technical question boss ce-2 (chorrral)

[bent]

hI,

I'VE BUILD THE BOSS CE-2 FROM TONEPAD CHORRRAL.....

I NEVER HAVE A CHORUS BEFORE, AND I DONT KNOW IF THIS IS NORMAL 
I NOTICE A TINY DROP OF VOLUME WHEN I ACTIVATED THE CHORUS, I DID ALL 4 MOD, AND WHEN I LFT THE SWITCH FOR THE VIBRATO, THE VIBRATO IS LOWER IN VOLUME....

I JUST WANDER IF IT'S NORMAL, CAUSE NEVER HAD A CHORUS BEFORE....

THANK'S   

BENT

[bent]

  no luck so far....

hope i'm not the only one who build this unit.... 

[Cliff Schecht]

The volume drop is a characteristic of the vibrato mod, at least from my experiences. It's been well over 2 years since I built the thing though..

[MikeH]

The chorus signal consists of 2 parts- an unaffected signal and the vibrato signal.  These 2 mixed together create the chorus effect.  You probably did the "effect level" mod; this simply adjusts the level of the vibrato signal- which, when in chorus mode, adjusts the intensity of the chorus effect.  Unfortunately, in vibe mode, it just adjusts the volume.  I think you'll find that if you turn the effect level all the way up, you won't notice a big volume drop in vibe mode.

[bent]

thank's 

that's the problem when you build a effect and never had one before, you cannot compared...

bent

[Free State FX]

Just reaffirming what Cliff said.  The vibrato mod in the tonepad layout is just removing the dry signal from the output which will lower the output volume.

[Mark Hammer]

The gain of IC1a is partly set by the value of R6 (47k).  As R6 gets larger in value, the gain goes up.

Let's say that R6 was replaced by a 47k and 3k9 fixed resistor in series.  That gives a feedback resistance of almost 51k, raising the gain a bit.  Hopefully not enough to distort the MN3007.

Okay, now let us say that as long as R21 (the 47k resistor that connects the dry signal to the mixing stage) is connected to provide a chorus effect, that additional 3k9 resistor is by^passed with a straight-wire connection so that the IC1a feedback resistance goes back to being only 47k.  But when the connection to R21 is broken, the same switch (a DPDT, by definition) now lifts the shunt/bypass straddling the extra 3k9 resistor such that the gain of IC1a is raised slightly.

Bingo.  Chorus/vibrato with automatic volume-balancing.  Don't take my word for it that the"magic" value is necessarily 3k9.  That's just a guess.  But the ideal value shouldn't be too far off from that.