Lejonklou Boazu 2.0

Wonderfull musical amplifier from the Swedish wizard Frederik Lejonklou. This Boazu is the 2.0 version and the latest and newest version of this amplifier and is performing way above the previous version.

Very airy, subtill, musical and smooth performing amp which unravels the music in a new way.

From the maker a short sum of what has changed vs the previous version:
So what has changed from the original Boazu?

1. Everything is now made in Sweden (apart from electronic components). This is more expensive than the original production in Estonia, but the advantages are many. The main one is that I have intimate communication with and immediate access to the assembly (an hour away by car), so we can sort out difficulties and improve how things are done. Several techniques used are also of higher quality and required a redesign of the main board.

2. The new case (also made in Sweden) is the same as on Tundra Mono 3, has more ventilation and sounds better (mainly due to the integral pillars that support power supplies and main board).

3. The inductors in the preamp section have been changed to the models used in Tundra Mono 3.

4. The internal cabling has been changed to the models used in Tundra Mono 3.

5. The inner layers of the circuit board have been optimised for capacitive coupling between layers. This is something I hadn't mastered in 2016 and takes a long time to evaluate. Basically it's a trade off between low impedance and unwanted capacitive coupling and most of the trial and error was done on Tundra Mono 3.

6. Selection of all components is more optimal, partly thanks to my soon to be employee Oscar, who's measured an enormous amount of components and selected them into small groups. On the original Boazu, I used all the selections that were left after making Tundra and Tundra Mono, but on Boazu 2 I decided to use the best selection of many parts. Resistors are inexpensive, so there we just bought more of them until we had enough of the best selection of each value. For transistors we decided to measure them under conditions that are closer to the actual working conditions, meaning that we clamp each one to a copper heat sink and pre-heat them with a high current for 45 seconds before measuring their parameters. This results in selections that are musically better performing.

7. Idling currents are a bit higher than in the original Boazu, which sounds better. This is fine tuned on each unit, which can sometimes take hours, as it involves changing components until optimal values are obtained. I wanted to have a quick trim feature on the boards to make this tuning easier, but I did not succeed in making one that sounds good enough. But, you might point out, there is an external trim knob on Tundra Mono 3? Yes, and it works perfectly. The problem is that it can't be used on Boazu due to it having two channels and being different in other aspects. So I tried and failed in making a "transparent" time saving trim feature on Boazu 2 and will therefore manually trim both the main board and the two power supplies on each unit.

8. The feedback loop has been fine tuned to a precision of 0.1 Ohm and 1 pF. In the original Boazu, the precision of the resistive part of the loop was 1% and now it's 0.0005%. This may seem over the top, but it does nail down the "pace" of the amplifier more precisely. It's one of those parameters that can easily be heard in the music and that appears to have no limit when you gradually increase the precision. Each time we tested one tenth of the previous precision, the musical differences were about as big as in the previous comparison.

9. RCA connectors now have gold plated barrels and tin plated signal parts. Original Boazu had nickel/nickel, because they were much less expensive than the gold/gold model I use on all other units (which appears simple and standard in its design, but is quite expensive). Instead of changing to the gold/gold model, I found this new RCA to be more musical than