@@TMSBRANDA I'll have to open it up and check. Currently, it serves as the base of a 12" rack because of its sheer size: the rack is just the rails for now. It receives MIDI commands and can change programs; it's just that I haven't yet been able to get sound out, mostly because I don't have enough time to dedicate to it. As for the power supply, I think I'd better look into replacing it, because the heat sinks become very hot, and it currently does not have a ground pin. Thanks for the suggestions, I'll take them to heart.
@@SeverityOne probably not necessary to replace the power supply. at first, check IC184 and IC185 parts, also measure the orange tantalium condensators (all of them) and measure the two big ELKOs. change them if its needed. if there is no sound, primarly these could be problematic. I repaired mine and some others by following these instructions I found in a forum entry.
@@scabatoth Thanks! I'll try checking all internals first (could be another loose cable) and then measure like you described. I'd still want to change the PSU, because (a) it gets very hot and (b) there is no ground pin, which is a bit scary. Obviously, I could go and connect ground to the chassis, but I'm not enough of an electrical engineer to know whether that would be enough.
There are soundcards too! Churchorgan, sinusorgan, theatreorgan and some more. I got this module a long time ago. Connected per midi with my hammondorgan.
Many thanks for your comment:-) Yes, it's not a well known synth in the synthesizer world, because it was just available as a construction kit for organ player and entertainment keyboarder as target customers, with Germany as the main market.
Sounds nice! Never heard of this synth before, what a rare FM powerhouse. And people built these from kits? Just when I thought I'd seen them all... :)
I think both using the same 4-OP FM chips from Yamaha. They should therefore sound very similar. The 4 x 9 was the later model with higher polyphony and 4-times multitimbrality, which can be easily layered to form even more complex sounds
![KSI - Dirty [Official Visualiser]](http://i.ytimg.com/vi/VoDh1h1dPUE/mqdefault.jpg)
I love what you did with this Böhm synth. Somewhat magical.
Many thanks for your nice comment :-)
I got a Böhm Dynamic 12/24 some weeks ago and it became my favourite synth in my setup.
I need to fix mine... got the fully expanded (24 voices) from eBay, but currently it doesn't produce any sound.
@@SeverityOne
1. Urgent OK? 5V, +12/-12V
2. Contacts between the two PCB/electronic-boards okay?
@@TMSBRANDA I'll have to open it up and check. Currently, it serves as the base of a 12" rack because of its sheer size: the rack is just the rails for now.
It receives MIDI commands and can change programs; it's just that I haven't yet been able to get sound out, mostly because I don't have enough time to dedicate to it.
As for the power supply, I think I'd better look into replacing it, because the heat sinks become very hot, and it currently does not have a ground pin.
Thanks for the suggestions, I'll take them to heart.
@@SeverityOne probably not necessary to replace the power supply. at first, check IC184 and IC185 parts, also measure the orange tantalium condensators (all of them) and measure the two big ELKOs. change them if its needed.
if there is no sound, primarly these could be problematic. I repaired mine and some others by following these instructions I found in a forum entry.
@@scabatoth Thanks! I'll try checking all internals first (could be another loose cable) and then measure like you described.
I'd still want to change the PSU, because (a) it gets very hot and (b) there is no ground pin, which is a bit scary. Obviously, I could go and connect ground to the chassis, but I'm not enough of an electrical engineer to know whether that would be enough.
In the mid-1980's I wrote a SYSEX-Editor for the 4x9 Expander to be run on ATARI ST. Worked really well 🙂
Cool! There is also a hardware controller available for the 4x9 from Stereoping
There are soundcards too! Churchorgan, sinusorgan, theatreorgan and some more. I got this module a long time ago. Connected per midi with my hammondorgan.
What a great discover, never heard from this instrument before. Beautiful composition. Many thanks for sharing!.
Many thanks for your comment:-) Yes, it's not a well known synth in the synthesizer world, because it was just available as a construction kit for organ player and entertainment keyboarder as target customers, with Germany as the main market.
@@christianssonicspaces494 For sure you're right, because there is none for sale on ebay.
Excellent work & great atmosphere!!! big like and sub ;-)
Many thanks for your nice comment :-)
Never heard about this unit, but brilliant....
Many thanks :-)
@@christianssonicspaces494 and now adding some analog sequences and/or arpeggios - ready for Berlin school
Haha, yes, yes, good idea :-)
Impressive diy synth and music!
Many thanks :-)
Sounds nice! Never heard of this synth before, what a rare FM powerhouse. And people built these from kits? Just when I thought I'd seen them all... :)
Many thanks :-)
Anyone has an Editor for the Böhm Dynamic Expander 12/24? (DOS, Windows 95/98/Xp or even Atari version is interested) Thank you.
Is ther sysex inside the 4x9 to transfer patches? Thnx
I have the other one, the 12/24, just now. Is this in any (or many) ways different?
I think both using the same 4-OP FM chips from Yamaha. They should therefore sound very similar. The 4 x 9 was the later model with higher polyphony and 4-times multitimbrality, which can be easily layered to form even more complex sounds
Is it me or does this machine sound both modern and retro at the same time?
I think so too :-D