madbeanpedals::forum

Projects => General Questions => Topic started by: CapnCrunch on August 10, 2010, 09:41:02 PM

Title: Need help with analog chorus
Post by: CapnCrunch on August 10, 2010, 09:41:02 PM
Hey all,

I'm hoping someone can help me understand what is up with a voodoo labs analog chorus that I have on my board.  As I understand it, the VL analog chorus is a copy of the Boss CE-2.  I like it, and would use it more but It has an interesting issue.  With some guitars it is nearly unity gain when kicked on, with others it is not. 

With my Les Paul (vintage PAF output Lollar imperial pick-ups) running behind my OD pedals on the board, it is a little hotter then unity but close enough to use.  With my Tele (a stock original 58 tele) output is lower than unity.  It's enough lower that it is really annoying.  I have a Strat with vintage SC pickups in Neck and Middle and a Seymour Duncan Hot rails in the bridge.  With that guitar, the chorus is WAY hotter then unity with all pickups.  It is such a jump that it is not usable with that guitar.  Also, when I try to use it with my accoustic with LR Baggs dual source run through an LR Baggs DI and pre-amp with the chorus in the effects loop, it drops the level significantly. 

I don't understand how, with one guitar it is dropping the level and on another it's like a 15 db boost.  Any ideas?  Is there anything I can do to fix this issue?
Title: Re: Need help with analog chorus
Post by: jkokura on August 10, 2010, 10:59:56 PM
I wonder if it has to do with your pickup impedance. The output impedance of the single coils (tele) will be less than the hotter PAF lawllers. If you could open it up and take some pics, perhaps we can see what the value of the input and output resistors and/or caps are. Perhaps there's a fix there.

Brian will know about this more than me I think.

Jacob
Title: Re: Need help with analog chorus
Post by: CapnCrunch on August 10, 2010, 11:09:07 PM
I had it apart a month or two ago.  It's kind of a pain because all the components are hidden.  They are on the pot side of the board and the pots are PC mounted.  I'll see if I can get some decent pics of it and then get them posted.  I can't remember if it has any trimmers.  I guess we'll see.

Thanks
Title: Re: Need help with analog chorus
Post by: CapnCrunch on August 10, 2010, 11:37:39 PM
O.K.

I pulled it apart, and took some pics but can't post them because they are too big.  They average about 1.9 meg each.  I suppose I can set the camera for email resolution, but then you won't be able to see much detail.  Hmmmmmm.
Title: Re: Need help with analog chorus
Post by: CapnCrunch on August 10, 2010, 11:55:05 PM
One more try.  I set up a web gallery.  Here is the link.  I had a bright A$$ light on but the pictures turned out a little dark.  http://gallery.me.com/boughtonfamily#100011
Title: Re: Need help with analog chorus
Post by: wasteofspace on August 11, 2010, 12:13:09 AM
What pedals do you have in front of the chorus? As an experiment, have you put a buffer or a buffered pedal between your guitar and the chorus?

That will highlight- or more to the point negate- any impedence issues.
Title: Re: Need help with analog chorus
Post by: CapnCrunch on August 11, 2010, 07:42:38 AM
I typically run my guitar into a planet waves tuner->ts9->old DOD distortion->chorus->analog delay->Trainwreck Rocket clone.

You've got me thinking.  When I get home tonight I'm going to play around with the order of the pedals and also the amp.  I used to run this pedal with a 65 Amps London which I dimed and ran through an attenuator.  The gain shift was barely noticeable with that amp which was compressed as hell, run in that manner.  Now I run into the Rocket whose volume I set at about 10:00 which is a nice sweet, loud, chimey, clean.  At this setting there is very little compression from the amp and I've noticed it is very sensitive to input volumes.  In other words a small change in pick attack equates to a huge change in volume from the amp, and small changes in gain or volume on one of the effects equates to a large change in volume as well.

I will also say that the perceived boost occurs primarily in the bass and treble when the chorus is kicked on.  The bass is O.K. but the treble is just way too much.   Maybe I need to ad a compressor.  I like the way compressors sound when other people play them but I hate the way they feel when I play with them.   
Title: Re: Need help with analog chorus
Post by: madbean on August 11, 2010, 09:32:05 PM
Does this happen if the chorus is the only pedal in the chain?

My thought is that there is an input gain stage which could be amplifying the different input signals disproportionately. If this is true, if could be modded. Or, you could actually put your own input gain/impedance control at the top of the circuit. A 50kB set as a voltage divider or variable resistor at the fx input would help you control the input level.