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Recently build an amp on the sIII V6 format and stiffed it in a pretty small chassis. I've checked heater wiring and adjusted all the wiring with a chopstick and the amp is pretty quiet but I am getting some hum it doesn't go up with the volume or get any louder I am wondering is this normal? Basically it sounds like a very small electrical transformer running. JK

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JGK

Did you get it sorted out? What power tranformers did you use? Did you use our layout?

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

Its not terrible but it's constant regardless of volume with the EL84s the 6V6s are dead quiet. I have your stock transformers and used the Trinity layout for the 6V6s. I have moved the wiring and changed tubes I'm thinking my next move will be to increase the cathoid resister. I am currently traveling but when I return I will post some pics. I just love the amp it smokes and I'm using a WGS speaker which give me a little less crunch but sustain is fantastic. Thanks JK

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JGK

The el84 could be badly mismatched causing that hum. Can you try a different pair or one ?

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

Yes, there may be something wrong with the EL84s, whether they're badly mismatched or just generally faulty. Also, changing the value of your cathode resistor won't affect hum, unless your EL84s are faulty.

BTW a small amount of mismatch in power tubes is desirable in a guitar amp, as it helps add nice even harmonics to the tone. A large mismatch can however give you a constant hum.

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Great tones come in small glass jars!

I have tried 3 different pairs of tubes (matched JJs a NOS set of Mullards and a set of used Telefunkens) that all sound fine in my sIII so I don't think its a tube problem it is a tight layout as I used a bit smaller chassis but moving the wiring doesn't change anything with the EL84s I may be being a little to picky. I am still traveling and when I get home next week I'll post some pics. Thanks for the help JGK

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JGK