Shin-Ei octave box....Fuzzless octave???

[BillyJ]

As far as I can tell from the clip here:
http://www.fortunecity.com/tinpan/humperdinck/223/effect.htm

And from talking to a fellow whom I am getting mine from this things seems to have no fuzz.....just nut squashing low tones. :twisted:

Well anyway I am curious to know if anyone else has the same or diferent opinions on the sound of this thing or other octave down effects.

I am really interested in good clean octave down effects and I am hoping I have found the one I will use from now on.

For some reason I seem to remeber this being a big deal and hearing that a clean or fuzzless octave down just either didn't happen or sounded sterile or something.

Anyway from the short clip I think it sounds really nice and look forward to playing with it.

If anyone can recommend other clean octave down effects that would be great!!!

Thanks!!

[cedric]

and i'm that guy! 8^)

it IS a fuzzless octave. i could upload some clips. but i think i'll leaveya'll in suspense (kidding - i'll do it this week me thinks)

[BillyJ]

I wonder why no one builds this one are these 2SC644's some issue to replace??...Hmm...
Anyway I am just curious why UI never hear much talk of these.
It seems cool. Can't wait to try it for myself. I hope I am not getting my expectations too high but that one clip (though hissy) sounds pretty cool.

[Paul Perry (Frostwave)]

I wonder why no one builds this one are these 2SC644's some issue to replace??....

According to this old book here, equiv is BC109 or BC549, easy enough!
Go for it, someone!

[Mark Hammer]

I have yet to see an octave down unit that does NOT rely on deriving a square-wave at half the input frequency, since the only simple inexpensive way to derive precisely half the frequency IS to divide by 2.  Depending on how that derived note is filtered before it hits the output it will sound more like a fuzz or less like one, but it sure as hell starts OUT life as a square wave.

Or are we talking about an octave-up unit here?

[BillyJ]

Yeah there probably is some fuzz there and I have no clue about the math but listen to that clip...sounds great to me.

Probably some fuzz in it. I don't know the math...just know I like the way it sounds and wondered if it hadn't been overlooked.


I think with it and some creative ploys I can get some reversed tape deck sounds from it....that's the plan anyway  

[Peter Snowberg]

Mark,

Take a look at the schematic if you have not already. The divider was kindly drawn all by itself.

It uses five of the same NPN.... #1 is in an LP filter, #2 & 3 are a darlington booster, and #4 & 5 make a descrete RS flip-flop. The output is them recombined with the dry signal, but with only one side of the divided wave (using a diode).

I've never seen anything like it.

-Peter

[Mark Hammer]

I've had the schematic for a couple of years now, but had never really looked that closely at it.

Assuming it is drawn and labelled correctly, that 6k8/0.1uf network rolls off the input to the octave generator section at around 234hz.  One of the things that would suggest is that the octave down is applied to some notes, but not all.

One of the other things suggested by the schematic is that there is no provision for any octave/normal balance.  There is an overall sensitivity/input-attenuation control and an overall (octave+normal) output level control, but nothing that lets you determine how much of the octave is in there.

The switching is a little confusing, though, I have to confess.

[Nasse]

http://www.freewebs.com/nassetronics/miscellaneous.htm

Just added a pic from my archives, it claims to be freq doubler, suitable for gtr. Nothing to do with Shin-Ei, i think.

[Ansil]

amazingly that is similar to what i am doing.  i  was playing with the CA tuner. and i  was using the chip that breaks down the octave as a basis of my ocatave pedal.  but squaring the wave as mark was talking about.  but before i do that i send it through a low pass filter  and taking off anything above 200hz... also i was expiramenting with putting a trimmer before the square waver so that it would take a more than just a little pick scratchin to get it going in to octave. also it would make it to where it would have a sort of gate on it as the note dies..

of course this is mostly all still in my head. but it is coming along..  also managed to get some garbled sound out of my ram delay.. no delay just some weird sounds.  and one blown  up chip.

[gez]

The Dano Chilli Dog is a really nice octave down pedal.  You can isolate the lower octave and use it for bass parts.  It does a pretty convincing job too and is nice and clean.  Sounds like a bass with dead strings and the highs rolled off, more of a sound for Drum & Bass /Reggae.

I took the back off it the other day and counted one dual op-amp, two quads, a couple of flip flops and a 4053 (presumably for switching).  Although I can't be 100% certain (its all SMDs so I'm not interested in doing a schematic - would take bloody years!), I'm pretty sure it's a Boss OC2 rip-off.

At less than £40 I don't think I could make one cheaper!  Casing is a little flimsy mind, it's probably made from the hides of the 10 year old kids who assemble them.

[Mark Hammer]

A little late to this particular party.

Finally finished wiring up a Shin-Ei Octave Box, using the Topopiccione layout (thanks Alessandro!).

Man, that's some serious bass.  Like all such circuits using a flip-flop, it is mono.  But play your cards right when you pick and it's a very pleasant clean bass tone.  Not a hint of harshness or fuzziness about it, thanks to the extensive filtering.  Works well down to about the 3rd or 4th fret, using light-gauge strings, which is a nice contrast to the shakiness and unpredictability of the Blue Box.

The switch allows you to include clean signal along with the octave-down, though it is simply on/off and not really blendable.  That could be easily modded to provide more clean if desired.

If you ever had a hankering to play the guitar+bass riff at the start of Pink Floyd's "Money" this is your ride.  Nails it.

[iainpunk]

I have yet to see an octave down unit that does NOT rely on deriving a square-wave at half the input frequency, since the only simple inexpensive way to derive precisely half the frequency IS to divide by 2.  Depending on how that derived note is filtered before it hits the output it will sound more like a fuzz or less like one, but it sure as hell starts OUT life as a square wave.

Or are we talking about an octave-up unit here?

it doesn't filter, that oct dwn square flips the polarity if the input signal, creating an octave down

cheers, Iain

[iainpunk]

[Mark Hammer]

Understood.  My 2003 comment was largely in reference to circuits like the Blue Box, which IS quite fuzzy, and intentionally so.