FOCUSRITE ISA 428 FOUR CHANNELS MIC PREAMPLIFIER

ISA 428 

Τετραπλός μικροφωνικός προενισχυτής. Διαθέτει διακόπτη για mic/line, phantom power,
έλεγχο gain του σήματος εισόδου και ανάστροφη φάσης. Έλεγχος input balance, έλεγχο
του σήματος εξόδου. Ένδειξη VU. Συχνότητα δειγματοληψίας έως 192kΗz.

Το PRE73 είναι ένα πιστό emulation του κλασικού Neve 1073 και σε απίστευτα χαμηλή τιμή. Είναι ο πρώτος μονοκάναλος προενισχυτής με full discrete ροή σήματος και με τρείς ξεχωριστούς μετασχηματιστές για την balanced είσοδο μικροφώνου, την line είσοδο και έξοδο.

The U5 high-voltage DI-preamp combines a unique passive tone selector with a variable
gain preamp and filter. The high input impedance accepts a wide variety of signal levels
and instruments from acoustic guitars to high-output active bass guitars and keyboards.
The U5 direct box is loaded with sonic character and user features professionals demand.

U5 FEATURES
Pure Class A, 100% discrete design
Smooth musical detail and sonic excellence
Variable gain preamp to +30dB.
Dual microphone and line outputs
Hi-Z   3,000,000 ohm input impedance
Very low noise -100dB
High headroom +30dB
Six tone bank selections.
DC coupled Class A output for superior bass
High cut switch eliminates noise
LED active signal indicator
Headphone monitor output jack
Low distortion less than 0.5% THD and IMD
High level 400 watt speaker input
Active to thru selector - ground isolation switch
100% discrete power supplies for audio path
Internal toroidal power supply for low noise
Long lasting, stainless steel hardware
 
SONIC EXCELLENCE
The Avalon U5 Pure Class A instrument DI & preamplifier is the most powerful direct box
available today.  Designed to optimize absolute signal integrity and musical performance,
the U5 includes many features and sonic excellence unequaled by lesser designs. The
U5 is ideal for bass guitar and acoustic instruments, electric guitars, keyboards, synthesizers
and low output pickups. 
Features include state-of-the-art, high input impedance input stage for zero load effect on
sensitive pickups and keyboards, 100% discrete, Pure Class A signal amplifiers, practical
user features and rugged hardware designed to deliver true high performance audio for many
years. 
DESIGNED FOR DEEP & CONTROLLED BASS
Avalon U5 DI-preamps have been in use around the world since 1995. They have found their way
into the world's leading musicians rigs and recording sessions and been featured on thousands
of the best selling (and sounding) albums and live performances.
MINIMUM SIGNAL PATH DESIGN
The U5 includes a variable gain Class A preamplifier to boost low level pickup signals and a high
level speaker input for capturing the live sound of the instruments amplifier. Six passive tone-EQ
curves are also included to enhance a variety of acoustic and electric instruments. A high-cut switch
eliminates unwanted acoustic pickup and high frequency noise, while a  headphone monitor amp
has been included for personal listening. Twin DC coupled Class A output amplifiers drive both low
level microphone preamp inputs and high level +4dB inputs for direct to tape recording or processing.
The active-to-thru switch selects either the instrument input directly or sends the boosted-equalized
signal to the amplifier via the front panel jack. A ground isolation switch eliminates any possible earth
loop or AC buzz problems with complete safety.

U5 SPECIFICATIONS
Circuit Topology:  100% discrete, high-voltage Class A 
Gain:  Switched 3dB steps, maximum gain +30dB 
Input Impedance:  3 ,000,000 ohm unbalanced (single ended) 
Maximum Input Level  +24dBu unbalanced, 400w speaker input 
Output Connectors (2):  XLR type, pin 2 hot electronic balanced 
Maximum Output Level (Class A):  +30dBu DC coupled, balanced 600 ohms (mic and line out) 
Headphone Output:  0.5w into 600 ohms 
Noise 20kHz Unweighted:  -100dBu minimum gain position 
Distortion THD, IMD:  0.1% at +10dB 
Frequency Response, -/+0.5dB:  5Hz to 100kHz 
Frequency Response, -3dB:  1Hz to 500kHz (input band limited) 
High Cut Filter:  -3dB at 8kHz minimum phase design 
Tone Selector:  Six position rotary switch, all passive filters 
AC Power:  Internal toroidal AC supply 
Dimensions:  8.5 x 3.5 x 12 in (216 x 88 x 305mm) 
Weight-Packed:  12lbs (5.4kg) 
Rack mount kit (1) RM-1:  Single U5 19 inch rack mount kit (holds one half rack unit) 
Rack mount kit (2) RM-2:  Dual U5 19 inch rack mount kit (holds two half rack units) 

Το νέο Pre -73 DLX ένας μονοκάναλος προενισχυτής μικροφώνου με vintage στύλ. Η διαδρομή του σήματος χρησιμοποιεί μόνο ξεχωριστά διακριτά στοιχεία, όπως
πυκνωτές, αντιστάσεις, και τρανζίστορ. Oι τρείς διαφορετικοί  μετασχηματιστές που διαθέτει σε  mic in , line in και στην έξοδο, ειναι  κατασκευασμένοι για να προσφέρουν το βέλτιστο αποτέλεσμα.

Αυτός ήταν ο τρόπος που κατασκευάζονταν τα audio εξαρτήματα πριν την δημιουργία  των ολοκληρωμένων  κυκλωμάτων.Η εξαιρετική  ποιότητα ήχου που προσφέρει  είναι
συνήθως καλήτερη απο αυτή σύγχρονων μονάδων, κάτι που γίνεται  προφανές στη καθαρότητα της σημερινής μουσικής η οποία έχει καταγραφεί με ψηφιακά μέσα.

Το κύκλωμα που χρησιμοποιείται στο Pre -73 DLX είναι παρόμοιο με το κύκλωματου κλασικού 1073, με αντίστοιχο  χαρακτήρα και εξίσου ζεστό, ζωηρό και γλυκό ήχο.
Αυτά τα χαρακτηριστικά έχουν ακουστεί σε αμέτρητες ηχογραφήσεις τα τελευταία  40 χρόνια και είναι ένας  ευέλικτος  ήχος  που λειτουργεί πολύ καλά με τις
περισσότερες πηγές ήχου και στα περισσότερα μουσικά είδη. Ο χαρακτήρας αυτού του ήχου είναι τώρα διαθέσιμη σε εκπληκτικά χαμηλό κόστος,
ώστε να είναι προσιτή  σε όλους.

ΧΑΡΑΚΤΗΡΙΣΤΙΚΑ

- Vintage Style electronics. No intergrated circuits in the signal path.
- Maximum gain on the mic input is 80 dB, enough to handle passive ribbon mics with quiet sound sources.
- Gain range on the Line input: -20 to + 10 dB.
- Switchable impedance on the mic input, 1200 or 300 Ohms, will change the tone of most mics.
- Switchable phantom power and absolute phase.
- A high-impedance instrument input for any sound module, electric guitar or bass.
- A simple but effective 4-step LED output level meter.
- The output level controls makes it possible to make fine gain adjustments and also to overload the main gain stage(s) for more character and then lower the signal to a suitable level before the output stage.
- Combo XLR/TRS input jacks and separate output XLR and TRS jacks for flexible connections.
- Insert jack for inserting EQ/s and other units.
- External high power power supply to avoid interaction with the audio circuits and transformers.
- A solid build quality that will last many years of normal use.
 

O PRE-73 DLX ΕΧΕΙ ΜΙΑ ΠΛHΘΩΡΑ ΒΕΛΤΙΩΣΕΩΝ ΣΕ ΣΧΕΣΗ ΜΕ ΤΟΝ PRE-73 MKII

- Tantalum capacitors in the signal path.
- Selectable 1073-style high pass filter, 50Hz, 80Hz, 160Hz and 300Hz.
- Output Attenuator -7, -14, -21 and -28 dB (located after the output transformer) allows overdriving the output stage and the output transformer for added character by lowering the output signal to a suitable level.
- The circuit board is prepared for Carnhill Mic and Line transformer and high pass inductor.
- The Insert jack can be switched in/out from the front panel. An internal jumper can select that the Insert jack always has an output signal.
- Switchable 600 ohm Output Termination and Ground Lift on the back panel.
- Selectable Active or Passive DI input and selectable input impedance in active mode, Hi Z or 100 kohm, by internal jumpers.
- The DI can signal can be selected to pass or bypass the mic input transformer by internal jumpers.
- Relays are used to control internal switching for DI input, Phantom power, Mic Low Z, Insert and Phase for shorter circuit board signal paths. The relays are controlled by front panel switches.
- Revised gain switch for added headroom.
- Circuit board star grounding scheme.
- Revised power supply with separate regulators for the audio circuits and relay and LED circuits.

Προενισχυτής μικροφώνου 8 καναλιών εξαιρετικής ποιότητας και κατασκευής. Με λειτουργία 192 kHz / 24 bit  και 8 προενισχυτές μικροφώνου, προσφέρει χαμηλά επίπεδα παραμόρφωσης και ποιοτικό ήχο.
 
8 x Mic / Line Preamp Input (XLR/TRS Combo)
8 x Line Output (TRS balanced)
8 x AD-converter (up to 192 kHz)
2 x ADAT Output (S/MUX, up to 96 kHz)
4 x AES/EBU Output (D-sub, up to 192 kHz)
1 x AES/SPDIF Sync Input
Phase, Low Cut and Phantom power per channel