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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: H₂O on February 07, 2009, 01:26:31 PM
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I just got my Grace custom Pre back from Grace Design.
Michael did the following updates:
- Replaced all Electrolytic caps in the signal path with Metal Film Caps
- add +48 and +120 V on off switches and LEDs to the PS - Makes it easier to switch between Tube mics and Phantom Powered Condensers
- added a ON/OFF switch to the Power Supply
- Laser Engraved the front of the Pre and Power supply
Below are pics of the unit Before and After
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I want that! Damn. Very nice.
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was it designed for one type of microphone? power supply?
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Details! Details!
was it designed for one type of microphone? power supply?
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It looks very similar to the Lunatec 316.
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Micheal built this for a friend of his (Sean Weber-Small) in 1995. I bought this unit from Sean in May of 2008. Sean told me he only used it to record a handful of shows and the rest of the time it sat in a closet. Sean used it to run a pair of KM56's.
All the information you are looking for is in the following thread:
http://taperssection.com/index.php/topic,102613.0.html (http://taperssection.com/index.php/topic,102613.0.html)
This unit was built to power 2 standard 48V Phantom Condenser mics or 2 AC701 Tube mics (i.e. KM53/KM54/55/56/253/254/255/256, Schoeps/Telefunken m221's, possibly AKG C60's, Neuman UM69, possibly M269, etc)
In summary with minor updates:
The Pre-Amp section is same as a Lunatec 316 (uses same boards) Components are the same but the boards in this unit are an earlier version with 2 pre-amp boards (1 for each channel); a pad relay, capacitor blocking, phantom power, etc board - this is a hand wired bread board. The 316 has a single main board with all components in the pre-amp section.- To the best of his knowledge Mike made 2 of these units - Sean's and another for Bill McReynolds
- McReynold's is different in that it was designed to power a Neumann UM69 Stereo Mic and Mike added a Polar Pattern switch (or switches) to the power supply portion
- The unit is powered off of DC 6V but can accept higher voltages upto 12V (Uses 2 Apogee DC-DC convertor Modules - 1 is used to drive the power for the Pre AMP boards, and Phantom Power, the other is used to provide the 120V needed for the AC701k's) - An included AC-DC Adapter outputs at 9.5V (not shown in the pics)
- Grace will still support it and still has the schematic's etc for the two he made (He has provided me a copy of the schematics for this particular unit)
- The only item that keeps the Preamp from being is clean as a V2 or V3 (per Mike) is some Electrolytic Caps in the output path - Mike can replace with solid Caps to put it at the same level as a V2 or V3 - (This is the same for all 316's)
- The V2 and V3 have a very similar pre-amp design to the Pre-Amp board used in this unit
- There are 2 boxes that must be used to run it:
- the power supply which is the same Width and Height of an Apogee AD1K and about 1/3 the depth (input 6V-12V DC; outputs various voltages to run Tube mics or 48V standard condinser mics)
- the pre amp - same Width and Height of an Apogee AD1K and about 3/4 the depth - inputs Mic cables, power from power supply; output balanced Stereo on XLR-3)
- To switch to 48V phantom from tube power there is two jumpers in the Pre-Amp section - Pins 1 and 2 on the XLR-5 map to pins 1 and 2 for +signal and -signal
Updates made on 2015-02-24
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those are some funky gain knobs
looks like a combination lock to a safe 8)
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my god that is sexy!
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cool..now what about your dignity?
;D ;D ;D