ADC 2 A/D Converter

Two chan­nel A/D con­ver­sion with Line/Mic in­puts and AES/EBU/Firewire out­put – this sum­ma­rizes the ADC2’s main ca­pa­bil­i­ties, but doesn’t tell much about its stel­lar sonic qual­ity and its plethora of features.

The ADC2 is the suc­ces­sor of our renowned two chan­nel ADC1-MK2 A/D Con­verter. It uses state of the art A/D chips in our proven “cor­re­la­tion tech­nique” con­fig­u­ra­tion, which low­ers con­verter im­per­fec­tions. The ana­log in­put stages are kept bal­anced from the in­put con­nec­tors through­out to the con­verter chips. A high qual­ity mi­cro­phone pre­am­pli­fier is built in as a stan­dard fea­ture. AES/EBU and op­tional Firewire out­puts work at up to 192 kHz/24 Bits.

Inputs

The ADC2 sports two separate input sections, one stereo pair for line level signals and one stereo pair for microphone level signals. The microphone input can be high pass filtered to cut off rumble noise. A 48 V phantom power source can be switched to the microphone inputs. After a relay controlled attenuator circuit, which uses 1 dB steps over a range of 42 dB, the signal hits the A/D converters. The analog input stage is kept balanced from the XLR connector to the A/D chips.

Converters

Two converter channels are used per audio channel which enhances the conversion quality. The analog to digital conversion process can run at 44.1, 48, 88.2, 96, 176.4 or 192 kHz. The parameters of the two conversion channels can be set independently, except for the sampling frequency and the POW-R dithering algorithm.

Syn­chro­niza­tion

Syn­chro­niza­tion can be from an in­ter­nal crys­tal os­cil­la­tor or ex­ter­nal through AES/EBU (XLR) or word-sync (BNC) con­nec­tors. The AES/EBU syn­chro­niza­tion in­put can also be used as a dig­i­tal au­dio in­put. This al­lows to use the ADC2 as a peak lim­iter and/or POW-R dither­ing proces­sor for dig­i­tal au­dio signals.

Peak limiter

The built in dig­i­tal peak lim­iter al­lows for set­ting a gen­er­ous head­room on the ana­log in­puts and still get a full scale sig­nal at the con­verter’s out­put. In ad­di­tion to the peak lim­iter with a thresh­old pa­ra­me­ter there is a dig­i­tal gain control.

Out­puts

The out­put word-length can be re­duced from 24 to 16 Bits with the built in POW-R dither­ing. It is pos­si­ble to have one out­put run­ning at 24 Bits and an­other one at 16 Bits. The out­put for­mats are AES/EBU in one or two wire tech­nique, S/PDIF in sin­gle wire as well as Firewire for a di­rect con­nec­tion to com­put­ers. The Firewire con­nec­tion can also be used to feed a sig­nal from the com­puter to the S/PDIF out­put of the ADC2. 

Me­ter­ing

For me­ter­ing a large bar graph shows the level to the A/D in­put, the out­put level, over­load con­di­tions and the gain re­duc­tion in the afore­men­tioned peak lim­iter. The peak hold me­ter with nu­meric read­out can be used to mon­i­tor a trans­fer and check for over­loads which may have oc­curred.