S O U experiences

[petemoore]

I'm using the same transformer as the Bobtavia uses [from RS]...but I have the Tychobrahe Octavia type also.
 What type of "Small Transformer" is used in this circuit?
 I'm trying another Simple Octave Up, using an LM741, and a NTE857 [substitute for some of the OA's shown on the SOU schematic]
 The voltages with the 741 look good V+ is 14v gnd is Gnd and the two inputs and output are near 1/2v.
 I'm using two NTE158's for clipping diodes, emitters to the transformer Bases tied to the volume pot.
 Nothing's coming out though...I have the diodes socketted and opamp socketted, the two 1M resistors from pin 3 to V- and V+.
 Pin 2 and 6 get a 100uf to 100ohm to ground.

[idiot savant]

you can use either radio shack part# 273-1380
or, i used mouser part #42tm013

the primary faces the GE diodes


i keep hearing people say that the octave up os faint, but i used the 42tm013 and 1n34a's and i get a screaming octave in mine.... :?

i have a perfboard layout that ill post soon

[jmusser]

I have that circuit over on JD's Site.  http://www.generalguitargadgets.com/diagrams/simplw_oct_up_ez.jpg  the Radio Shack Transformer is used in the Botavia, SOU, and the NeoOctavia, I would guess, since it's Bobtavia derivitive. Part#273-1380 1000 ohm primary, 8 ohm secondary. The Tycho transformer is the Mouser #42M011 with a 500 ohm primary, 1.5K secondary.

[jmusser]

I just looked up that 42TM013 transformer, and it's primary and secondary are the same resistance as the radio shack 273-1380. I'll thank the "Idiot" for the second source for that transformer. Until he said that this transformer was connected the way it was, it had never occured to me that this transformer was turned around backwards! :oops: I had just wired to the schematic, not realizing it all this time. On anything I've seen, the primary is ALWAYS inducing into the secondary. Is it used as a step up when it's backwards? i would guess that with the low voltage going through it, that the orientation doesn't matter, because the windings are plenty beefy enough to handle it. I also agree with the "Idiot", if the octave is faint in someone's build, then there has to be something wrong, because this one is definitely and in-your-face octave circuit!

[idiot savant]

yeah i had a helluva time trying to get specs on that f'd up rat shack transformer, the mouser is MUCH easier to place on a board, the orientation kinda confused me at first also because the mouser has a center tap on the secondary too, which i didnt connect, im not sure if i should ground it though, as i have really only seen transformers used the way you described...

mine will go from mostly clean to all out fuzz, and the octave up should not be faint on this one,  the SOU is a great circuit

[bluesdevil]

I followed the EZ layout on the General Guitar Gadgets site and used the Radio Shack transformer. Mine works but would it sound any different if I  swapped the wiring of it? Let us know if you give it a shot, Jeff!!!

I just looked up that 42TM013 transformer, and it's primary and secondary are the same resistance as the radio shack 273-1380. I'll thank the "Idiot" for the second source for that transformer. Until he said that this transformer was connected the way it was, it had never occured to me that this transformer was turned around backwards! :oops: I had just wired to the schematic, not realizing it all this time. On anything I've seen, the primary is ALWAYS inducing into the secondary. Is it used as a step up when it's backwards? i would guess that with the low voltage going through it, that the orientation doesn't matter, because the windings are plenty beefy enough to handle it. I also agree with the "Idiot", if the octave is faint in someone's build, then there has to be something wrong, because this one is definitely and in-your-face octave circuit!

[petemoore]

General Guitar Gadgets is the same as Guitar Effects Projects...JD Sleep right?
 I don't see simple octave up or anything labeled EZ on the site...where should I be looking?  
 When I try this link
 http://www.generalguitargadgets.com/diagrams/simplw_oct_up_ez.jpg
 I get TPCBD

[bluesdevil]

Regular schematic:
http://www.generalguitargadgets.com/diagrams/simple_oct_up.jpg
EZ BUILD:
http://www.generalguitargadgets.com/diagrams/simple_oct_up_ez.jpg

I just got a PM from Jeff about my confusion over his post about the transformer. I followed the schematic and my build works like it should, but just got  concerned about switching things around when I read that post. Just a note: 22uf and 100uf cap polarities are noted on the regular schematic but not the EZ build.
             Thanks!!!

General Guitar Gadgets is the same as Guitar Effects Projects...JD Sleep right?
 I don't see simple octave up or anything labeled EZ on the site...where should I be looking?  
 When I try this link
 http://www.generalguitargadgets.com/diagrams/simplw_oct_up_ez.jpg
 I get TPCBD

[petemoore]

EZ Build looks much clearer.
 I looked up the data sheets on TL081 and LM741, tho the Tl series look 'snazzier' the 741 looks 'operationally' about the same, and seems to bias in my board..the NTE857...I don't remeber ever getting anything out of that chip :?:  :?

[petemoore]

741 got it popping, then I tried the NTE857, I think that chips blown.
 I used 1/2 of TL082's one of many was definitely more output, it has print that is thicker than the usual RS ones. I stumbled upon the 'ol dual to single conversion socket I made.
 Nice heavy Octave pops right out !!

[jmusser]

Pete, I'm guessing since you mentioned seeing the SOU EZ Build, that you found it. For those that are still looking, hit the link, and when it says "Page not found" click on the General Guitar Gadgets address to get you there. Next, click on "Cross-Reference", then "Schematics". The EZ Builds are at the bottom of the page.

[petemoore]

ok I'll take a look there too. Thanks J !
 Yupp SOU is Octaving !!!