5E3 Bass Resonance

[Doclinz]

I puchased a 5E3 Tweed Deluxe clone built with vintage iron, 12” Jensen, NOS components.

The bass - in particular the low E string - resonates. The first thing I did was to swap out the vintage Jensen speaker. No appreciable improvement. I patched the amp into an external speaker cabinet, and the same problem occurs.

Next, I changed the 25 uF cathode bypass caps on the input stages to 1 uF which helped to tighten up the bass, reduced blocking distortion, and helped to damp the resonance a bit, but the E string (and to a slightly lesser extent, the A string) still seems to ‘bloom’ and nothing really seems to bring the low bass into tonal/amplitude balance with the other strings. E shuffle on guitar just sounds nasty thru it.

Not quite sure what to try next.

By design, there is no feedback in this tweed amp, so I imagine that it could be generating bass resonance somehow? Seems pointless to try negative feedback to see what happens. Not sure that does much but reconfigure the 5E3. I suppose if it solves the problem, that would tell me something, but just what I’m not sure.

I have heard a lot about what exemplary tweed era amps these Deluxes are but despite lots of info out there, I can’t find any discussion that seems to resemble the exact symptoms I’m experiencing.

Any guidance appreciated.

-Martin

[xtian]

Very common problem for Tweed Deluxe. Here are some great suggestions:

https://robrobinette.com/5e3_Modificati ... ad_Channel

[printer2]

Try a little NFB. Without it the output section works more as a current source as compared to a transistor amp that acts as a voltage source. What that means is that at the resonance of the speaker the amp tries to put more power into the speaker than if there was NFB. The one negative would be any additional treble the amp puts into the speaker (because of the rising impedance curve) will be lessened.

[Stevem]

You might also try out lowering the heights bass side of your pickup(s) .
On a buddy's of mine Strat he want a bit less of a drastic low end boost from his neck pickup as compared to the bridge, so one afternoon we played around on the neck pick with in line cap values until he got what he was looking for.

This so darn easy to do that I can't see why more players don't do it, plus a SPST mini toggle across it short it out of the circuit when you don't want it.

[sluckey]

There are four 0.1µF coupling caps in the amp. Change all four to .047µF.

[Reeltarded]

The sounds you like on records the amps are not run wide open.