Keyclick with sounds4/5/2023 ![]() ![]() ![]() On the B2, C2, and RT2 organs with the AO10 preamplifier you can disconnect the C1 40 pf feedback capacitor of the V1 6SJ7 tube of the non vibrato channel, and the C7 25 pf feedback capacitor of the V2 6SJ7 tube of the vibrato channel. On the 1940's BV, CV, G and RT organs you can disconnect either the C1 0.001 uf capacitor or the R1 22 K resistor which are located inside the rheostat box. On the 1930's/ early 1940's Model A, AB, B, BA, BC, C, D and E organs, you can disconnect either the C4 0.001 uf capacitor or the R4 20 K resistor which are located inside the rheostat box. If you have a copy of the Hammond organ schematics or the service manuals, and if you are competent and confident to work on Hammond organs, and especially when it comes to the organ preamplifiers with the dangerous high voltages inside them, then you can increase the key click effect by disconnecting the treble cut / key click filter. The other tonewheel organ models including the E-100 series H-100 series, L-100 series, Porta-B, R-100 series, T-series, XTP and the X-77 organs also had treble cut filtering in the amplifiers acting as the "key click filter", and the treble cut / key click filtering on these particular organs was more severe than what it was on the previously mentioned organ models.Ī lot of us Hammond enthusiasts love the key click sound so therefore we like to undo Hammond's attempts to reduce the key click. The B2, C2, and the RT2 organs with the AO10 preamplifier, and the A-100 series, B3, C3, D150 series and the RT3 organs with the AO28 preamplifier and the M3 and the M-100 series organs with the AO29 or the AO67 amplifier used a treble cut filter consisting of very small value capacitors in series with very high value resistors wired as part of the negative feedback circuit between the input grid and the output plate of the input tube of the non vibrato channel and the input tube of the vibrato channel. This 20K or 22K resistor/ 0.001 uf capacitor treble cut filter reduced the key click by rolling off the treble response, as well as bringing down the levels of the "premphasized" midrange and treble TG notes so that their volume levels through the preamplifier were better balanced with the lower frequency TG notes. The secondary winding of the drawbar matching transformer on the early era organs of the 1930's and 40's such as the Model A, AB, B, BA, BC, BV, CV, D, E, G and the RT organs had a very simple treble cut filter consisting of a 0.001 uf ( 1 nf) capacitor wired in series with a 20K or 22K resistor between the output wire of the secondary winding and the ground. ![]() Hammond reduced the key click by calibrating the tonewheel generator to have the "pre-emphasis" in the midrange and the treble TG notes which meant that the midrange and the treble TG notes were set to have a progressively upward rising output curve in their output levels. Whilst dirty key contacts or busbars and also deteriorated grounding connections can enhance the key click, the key click is always present even with perfectly functioning and clean key contacts and busbars and perfect grounding connections so therefore Laurens Hammond and the subsequent Hammond designers tried to suppress the key click sound right from the start in 1935 until the end of Hammond tonewheel production in 1975. Many Hammond organ simulators include a key click control to reproduce this characteristic.įor a detailed analysis of key click and the interaction of the key contacts on busbars see: Additional info from Kon Zissis: Later rock and blues players found the key click characteristic to be desireable and some jazz organists consider it to be essential. ![]() In later console organs like the B3, the higher harmonics were pre-emphasized and the preamp designed with an upper frequency roll-off to help conceal the click. In the patent, key click was to be removed by a bypass. The sine waves from the constantly running generators would be connected at random points in their oscillation.Ĭonsiderable design efforts were made to reduce it but it could never be eliminated. As a key was depressed, the nine contacts under the key closed against their respective busbars at slightly different times and bounced as they closed. This was considered a defect and was caused by the audio signal being routed directly through the key contacts. There was an attack transient that sounded like a click or pop when a key was pressed. The sound produced by early Hammond Organs differed from pipe organs in one characteristic way. Key Click Excerpted from the Original Hammond Leslie Faq. ![]()
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