Chorus chips and sound

[trickpony]

So I got a new amp this weekend. SS Fender Ultra Chorus...not everybody's cup of tea, but I love the clean channel with my Ricky and for $125 I now own an American made amp...yea!

Anyway, one of the surprises for me was how good the built in chorus is. I compared it against my BYOC chorus, and the main thing I find different is a separation of notes (someone help me here), with the BYOC, the notes seems to blend together more...I dont want to say muddy, but the Fender is definitely clearer to my ear at any level of depth.

My question is would this be just related to the ICs?...the fender uses 3101 and 3007 and the byoc uses 3102 3207. I thought maybe as the mn3007 can take 15vdc, maybe the amp was providing more power, but TP18 on the following schematic shows 8vdc.

I noticed that the Pork Barrel has the option of using either pair. Have people done a comparison?



http://support.fender.com/schematics/guitar_amplifiers/Ultimate_Chorus_schematic.pdf

[Scruffie]

It is running at 15V, that's the bias point.

It's probably more down to the different filtering though, a MN3007 at 15V will give you more headroom than a 3207 at lower voltage but they're completely different choruses (I assume without looking at the BYOC Schematic).

[RobA]

It's a stereo amp? Two power amps driving a 12" speaker each. If so, it's probably similar to the Roland Jazz Chorus. The stereo separation on the chorus is really nice.

[trickpony]

It is running at 15V, that's the bias point.
--- Indeed, my mistake

Two power amps driving a 12" speaker each
--- Yes, it has this

The stereo separation on the chorus is really nice.
-- Ok. If I understand this...the output of 3007 goes thru an LFO that changes the phase between 2 outputs.  So I could, say mod my byoc and add that LFO and return a stereo signal out of it..right?

Also, would it be nicer to pull those 2 sides further apart...say take the stereo efx out and split the wire, sending the left channel to another amp's mono efx return and the right channel to umm the mono efx return of the original amp (this last part seems odd but seems possible from the schematic)

Thanks,
Ben

[RobA]

I haven't looked at the schematics for your amp, so I don't know how it does the stereo chorus. I think that the Roland JC 120 took the simple approach of feeding one speaker/amp the chorused signal and the second a dry signal.

I've made a nice chorus by taking a pair of amps, side-by-side, and running one clean and the other with a vibrato. If the separation between the speakers isn't too great, this works very well.

If you want stereo separation, you need to do matched choruses with the LFO's in quadrature. I've written computer plugins in digital that do this. I run four LFO's; sine, cosine, inverse-sine, and inverse-cosine. I use these to generate four choruses and mix them two to one side and two to the other. 

[Guitar Master]

I have the same amp and love the chorus, I have no idea what chip it is though