5E3 Controls and Results

[keithb7]

Hi folks I built a 5E3 clone a few years ago. It sounded great and the volume and mic controls really did interact with each other. The results were easily heard.
I recently acquired a 100% original 1959 Tweed 5E3. Everything is original. It does sound amazing, but it does not seem to have interactive channel controls like
my clone did.

The tone pot, if I understand it, is a treble bleed pot. As I turn it down it cuts treble frequencies out of the line signal. At max treble, the tone pot is for all intents and
purposes, out of the the circuit. Am I right so far? If I plug a my Strat into either the mic or guitar channel jack and crank its related volume, the amp goes into over drive
very nicely as expected. However the unused volume seems to have no effect until it reaches near the end of is maximum sweep. Then it cuts the volume of the overdriven
channel way down. Cancelling out tone and dirt it seems. As I turn the unused knob up I get nothing through to about position 10.5 out of 12. Then its like, bam. It affects
the other channel quickly. I seem to recall the other pots on the clone amp I built to be more interactive all the way though the pot sweep. The other comment I have
it the tone knob. Let's say I have the amp cranked up for lots of dirt. Like over 5 on the volume knob. As the tone knob is turned down, the gain drops off. Less dirt. I think
this is normal no? So with the tone pot on 12 I get more dirt from a cranked up channel. As I roll the tone down, less dirt. Again, I don't recall my clone behaving exactly like this.
Or maybe not to this level that I can I really hear. What I have been doing is cranking up the tone to max to get gobs of dirt from a cranked up volume setting. The amp is pretty
bright with the tone maxed. However, by rolling down the tone pot on the guitar I can control the brightness, but still have gobs of gain on hand.

I have not yet checked all the voltages at different points in the circuit. I'll get there soon. B+ caps and a new cord are ordered and on the way. This is just an early observation.
I sold my clone amp about 3 years ago so I can't
compare it to the stock original one I have now. Am I getting different sounds and results than other 5E3 users here? Here's the amp. Thanks, Keith

[Dave H]

The tone pot, if I understand it, is a treble bleed pot. As I turn it down it cuts treble frequencies out of the line signal. At max treble, the tone pot is for all intents and
purposes, out of the the circuit. Am I right so far?

The tone pot isn't out of circuit at max treble. It puts the 0.0005u cap across the volume pot from wiper to CW (effectively a bright cap) which is why you have to turn down the the tone pot on the guitar.

[nosaj]

For one I could almost guarantee you have some caps that need to be changed.

nosaj

[loudthud]

Did your clone have a 22uF bypass cap on the first stage? Electrolytic caps in that range have significant ESR which lets some signal feed through to the other channel. Original 5E3s have a 250uF which may have a lower ESR.

Did your clone have a 12AX7 or a 12AY7 as the first tube? What does your original have in that position?

The .0005uF cap on the tone control will peak the treble on the instrument channel, but only when the Volume is less than max.

[Steve A.]

The interaction between the two channels comes from shared components at the cathodes of V1A and V1B which is simple enough to check and reverse if necessary.

Steve Ahola