Kyles Keppinger

Kyle hasn't posted this link. He's finished his power supply chassis....

http://www.youtube.com/watch?v=auzvXnjG8-8

Philip Neidlinger

Always nice to see tube stuff brought up and running!

There's something sort of "organic" about it ... maybe because of the glow of filaments and being able to see the active elements thru the glass.

Transistors are just not all that exciting ... no wonder we hide them away in little plastic packages inside metal boxes! Well not exciting until they decide to burst into flames to protect those "valuable" fuses in their supply lines. :)

Don

[i]"There's something sort of "organic" about it ... maybe because of the glow of filaments and being able to see the active elements thru the glass."[/i]

Don, do you remember, a long long time ago.. Transistors were constructed in clear plastic mini 'test tubes' which were then painted black - one could scrape the paint off and see the innards through the clear goop that filled the tube.. they were photo-sensitive in this state - and were truly exciting! .. I still have some OC series transistors modified in this way (not sure what they are - Scraping the paint off also scraped off the identifier! LOL! - but they are a little like mini 'tubes'.

Back in those days I had a load of tubes which were housed in metal containments - one could not see inside these, and they were boring! One could also buy surplus 'computer' transistors in metal cans - these were fun.. applying a pulse of the right energy caused them to explode and shoot their caps off violently - As a 12 year old I had great fun designing and building electronic 'cap' guns based on these (god only knows what toxins I was blasting at "the enemy").

Seeing a VT construction like this does bring back some sweet memories.. But, apart from sentimentality, it seems a bit pointless to me to design and build new equipment from the old and expensive parts - ALMOST everything that can be done with VT circuitry can be bone better, cheaper, and more environmentally friendly using modern components - Perhaps there is room for a VT in a pre-amp stage, and there certainly is reason to restore vintage VT equipment.. but, for me, thats it.

I would not want to go back to those old days..

I'd be more interested in Mark's new design... but it seems that the recent discussions didn't encourage him...

Well,

Kyle is a young lad of considerable talent. I wish I had his gifts when I was his age. He got I think the last chassis set Mark had.

As to the solid state project, it is still prototyping. He got a LOT of comments, and not just from here.

Remember that Mark like the rest of us, has a full time job as well designing exhibits for a large science museum.

I may be getting the first boards for review soon.

We'll keep all of you posted.

Philip Neidlinger

[b]"I'd be more interested in Mark's new design"..[/b]

We have seen the schematics for this 'new' design - which Mark is the first to state is not 'new' at all - bits have been copied from Moog designs. Mark's 'new' design is entirely based on a voltage generating front end - it is two capacitance to voltage converters, one for pitch, one for volume - all following circuitry is voltage controlled analogue synth circuitry.. no heterodyning occurs at any stage in the process.

I do not know how Mark has overcome the inherent problems with the kind of front end in the schematics.. I was not able to get stable output when I tried an almost identical topology (months before the new MK design was published).. I concluded that having a fixed frequency and deriving the capacitance sensing from amplitude / phase modulations could not be done without massive integration which caused audible delays... Mark says he has solved this (or doesnt have this problem).. So I am excited to see what he has done..

But, as I have declared many times.. Theremins are not like other systems where one can predict how close one is to completing / marketing a product... The tiniest, most 'irrelevant' bug can (and usually does) require a complete redesign to solve..

I have learned this lesson the hard way - and try to share what I have learned so that others can avoid the frustrating mistakes I made.. I will also now never say that any Theremin I am working on is "nearly there" - One can only say this if you are copying or modifying an existing, established design... Those of us who embark on Actually designing something NEW are going to be dissapointed when 90% of what we believed would work actually has some tiny bug we never foresaw which sinks the concept.

It is easy for those who do not understand the difficulties to take a mocking tone.. [i]"Ah, but you had your Theremin 'nearly ready' a year ago"..[/i] I was once of the opinion that I could easily redesign the Theremin, and that the state of the 'art' demonstrated gross incompetence by those engaged in Theremin design.. I was utterly foolish and arrogant in this view - Those who stick with the objective of building new / better Theremins do so out of love for the possibilities of this instrument - there is no other justification - there are FAR easier ways to make a living! (those who do not fall in love with the instrument will drop the project, or copy some standard design) Whatever Mark brings to market, it will not make him rich - He is doing it out of love for Theremins and electronics and exploration -

If I present a technical idea, and it is shown to be flawed, then the person/s exposing my error have done me a great favour, and saved me a lot of effort .. Yes, its painful.. but the pain is worth it. This is different to personal snipes and jibes one gets from a few people - These are (or can be) the truly discouraging inputs which make life harder, until one recognises that the source/s of such jibes is the one who is ignorant.

[b]"but it seems that the recent discussions didn't encourage him"[/b]

There was only one person on TW who really 'slammed' the new MK design, and that was me! here (http://www.thereminworld.com/forum.asp?cmd=p&T=3691&F=3&p=2) I regreted having been so brutal - but did everything I could to minimise any damage I might have done.. All my critisism was entirely technical and impersonal. I had been starting a collaboration with Mark on the design of a Theremin, and the announcement of this new Theremin came as a shock as I had no knowledge of this - Something of a misunderstanding / communication failure had occurred.. I contacted Mark and appologised for having made my comments without consulting him first - I appologised here and on Levnet for this, and I deleted my postings where I made derogatory comments about the design.

Technically, I still think I was / am right - but I hope I will be proved wrong!

Sir

I can simply say only that Mark will be ready when he is ready. The rest of us will have to be willing to wait and be patient. Given the excellence of his tube design (I play Gabriella joyfully whenever I can), I am confident he won't release anything until it is ready for the world at large.

Have a good weekend!

Philip

[i]"I can simply say only that Mark will be ready when he is ready. The rest of us will have to be willing to wait and be patient. Given the excellence of his tube design (I play Gabriella joyfully whenever I can), I am confident he won't release anything until it is ready for the world at large."[/i]

I absolutely agree with these sentiments, Philip - or, as some would say, [b]Amen to that![/b]

Good weekend to you too!

Just ran across this again in Fred's comments:

Don, do you remember, a long long time ago.. Transistors were constructed in clear plastic mini 'test tubes' which were then painted black - one could scrape the paint off and see the innards through the clear goop that filled the tube.. they were photo-sensitive in this state - and were truly exciting! .. I still have some OC series transistors modified in this way (not sure what they are - Scraping the paint off also scraped off the identifier! LOL! - but they are a little like mini 'tubes'.

Maybe that was just something in the UK? The oldest things I ever saw were the old CK722 (http://www.ck722museum.com) germanium transistors. Those had a very thin aluminum can and inside the die was supported vertically with bond wires going to the pins ... similar to the way vacuum tubes are constructed. They didn't have anything else to model the assy from, so no surprise there.

Don

Kyle has completed the electronics of his new, home-built Keppinger tube theremin and she is now able to sing in full voice. She sounds great!

I hope he doesn't mind if I share this.

Kyle's Theremin (http://www.youtube.com/watch?v=EvYTbohTXe4&fmt=18)