Preamp switch

[danieldroukas]

If one wanted to build a 5E3x2 (via weber) BUT wanted to modify the preamp to have treble-mid-bass control... could one simply build in the preamp of the 5F8 (ignoring supply voltages)?

Reference the following schematics:
https://taweber.powweb.com/store/5e3x2_schem.jpg
https://taweber.powweb.com/store/5f8a_schem.jpg

From the tweed twin (5F8), could you simply pull over the preamp from the PI input (treble output, before the 0.022 cap) into the 5E3x2 PI input (pin2, V2A)?

Thanks for your input.

[hasserl]

The Twin has three 12AX7's, or 6 triodes, to accomplish all of that, the 5E3 only has two. No, you can't do it without adding a tube.

[danieldroukas]

yeah, adding the tube is understood and no problem... i was just curious if there would be any adverse effect of plugging in the twin preamp into the deluxe PI using the points I mentioned in the previous post.

[hasserl]

Basically, what you want then is a 5F8 with four 6V6 output, right? Or are you considering using the 5E3 cathodyne PI? In which case you're looking at a 5E5A or 5E7 or 5F4 with four 6V6 output, right?

[danieldroukas]

Basically what's desired is a tweed deluxe with TMB controls... presence optional. We'd like to retain the cathodyne PI. The pro, bandmaster, and super you mentioned all have only treble and bass controls (with the negative feedback presence control on some). The tweed twin has all the tonestack features we'd like but we'd like to retain the same power stage voltages, cathode biasing, transformers, and all that jazz native to the tweed deluxe.

So could I just build a true-to-schematic tweed deluxe sans preamp then drop in the tweed twin preamp? Schematically: take the output from the twin treble control and drop that into pin 2 of the deluxe cathodyne PI?

[hasserl]

Yes, you could do that and it would work fine. Note that Weber VST has a kit for the 5E7 that includes a Mid control. Check it out:
https://taweber.powweb.com/store/5e7m_schem.jpg

I think that is pretty much what you are wanting to do, except with two 6L6's instead of four 6V6's. The amp wouldn't care either way, the 6V6's would go into breakup at lower voltage levels, the 6L6's giving a bit more headroom.