Vulcan-74 - A 6502 Powered Retro MegaProject

[Oneironaut]

Thanks, that OTP might be an option since you have verifies it works at 14 MHz.
I am only allowed to use DIP parts, and I see they are available...

https://www.digikey.ca/en/products/deta ... PU/1118860

I will have to ensure that my OS is decent at 14Mhz, but so far things are looking ok.
With my new design, I am not displaying much during a recording operation, so I have zero latency so far.
Having the second 6502 doing the bare metal sample playback functions makes all the difference.

So far the most cycle intensive routine is my full screen text scrolling function and the drawing of 640x224 bitmaps of waveforms.
That's ok though as these operations are not happening during live playback or recording.

I am 55 and still far from saying "heh? speak into my good ear"!
I can hear 16Khz, and often find others in my ancient group have things up too loud.
Of course, I am still young enough to just want to blast out the windows when I jam, so this latest upgrade is most excellent.

I did up some samples that are similar to Roland JX8 on Final Countdown last night and the sound is so much better with these speakers.
Having way more power than necessary means that on a moderate level they are ultra crisp.
But that bass... wow, I would totally recommend the DM-112 to anyone for a full range of use.

Now I am just pondering one final possible mod... going to greyscale on the display instead of mono.
Right now, the syncgen hurls out pixels via shift register from the sram. Simple, easy, low ram needed.
But it is actually less hardware to push all 8 bits into an R2R DAC and have up to 256 shades on the mono CRT.
Drawing will take longer, but this is not a timing critical operation.

The benefit is that an OS can look so much more refined with shades.
I am also implementing wave creation tools, so drawing waveforms will look more detailed as well.
To the CRT, it's all the same simple composite signal, so the hardware is all good.

The only downside is that I have to rewire the entire video circuit again!
I will think about it all day at work when I am installing APs and stringing CAT-6 across a warehouse.

The attachment V6.0.jpg is no longer available

Later,
Brad

[Oneironaut]

A random turn on the internet revealed this echo of the past...

Even in the 1936 they understood the importance of wall pounding sound in a keyboard.
This amazing creation has more wood and speaker real-estate than mine!

[barnacle]

But you don't have to pedal yours

Though... are you part grasshopper, to keep your ears in your knees? :p

Neil

[Oneironaut]

Mine does have two analog pedals.
One is for the control of the decay ramp (basically a sustain).
The other is assignable to effects, like a low pass while leading into a beat.
During a mix bounce or track replay between RAMs, effects are recorded live.

barnacle wrote:

But you don't have to pedal yours

Though... are you part grasshopper, to keep your ears in your knees? :p

Neil

[BigDumbDinosaur]

barnacle wrote:

But you don't have to pedal yours

Actually, the Orgatron was a hybrid electronic instrument, using free-beating reeds for tone generation and vacuum tubes for mixing and amplification.  The pedals were “expression” pedals.

When I was a kid, I had an uncle who had an Orgatron in the living room.  Yours truly would annoy the cr*p out of everyone playing around with it. 

[barnacle]

Aha, I saw it as a harmonium; a foot-pumped keyboard reed instrument.

Neil

[BigDumbDinosaur]

barnacle wrote:

Aha, I saw it as a harmonium; a foot-pumped keyboard reed instrument.

It does have a strong resemblance to a harmonium.

The Orgatron (something about that name that conjures naughty thoughts ) was one of several attempts to get around Hammond’s patents on the tone-wheel generator.

Hammond’s objective in developing his organ was in imitating the additive synthesis that makes the pipe organ sound the way it does. The basic problem Hammond had solved with the tone-wheels was that of generating the multitude of frequencies needed to cover the full range of the instrument, plus a high octave for overtones.  There were 96 tone-wheels in most models, producing an approximate eight octave range, starting with C1 (~32 Hz) in the pedals.

Using tubes to do the tone generation wasn’t practical—96 oscillators would be needed, with at least one triode per oscillator.  Similarly, generating 12 tones to cover one (high) octave and then feeding these oscillators through a chain of frequency dividers would have used even more tubes.  The alternative, subtractive synthesis from a harmonic-rich source, was equally tube-intensive and as it turned out, muddy-sounding compared to what Hammond had achieved.

So getting around Hammond’s tone generation patent was front-and-center prior to the development of solid-state tone generation.  Anything that was devised had to be compact, reasonably energy-efficient, frequency-stable and reasonable in cost. The Orgatron was one such effort, but didn’t cut the mustard.  It didn’t sound like the Hammond instrument and lacked the flexibility of Hammond’s drawbar system for controlling timbre and balance.

[barnacle]

<something about that name>

Barbarella!

[BigDumbDinosaur]

barnacle wrote:

<something about that name>

Barbarella!

Yep!  I had forgotten all about that movie.    As I recall, it was a tad short on plot, but long on eye candy. 

[Oneironaut]

Once again, the monster is on the move.
I have been renovating my basement, so the synth has traversed the 18 steps to find it's home in my new tiny secret 12x12 lab.
The frame isn't all that heavy (maybe 50 pounds), but it quite a dance to get it around corners without scuffing the walls.

As planned, it just fits along the 75 inch wall I left for it...

You can also see the video generator being redone on my smaller breadboard.
I have decided to change the typical monochrome shift reg video output to 8 bit greyscale.
Screen drawing will be a bit slower, but now I can really make a nice looking user interface.

Oh, and of course the two removable pillars are going to need a rework now that they are to contain those 1200 watts worth of window blasting speakers!
That will have to wait until the snow is gone as my welding shack is buried out in the back 40 for a few more months.

Later,
Radical Brad

[BigDumbDinosaur]

Oneironaut wrote:

Once again, the monster is on the move...

(Conjuring an image of mastodons on the move to new grazing grounds)

[barnacle]

For some reason, this https://www.youtube.com/watch?v=ho9rZjlsyYY is drifting through my thoughts...

Neil

[BigDumbDinosaur]

barnacle wrote:

For some reason, this https://www.youtube.com/watch?v=ho9rZjlsyYY is drifting through my thoughts...

I like this version better...much stronger in the pedals, and the toccata is more dramatic.  However, of all of Bach’s contrapuntal works, this fugue is my favorite.

For some reason, I’m thinking Brad would be doing this sort of stuff.

[BigDumbDinosaur]

On second thoughts, this is likely what Brad is planning.    Turn up the amps!

[Oneironaut]

I like all of the above!
Yes, I will be planning to create a very high quality organ sample set.
I have already done a Grande piano set with fully samples strikes for every 4th key.
It actually sounds almost as good as my modern digital!

Since you guys have mentioned pipe organ so often, I shall dedicate to doing that sample set next.
I can imagine it will sound very close to the original with samples on every 4th key and pushing through those 1200 watt 15 inch monsters!
I can sort of play that Bach D-Minor organ tune, but will need to listen to it a few more times to get it close enough.
That will be my next video demo to post.

Brad