B.Flat Posted June 15, 2022 Share Posted June 15, 2022 Hi all. Might there be anyone out there who has a circuit diagram for a Warwick preamp, ref; MEC BEC2 H LM 2002, three knob version. I have tried to obtain it from Warwick but I am told they do not publish their circuits, despite have a couple from the internet, but not this one. The reason I need it is that I want to add a passive tone pot, pre-active circuitry, which will work globally over the active tone controls as well; Any comments on that would be great. Brian Quote Link to comment Share on other sites More sharing options...
itu Posted June 16, 2022 Share Posted June 16, 2022 pickups - blend - vol - tone stack - output This is a very common signal path of a bass. I suppose yours has a battery powered tone stack (the most common) and everything else is "passive". You may connect the tone to the vol. You can connect a 250k or 500k logarithmic pot and a suitable cap to the vol pot. There you go. I think you are able to find out the way to connect the cap to the pot. Could you explain me one thing: Why do you want the tone before the existing tone circuitry? Is there some particular reason for that? If you take a look at the signal path, you should also understand, that the extra impedance after the pickups BUT before the tone stack, will lower the signal, and cut some of the highs. After the tone stack, the reduction is smaller (because the tone stack has very high input impedance, far more than 500k). Quote Link to comment Share on other sites More sharing options...
verb Posted June 19, 2022 Share Posted June 19, 2022 Do you need the circuit diagram for the preamp board or the bass? The bass schematic diagrams can be found in the support section on the Warwick website. By three knob version, I assume that is three band EQ. The Masterbuilt Streamer Stage 1 section shows various years of schematics. Quote Link to comment Share on other sites More sharing options...
LeftyJ Posted June 20, 2022 Share Posted June 20, 2022 If by 3-knob you mean volume-balance-stacked 2-band EQ, then the wiring schematic is right here in their webshop. I hope this helps: For passive pickups (typically labelled "MEC Dynamic Correction" on the pickup casings in silver): https://shop.warwick.de/en/pickups/accessories-parts/bass-electronics/20995/mec-2-way-electronics-for-passive-pickups https://shop.warwick.de/media/pdf/11/cf/e3/M_60013_Schematic_Drawing.pdf For active pickups (typically just labelled "MEC" on the pickup casings in gold): https://shop.warwick.de/en/pickups/accessories-parts/bass-electronics/22373/mec-active-bec-2-electronics-for-active-pickups https://shop.warwick.de/media/pdf/64/8d/20/M_60003_Schematic_Drawing.pdf This difference is important, as you may need to match the pot value to the pickup impedance. It surprises me both of these schematics use a 500k volume pot. However, they do not have the same part number between the two schematics, despite both being B500k push/pull pots. Not sure what's going on there. Quote Link to comment Share on other sites More sharing options...
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