Does this come with the soft start circuit to avoid the loud thump sound at startup time.
What are some of the other equivalent amp designs out there without spending a fortune.
It has a DC protection relay which is also the soft-start - there's no turn-on thump, but there might be a slight turn-off thump in some situations.
There's no comparable chipamp design at any price point. If you go for fully discrete designs, a carefully-built Symasym is pretty good and can be made to sound almost as good as a MyRef, but it requires bias setting and offset adjustments which tend to drift with temperature and aging. A Symasym is more powerful though, and can easily go up to 75-100W per channel.
Those have since been packed off to my brother-in-law's place.
