This may come in handy if you don't have the appropriate Audio/Log pot at hand (because of an odd form factor or dual pot configurations), or if you wish to tailor the log curve.
Usually the three lugs or terminals are numbered: 1. input 2. Wiper 3. Ground
The usual solution is to add a resistor between the pot wiper & ground. If you can pick the right size, the result will be close
to a logarithmic response. This is usually OK for most audio
applications. You don't have to stop there. Fixed resistors can be added
to both ends. .... ie between the input & wiper, and ground &
wiper. The results can be wonderful ... or crazy. It's all about taper.
Usually a resistor value of 10% to 20% of the pot resistance gives a good approximation of an audio-taper pot. Smaller values will give less change in volume at the lower portion of pot rotation, higher values will give more change.
Some pics of the LA67 102.... Dual Stereo Locator
It's not a Buchla Module.
It follows the same size, format & the circuits used are I understand based on Don's schematics.
I hope one day, Buchla will release an official 102.
I've only seen one real Buchla 102 in the flesh. These are as rare as hen's teeth.
The LA67 version is a pretty easy build, though trying to match the JFETS is tricky.
(I'm still trying to get it perfect at the time of writing).
I'm not affiliated with the manufacturer in any way. I'm building this to learn how it works
and these notes are just my personal doodles to help trouble shoot any issues I may encounter during the build.
Metro Modular also make a module inspired by the 102 which is worth exploring if this module interests you. (I would also love to see a Buchla USA version).
Anyway, back to the LA67 module.
The virgin PCBs, etc.
This module has a 0v & +15 power supply. The original used an additional +24V rail.
The original op-amp was most likely a LM301 (which has a +V rating of +18V)
This module's BOM calls for a TL071.
The BOM calls for J201's
Mouser No 106-J201
My sources tell me that the original used 2N4339 JFETs
Prosound & Lighting are holding a synthesizer event in 2 days in Wollongong
(Sat the 7th December). Starts at 2pm.
Bring a synth if you'd like to perform. It.s an open event. Doesn't have to be modular.
There will be live performances on all types of synthesizers (modular, non-modular, keyboards, drum machines, etc).
Prosound held a similar event in 2017 which was very successful.
This is a family event and will be held in the carpark of the Pro-sound showroom in Flinders Street Wollongong.
Kyle & Robert were interviewing Suzanne Ciani and the question came up about how electronic instruments interact with live traditional orchestras. She mentioned a classical piece by the Polish composer Krzysztof Penderecki and (if my interpertation is correct) ...how his methods could be used to score electronic music.
It's titled: "Threnody to the Victims of Hiroshima"
The piece is 8 and a half minutes long (it was originally titled 8'37") and belongs to what was in the 1960s a new approach to music composition. The name "Sonorism" was coined. This non traditional type of composition focuses very much on timbre, texture, motion, articulation & dynamics. We all know how these characteristics are fundamental to electronic musicians. The piece uses 52 string instruments (mostly violins) but I can easily see how these could be swapped.
"Sonorism emphasizes discovering new types of sounds from traditional
instruments, as well as the creation of textures by combining different,
often unconventional instrumental sounds in unusual and unique ways.
The term sonoristics is used to describe this novel approach,
which went beyond merely injecting individual color, quirks, and
experimentation. It aimed to establish new structural functions in a
composition, such as employing non-functional chords for sonorous
effects, and emphasizing the sonic aspect of texts in vocal music" (Granat 2008).
Suzanne's interperation was facinating.
"Don B was adamant about the danger of associating a keyboard with the Buchla instrument as it short circuited the whole concept of the instrument". (Suzanne Ciani)
Listen to this piece by Suzanne {Seven waves). She is a classically trained pianist, and this is one of her solutions to (in her own words) "fuse her classical melodic roots with her electronic vocabulary.........
This was a composition with a score".
Getting back to Penderecki.
"It has an electronic sensibility but it is done with acoustic instruments. (but) the language is electronic.
...... The score is graphic..... and the conductor is the key to getting it all to gel." (Suzanne C)
So what did Suzanne mean by "a graphic score"?
The problem with sonorist music is that it's difficult to score using traditional notation.
How do you write a score recording changes in timbre? So Penderecki constructed a road map of sound.
Here there are no conventional bar lines or time signatures. Rather, the music is divided into intervals of real time (seconds). Notes are often assigned to individual players. Players, are often assigned to groups to create "sound clusters".
AS far as I know, this is all family owned. The Mori company was founded by Taikichiro Mori, (an economics professor). He became the richest man in the world in 1992 with net worth of 13 billion. (at the time Bill Gates was worth 3 billion). Anyway, the main reason I visited was the art gallery. This was sadly closed. However, the views from the 52nd floor are magnificent, and well worth the 20AUD ticket.
bELOW is the National Art Center
cOUldn't resist. A fitting final last Japanese meal
Some pics of a Roman 284r.
It's compatable with Buchla modules.
I initially had problems triggering some of the envelopes, but all seems to be working now.
I'm not affiliated with anyone and I'm not a professional synth technician. This is my hobby and I hope these pics will help others trouble shoot their builds.
Good Luck.
Some pics from the build process
Some closeups
wHEN calibrating, adjust the trimpots carefully.
Initially, envelopes 2 & 4 didn't trigger.
After adjusting some of the trimpots, I managed to get them to fire.
This is how you self trigger.
Plug the pulse out into pulse input, then flick the sustain switch.
It's useful, if you don't have an external trigger, like a sequencer, or a 281, a 248, etc