Warwick preamp circuit

[B.Flat]

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I have tried to obtain it from Warwick but I am told they do not publish their circuits, despite have a couple from the internet, but not this one.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

[itu]

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).

[verb]

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.

[LeftyJ]

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.