MP2 & MP8 | Mic preamp

ELBERG MP2 & MP8

The ELBERG MP2/8 are two high resolution microphone preamplifiers with extended frequency range.

The ELBERG MP2/8 is an 2/8 channel high resolution microphone preamplifier with extended frequency range. The DVD norm specifies frequencies up to 100 kHz (-3 dB), and that’s why the ELBERG MP2/8 has been built to handle frequencies from 2 Hz to 100 kHz (-1 dB).

There is still a vivid discussion raging, whether this frequency range has any effect, as most people cannot hear much above 17-19 kHz. However, newer investigations show that human perception goes far beyond that. At ELT, we strongly believe that the ELBERG MP2/8’s wide frequency range can be clearly felt, and that you too will enjoy the clarity and relaxed way of handling complex sound-combinations and even ultra-fast transients.


Operation
Each of the 2/8 channels comprises a high quality golden rotary switch which sets the gain in steps of 5 dB from 20 to 70. Next, a push switch will dim the input with 20 dB, allowing even line signals up to +24 dBu to be handled. After a 48 Volt phantom power switch, a variable high-pass filter may be switched in. Its frequencies (potentiometer controlled) range from 40 to 270 Hz (-3 dB – true 12 dB/octav). By the three switches, an LED peak program meter shows the output level. Further to the right, a fine gain potentiometer allows you to ’fine-tune’ the gain of the MP2/8 from 0 to +6 dB. Finally, a push switch reverses the phase of the output without the usual ’bang’. Each push button includes an LED, giving a quick visual overview of the state of the MP2/8. On the back-plate, a 3-way toggle switch determines whether the chassis is connected to audio ground, power ground or floating, allowing trouble-free mounting in racks or as stand-alone, as well as connection both with and without power ground. This switch is disabled on certain overseas models due to legal matters concerning mandatory power grounding (chassis is then hard-wired to power ground).


Construction
Each component in the MP2/8 has been carefully tested and selected to ensure perfect performance for 15-20 years and the MP2/8 comes with a full 5 years guarentee. Due to the wide frequency range, our preferred method of switching signals with FETs (Field Effect Transistors) cannot be used here, due to the FETs rather poor switching capability at very high frequencies. Instead three state-of-the-art golden relays in each channel do the switching. The audio signal doesn’t pass through any push switch at all, as the life-time of these is limited to 5-6,000 operations with audio. Instead the switches control the voltage to the relays, and as two poles of each switch are further parallelled, we expect more than 100,000 operations per switch. The same technique has been used on the ’Fine Gain’ pot which is in fact a dual pot parallelled, prolonging time of smooth operation even in smoky environments. The gain rotary switches are made by Swiss ELMA, and 25,000 operations are guarenteed. They might, however, prove to be the first thing that fails. In 15-20 years that is! They can then be replaced, if further life-time is requested. Inputs are balanced by custom designed, high-quality Lars Lundahl transformers, outputs electronically with a ’transformer-like’ circuit which will give the same output whether used balanced and unbalanced.

Specifications:

Frequenct response:

2 Hz - 100 kHz (-1 dB)

Harmonic distortion:

≤0.05% (+20 dBu out)

Input impedance:

1.2 kOhm transformer balanced

Output impedance:

47 Ohm electronically balanced

Noise (EIN):

-129.2 dBu(A) (Rin = 200 Ohm) -131.2 dBu(A) (Rin = 0 Ohm)

Gain range:

0 to 76 dB

Maximum out:

+26 dBu into 600 Ω or more

0 dBu = 0.775 V. All XLRs are connected according to IEC 268-12 (1=GND, 2=HOT, 3 =COLD). This will present no problem to US-users, as both inputs and outputs are wired this way. No special cables will be needed. ELBERG MP2/8 fully complies with the Nordic Radios' specifications sheet N10 (4th edition). Other specifications on request.


MP2 (upper left) in operation in one of Danish Broadcasting Corporations eiditing suites.