vox repeat percussion

[Doug_H]

Sounds good. Is the oscillator fairly quiet on this one? I breadboarded a sound-go-round and it sounded good except that the multivibrator was pretty noisy.

[stobiepole]

Considering how simple it is, it seems pretty much silent (I haven't boxed it yet either). There may be a volume drop - again, I haven't bothered with the switching yet. But it's definitely a keeper.

[RickL]

Alright! Mine works now too. A combination of the corrected schematic and the advice to twist the pins on Q1 did it (I used a metal can 2N2646). The orientation of Q2 doesn't seem to make a difference - it works with either the emitter or the collector to ground. And I used a polorized cap for C1 with the - to ground.

Perceived volume is a little lower than when bypassed. This makes sense if the LFO is just turning Q2 on and off. I wonder if a tweak of one of the resistors around Q3 would raise its gain a bit to make it sound a little louder?

Edit - yup, lowering R13 (or shorting it) or bypassing R13 with a cap (I tried 22 uF and 47 uF with about the same results) raises the percieved volume. The downside is that the ticking is much more noticable. I went with the simplest solution and shorted R13.

[Antero]

Where's the corrected schematic/layout?  Sounds badass! 

[Doug_H]

Where did you guys get your UJT's at?

[stobiepole]

All right...I got the schematic from the EH Man. He has fixed the mistakes in the original Vox schematic. If you email him and ask him nicely he should send it to you (an offer he made earlier in this thread). You'd have to ask him if it's okay to post the revised version on te forum...

I got my 2n2646 from Jaycar (in Australia). They were reasonably expensive - about four bucks - and came in a metal tin, with an E-B-B pinout (so the E had to be bent to go in the middle).

Chris

[Doug_H]

Any chance you could fwd the schem to me (email link in my icon)? Ron doesn't seem to be around right now.

Thanks,

Doug

[rove]

I had one of the repeater plug ins for about a week ten or fifteen years ago, it turned out to be busted so I returned it, not knowing how i could fix it at the time.. I was familiar with the sound from Spaceman 3 who used the vox guitar with built in repeater to great effect.
I would be very interested in a layout/schematic when it turns up! 

[reverberation66]

Futurlec has those 2n2646's for $1.60 apiece.  this definitely looks like one to build, spacemen are go!

[Doug_H]

Thanks Darryl & Chris for the schem. Darryl I tried to reply but your email puked.

Doug

[somasix]

I just wanted to check in and see how everyone is doing with this.  Ron was awesome enough to forward me his corrected schematic.  Thanks Ron.  In August, I tried to find the plug-in Repeater supposedly buried in my Mom's garage somewhere, but to no avail.  I'm excited to get into this, but it's going to take a while.

I have to finish up the Paia Theremin, and debug the 4ms Phaseur Fleur (anyone ever build one of these?), before I can start on a new project.  Meanwhile, this thread has kept the dream alive, and gave me another reason to order parts from Futurlec (thanks to Reverberation66 for the tip on transistors).  So, I thought I'd post and keep this thread going.

[Doug_H]

I got some 2n2646's from Ebay but haven't breadboarded it yet.

[doug deeper]

can one of you guys send me the corrected schematic for this?
midfielectronics at hotmail dot com

[rove]

Hi, trying to breadboard this and getting a bit of a headache (first breadboard attempt ever).  Has anyone come up with a layout they could post?
thanks.

[R.G.]

I did a quicky trial layout. It can be done in 1.2 x 1.6" with all components laying down. Standing resistors on end would get it smaller, of course.

Probably the way to mount it is with velcro to a battery.

[puretube]

http://www.ronsound.com/pedals/tremo.html
http://www.voxamps.co.uk/support/circuits.asp
http://www.pat2pdf.org/patents/pat3497605.pdf

[theehman]

Hello everyone!  I offered a copy of the corrected Repeat Percussion schematic in this thread a while back but it's been recently brought to my attention that the 2N2646 has been oriented incorrectly.  Apparently the datasheet I used has a non-standard pinout shown for the 2N2646.  As a result I've once again updated my schematic and have posted it for downloading here: http://www.ronsound.com/misc/VoxRptPerc.pdf

I apologize for any inconvenience and urge everyone to discard their older copy and replace it with this new, corrected version.

[doug deeper]

ahem.
http://www.smallbearelec.com/Detail.bok?no=550

there are in the diode section.

[theehman]

Hello everyone!  I offered a copy of the corrected Repeat Percussion schematic in this thread a while back but it's been recently brought to my attention that the 2N2646 has been oriented incorrectly.  Apparently the datasheet I used has a non-standard pinout shown for the 2N2646.  As a result I've once again updated my schematic and have posted it for downloading here: http://www.ronsound.com/misc/VoxRptPerc.pdf

I apologize for any inconvenience and urge everyone to discard their older copy and replace it with this new, corrected version.

Screwed it up again, but it's all good now.  Please use the above link to download.

[rove]

Hey, has anyone worked up a vero layout for the repeat percussion yet?
thanks!