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previous: M.Romasco Does anyboby know how the five posi... -- 1/28/1998 5:39 AM View Thread

Re: Tone Switch

2/2/1998 5:17 PM
Mike B
Re: Tone Switch
I've never seen a schematic for  
the DC/30 but my guess is that  
the tone switch selects different  
coupling caps between the EF86  
preamp tube plate and the volume  
control for that channel. It  
probably looks a lot like an  
AC30/4 EF86 preamp modded with  
a selector switch and multiple  
coupling caps. This would have  
the effect of rolling off more of  
the low end as smaller values of  
caps were switched in. This  
seems to be what happens on  
DC/30's I've tried. Maybe it's  
more complicated than that but  
it doesn't seem so.  
I experimented with this scheme  
on a Spitfire clone that I built.  
I used a six position switch  
to select the caps prior to the  
volume control. I honestly was  
not that impressed - simple bass  
and treble controls provide a lot  
more flexibility and tonal range.  
Mike B