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Nekolab Posts

Nekolab

Den grimme ælling

As in Hans Christian Andersen’s fairy tale The ugly duckling, can a small, insignificant cheap DAC become a well-sounding high-end DAC? In most cases the difference between an economical DAC and a high-performance DAC is found in the analog output stage. Take for example the Douk Audio DSD 1796 (price below 100,00 euros): it is equipped with an excellent XMOS interface and an equally good DSD1796 DAC characterized by 24 bit resolution, 192 kHz sampling…

AIDA LCR RIAA Tube Preamplifier

In my personal persuasion ʺ the fewer, the better ʺ I designed a phono preamplifier with only two gain stages ( to minimize sonic coloration ) and without negative feedback. Mostly, the first stage is the heart, the crucial part of any RIAA preamplifier. Aida phono preamp uses a new all tube high performance circuit with very high gain, low distortion and super low noise. The goal is to achieve the maximum possible amplification at…

Figaro Tube Line Preamplifier

16 dB gain, zero feedback all tube line preamplifier, 500 ohms output impedance. Very short signal path from the 6 inputs to line or tape outputs. State of art components: paper ( or MKP ) in oil capacitors in signal path and PSU, carbon composite resistors, silk parts cathode capacitors. High selected NOS tubes ( two 12B4A, two 6J51p and one 5Y3GT ). Very quiet noise floor ensured by “floating” power transformer, CLCL filter plus…

Macbeth DHT Tube Line Preamplifier

Macbeth…the ULTIMATE Line Preamplifier. 16dB gain, zero feedback, active load DHT tube stage. Double power supply: Tube rectifiers, CLCL regulator plus dual mosfet stabilized stages for HV anode and SLA battery PSU for DHT filaments. LED Display for battery check, internal battery charger. Polypropylene and oil filled polypropylene capacitors in PSU. 6 NOS tubes ( two 4P1L, two E810F and two 6AX4GT ). Only one copper polypropylene coupling capacitor in the signal path. Macbeth…the ULTIMATE Line…

Stiffelio USB DSD Tube DAC

This DSD DAC is dedicated to true audiophiles who want to listen the best vinyl like or reel-to-reel tape sound. Stiffelio DSD DAC is a single USB input and use a class A transformer coupled tube circuit plus a minimalist approach filter to remove carrier data from DSD streaming to obtain a natural pure analog output signal. With Stiffelio DSD DAC you can play all type of music files ( Flac, Iso, Dsf, Ape, Wave….)…

Otello Tube Phono Preamplifier

For a RIAA preamp it’s very important keep a short path for audio signal from input to output. Otello is a tube phono preamplifier, zero feedback circuit with an ultra low noise tube-hybrid power supply. Otello use a passive RIAA network, only one high quality  coupling capacitor in the entire signal path and a star ground circuit with separate path for signal and power supply. Two choices are available for gain: 42 dB for MM cartridge…

Nocturne MKIII Tube Headphone Amplifier

  Three years ago I build the first version of Nocturne – a transformer coupled tube headphones amplifier – equipped with 6C45p triode and then last year a second version with a more performing ( and more gain ) D3a triode strapped, both intended to drive with excellent performance a AKG K550 back closed headphones ( 32 ohms, 114 dB sensitivity ). A few months ago I got to try a planar magnetic open back…

Mimì two way compact speakers

Many hears ago, in a Hi-Fi show, I listened the ProAc Response Two speakers and I was really impressed by their performance. These speakers just simply disappeared, leaving behind an ambient soundfield that changed very little with head movement. Driven by an excellent Audio Reserch tube pre/power amplifier, they had put the singer right here in the room with me!! Also all acoustic instruments like the guitars, violins, percussions were played with a breathtaking sense…

Attila 6C33cb SE Power Amplifier

The 6C33C-b is an attractive tube. This indirectly heated, high transconductance, high current capability and low internal resistance, inexpensive triode, from Russia, with a large 60W anode dissipation, originally designed as a voltage regulator for the avionics in Russian military aircraft, it is the ideal “high current” triode for audio applications. The downside? The 6C33C-B requires a relatively high anode current (typically 180-220mA at 180-210V) a high heater current ( 3,6 A with filaments connect…

New Crossover for K2 Klipschorn clone

During the last year of listening my K2 Klipschorn super clone speakers (info and specs here) I put the attention on some point to upgrade. I focused my attention on the crossover frequency on both low-mid and mid-high cells. After many weeks of listening session I found some benefits to lowered both crossover frequency. The inductor in series to K33e woofer is now 8,2 mH ( old value 3,6mH ) put in a separate plastic…