crybay mod advice and experiences ?

[gazza]

Hi,

I've got a stock crybaby 95 (thanks santa) and I want to add a 'sweep' and a 'Q'  control to it, plus I'll consider doing a true-bypass on the thing.

I've played with the 535Q model and would like my mods to be at least as flexible, hopefully better !.

does anyone know what the 'Q' control is on the 535 ?    is it simply a variable resistance in the place of the 33k resistor in parallel with the inductor ?  and if so over what value does it sweep ? i was thinking i'd try 20k-70k may be ?  I want it to be both sharper and softer than stock, but i don't know which whay the resistance needs to go.

My plan is to have two controls outside the pedal, sweep and q.  I may put trim pots in for other resistors that people seem to like tweaking, like the emitter resistor onthe first transistor (gain i guess), that 1.5k resistor and the input resistor.

can anyone explain what the capacitor mods either parallel to or in series with the main pedal 100k opt do ? these seem to have been done on the dunlop JH models.  do they 'mellow' the pedal feel somehow ?

sorry for all the questions !

Happy new year All,

Gareth.

[Fret Wire]

You'll should do the true bypass first, and consider adding an output buffer if you want to use your wah before a fuzz. The 33k resistor is refered to as the "Q". Same on the 535. You certainly can mount an outside pot for it. Dunlop uses a long shaft trim pot that extends through the bottom plate. I doubt you would want a value less than 33k. Use a 100k pot, so you can go from 33-133k. The Clyde wah used a 100k for the "Q", although usually somewhere between 33k and 68k works for most people . The cap selector is a good choice, so are the 1.5k (midrange) and the 68k (volume boost) as internal trimpots or outside pots.

You can mod the Dunlop board, or get a ready to solder board and really go to town. Here's some sites to check out, and get a better idea of what you want to do. Having the important values adjustable helps because a particular value that a site suggests may not mesh with your rig or preferences. Plus, if you later change your inductor or pot, you can re-adjust your values if need be.

http://homepage.ntlworld.com/s.castledine/greenfuz/wah.html

http://members01.chello.se/pastorn/fx/mods/dunlop.htm

http://www.geofex.com/Article_Folders/wahpedl/wahped.htm

http://www.happybob.com/marc/pot_adjustment_procedure.htm

http://www.generalguitargadgets.com/index.php?option=content&task=view&id=112&Itemid=158

http://www.tonepad.com/project.asp?id=29

[bass_econo]

I did the vocal mod and the volume mod for a friend.   The vocal really made the pedal sound better.  I wouldn't recommend the volume unless you are ok with the fact that it will not be zero volume wah is back.  It goes about 75% down.  My friend actually liked this though because he can get a sort of tremolo effect by rocking the the pedal.  

that's my $.02.

[vanhansen]

I've modded mine with true-bypass, the voice mod, mid boost mod, adjusted the pot properly, and added a .01mf cap in parallel with the inductor (opposite side from the 33K resistor). I used 68K for my voice mod.  Good sound.  The additional .01mf cap (which is also in the JH-1) took out some of the high end harshness and smoothed it out some.  It's an older board (Rev. E) so I didn't have to worry about a lot of the stuff in the newer ones.

[gazza]

Thanks for the replies.

A few quick questions,  

does an increase in the 'Q' resistor from 33k towards 100k make the resonant peak narrower or broader  ?   it's not very clear from the info that's posted about.    With the 535Q  i tried, it sounded like the 'Q' control made the peak broader ?

do people think I might be able to use a 4way 3 pole rotary switch and be able to set up 4 voicings with different, 'Q', sweep and maybe a parallel caps like the hendrix crybaby ?   any suggestions as to the best combinations ?  It would be a lot easier to only have to drill one new hole !!!

seems like the following might be possible :

stock       :   33K 'Q'      0.01uF  sweep   none
bass        :       ?   'Q'     0.068uF sweep  none
'hendrix' :   68K  'Q'      0.02uF   sweep  .01uF parallel inductor ( 'Q' resistor)
other ?    :   ?                       ?                                 ?  

Any suggestions for the missing values ?  

I am thinking that a perfboard with all the trim pots and connections to the switch would allow for sockets for the sweep resistors and Q caps. and I could leave the main board fairly stock. Would running leads all about to this new board cause noise pickup problems ?      

I'll let you all know how I get on

cheers  

Gareth.