Elkavox Tone generator

[jdam01]

Does anyone have experience repairing an elkavox tone generator. Im planning on buying one that has the midi module installed. It works and Im just worried about what will happen when it breaks in the future. Simple capacitor replacements are easy however past that I would have to learn. Does anyone know how long these devices would last?

Also, can I bypass the pedal since It is a potentiometer i assume?

Thanks

 

[JerryPH]

The pedal on the Elka tone generator is mostly for controlling the volume. I never used mine a lot, but when I did use it, it was needed. I also used it for the right-side switch 1/2 tone note drop in various songs. I did have it modified so that the left side switch triggered the arranger drum fill and the start/stop button started and stopped my (Ketron-made) Solton Programmer 24 arranger instead of the factory original Wilgamat drum machine (both of which I still have sitting in my basement at this time).

As far as repairing it, any good electronics shop should be able to figure out the analog electronics. Your bigger challenge will be to find the parts needed to get it going, if its not functional at this time.

Seriously, unless you own an Elka 83 (or similar) and want to toss out some cash, I would avoid investing in this direction... and this coming from an Elkavox 83 owner.

 

[Ben-jammin]

Just my 2 cents. This is a technology that’s getting to the point where even though a competent electronics technician can figure it out they may or may not consider it worth their while when to cost it competitive they have a lower profit margin than the other business competing for their attention.

From a players standpoint modern midi systems are a better proposition. Less proprietary components to potentially fail and in the twilight of their serviceable life.

 

[jdam01]

Just my 2 cents. This is a technology that’s getting to the point where even though a competent electronics technician can figure it out they may or may not consider it worth their while when to cost it competitive they have a lower profit margin than the other business competing for their attention.

From a players standpoint modern midi systems are a better proposition. Less proprietary components to potentially fail and in the twilight of their serviceable life.

I accidentally shorted it out and diagnosed the circuit fault to a blown fuse. It's definitely a fun learning experience using this old technology. I agree though modern is better and more reliable

 

[Ben-jammin]

As a hobbyists project it’s probably great, and also fine for in home use for fun. To me though it’s at that point where replacing the tone generator may be cheaper than getting one repaired and then your still stuck with a system that is full of 40 year old electronics that are potentially on the verge of failure.

 

[jdam01]

I got in contact with someone willing to install musictech midi. It costs about 4k cad. That's something I'd consider later on once the tone generator hits it's last leg

 

[Ben-jammin]

fair play. Hopefully that is using Hall effect sensors at that price.

 

[jdam01]

fair play. Hopefully that is using Hall effect sensors at that price.

Hall effect! Touch sensitive you mean ?

 

[Ben-jammin]

Hall effect is a “non contact” method of switching that uses magnetism. The elka 83 will use spring contacts which are a contact dependent switch mechanism which require more maintenance and is prone to performance issues. At 4K I would assume that entails changing the switching method to the superior technology.

There may be schemes to use multiple Hall effects to detect key velocity but I believe most accordion installations for midi just use a single Hall effect sensor for each note for “binary” on off. I believe musictech does offer midi systems to register the bellows for amplitude but I’ve never investigate how they register (I would guess differential pressure at the bellows) and I have no experience with it.

 

[jdam01]

Hall effect is a “non contact” method of switching that uses magnetism. The elka 83 will use spring contacts which are a contact dependent switch mechanism which require more maintenance and is prone to performance issues. At 4K I would assume that entails changing the switching method to the superior technology,

Thanks for letting me know. I will have to ask once I consider going that route

 

[Ventura]

one issue is the younger gen measures old electronics based on what they know,
which is modern digital small and works mostly by some kind of magic

they eBay an old analog Sano or something and say "perfect condition"
but we don't have any way to test the electronics inside but they probably work
perfect because the thing is in pristine condition

except there is nothing to work inside except switches, and sometimes
those shiny perfect looking things don't even have reeds
(the bellows were like a volume control) or one of the other
umpteen weird and short lived more or less organ accordions
that were rushed to market

even in the 1970's you could really only get good service by bringing
your unit back to Chicago or New Jersey or Philly because while a local
TV/Radio tech could troubleshoot a circuit and get it basically working
again, they had usually zero understanding or how it was SUPPOSED to work,
and so local repairs were usually frustrating.. probably why the one Jerry
remembers had no ballz..

i played a thousand typical school auditoriums and huge under
the church community rooms for Rock n Roll Dance's or weddings
and those twin speakers and push pull tubes filled them all.. my
Guitarist had a huge MAGNATONE amp and we were neck and neck
(Brad had a nice set of Slingerlands and great Zildjians cuz his dad was
a pro drummer when he wasn't doing the day job dentist thing)
so we packed pretty good thunder and lightning in 1969

personally i studied and learned how to fix my own Cordovox's because
no-one could get my WaWah circuit to work RIGHT, which frustrated them
no end because they couldn't understand my benchmark

so i did it myself

diode switching formant filters top octave generators push pull 6v6 power amp's
oscillator controlled voltage controlled vibrato circuits keyswitching silvered springs
all that good stuff.. solenoid sustain circuits neon limiters then Mosfet power amps..
then we hacked mods into the circuits to control the decay or tone of chords and bass..
fun stuff like that

lets not forget SPRING REVERBS

then how about motors and footswitches crossover and bypass filters to
feed the leslie, tweaked to perfection for the natural frequency range
of the speaker..

oh and the speaker means the thing inside the cabinet.. that funny round
or oval grey cardboard sort of thing in a metal frame

nope, critical and unique replacement components are simply not available,
eeproms and programmers and even the programming are non existant,
so unless the "problem" is some simple basic power supply issue
or common component breakdown, you are S.O.L. for a repair

and if you DO find one intact, don't just power it up.. turn it on then off a few
minutes later.. then again a little longer.. do this a few times leaving it on
longer each time.. you are trying to wake up the big Capacitors to get to
saturation without blowing their minds from the deep sleep

 

[JerryPH]

To me though it’s at that point where replacing the tone generator may be cheaper than getting one repaired and then your still stuck with a system that is full of 40 year old electronics that are potentially on the verge of failure.

Good luck in finding a second generator in any better condition than the one that needs work... they *all* need work at this point.

 

[SteveBox]

There may be schemes to use multiple Hall effects to detect key velocity but I believe most accordion installations for midi just use a single Hall effect sensor for each note for “binary” on off.

I have a Limex MIDI system, and it can measure key velocity with only one hall effect sensor per key. Limex uses analog hall effect sensors, which output a voltage proportional to the strength of the magnetic field. So a voltage measurement gives an indication of how close the magnet is to the sensor. My educated guess is that the Limex computer is measuring the voltage of each sensor on each scan. By comparing the voltage readings of two consecutive scans, it can calculate if a key is moving and how fast.

 

[Ventura]

cool, had not known of graduated strength hall sensor being used this way

sounds like a cool trick of programming they pulled off !

thinking it through, it seems the placement of magnets
and relative strength of those magnets needs to be quite precise
note to note, as there must be a threshold point of "strength"
as the reading ramps up that actually triggers the note on message..
so they are basically noting the fluctuation as soon as it begins
and relatively compute an appropriate value/values up to the trigger,
and since this is a variable, for the keyboard to be "level" in feeling,
the physical precision must be there right off the bat

this should be more sensitive than the dual trace top-hat or dual switch system,
as there is only the (time factor) between first and second contact for those,
and the note cannot voice "on" until second contact is reached. This
is what annoys me about most keyboards, that even if you switch to
a sound, like organ, that needs no velocity, it still does not "trigger"
until the second contact in the vast majority of designs

i would also think that with the increased data of a graduated fluctuation
from the magnetic field, they can also lower the physical point for the
threshold trigger.. in other words, you have to push down a key quite a way
to trigger a note in a dual contact system, and this varies somewhat from
brand to brand and keyboard design, and sometimes that "depth" of
touch needed is a bit unnatural compared to the acoustic instrument, while on
the Limex system, the computing power of the CPU and it's potential
speed and accuracy for interpreting the fluctuation data is the factor
that sets the physical key depth "spot"

this would represent a true advancement, and i would like to
have a look at this on my workbench.
guess i need to contact LIMEX and learn more

i wonder at which point in time CPU power allowed them to
convert to this system

 

[Ben-jammin]

I would be interested to see how they have it configured. Are they using two analog thresholds and monitoring the time delta between them or are they using a fixed time after an initial analog threshold is met to measure the difference in analog value. I would guess the voltage/distance relationship is not linear with these devices so using the latter option would likely require some additional math to generate a linear velocity value from the two analog values.

 

[SteveBox]

You go through a calibration process when you set up a Limex system, and anytime you think the calibration might be off. The computer records the at rest voltage and fully depressed voltage of each key sensor individually. So there is no requirement that they all be precisely the same. There are user settings where you can set the desired key switching on threshold and hysteresis.

Although it is a clever design, in practice, I find that the key velocity is hard to control with one's playing, because of the light touch of an accordion keyboard.