THERMIONIC CULTURE TheEarlybird 2.
WARNING For your personal safety, please read this operating manual and warning thoroughly before using the equipment. This unit must be installed in such a manner that operator access to the mains plug is maintained. Where the product is to be rack mounted, this may be achieved by having access to the disconnection device for the whole rack. To reduce the risk of electric shock, it is essential that the unit is disconnected from the mains supply before removing the cover.
CONTENTS Section Page 1 Introduction 3 2 Controls 4 2.1 Function 4 2.2 Gain 4 2.3 Bass cut 4 2.4 Active lift 4 2.4.1 Top 5 2.4.2 Mid 5 2.4.3 Bass 5 2.5 +48V 5 2.6 Phase reverse 5 2.7 Output trim 6 3 Metering 7 4 Connections 8 4.1 Mic Input 8 4.2 Line Input 8 4.3 Pullet 8 4.4 Output 8 5 6 Operational suggestions 9 5.1 Impedance 9 5.2 PAD 9 5.3 Pullet 10 5.4 EQ 10 5.
1 Introduction The Earlybird 2.2 is a two channel all valve pre-amp employing a balanced push-pull circuit, which as far as we know, is unique in this application. The use of this type of circuit gives very low noise and plenty of headroom with minimal distortion. These factors coupled with a switchable input impedance will mean the user can get a very natural interpretation of whatever sound the microphone is picking up, whether the mic is valve, ribbon, moving coil or FET.
2 Controls 2.1 Function This control selects the basic operating mode of the Earlybird. The pre-amp can be aligned to operate as: 300Ω:- A mic-amp with an input impedance of 300Ω 1200Ω:- A mic-amp with an input impedance of 1200Ω PAD:A mic-amp with an 18dB attenuating pad in front of its transformer. LINE:A pre-amp that accepts line level signals PULLET:- A pre-amp that provides the make-up gain for the passive EQ network provided by the Pullet in order to bring the signal back up to line level. 2.
2.5 2.4.1 Top This control uses our award-winning 'Varislope' lift circuit where the lift is a nearly flat "shelf" at low settings and as the control is advanced it accentuates the higher frequencies, resulting in a peak of 20dB at 10kHz (with gain set at 36 or 44dB). 2.4.2 Mid A very broad lift peaking at either 800Hz or 2.5kHz depending on the position of the Mid lift frequency selector switch. The maximum lift available is 15dB. 2.4.
2.7 Output trim These controls are reverse linear attenuators, operating after all of the electronics. The full output of the electronics is sent to the output plugs when the controls are set to maximum. These controls can be used as a ‘fine’ level adjustment or an output attenuator so that the unit can be run ‘hot’ in order to get some distortion without overloading the next piece of equipment in the chain. ©Thermionic Culture Ltd.
3 Metering The meters are a VU type, however they do have a compressed scale above 0VU. This feature has been applied to the meters because a mic-amp will naturally have un-compressed signals passed through it. A signal like this, on a normal VU scale, will tend to look as if there is either too little level, or so much level that it is ‘off the scale’.
4 Connections There is a row of input and output sockets on the back of the Earlybird, which allow it to be left permanently connected for it’s various configurations. 4.1 Mic input These XLR sockets are for connecting microphones to the Earlybird. The 48-volt phantom power supply will applied to these sockets only. The Mic settings on the Function switch will all select these inputs. 4.2 Line input These XLR sockets are to be used when connecting a line level signal to the Earlybird.
5 Operational suggestions 5.1 Impedance The Earlybird has a switchable input impedance for its mic-amp inputs. This control has a large effect on the tone obtained from whatever microphone is being used. Technically 1200Ω is a good impedance for Neumann FET mics whilst 300Ω is a good impedance for ribbon mics such as the Coles 4038. However we have found that the impedance control can be used as a creative tonal adjustment.
the PAD will stop distortion in the input transformers of the Earlybird mic amp. 5.3 Pullet Setting the Function control to Pullet will configure the Earlybird to take its input signal from the Pullet sockets on the back of the unit. This means that a line level signal can be fed into the Pullet and then into the Earlybird.
If the Earlybird is configured as a line amp then it can be a very useful valve EQ. We have had very positive feedback from users who like to EQ their electric guitars with the Earlybird mid range on mix down. There is no mid cut control but a little mid cut at 700800Hz can be achieved by setting Bass Cut to 800Hz and Bass Lift to near max. When using the Pullet, the EQ of the Earlybird provides the necessary bass end control.
6 Specification Included are the figures for noise, distortion and EQ. They are all measured with the Earlybird set up for 44dB mic gain / 0 dB line gain and a 10kΩ load. Input impedance Mic Pad Line Pullet Output impedance Maximum gain Maximum output level (MOL) Distortion (THD) @ 1kHz 100Hz Frequency response ±0.
Earlybird 2.2 Frequency response curves 25 15 Gain (dB) 5 10 100 1000 10000 100000 -5 Flat Bass Cut 40Hz Bass Cut 100Hz Bass Cut 800Hz Bass Cut 800Hz Bass Lift at '8.5' Bass Lift at Max Mid Lift 0.8kHz Mid Lift 2.
Thermionic Culture Ltd., Harlow, Essex, UK Tel: +44 (0)1279 414770 Fax: +44 (0)1279 412233 www.thermionicculture.com ©Thermionic Culture Ltd., September 2010. Printed in UK.
