Volume issues Tweedle De Deluxe

[DucDone]

Hi. I just finished my Tweedle Dee Deluxe build, and i sounds great. Except for one thing: The volume is rather low, playable, but lowe.

I have a Fender Style 5E3 Output Transformer 25 W / 4-8-16 Ohm. so I would think it should be loud(er). It runs on two 6v6GT's, two 12ax7's and a GZ34 rectifier.

I have tried most tests, voltages seems within limits, changed tubes etc.

What I am wondering about is what could be the reason for this? Is there any part in the setup that restricts the volume in any way, rhetorically speaking?

I have included the layout I am using. Just need some tips, not a "repair"...

 

[Jon Snell]

A schematic would help.

 

[Mark the Moose]

Cold solder joint at the input or speaker out stage? Wrong input resistor? Bad speaker or speaker cable? I’ve never heard anyone describe a 5e3 as too quiet!

 

[Wally]

Doc done, there is an ancient test that can help one locate a problem. In obtaining the voltages when one makes up their voltage chart, start at the power tube. You should hear a pop through the speaker when you contact the plate for that voltage measurement as you move back through the circuit, the pops form the plates should get louder the pop at th epilate on the input stage should be the loudest. When one incurs a reaction that does not produce a pop that is louder than the test that preceded that stage, one has found a problem area. Fwiw, we like to see a voltage chart. Sometimes an experienced eye notes something that others missed. Plus on with Jon Snell’s suggestion. Yes, anyone can take the time to reference a schematic; but having what the builder worked from in the thread is handy.
Do both channels act the same way? that is a clue. Are all tubes known to be good? A careful and questioning review of all components, their values, and connections should be done.

 

[D'tar]

Photos please. As Wally says.... conponent values..... check your plate load resistors.... often 100 ohm are mistaken for 100k ohm, which would yield your symptoms. Best of luck.

 

[DucDone]

Here is the schematics.

 

[DucDone]

Do both channels act the same way? that is a clue

There are three pots. two Volumes and one Tone. When I turn off the tone pot, the volume also shuts down, the two volumes use the V1 and sound very similar, any input used. They also seem to interact. The one clears up to other when set to full?(As in not so overdriven.) The amp doesn't have a clear output, overdriven from zero and upwards.

 

[DucDone]

And then there is the question about the pot for the NFB. I have included a pic of it. I have the middle pin (wiper in the direction of the arrow, and the two other sides each to the outer pins. There is no audible reaction to the pot being used.

 

[clydethecat]

There are three pots. two Volumes and one Tone. When I turn off the tone pot, the volume also shuts down, the two volumes use the V1 and sound very similar, any input used. They also seem to interact. The one clears up to other when set to full?(As in not so overdriven.) The amp doesn't have a clear output, overdriven from zero and upwards.

If the tone control completely shuts off the sound, you've got a serious miswiring problem somewhere on the front panel. Perhaps check your grounding.

 

[Lowerleftcoast]

If the tone control completely shuts off the sound, you've got a serious miswiring problem somewhere on the front panel.

AFAIK, with the tone set near zero the 4n7 cap would allow all guitar freq to ground.

 

[Jon Snell]

Here is the schematics.

The schematic has no NFB. Where does the pot come in? Maybe that's why it doesn't do anything because there is no connection to the loudspeaker winding.

 

[DucDone]

The schematic has no NFB. Where does the pot come in? Maybe that's why it doesn't do anything because there is no connection to the loudspeaker winding.

I was wondering about that, could I omit that pt, and wire without it?

 

[Lowerleftcoast]

I was wondering about that, could I omit that pt, and wire without it?

That pot is a phase inverter balance pot. It is used to balance or unbalance the the inverted signal. It has nothing to do with NFB.
If you want to get rid of it you can just follow the standard 5E3 circuit or guesstimate the tweedle dee values.

 

[D'tar]

Photos please

 

[clydethecat]

AFAIK, with the tone set near zero the 4n7 cap would allow all guitar freq to ground.

I just went and tried it with a 5E3 and no, turning down the tone control does not mute the signal.

 

[clydethecat]

Is it possible that half of the phase splitter is not passing audio and the amp is running as a crippled single-ended?

 

[DucDone]

Is it possible that half of the phase splitter is not passing audio and the amp is running as a crippled single-ended?

Interesting. What could I do to check that?

 

[Jon Snell]

The photo is a drawing.

David has a good point.
Have you checked the anode voltage, cathode voltage and the cathode voltage splitter for the lower half of the phase splitter?
The pot shown is 1/8th Watt and will burn up in a short time and not suitable for this sort of application, unless the old style open frame pot is used as they are 1/2Watt.
If it is faulty, use a standard known working circuit, after all it will do nothing until the output stage is driven hard into distortion.

 

[DucDone]

On the V2 I have 165v and 223v on the plates, 1.4 and 44v on the cathodes and 16v on the grid (7)

On the CC's that leads to the power tubes I have only 29mV.

I use a 2w 10k pot as the divider.