Date: Sat, 28 Oct 1995 12:19:49 +0000 From: Graham Hinton Subject: Re: Whiteface = SEM? -> ARP filters Cc: analogue@hyperreal.com >With all this talk about SEMS going through the roof in $$ does anyone >want to venture an educated opinion on the sound of a 4012 vs a SEM? Actually there were at least three different ARP filter modules: 1)4012 early (epoxy encapsulated) 4-pole Moog transistor ladder based on the Minimoog circuit, but improved for larger signal level, better noise and temperature stability. After legal moves by Moog this was replaced by: 2)4023 2-pole State Variable with 3080 control elements. Early versions of this may have been encapsulated as well - hence the confusion. This is similar to the Oberheim SEM circuit, but it won't sound exactly the same because the envelopes have different shapes and actions and there are different modulation routes. and later replaced by: 3)4075 4-pole Resonant filter fitted to later black/orange models. This is the one that could oscillate AND pass the original signal at the same time. Very clean and stable. The changes in filter module did not correspond exactly to the case colour/style changes. There was also a 4035, but I'm not sure if this an early 4075 or something different. Graham Hinton Hinton Instruments Analogue & Digital, Hardware & Software Design for MIDI and Pro Audio WWW Page: http://www.hollis.co.uk/hinton.html From: DPRO5@aol.com Date: Wed, 6 Dec 1995 01:03:52 -0500 Cc: roderick@serv01.net-link.net Subject: Re: ARP Odyssey "version" question... roderick asks... >I just bought an ARP Odyssey (sight unseen) for $300 and am >curious >which model it is. I've checked the archives but they seem to >conflict >with the info I recieved from the person selling it to me. He >said it >says model 2800 on the back but that it is black with gold >lettering. >The serial # is 282896. Should I expect this to have the Moog >filter? >I,f not, what should I expect this thing to have? Any info >appreciated... You have an Oddessey with the 4023 filter in it . It does sound better than the later ones which had the 4072 . But no it is not the Moog copy which was a 4012. It is actually a 2 pole design that has some similarites to the Oberheim but is different. Peace, Dave DPRO5(synth junkie)