Chunk Chunk 3rd stage mods

[oldhousescott]

As most know, the 3rd stage of the CC is different from the Recto on which it's based. The cathode resistor in the Recto is 39k. When using that value in the CC, the trimmer cannot be turned down enough to bias the stage correctly. However, if you change the trimmer T3 to 500k, you can use 39k for R9 and get the stage to bias correctly. This also reduces the gain and tendency of the circuit to squeal from instability.

[jimmybjj]

sweet, will definitely give this a go.

[nzCdog]

Nice tip... I want to try this

[garfo]

To what version of the Chunk are you referring to, did you try this mod?

As most know, the 3rd stage of the CC is different from the Recto on which it's based. The cathode resistor in the Recto is 39k. When using that value in the CC, the trimmer cannot be turned down enough to bias the stage correctly. However, if you change the trimmer T3 to 500k, you can use 39k for R9 and get the stage to bias correctly. This also reduces the gain and tendency of the circuit to squeal from instability.