AC mains cable does make a difference!

Until I had not tried Nordost Brahma mains cable (on mbl 7006) I did not believe that mains cable makes a difference. I said that they cannot possibly make a difference after all these miles of lousy cable all the way from the power-station, well from the transformer. However, they do...


Therefore, I will most likely DIY one.


One DIY project: TNT TTS
And maybe more scientific approach: VH Audio
And another: Scoobidoo



Intersesting it is that no shielding is used (to achieve lower capacitance) - also Brahma does not have it.

Matej

Aikido is in the game!!!

Today I replaced AudioNode output PCB with Aikido (w/ tantalums and Mundorf Silver/Oil coupling caps). Result?! Outstanding! Sound is more natural, instuments have more body, dynamics is unbeliveable - you can feel (sonic waves) the music. Bass has tightened.


I have to solve one issue - one channel has 160V other 210V. Aikido balances this, but I have to solve this.


Matej

My parts selection

My best-of selection:

Coupling caps: Mundorf Silver/Oil
Polypropyene caps: WIMA MKP
Low-noise (digital) caps: BG NX
HV PSU caps: EPCOS 435xxx series (did not try others)
Resistors: Vishay VTA52/55 (of course, tantalums are not bad)

Riken Ohm : Good balanced sound; improvement on cheap metal films.

Tantalum (AN and Shinkoh) : A little more detail than Riken, nice midrange, but upper midrange and treble can be a bit harsh.

Vishay VTA52 / VTA55 : Amazing. By far the best. More detail, smoother sound, very lifelike.

Matej

Aikido

I started working on Aikido. Aikido is a great topology (noise cancellation). It can be used for headphone amplifier/line stage/pre-amp, etc. See picutres.


I plan do do a class-A power amplifier based on Aikido input stage and MOSFET output stage - called MOSKIDO ;)

Cheers,
Matej

Battery Powered PSU - Daja

Today I've finally completed Battery Powered PSU (named Daja). Its is fully automatic (no switches at all, triggered by client - 12V trigger) based on relays. When not used battery are being charged. Charging is advanced using several stated: batery revival (trickle charge), current limited charging, voaltage limited charing and finally float charge. No maintainence is needed. Connectors are RCA and all fully fused.

See pictures with comments.

Cheers,
Matej

Aikido

Now DAC output stage is a "simple" SRPP. It sounds nice, but.... it can be made better. After lots of investigation I decided to go Aikido way. It is really great design and very flexsible. I might try Moskido as well.

I've removed digital PSU out of DAC and mounted new PSU. Now everyhing is nice and clean. No bruuum and background noise. Great!

SLA battery chager (UC3906) prototype works. I plan to built 4 on them on a board and put SLAs in nice separate chassis. I will use RCA conectors (standard and thay have good connections).

Matej

Coupling caps

After quite some investigation I will most likely go for Mundorf Silver/Oil. Possible candidaces are: Audience Auricap and Audio Note Copper Foil (Silver Foil are way too expensive). Since I have WIMA MKP at home, I will try these as well (for fun - they should be very transparent and thin).

Value is determined by C = 1/(2*pi*R*f), where f is a roll-off frequency. Coupling cap forms a high-pass filter with resistor and impedance of the next stage (power amplifier). I recommend values 470nF and larger.

Matej