Ampeg Scrambler build & Gut shot - Impressed !!

[MartyMart]

For "nelson" - have not built anything for about 9 days, been away in
Germany/Hungary and Russia playing some shows !!!
( before you start cursing me again !! )


There seems to be "mixed feelings" about this circuit and a few comments about it sounding "crap" on its own and not boosted by something else !!
Well, I build one on vero, from GGG's schematic and made a few changes :
1N4002 reverse protection diode
100uf power filtering cap
Input cap 22n
Q1/3/4 MPSA13
Q2 2N5088
Matched voltages for all the 1N4148 diodes used
Left out the final 47k to ground at the output and used a 100k lin pot as
blend/volume.
"Fuzz" pot is a 22k lin with a 22k resistor across it, so approx 11k pot

Fired up first time ( Hoorah !! ) and I have a GREAT sounding Fuzz/octave
circuit !
The "blend" control is very nice, I may add this to a couple of other octave builds.
Using neck pickup on a Humbucker gtr with the tone rolled back gives the
best "octave" from mid way up the neck.
"Fuzz" pot goes from a very nice "FF"/Distortion tone through to "wierd"
Psychtar type tones and bell "ring mod" noises.
Which means that you're not stuck with "wierdness" all the time  

Plenty of volume for all effect/all clean but a little quiet at 50/50 ?

After an hour of playing, it seems to be one of the better and more useful
"Fuzz/Octaves" I have, though I do have better "octave" performers.

A great "all rounder"  
Photo's :
http://www.pbase.com/image/48746392
http://www.pbase.com/image/48746399

Marty.

[nelson]

Not ANOTHER FUZZ!  :roll:

nah just kidding

I really like this circuit. I used home made darlingtons made out of 2N5089's.

I like it boosted with another fuzz.

Its the only octave pedal I have built.

Wow, I would love to play russia! Congrats!

[MartyMart]

Wow, I would love to play russia! Congrats!

Its my fourth time there, dangerous place though, Internal flight was very scarey !!  "ZERO" tread on the Jet's Tyres  !!!! and it looked about
50 years old ??
Great people and some of the most gorgeous looking women that I've ever seen   :twisted:

I'm very happy, so I'm being a "good boy" ......  :roll:

"Prado " is a V- exclusive little club in Moscow and worth a visit, as is the
"Pyramid bar"   :wink:

Marty.

[jimbob]

Congrats! I just finished mine as well.  I really like the sound of it. You also have to like a different/ variety of sounds to have an appreciation for this evil little beast.

[jmusser]

Of course we've talked about it before, but that sure looks familiar. I have boxes full of those waiting for finished eclosures! Did you choose to change the transistor type because you didn't like the sound of the specked ones (2N3565?) or is that just what you had to work with? I was going to order those specifically for the Scrambler, along with some low gain Si types from Small Bear, since someone mentioned they would like to have some besides me :wink: .

[Toney]

Excellent, Marty.

I finished the one of these last week but have yet to fire her up. Haven't had time to do the offboard wiring.
Did you try the original input cap first and work yr way up?
Also, if anyone can chime in with the differences btw the specified diodes (1n456) and 4148s I'd love to know.
I used 4148s but have some the others coming from Small Bear which is typical of me getting excited about building with what I can get my hands on right now...... then wondering about the sound if I had used the original components.

[MartyMart]

Excellent, Marty.

I finished the one of these last week but have yet to fire her up. Haven't had time to do the offboard wiring.
Did you try the original input cap first and work yr way up?
Also, if anyone can chime in with the differences btw the specified diodes (1n456) and 4148s I'd love to know.
I used 4148s but have some the others coming from Small Bear which is typical of me getting excited about building with what I can get my hands on right now...... then wondering about the sound if I had used the original components.

Toney, I'm no "expert" but have built most of the "octave/fuzz" circuits
out there, in my experience, "matching" the diode's forward voltage gives
way better results than any "specific" diode.
I've used 1N34A's 1N4148's and 1N90's with good results after matching.
As far as the input cap goes, I hardly ever use anything smaller than a
47n, when I see "10n" I think "thin and weedy fuzz" !!
However, the 22n seems to work well here, 47n got a little "woofy" for me.
Jeff,  yes that's all I had available, if you have some others though ...??


Marty.

[jimbob]

I tried the 2 diff diode w out noticing any difference.

[Bernardduur]

A bit OT, but would the unit work on 18V?? I am planning to build one (when I have time) and would put it into a duo pedal (together with my homebuild Bassdrive / Fulldrive II clone); the other pedal works on 18V and I want to use only 1 DC input jack.

[MartyMart]

A bit OT, but would the unit work on 18V?? I am planning to build one (when I have time) and would put it into a duo pedal (together with my homebuild Bassdrive / Fulldrive II clone); the other pedal works on 18V and I want to use only 1 DC input jack.

You would have to "adjust" the circuit otherwise it would sound very "clean" at 18v
If your caps were rated high enough etc, then its a matter of the bias on
those trannies ..... !
At 18 volts, they are going to be wanting "half" that at the collector ... correct ?

Marty.

[Bernardduur]

Any thoughts on the new values?

[MartyMart]

Any thoughts on the new values?

No, not off the top of my head, collector and emiter's values have to be
set up differently to get you the same amount of "fuzz" - the octave part
should work as-is ....

Marty.

[gaussmarkov]

As far as the input cap goes, I hardly ever use anything smaller than a 47n, when I see "10n" I think "thin and weedy fuzz" !!  However, the 22n seems to work well here, 47n got a little "woofy" for me.  Marty.

interesting ... have you built the rog sili face 2 marty?  the input cap on that circuit is 10nF.  by coincidence, i was just looking at it yesterday.  

[gaussmarkov]

and nice pics.  i seem to always learn something basic from your projects, marty.     are those ground and +9v rails that you have marked on the top of your perfboard?  this weekend, i was just toying with the idea of transferring breadboard layouts to perfboard where the same kind of layout is natural.  then i got to wondering about twisting the ground and supply wires to avoid noise and whether that matters on circuits in stompboxes.  you seem to keep your rails mostly separated.  do you have any thoughts about this? :?

[Bernardduur]

Will try stuff when I build it. Thanks!

[MartyMart]

and nice pics.  i seem to always learn something basic from your projects, marty.     are those ground and +9v rails that you have marked on the top of your perfboard?  this weekend, i was just toying with the idea of transferring breadboard layouts to perfboard where the same kind of layout is natural.  then i got to wondering about twisting the ground and supply wires to avoid noise and whether that matters on circuits in stompboxes.  you seem to keep your rails mostly separated.  do you have any thoughts about this? :?

Yeah thats the two rails marked in red & black.
I had to bring 9v "down" at one point, so I have them very close !
I like to keep 9v at the top and ground at the bottom if poss, 1) its easy
for me to "see" what's what and 2) perhaps keeps some noise down and
prevents any chance of "grounding" the 9v rail !!
I dont always "mark" them, but it helps when returning to a build some
weeks later.
I use a small "green" marker to spot the in/out also

Marty.