DAP AUDIO D1537 ELI-101 Stereo Hum Eliminator

Tube-buffered DI-Box DI-1000

The Tube-Buffered DI-Box DI-1000 allows the extraction of all the musical details of
musical interfaces without degrading the sound. This can only be achieved by
providing a very high input impedance to avoid any loading of instrument pickups.This
design approach allows seemingly infinite headroom to preserve the real dynamic range
of the interfaced instruments.A vacuum tube enables all these goals to be achieved
without any compromises in sound quality.The sonic difference between a standard
DI-Box and the Tube-Buffered DI-Box is comparable to the musical resolution difference
between a standard microphone and a studio microphone.One of the best transformers,
the very transparent sounding JENSEN JT-DB-E, was chosen providing complete ground
isolation. The parameters of this transformer, like frequency response, phase response,
group delay and geadroom capabilities, play a vital part in the performance of this DI-Box.
 
Technical Specifications
Input
The signal of the instrument is directly fed to the tube circuit with > 20 MOhms input
impedance to prevent any signal degradation, inevitable in traditional designs.
Buffered Output“
The second stage of the vacuum tube is used to buffer the signal and lower the output
impedance to < 8 kOhms. This unity gain output allows for cable runs of 10 meters
without loosing high frequency information.
Boost circuit
The boost circuit increases the signal send to the output transformer by 15 dB. This may
be useful for instruments with extremely low output, but decreases headroom capability
to 6 Volt rms. Under these circumstances the signal may be clipped, concerning the output
transformer?s signal, which gives you 2nd harmonic tube-like distortion. This distortion
normally does not occur - but is sometimes desirable, being the reason for this special feature.
Unity circuit
The unity circuit feeds a low distortion unity gain signal to the JENSEN output transformer.
This gives the best possible sound quality.
Ground-lift“-Switch
This front panel mounted switch allows complete ground and electrical isolation between the
direct injection box and the console or recording device.
 

Mechanical Specifications
Cabinet 2 mm stainless steel
Front- and rear-panel 1,5 mm stainless steel lasercut and photo-chemically etched
Dimensions 185 x 100 x 40 mm
Vibration insulation 4 high-compliance rubber-elements
Operating Voltage
220/110 V AC, selectable via rear panel mounted switch. The fuse is easily
accessible from the rear panel. IEC mains connector with optional fixture.
Construction details
Double sided glass fibre contacted PCB with 70 mm copper plating. 1% metal film resistors
and the finest polypropylene capacitors are used in the signal path. MIL type Switchcraft jacks
and high performance switches ensure flawless operation. The power supply is optimised via
measurement quality toroid transformer and a low impedance design to ensure the lowest
possible noise. Through a double sided PCB all parts are roadworthy secured. A waterclear
blue LED perfects the aesthetics of the DI box.

Technical Data
Input impedance > 20 MOhm
Output impedance180 Ohm at 1 kHz
Frequncy response 20 Hz - 20 kHz (-0,1 dB)
                             5 Hz - 120 kHz (-3 dB)
THD at 0 dBv  0,06% at 20 Hz
                      0,04% at 1 kHz
                      0,035% at 20 kHz
Signal to Noise Ratio 86 dB
Tube ECC 83/7025 A - military E 83 CC optional
Output transformer JENSEN JT-DB-E
Polarity Pin 2 Hot , AES/IEC -Standard
Max. Input voltage > 30 V peak
 

Inline Transformer IA-2

The model IA-2 line matching transformers !S designed to properly match a low impedance
signal to a low impedance source. The advantage of "ground lift" switching allows to optmize
hum problems.
 
Technical Data
Frequency response 20 Hz - 20 KHz + 1 dB
Impedance 600 : 600 Ohm
THD K3 50 Hz = 0.5 %
Level < + 6 dBm
Weight 100 g
Dimensions diameter 17 mm, lenght 115 mm