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4. Appendix 1, Microphone voltages list

AKG 
C12, C12VR: 120 V & 6.3 V, HT-var +0 V position 
C24: 120 V & 6.3 V, HT-var +0 V position (this microphone is stereo and needs two 
power supplies and a cable splitter).  
(Telefunken) Ela M250, Ela M251, US version: 120 V & 6.3 V 
(Telefunken) Ela M250, Ela M251, EU version: 120 V & 3.9 V 
C12a: 120 V & 5.2 V, HT-var +0 V position 
C28A, C29A, C30A, C60/CK28, C60/CK26: 120 V & 3.9 V: the MP1 cannot be used 
with these microphones because their output transformer is mounted in the supply.

Microtech Gefell 
CMV563: 120 V & 6 V 
UM57: 120 V & 6 V, HT-var +0 V position 
UM92, UM75: 120 V & 5.8 V, HT-var +40 V position  
M990: 120 V & 5.8 V

Neumann (Telefunken) 
KM(2)53, KM(2)54, KM(2)56, KM(2)64, KM(2)66, M50, M250: 120 V & 3.9 V 
M49, M249, M269: 120 V & 3.9 V, HT-var +0 V position 
U67: 210 V & 5.8 V 
SM69, SM23: 120 V & 3.9 V, HT-var +0 V position (these microphones are stereo 
and need two power supplies and a cable splitter). 
U47, U48: the filament supply of these microphones is derived from the HT supply. 
Please buy our MP47 in stead of the MP1, because it is especially designed for this. 
M147, M149, M150: these microphones are partly solid state. They need + and -70 
V and 32 V and cannot be used with an MP1.

Schoeps (Telefunken / Philips / Siemens equivalent) 
CV60, CM61: 145 V & -5.7 V 
M200, M201: 150V  & -6.3 V 
M221b: 120 V & 3.9 V 
M222: the MP1 cannot be used with this microphone because the output circuitry is 
mounted in its power supply.

Sony 
C37A: the MP1 cannot be used with this microphone because the output transform-
er is mounted in its power supply. 
C800, C800G: These microphones need 276 V which the MP1 cannot deliver. The 
C800G also needs an additional 6 V for the Peltier element. 

For power supply voltage information of other (contemporary) tube microphones, 
please consult the original manufacturer. The MP1 will most likely support them.

Summary of Contents for MP1

Page 1: ...Please read this manual before operating the unit ...

Page 2: ...TPInLB ...

Page 3: ...Table of Contents Introduction 4 Important Safety Instructions 5 1 Operation 7 2 Modifying factory settings 8 3 Specifications 12 4 Appendix 1 Microphone voltages list 13 5 Grimm Audio Limited Waranty 15 ...

Page 4: ... unique and very costly tube microphones from the fifties and sixties Contrary to what many believe these old power supplies can be improved upon both with regard to stability noise level and last but not least sound quality And this is not just because the electrolytics in the old sup plies tend to dry out and carbon composite resistors have shot up in value or gone noisy even if these have been ...

Page 5: ...uien a petición se encargaría de enviarle la correspondiente traducción Please follow these precautions when using this product 1 Read these instructions 2 Keep these instructions 3 Heed all warnings 4 Follow all instructions 5 Dangerous voltage is inside this apparatus Opening is only allowed by qualified service personnel 6 Verify line voltage before use 7 Do not defeat the safety purpose of the...

Page 6: ... with a cart stand bracket or table designed for use with professional audio or music equipment In any installation make sure that injury or damage will not result from cables pulling on the apparatus and its mounting If a cart is used use precaution when moving the cart apparatus combination to avoid injury from tip over 18 This unit runs slightly warm when operated normally Operate in a normal v...

Page 7: ...reo 1U 19 unit An MP1 generates some heat When using a stereo set of MP1 s in a 19 rack it is advised to keep one free rack space below and above to provide optimal cooling Technology The MP1 features a specially designed discrete shunt high voltage regulator fed from a current source to maximise suppression from mains induced anomalies It also offers very low noise typ 96 dBV or 16 uV 20 20 000Hz...

Page 8: ... extra safety a crowbar circuit will shut down the current source in case the output voltage ex ceeds the nominal value by more than 12 due to malfunctioning However Grimm Audio cannot accept liability in case of damage to microphones should even the protection circuit fail For the heater voltage two preset values are available 6 0 and 3 9 V These values are chosen in conjunction to what is prescr...

Page 9: ...e is not available at the 210 V setting as there are no micro phones that require that Changing the internal settings Opening up the MP1 and changing its internal presets or trimmings is best left to a trained technician When switched on there are potentially dangerous voltages as high as 300 V inside Grimm Audio cannot accept any responsability for damages to either persons or the MP1 itself or t...

Page 10: ...T output voltage The crowbar protec tion thresholds remain fixed Trimming the output voltage close to the treshold values is not recommended as this increases the risk of ill triggered shutdown To reset a crowbar action it suffices to switch of the MP1 wait a few seconds and switch on again Heater Voltage Settings The jumpers setting the heater voltage are located to the right in fig 1 First take ...

Page 11: ...heater voltage between 3 6 and 7 0 V One can use this for tube mi crophones with unusual heater voltage requirements or in case of very long cables to adjust the heater voltage at the microphone to an exact value e g 5 8 V or 3 8 V The best procedure is as follows First disconnect the mic cable Decide what the voltage Vx should be which would set off the crowbar protection as a rule 10 higher than...

Page 12: ...with a 7 pin XLR Maximum ambient temperature for operation 40 C Life expectancy power supply electrolytics 45 000 hours Power supply voltage range 6 10 Fuses 120 V USA fuse 500 mA T 100 V Japan fuse 500 mA T 230 V EU fuse 250 mA T Weight 2 3 kg Dimensions 215 x 175 x 44 mm Power consumption 20 W Wood type of front Cherry XLR pinning of both 6 and 7 pin XLR s Pin 1 GND Pin 2 Audio Pin 3 Audio Pin 4...

Page 13: ...r 0 V position these microphones are stereo and need two power supplies and a cable splitter U47 U48 the filament supply of these microphones is derived from the HT supply Please buy our MP47 in stead of the MP1 because it is especially designed for this M147 M149 M150 these microphones are partly solid state They need and 70 V and 32 V and cannot be used with an MP1 Schoeps Telefunken Philips Sie...

Page 14: ...14 Grimm Audio contact information Grimm Audio CV Strijpsestraat 94 5616 GS Eindhoven The Netherlands 31 0 40 213 1562 Email info grimmaudio com Website http www grimmaudio com ...

Page 15: ...Audio or an authorized Grimm Audio repair facility postage prepaid insured and properly packaged Proof of purchase must be presented in the form of a bill of sale or some other positive proof that the product is within the warranty period Grimm Audio reserves the right to update any unit returned for repair Grimm Audio reserves the right to change or improve design of the product at any time witho...

Page 16: ......

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