Open Baffle speaker
- Drivers are Fostex FX120 and Eminence Alpha 15
- Active crossover using a minidsp 2×4
- Asymetrical crossover at 200Hz 2nd order LR and 500 Hz 2nd order Bessel
- 3DB bass boost; 0.9DB gain high shelve, Q 0.7 @7KHz
- Drivers connected in phase
- Baffle size is 510 x 950 mm; beech wood 26mm, braced on the back using 40×40 mm beams
- Designed using MJK licensed calculation models
- Bi-Amplification using my Bob Latino Dynaco ST70 tube amplifier for the extended range driver and my LM3886 chipamp for the bass.
I finished another chip amp kit I bought at Chipamp. The base of the cabinet is made of 18mm bamboo plywood. The top plate is 3mm aluminium, a custom order from Schaeffer AG. In the US their subsidiary is called Front Panel Express. The construction is fully dual mono. Inside the cabinet are two 300VA, 2*24V shielded toroidal transformers (bought at www.toroidy.pl at EUR 34 a piece) and the standard chip amp boards and parts. The amp chips are mounted to a 10mm * 120mm * 200mm block of aluminium that serves as heat sink. That block is attached to the top plate underneath the vents. Here are a few pictures:
Since I still like the sound of the Jordan VTL speakers and listen to them literally every day, I decided recently to get rid of the ugly and unfinished MDF cabinets. Inspired by Blumenstein Audio’s Orca fullrangers, I have decided to use Bamboo plywood as well.
So, off I went to the next local woodshop and ordered the material. I opted again for speakon speaker terminals and Bluejeans speaker cable for both internal and external wireing. The drivers are mounted using proper nuts and bolts rather than just plain wood screws. The cabinet is finished using furniture grade wax.
Here some pictures:
Just a quick update. Based on a recommendation I have upgraded the capacitors of Jerry’s kit with 470uF 35V Elna Silmic II Electrolytic Capacitors. I soldered the caps to the underside of the PCB as the caps a bigger in size than the stock ones. This is a great improvement. More bass, really mature sound.
I have also built a full power supply for the amp.
I started a new project to build another preamp. I very much like my Bottlehead Quickie, but it has only two inputs and having to change cables to listen to another source is not really great.
Since I was very satisfied with Bob Latino’s VTA ST70 power amp, I decided to go with Tubes4Hifi’s SP14 kit.
I ordered a custom top plate in order to have proper labels for my sources. I also added optional Mundorf silver PIO output coupling caps and an input selector relay board.
The ordering process was flawless, friendly and professional. Shipment arrived on my doorstep after only 5 days. Not bad from the US west coast to Switzerland. Everything was well packed and in mint condition.