Taming the Treble...

[Mark Herrick]

Again, great info here! (But I'm getting a little dizzy...)

I think the JBL K-130 sounds pretty warm, and I like the "crispness." (It is an original 4-Ohm cone.)

I have done a Blackface mod on the phase inverter circuit, but I couldn't sense much difference. The filter caps have also been changed (Sprague Atoms) as well as the grid resistors on the power tubes and plate load resistors on preamp tubes.

Pre-amp tubes are: V1 GT 12AX7M (don't use this channel), V2 JAN Phillips 12AX7WA, V3 Mullard CV-4024 (12AT7), V4 GT 7025, V5 GT 7025, V6 Mullard CV-4024. Power tubes: Phillips 7581A.

I usually keep the MV on about 7. If I go higher I start to get some noise. Preamp volume usually on about 7 as well.

Think I'll play with the tone controls for a few days as suggested and see how it sounds before doing any more soldering...