The here has no potted black box, only a bunch of TL and which don´t appear in the schematic I have (with the black box). Download Drawmer Drawmer mic pre & compressor ✅ Professional audio systems service manuals and repai information. Drawmer mic pre & : Full Text Matches – Check >> Voroshilov- jpg, , Schematic diagram OLDEST bulgarians doorphone.

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Avoid running at excessively high output levels as this reduces the available amount of signal headroom and could drawmet to distortion in extreme cases. Because the compressor is a soft knee type, it requires few controls. Switches the meters to show either the output level VU or the amount of gain reduction GR.

Bypass only takes the compressor out of circuit leaving the vacuum tube warmth in the circuit path; the output signal is taken from the signal insert return point. Gain The Output level may be amplified or attenuated by up to 20dB to compensate for level changes xrawmer by compression and limiting. Replace with a correctly rated fuse for the selected operation voltage.

Drawmer Electronics 1960 Mic-Pre/Tube Compressor User Manual

Compressing during a mix does increase the subjective level of tape and other background noises during pauses and quiet passages as maximum gain is applied when the signal level is minimum. Harpo Member Rahden, Germany Posts: The first version of the potted VCA burned up and died pretty regularly. A major advantage of the hybrid approach 1690 that schfmatic combines the reliability and stability of modern solid-state designs with the warm, detailed sound of vintage classic tube designs.

If for some reason the unit is to be used at a mains input operating voltage which is different to that as supplied, 19600 following procedure must be carried out.

Furthermore, when the schrmatic is deliberately overdriven, it can be used creatively to produce level ‘pumping’ effects which can be useful both on electric guitar or rock vocal sounds.

The Threshold range is continuously variable between infinity and dB, the theory being that signals below the threshold are essentially unprocessed and the signals exceeding this threshold are subjected to increasing amounts of gain reduction dependent on by how much they exceed the threshold.

Tubefreak Member Netherlands Posts: Using a number 1 size pozidrive screwdriver, remove the two self-tapping screws holding the voltage selection switch cover plate on the rear panel.

Adds 10dB of gain in the High position. This was a repair i did 4 to 5 years ago and the unit has been in daily use since then without problems. As with other Drawmer products, the schdmatic switch offers a choice of Normal, By-pass and Side Chain Listen modes so that if you have patched in any additional side chain processing, you can easily monitor what effect it is having.


For high quality location recording, the makes the perfect partner for a DAT machine, as it combines the functions of stereo mic preamp with that of a compressor. This powerful combination of the classic valve circuit, offering unsurpassed tonality, and the low noise balanced microphone input with up to 60dB of gain has allowed engineers throughout the world to exploit the schekatic potential of high performance condenser microphones.

The fully conforms to the EMC standards, if ddawmer propose to use the unit where it maybe exposed to high levels of disturbance such as found close to a TV or radio transmitter we suggest that the screen of the signal cable is connected to the chassis connection on the XLR type connector.

Averages the left and right channel control settings when the unit is used for processing a stereo signal. Re-connect to mains power source.

Switchable Attack and Release settings are provided along with a fully variable Threshold, two of the Release settings being programme dependent.

In addition, the incorporates two low-noise microphone preamplifiers with provision srawmer phantom powering, plus a versatile instrument preamplifier with passive EQ and brightness switch. The signal path incorporates a switchable high-pass filter which may be set to 50Hz, Hz or Off. Fibre or plastic washers may be used to prevent the front scheematic becoming marked by the mounting bolts. If necessary, change the Attack and Release settings to suit the material.

I have the schematics and have been tracing through the unit, but haven’t found anything to lead me in the right direction.

Drawmer mic pre & compressor – Service Manual Free Download

The VU meters may be switched to monitor either the amount of gain reduction taking place or the output signal level and the two channels may be used either independently or as a stereo pair, depending on the setting of the stereo link switch.

The side chain access points may be used to patch in equalisers to enable the compressor to act as a de-esser. A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.

Hi, Not sure about age and scgematic contacted Drawmer as I got the unit second hand for very cheap Has anyone had any experience tech-ing one of these units?


For use with stereo drawner such as complete mixes or submixes, the unit should be switched to Stereo Link mode and both sets of channel controls set to the same position. Phantom power is individually switchable on the two channels and a peak overload LED warns when clipping is imminent. It incorporates the same type of passive equalisation circuitry used in traditional tube guitar amps, while the Bright switch emulates the voicing of a typical guitar amplifier.

I ddawmer had many on the bench that had dirty pots.

Avoid mounting the unit directly above power schejatic or power supplies that radiate significant amounts of heat and always connect the mains earth to the unit. The mic inputs provide up to 60dB of gain while maintaining a noise figure comparable with the better ‘in-desk’ mic preamps.

Started by robinball The Lab.

Drawmer – Manual

Re valved it and problem cured for a short while before fault reappeared. By increasing the Gain control setting, the input stage can be made to overdrive in a manner similar to that of traditional schemayic guitar amplifiers.

What do you mean with OTA? Btw, is yours the one that just sold on ebay? Strictly speaking, a soft knee design does not have a rigidly defined threshold but the title ‘Threshold’ has been retained for the “amount of compression” control for the sake of familiarity.

Disconnect the unit from the mains. Some pots are between DC coupled opamps. Interestingly, the attack times are further modified by the choice of release setting so the range of choices are wider than it might first appear. I suppose that if it is the VCA, getting assistance through Drawmer may be my only hope. The non potted vca schematic is posted at the gmail site Not a good design practice with non-precision opamps and carbon pots. If not – continuity check between sidechain tip and ring – if this isn’t showing low resistance clean the jack contacts or temp solder across the contacts and check.

The Drawmer is a two channel unit with each channel comprised of a completely natural sounding “soft knee” vacuum tube compressor and an extremely low noise microphone pre-amplifier with switchable 48 volt phantom power.

Make sure that the pots are solid. The Gain control may be set to provide the required output level using the level meter as a guide.