Anyone buil a Dean Hazelwanter Pitch Shifter?

[anyuser00]

There is a mp3 clip on runoffgroove, but the settings aren't given and it sounds like it has the robot setting on.

Is that how they're supposed to sound?  Also in another thread someone mentioned they only go up to about a 5th up or down.

Anyone built a MXR Pitch Shifter?

[RickL]

If it's the one that uses momentary switches to select either pitch shift or robot and to scroll through the pitch shift intervals I've built it. It's probably more suited to voice than guitar but it works.

IIRC one of the selector switches toggles between robot and pitch shift and the other always goes to robot. I left the second switch out on my build because it seemed redundant. I used the published layout (one of 'em, I think their are two available now?) and it worked perfectly from the start. It's a little confusing to use because the toggles have to be in exactly the right position for the scroll switches to work but once you get that figured out it's usable.

[Aharon]

I built it and took it appart after.In my opinion it could use some sort of compander circuit or something to improve the performance but I'm talking out of ignorance.
Those pitch shifting chips lack the sound quality,distort easy etc.and at $15 makes me wish I bought something else but somebody will add the missing link and could become a good effect.One thing I played with that had promise was to play with the one of the knobs that controlled the up and down or interval of the effect and I guess in a rocker pedal it could've been a poor man's Whammy sort of thing,but it lacked volume and balls,maybe a resistor tweak to make it more than unity gain or a NE571 circuit in there,I don't know.
Aharon

[jsleep]

I've built it and I like it.  It's a little crude, but it's got some good stuff going on.  I like the runoff groove clip, it's a good sound IMO.  The Ocillation control is unique and cool, good app for an expression pedal.

Don't expect Boss PS-5 type sounds from this thing, it's fairly crude and lo-fi, I mean Radio Shack use to sell the this IC so that should give you some indication ;-)

I'm not sure what companding, etc would do to help it, mine doesn't seem noisey or unruley.

It's not exactly crystal clear on the data sheet, but on page 5 you can see that it does harmonies in 3rds up, 6ths up, and octave up (I think),  and I don't know what to make of the downs probably the same.  Least that's how I read it.

JD

[Aharon]

That's true,it's not an overly noisy or unruly pedal,it's low-fi tho'.
Aharon

[Dean Hazelwanter]

I agree that it's decidedly lo-fi and it would *definitely* benefit from using a compander like the 570 (as would the DH Echo). From the schematic, you'll see that the Holtec chip is necessarily being run from a 3.6v supply, which means by itself it will have very little clean headroom. This is the distortion Aharon refers to. The signal should be compressed going into the HT8950, and expanded after.

Regarding the switches and intervals, I did the layout to support both relative mode ('tone-go-up'/tone-go-down')  and absolute mode (explicitly go to *this* interval). Either/both could be used, but the most sensible operation to me was absolute mode. Instead of guessing what interval it would be set to, and stepping through all the possibilities to get where you wanted to be, explicitly set the interval you wanted with a rotary switch and you know where you are. Others might prefer the relative mode and change intervals on the fly, even when playing. So yes, using both sets of switches is redundant, but I left both sets in for flexibility. Seems to me that there were notes on this before...

[Aharon]

Dean Rules!!!!!!!!!!,one of the BIG contributors to tthe DIY community.
Aharon

[Dean Hazelwanter]

Yeah, sometimes I have to pinch myself!  :lol:

[Dan N]

Those chips are only $5.00 from Smallbear now.

[Aharon]

I paid $15 for mine about a year ago or more.Time to redesign the sucker then and start building shifters.
Aharon

[ryanscissorhands]

Yeah, sometimes I have to pinch myself!  :lol:

Hey, you used that line two days ago!
(Quoting an email)

"Yeah, sometimes I have to pinch myself!  ;^)"

Anyway, if anyone who has built this and can send me a sound clip too, I'd appreciate it!

ryanscissorhands@hotmail.com

[Dan N]

Ryan, there's a sample here:
http://www.runoffgroove.com/salvo.html
and a very weird one here:
http://www.moosapotamus.com/othercoolstuff.htm

[ryanscissorhands]

Ryan, there's a sample here:
http://www.runoffgroove.com/salvo.html

Is that with the robot voice on?

[moosapotamus]

It's been a while since I built it. I recall there being some differences between Dean's scheme and the ones in the HT8950 datasheet. So, I spent some time tinkering around with it. Very cool lo-fi effect. Lots of opportunities for mods and other things (like envelope control of the frequency) to get a lot more weirdness out of it than it was probably originally intended for, like that bazzar-o droning electrositarsynth-like clip I did. In fact, the true potential of the HT8950 may still be waiting to be tapped.

~ Charlie

[smallbearelec]

I bought my initial stock of the HT8950 and 8955A from the thieves at U.S. Bid, and my prices at the time reflected what I had to spend. I have since subscribed to one of the on-line "bourses" that is maintained by a consortium of brokers, and I also now have a decent Rolodex of suppliers in the Far East who will fish for me if they don't have what I want.

The 8950 is reasonable now because I found inexpensive stock and invested. I am now sold out of the first lot of 8955A, but I expect to be able to re-stock at favorable prices soon. Can you say "H-Echo"? Will post.

Regards
SD