emulatorII-list

So tonight I'm looking at the filter schematics trying to determine why the resonance on one of my voices has a higher Q than the others... and noticed that the SSM2045 filter chip has both 2 pole and 4 pole outputs!
Since there is just a single 4.7K resistor connecting the output of the 4 pole filter to the input of the amplifier, it seems quite simple that one could remove this 4.7K resistor, run wires from the 2 and 4 pole outputs each to seperate 4.7K resistors which are then connected to the two positions of a toggle switch, the switch common connection then routed to the input of the amplifier. 
Add this stage for each of the eight voices, and then mount the toggle switches just above each voices output jack. 

I think this could create some interesting results. Being able to play both 12db and 24db filter types at the same time. Or creating rhythmic filter type changes as individual notes rotate through the voice assignments. Plus in my opinion with these SSM and CEM chips the resonance seems to sound better on 2 pole settings. 

There is also the ability to use the unused portion of the SSM2045 to create a high pass filter as well, although adding this mod would most likely be a bit more complicated. 

Well I for one am at least going to try seeing what the 2 pole filters sound like.

By the way, has anyone ever used their EII as a stereo sampler?
Taking individual left/right samples assigning them to the same key ranges, but sending them to say left/voice 1, and right/voice 2.

Wow, Mr. Moron, excuse me I mean Morton... I find your response incredibly ignorant. Perhaps we should all just rely on presampled sounds and be content with that. 

FYI, I already have quite an eclectic collection of vintage and modern instruments (more than 100 throughout my years), and am quite fond of 8 bit samplers. However, in my opinion it is obvious that the folks at EMU were more computer engineers than analog circuit designers. Otherwise they would have taken full advantage of the options found in the SSM2045 filter chip (such as 2 pole, 4 pole lowpass filtering, as well as high pass filtering, or using the additional OTA's in that part for panning monophonic sounds) instead of implementing the most basic circuit layout found in the SSM2045 datasheet. Not to mention digital envelopes with 4ms slew rates.
Want to create really snappy percussive sounds anyone? Too bad. 

I always look for ways to expand the capabilities of the machines I use, or step outside the box and use the machine in ways others have possibly overlooked. Otherwise how will we ever discover anything new if we only see things the way someone presents them to us?

I think the most important word in the owners manual is "experiment".

I would hope at least some people on the list might find this modification info useful. And would like to see more people on this list contribute more creative ideas as such to get the most out their equipment. 

My only warning to those wanting to do this mod is, if you do not have the technical and soldering skills, don't attempt to do it.  


--- In emulatorII-list@yahoogroups.com, Douglas Morton <doug@...> wrote:
>
> you should get a modern sampler and throw you e2 in the trash
> On Apr 1, 2010, at 11:18 PM, futureretro2001 wrote:
> 
> > So tonight I'm looking at the filter schematics trying to determine why the resonance on one of my voices has a higher Q than the others... and noticed that the SSM2045 filter chip has both 2 pole and 4 pole outputs!
> > Since there is just a single 4.7K resistor connecting the output of the 4 pole filter to the input of the amplifier, it seems quite simple that one could remove this 4.7K resistor, run wires from the 2 and 4 pole outputs each to seperate 4.7K resistors which are then connected to the two positions of a toggle switch, the switch common connection then routed to the input of the amplifier. 
> > Add this stage for each of the eight voices, and then mount the toggle switches just above each voices output jack. 
> > 
> > I think this could create some interesting results. Being able to play both 12db and 24db filter types at the same time. Or creating rhythmic filter type changes as individual notes rotate through the voice assignments. Plus in my opinion with these SSM and CEM chips the resonance seems to sound better on 2 pole settings. 
> > 
> > There is also the ability to use the unused portion of the SSM2045 to create a high pass filter as well, although adding this mod would most likely be a bit more complicated. 
> > 
> > Well I for one am at least going to try seeing what the 2 pole filters sound like.
> > 
> > By the way, has anyone ever used their EII as a stereo sampler?
> > Taking individual left/right samples assigning them to the same key ranges, but sending them to say left/voice 1, and right/voice 2.
> > 
> >
>

Facetious story )))
I think Douglas expected to get an answer to some pimple-faced lad but not to Jered Flickinger owner of Future Retro.
Douglas, check the link:
http://www.future-retro.com/company.html

Jered, I played a lot with SSM filters, especially with SSM2044 and made separate stereo unit with midi control. It's true that EMU didn't implement all possible features of that 2045 but I don't think that tweaking inside is better than do the same outside with additional SSM filters. Thanks to eBay that we can still buy it new old stock. I spent few month by servicing my EII and don't want to open it anymore ))) Meanwhile I'll probably support you in this idea. 
BTW about 4ms "open filter-delay"..- Have you made this HW fix? I did it, quite happy, one of "must have".

Andrei Kudryavtsev, Deftaudio Russia. 


--- In emulatorII-list@yahoogroups.com, "futureretro2001" <jered@...> wrote:
>
> Wow, Mr. Moron, excuse me I mean Morton... I find your response incredibly ignorant. Perhaps we should all just rely on presampled sounds and be content with that. 
> 
> FYI, I already have quite an eclectic collection of vintage and modern instruments (more than 100 throughout my years), and am quite fond of 8 bit samplers. However, in my opinion it is obvious that the folks at EMU were more computer engineers than analog circuit designers. Otherwise they would have taken full advantage of the options found in the SSM2045 filter chip (such as 2 pole, 4 pole lowpass filtering, as well as high pass filtering, or using the additional OTA's in that part for panning monophonic sounds) instead of implementing the most basic circuit layout found in the SSM2045 datasheet. Not to mention digital envelopes with 4ms slew rates.
> Want to create really snappy percussive sounds anyone? Too bad. 
> 
> I always look for ways to expand the capabilities of the machines I use, or step outside the box and use the machine in ways others have possibly overlooked. Otherwise how will we ever discover anything new if we only see things the way someone presents them to us?
> 
> I think the most important word in the owners manual is "experiment".
> 
> I would hope at least some people on the list might find this modification info useful. And would like to see more people on this list contribute more creative ideas as such to get the most out their equipment. 
> 
> My only warning to those wanting to do this mod is, if you do not have the technical and soldering skills, don't attempt to do it.  
> 
> 
> --- In emulatorII-list@yahoogroups.com, Douglas Morton <doug@> wrote:
> >
> > you should get a modern sampler and throw you e2 in the trash
> > On Apr 1, 2010, at 11:18 PM, futureretro2001 wrote:
> > 
> > > So tonight I'm looking at the filter schematics trying to determine why the resonance on one of my voices has a higher Q than the others... and noticed that the SSM2045 filter chip has both 2 pole and 4 pole outputs!
> > > Since there is just a single 4.7K resistor connecting the output of the 4 pole filter to the input of the amplifier, it seems quite simple that one could remove this 4.7K resistor, run wires from the 2 and 4 pole outputs each to seperate 4.7K resistors which are then connected to the two positions of a toggle switch, the switch common connection then routed to the input of the amplifier. 
> > > Add this stage for each of the eight voices, and then mount the toggle switches just above each voices output jack. 
> > > 
> > > I think this could create some interesting results. Being able to play both 12db and 24db filter types at the same time. Or creating rhythmic filter type changes as individual notes rotate through the voice assignments. Plus in my opinion with these SSM and CEM chips the resonance seems to sound better on 2 pole settings. 
> > > 
> > > There is also the ability to use the unused portion of the SSM2045 to create a high pass filter as well, although adding this mod would most likely be a bit more complicated. 
> > > 
> > > Well I for one am at least going to try seeing what the 2 pole filters sound like.
> > > 
> > > By the way, has anyone ever used their EII as a stereo sampler?
> > > Taking individual left/right samples assigning them to the same key ranges, but sending them to say left/voice 1, and right/voice 2.
> > > 
> > >
> >
>

For anyone who is interested in having a 2 pole filter in their EII, I did try this mod out, and it works just as expected, and predicted in my original post. All you need is a simple toggle switch and I believe 1 additional resistor for each voice. 

That said, there really wasn't too much of a noticable difference between the 2 and 4 pole setting for most people to want to try this. The 2 pole obviously provided a slightly brighter sound. Although I imagine the difference would be more noticable if the filters in the EII reach self resonance. 

The filters in my unit do not self oscillate, almost but not quite. 

I have yet to try psuedo stereo sampling on the EII, my goal is to sample similar sounds or even the same sound, assign one to an individual output panned hard left, the other assigned to another output panned hard right. The key would be to use slightly different loop points so you get more natural phasing between the two samples to open up the stereo field. Or even pan them both center, to breath some life into static loop points and create the chorus/beating you hear in analog oscillators. 

Jered



--- In emulatorII-list@yahoogroups.com, "andrei.kudryavtsev" <andrei.kudryavtsev@...> wrote:
>
> Facetious story )))
> I think Douglas expected to get an answer to some pimple-faced lad but not to Jered Flickinger owner of Future Retro.
> Douglas, check the link:
> http://www.future-retro.com/company.html
> 
> Jered, I played a lot with SSM filters, especially with SSM2044 and made separate stereo unit with midi control. It's true that EMU didn't implement all possible features of that 2045 but I don't think that tweaking inside is better than do the same outside with additional SSM filters. Thanks to eBay that we can still buy it new old stock. I spent few month by servicing my EII and don't want to open it anymore ))) Meanwhile I'll probably support you in this idea. 
> BTW about 4ms "open filter-delay"..- Have you made this HW fix? I did it, quite happy, one of "must have".
> 
> Andrei Kudryavtsev, Deftaudio Russia.

RE: pseudo-stereo sampling.  haven't tried it on the EII, but this
was fairly common to do back in the days of the 12-bit mono Roland samplers e.g. S-550.  Some of Roland's library did this for pseudo-stereo strings, etc.  It was a pretty good stereo effect as I recall.
I'm less interested in mimicking that on the EII, as I prefer it to sound lo-fi :-)

David



--- In emulatorII-list@yahoogroups.com, "futureretro2001" <jered@...> wrote:
>
> So tonight I'm looking at the filter schematics trying to determine why the resonance on one of my voices has a higher Q than the others... and noticed that the SSM2045 filter chip has both 2 pole and 4 pole outputs!
> Since there is just a single 4.7K resistor connecting the output of the 4 pole filter to the input of the amplifier, it seems quite simple that one could remove this 4.7K resistor, run wires from the 2 and 4 pole outputs each to seperate 4.7K resistors which are then connected to the two positions of a toggle switch, the switch common connection then routed to the input of the amplifier. 
> Add this stage for each of the eight voices, and then mount the toggle switches just above each voices output jack. 
> 
> I think this could create some interesting results. Being able to play both 12db and 24db filter types at the same time. Or creating rhythmic filter type changes as individual notes rotate through the voice assignments. Plus in my opinion with these SSM and CEM chips the resonance seems to sound better on 2 pole settings. 
> 
> There is also the ability to use the unused portion of the SSM2045 to create a high pass filter as well, although adding this mod would most likely be a bit more complicated. 
> 
> Well I for one am at least going to try seeing what the 2 pole filters sound like.
> 
> By the way, has anyone ever used their EII as a stereo sampler?
> Taking individual left/right samples assigning them to the same key ranges, but sending them to say left/voice 1, and right/voice 2.
>