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Hello,

I just finished my first build of the 5E3 kit and I am truly amazed by the sound quality. What a wonderful articulation this amp has!

I do however have some issues with loud Hiss/White-noise on high volumes (from 11-12) on both channels. And a little Hum.
The Hiss is more prominent on the Bright channel and starting at lower volume and increasing in volume with the dial.
On he Normal channel the Hiss only becomes disturbing when the volume is past 11.
The Hum is more prominent when the volumes are both on 1 and by turning up the tone.

As this is my first build I am probably overlooking something obvious and hope your collective know-how can pinpoint the solution to my problem.
I did all my investigations without anything plugged into any of the inputs.

I changed the V1 and V2 with different tubes to see if that made any difference, but sadly it didn't.
When V1 (12AY7) was removed the Hiss was gone, but substituted by a Hum. This hum becomes more noticeable the more I turn up the tone control.
When I remove V2 (12AX7) there is no hiss or hum.

I checked the continuity on the ground wires and I get a solid "Beep" from my Multimeter, so I guess they are fine?
I tried moving the wires so they aren't touching too much. No change.
When I probe the yellow wires coming from the 4 68k resistors and probe the resistor-bodies with a chopstick, I can hear the probing amplified through my speaker. Is this normal?
Whenever I check the voltages on the filter caps before I start probing inside my chassis, I also check the caps too. Don't really know why...must be a weird habit I am developing
The 1st 0.1 uF one (next to the filter caps) never has any volts showing (0v) and neither does the 0.022 uF cap. But the other 3 0.1 uF caps always have the same value as the filter caps do. Is this the way it should be?

What I also noticed is, that when I touch the chassis with my hand the hum is slightly reduced.
When I touch the impedance switch with my finger there is a faint "pop"/tap sound.
Also, when I have my hand above the area where the Silvered Mica cap is, I can hear an interfering noise.

Maybe this is all normal and I know most amps have a hum so I can live with that. Only the loud Hiss is making the 11-12 volume settings unusable atm.

Hope you can help out in any way.

I will attach some images of my build.

Greetings,

David

When you say volume at 11, are you referring to the numbering on the chassis? If not, at what setting does the hiss become so loud?
There is inherent hiss with the Teeed amp due to the carbon composition resistors used. This can be reduced by substituting carbon film resistors in places in the signal path and plate resistors?
The hum is increasing when you touch the amp probably because of a poor solder joint somewhere. Try touching up the joints in areas that seem noisier when you probe and tap them with a chop-stick.
Also, it is normal for your body to induce changes in the signal when you move it close to circuirty.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Hi Stephen,

Thanks for your reply.
I am indeed referring to the number on the chassis.
Can I change the carbon film resistors with 0,5 W metal film resistors? Or do they need to be 1W?

Cheers,

David

11 is about the maximum setting so I would not be concerned about that amount of hiss/noise.


Yes you can, but as above, I doubt you will get it much better than it is.

Capacitors block DC voltage so on one side you will normally have DC and none on the other.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps