pitch to CV

Michael Glaviano · Post by **Michael Glaviano** » Fri Apr 08, 2005 10:45 am

When I did my first post asking for help in getting started with this line of gear, one of the responders mentioned that using a pitch to control voltage converter on my guitar could offer still more interesting effects.

My question: does anyone still make a pitch-to-CV box for a guitar? I have tried several google searches but found no contemporary gear and only a small amount of (really) old stuff.

Since tracking speed & accuracy might not be such an issue as in a pitch-to-midi situation, I thought maybe I could make a pitch-to-CV box using a tuner and a simple transistor-based amplifier circuit. What do you think about that?

Thanks!

MC · Post by MC » Fri Apr 08, 2005 11:35 am

There are no new pitch->CV converters made today. Vintage gear is the only resource, and not much out there.

The tuner approach would pose one problem: latency.

Pitch->CV is a hard conversion to nail with all the nuances in guitar playing technique. The converter that got closest was the Roland 300, but that does not output a CV.

Impossible Sound · Post by **Impossible Sound** » Fri Apr 08, 2005 4:06 pm

Doepfer makes a pitch-to-CV module as part of their system, so it's not a stand -alone box. For older units, there's the Gentle Eletric GE-101 and the Korg MS-03. The Korg MS-20 synth also has pitch-to-CV ability.

I own a MS-03, and have used it with guitar in the past. First of all, it's monophonic, i.e., one note at a time. Also, a careful playing technique is required to get good tracking. I personally found that the envelope follower and trigger outs were more useful in conjunction with other CV gear than the pitch output.

sir_dss · Post by **sir_dss** » Fri Apr 08, 2005 7:39 pm

Also the Korg X-911 but remember Korg stuff is 1vt/Hertz.

peter ripa · Post by **peter ripa** » Sat Apr 09, 2005 6:59 am

i have the ms20 and the x911 and they work fine as long as you play one note, if you play a chord you get nice flabbering

Impossible Sound · Post by **Impossible Sound** » Mon Apr 11, 2005 8:40 am

The Korg MS-03 is both Hz/V and V/Oct.

swaglamp · Post by **swaglamp** » Thu May 19, 2005 7:31 pm

EMS made a P2V in the early seventies that Eno was known to use. They are very rare - perhaps less than a hundred manufactured. There was recently one for sale at Sonbird Music in Toronto , but I'm not sure if it's still available - they have a website that you can check out. I own one myself and have been seriously considering selling it along with a VCS3.

pelican1 · Post by **pelican1** » Mon May 30, 2005 12:36 pm

I too have an ems pvc. It's very good. When I first got it I thought it would be a simple device, but after reading the expanded manual and lots of experimentation- there is really a lot you can do with it. I don't know if the EMS pvc is the best available, but it has the most features of all the pvc models. As for the rarity -it is rare, but I would think more than a hundred. Mine is one of the later ones as it was made in 1977. Current prices are around $500-$1000 depending on condition. They pop up on ebay every once in a while.

swaglamp · Post by **swaglamp** » Mon May 30, 2005 11:03 pm

The gear geek in me is curious what the actual production numbers are, but I'm really more interested to hear how you use the device.

pelican1 · Post by **pelican1** » Tue May 31, 2005 7:43 am

I mainly use it to track my guitar into my modular sometimes samples....from the manual convert note times, logarithmic or exponential envelope follower, normal envelopes, any thing output on ch.2 is invertible, channel 2 sample +hold, manual trigger, anyways does more than pitch to voltage.

willi · Post by **willi** » Tue Mar 27, 2007 3:47 pm

Impossible Sound wrote:Doepfer makes a pitch-to-CV module as part of their system, so it's not a stand -alone box.

Which module are you referring to? Thanks!

nicholas d. kent · Post by **nicholas d. kent** » Wed Mar 28, 2007 2:58 pm

willi wrote:
Impossible Sound wrote:Doepfer makes a pitch-to-CV module as part of their system, so it's not a stand -alone box.
Which module are you referring to? Thanks!

Actually I believe Dopefer has had one on the future modules que for a while but it's not released. Analogue Systems has one as a eurorack sized module, the RS-30. Also there's one built into the Korg MS-20, but they're no longer inexpensive used and use the Hz/V "standard".

I think the "secret" is, unfortunately they aren't very accurate in a lot of circumstances. You can sometimes have good results, especially within in a reasonable range of pitches with some kinds of input, but some material will come out messed up.

The modular builders might be afraid of many people returning them because they "don't work" or getting bad reviews.

I am kind of surprised that with so many builders out there there are soo few. It probably has to do with everyone being inspired by (or more or less copying) Moog and his not including one in his system. Then there might not be many "ready to use" existing schematics. Most modules aren't designed from scratch, they are adaptations based to different degrees on published magazine articles or service schematics of commercial designs.

You'd think someone would be cloning the EMS or the Gentle Electric (which was included in some Serge Systems under license besides as a stand alone unit). Perhaps there are still patents on them or they need too much work because of their age and/or scarce parts that aren't easily swapped.

I believe the issues are at the beginning of many instruments there is a bit of a chaotic pitch in the attack and then then a sound rich in overtones may track an overtone or even jump. And of course all these units are monophonic.

willi · Post by **willi** » Wed Mar 28, 2007 3:03 pm

Yeah, I realize they aren't known for their accuracy. However I don't want to use it for precise musical output. My interest is in using it to control CV modulations; e.g. getting cutoff frequency of my MF101 LPF to automagically track an external analog source. In this application I think the tracking might be acceptable (assuming the filter isn't completely self oscillating at the time). I suspect using a lag processor for the resulting CV would also help smooth things out.

It is a little confusing as to whether the RS20 is v/Hz or v/Oct, though... seems to say different things on different pages.

nicholas d. kent · Post by **nicholas d. kent** » Wed Mar 28, 2007 3:21 pm

Well a lag processor is the heart of envelope following (= amplitude to CV).

I belive pitch to voltage conversion requires counting the times a signal passes through zero and generating a control voltage once the frequency is determined.

Now there is definitely a place for filtering, which lag processing is arguably a simple form of, as i think you are figuring out yourself, you want to filter the extra high or low material out of your source prior to pitch to voltage conversion because it narrows out the chance of stray high and low content being suddenly tracked. Note that the MS-20 has a high and low cutoff to do just that

bunnyman · Post by **bunnyman** » Wed Mar 28, 2007 11:30 pm

[quote="willi"]It is a little confusing as to whether the RS20 is v/Hz or v/Oct, though... seems to say different things on different pages.[/quote]

I assume you mean the MS-20, which is, indeed, v/Hz. The confusion comes frm the fact that if you plug a CV into the total control input instead of the pitch input, you need a v/Oct. But the P/V converter is definitely v/Hz. I bought my MS-20 brand new back in 1980. I went to the store hoping to buy an Arp Axxe, but the salesman must have got a better commision on the Korg. Best decision I ever made

Still gets loads of use 27 years later!

-andrew bunny