Building a 5W tube amp Fender Champ AA764 model copy

 It is a fender AA764 (silver face) copy, with some mods: 

- Solid state rectifier (FRED diodes)
- Standby switch
- NFB pot and switch
- Two Fat switches

- One Bright and treble tone cap switch
- Master Volume
- Coupling cap value 6x switch (before the master vol pot)
- 6V6 Tung-Sol and 12AX7 Tung-Sol
- Orange drop capacitors

- EL84 paralell tube socket option (not tested). * Using one or another (6V6 or EL84)

- Presence switchable control

- Mid control

- TMB turn-off switch

- GB128 speaker

** AA764 is a 5F1 with TMB tone control and a little diferent NFB.

Pictures:

Optional EL84 socket:

Stratocaster tremolo piezo + piezo mod

This is a mod to adapt a under saddle acoustic guitar piezo to a stratocaster block tremolo anda a common piezo inside the guitar body.

 

• Use a rotary tool and a file to make a groove at the upside of the block:

• ... until the piezo fit it, with only a small part outside:

   

• Screw the other parts of the tremolo with the piezo wire out of the block:

*Maybe you will have to file the wood of the guitar under the bridge, a litle bit, to adapt the extra wire.

•  Othewise, if you don't use the tremolo arm, like me, it is possible to use the other side of the block, making a extra hole to pass the wire:

•   Set up the tremolo at the guitar, use the grounding hole to pass the piezo wire and conect it to the guitar circuit. Some hot glue will fix better some parts:

•  Next step....fix a common piezo at the inside of the guitar body, near as possible of the bridge, using a double face tape:

   

 

The tromolo piezo will have a lot of influence of the coils, producing a lot of reverbation. My sugestion is to mix the two piezos with a resistor (or a pot) like that:

 

* 1M or less... depends on the piezo output level.

Finaly, mixing the pickup mod (http://guitar4geek.blogspot.com.br/2016/06/stratocaster-wire-mod-series-pickups.html) with this piezo mod:

*All pots are 500K

* Other suggestions:

Sample:

Tks to Pete from MukerBude.de: http://www.mukerbude.de/_MATERIAL/Anleitung%20-%20Stratylon.pdf

Boss MT-2 Metal Zone and Behringer UM300 Ultra Metal Mod

Mods for more thicker and compressed sound:

• Change the DO04 and DO03 to Germanium diodes, or use a switch to select the original Se diodes or the Ge diodes. I have used two 1n60 diodes.

See the picture:

*Use Boss schematic above to mod this Behringer stomp box.

Boss Chorus CH 1 and Behringer UC200 Mod

Mods for more thicker effect options:

• Add a toggle switch (on-off-on) to select the C18 values, this will change the delay time of the out of tune signal, before it is added to the guitar signal. The middle position will be off and only a 5pf (or 4,7pF) value is seeing by the circuit, no delay at all, the others positions will select two 0 to 100pF trimmers that can be adjusted as you wish, for a pleasant delay color. Adding more delay time, more thicker will be the chorus effect.
• Optionally, reduce the value of C30 (or remove it) to upper the trebles, only in case of a dead tone problem.

*     In place of one trimmer, could be used the original 47pF capacitor.

**   Behringer have originaly  a 5pF in parallel to a 47pF (C18) capacitor.
*** The C18 mod is very famous in the internet foruns.

See the picture:

*Use Boss schematic above to mod this Behringer stomp box.

Boss Tremolo TR 1 and Behringer UT100 Mod

Mods for more tone options and balance the on and off stomp's volume:

• Replace the R9 resistor from 10K to 18K (or more), to balance the on and off stomp volume. I've choosen 18K.
• Add a on-off-on toggle switch to select the C4 values (or no C4), this will make a subdued, but perceptive, diference in the effect tone. The middle position will select none capacitor, the Boss TR1 came originally with 0,1uF cap and the Behringer came with a 0,68uF eletrolitic cap. You can select 0,1uF, 0,68uF and none capacitor, or try out others values.

See the picture:

*Use Boss schematic above to mod this Behringer stomp box.

Boss HyperFuzz FZ-2 or Behringer Super Fuzz SF300 Mod

Mods for a more pleasing distortion without the "octave" effect and adding the volume control in the boost mode:

• Remove Q13 and its circuit to get the octave effect out, as the picture shows, its possible to remove the 1k resistor initially to test this mod.
• Replace the 10K in Q14 base for a 1K resistor, to increase the stomp volume.
• Jump the part of the mode switch and cut one lead, to add the volume control to the boost mode (see in the picture below).

See the picture:

*Use Boss schematic above to mod this Behringer stomp box.

Les Paul wire mod

First MOD:

The first mod is the following:

• A piece of a 0,5 mm thick guitar cable (I take off the rubber insulation and put a  shrink tubing in place), linking the jack to the pickups switch.
• I have Used two 22nF russian PIO capacitors at the begining, and then have changed one 22nF to 15nF to the rhythm pick-up (copying the popular woman tone mod).
• All wire used are non tinned copper thick wire.
• Implemented a 50's style wiring to increase the highs.

*The tone is warm and big, a lot of bass and low middle, good detailed highs.

 - I guess, IMO, this tone is because the non tinned cooper thick wire and the PIO caps.

Pictures:

             Using a 15nF PIO:

Second MOD:

The second and current modification is as follows:

• All wire are tinned copper wire (vintage style wire for guitar).
• Used two Russian capacitors PIO, one 22nF for treble and one 15nF to the rhythm (yes, the woman tone mod).
• The 50 's style wiring, to increase the highs, remains the same.
• Big potenciometers Gotoh 24 mm for a better construction.

*Sugestion: treble bleed mod (only the capacitor without the resistor option) for volume pots - 250pF to 680pF (sorry no pictures taken).

** The tone is dry, vintage, more single coil style, most of the bass and low middle are gone , highs became more extended and predominant.

- I think, IMO, this tone is because the tinned copper cable.

Pictures: 

• Recently I have unpotted the pickups, seeking for a more detailed tone.

X-VAMP input signal mod

Mod for more open sound, more top end and bottom end:

• C5 10 nF to 47nF (or try other values as you wish).
• Remove C26 (47pF) for more aggressive top end.

** Be carefull about the metal shield removing, its quite dificult !! **

See the pictures:

* These pictures show how I try out the mod, after this I put the capacitor at the right side and the metal shield at its place.