# JAF Model One — Virtual Analog Ladder Filter > Virtual analog transistor ladder filter with stereo processing and MIDI control. (iPhone/iPad app by Jens Guell.) - Source: https://appshunter.io/ios/app/jaf-model-one/id1472652593 (this page in markdown: same URL + `.md`) - Developer: [Jens Guell](https://appshunter.io/developer/1195004865) - Category: Music, Productivity, Music - Price: $9.99 - Rating: 5.00/5 from 12 App Store ratings · 7 written reviews indexed - Age rating: 4+ - Requires: iOS 12.0 · 12 MB - Languages: English - Released: 2019-07-28 - Data updated: 2026-07-26 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/jaf-model-one/id1472652593/reviews.md ## What is JAF Model One? The MODEL ONE is a selected, fine-tuned general purpose (transistor ladder model) analog modelled filter with the ability of self oscillation. The cutoff slope is approximately 24dB. It can be switched to low pass or high pass processing mode. The Model One, like all our filter models, is a true stereo processing audio effect, which includes a special audio-rate (high frequency) modulation oscillator, that can modulate the main parameters of the filter to its extremes. The modulation oscillator is not related to the inbuilt unison oscillators, which is a complete separate, different unit. All our models have also an inbuilt additional saturation unit for the extra bit of analog drive. This saturation unit and the oscillator section can be used without the filter module, because the filter unit can be switched to pass the incoming audio signals thru. The available vintage warmer tube/tape saturation type for instance is an excellent choice for breathing life into any obvious digital audio material. It can be applied to entire mixes as to individual tracks and voices. The hosting app for the Model One has special MIDI connectivity, thus parameters can be automated with realtime MIDI Controllers (See MIDI implementation chart).  The MIDI features on the audio unit depends on the fact, whether the host application will send MIDI messages to the plugin in any way with the audio processing block or not. The audio unit can be loaded into all supporting audio unit hosts. If successfully loaded into a host, all parameter automation and preset handling will be handled by these host applications. ## Key features - Virtual analog transistor ladder filter - Self-oscillation capability - 24dB cutoff slope - Low-pass and high-pass modes - Stereo audio processing - Audio-rate modulation oscillator - Inbuilt saturation unit - MIDI connectivity for parameter automation ## Recent user reviews (7 of 7) All indexed reviews: https://appshunter.io/ios/app/jaf-model-one/id1472652593/reviews.md ### 5/5 — EXACTLY WHAT I NEEDED *2019-09-02* And it was “free” ... or a “GET” app. Considering what this thing is doing for my AUM mixes, I think my next app will be the developers main paid filter app. If this is an indication (advertisement) of what that one does, then its a must have. ### 5/5 — I’ve got a handful... *2019-08-20, version 1.4* ...of paid-for filters. This one sounds better than any of them. I have no clue what the guy who gave the one star review is yapping about. Everything works perfectly on my iPad. ### 5/5 — Beefy Skronky Filter *2019-08-16* Great sounding filter, very organic. Only wish the controls were a little bigger inside Beatmaker 3. ### 5/5 — Works just fine- indeed, better than fine *2019-08-11, version 1.3* Contrary to what one Lubyanka (that superscript TM is suspicious imho) would have the community believe, this app works splendidly, and is easy to find in the list of AUv3s so long as one remembers that they are stored in alpha order of developer, rather than name. In fact, this little gem works really well as a one-stop tamer of OTT reverbs and the like- just stick this in your fx chain in AUM or whatever and simply dial the effect down (or up, if you must) without having to mess with half a dozen parameters in the original fx. This one’s a keeper! ### 5/5 — nice *2019-08-06, version 1.3* this good and free 😵 ### 5/5 — Nice filter! *2019-07-30* Nice filter in a handy AU formet. Free as well, and a good ad for their 10 filter package. EDIT: Ha - I can't count. Yes, 30 nice, beefy filters in the full collection. **Developer response:** 10 filters?? Who, the heck, has stolen the others then !? ^^ (There are currently 30+ different filter models inside the JAF collection, an analog modeled saturation unit, a high speed audio frequency modulator and an 8x analog unisono oscillator section inside the JAF Collection.) Just to be precise. ^^ ...ahh... forgot to say, there‘s an amp modulation (AM) unit, a ring modulation unit (RM) and a Bode-like frequency shifter (FM) unit built in too. All of these additional units are also available with the free Model One. Thank you very much for the review! ### 1/5 — Avoid! No IAA, no AUv3 functions. *2019-07-26, version 1.1* Update 26 July 2019: Developer, you are asking me to try what I already described trying in my review. Your apps are non functional space wasters, blaming my ineptness will not change that. AUv3 = Audio Units ____________ Tried to use this a bunch of ways including Audiobus. Alleged app was completely missing from all input/fx/output lists in every IAA/AUv3 host I tried. I can get other IAA/AUv3 apps to work just fine. This one fails at advertised functions. I can only conclude that this app and its pricier sibling may both be scams. Avoid. ## Frequently asked questions about JAF Model One ### What is JAF Model One? JAF Model One is a virtual analog transistor ladder filter audio effect plugin. It offers stereo processing, self-oscillation, and an audio-rate modulation oscillator for extreme parameter control. The plugin also includes an integrated saturation unit for analog drive. ### What devices does JAF Model One support? JAF Model One is supported on iPhone, iPad, and iPod. It is designed to be loaded into any supporting audio unit host application on these devices. ### How much does JAF Model One cost? JAF Model One is a paid application, available for $9.99. There are no in-app purchases or subscription options for this product. ### Does JAF Model One have ads? No, JAF Model One does not contain advertisements. As a paid application, it offers an ad-free experience for users. ### What is the age rating for JAF Model One? JAF Model One has an age rating of 4+. This indicates it is suitable for a wide range of users, including younger individuals, with no mature content. ### When was JAF Model One last updated? The latest version of JAF Model One was released on February 20, 2023. This indicates ongoing support and potential for future updates from the developer. ### Can JAF Model One be used offline? As an audio effect plugin, JAF Model One requires a host application to run. Its functionality is dependent on the host application's ability to process audio, but the plugin itself does not require an internet connection for core operation once installed. ### What kind of saturation does JAF Model One offer? JAF Model One includes an inbuilt saturation unit that provides a vintage warmer tube/tape saturation type. This can be used to add analog drive and breathing life into digital audio material, and can be used independently of the filter module. ## Version history (last 5 releases) ### 1.5 — 2023-02-20 Updated for latest technology support (ARM64, M1/M2) ### 1.4 — 2019-08-18 1.4. (fourth maintenance update) A. moveable modal boxes we have made the 'modal boxes' for the modulator, oscillator and saturator modules moveable now. the boxes will be ready to be moved freely inside the plugins effective area, if no internal control is hit. the positions are remembered for the current session only, as it would create problems while loading with different host apps due to different window sizes and handling. there can only be one modal box opened at same time for certain reasons, but the positions are individually remembered for each type of dialog while working with the plugin. the global zoom feature affects everything, not merely individual boxes. The move feature can be globally locked with the freeze button. the freeze button will be invoked or hidden by a long press gesture. to close a box, one must tap outside the visible area of the box. the double tap with 2 fingers will reset everything to default positions. B. zooming behavior the model selector (exposed via [ menu ] button) will not disappear anymore by tapping outside, to support zooming while it is open. The menu button must be tapped explicitly to close the menu. this affects JAF Collection only. if you want to zoom into open modal boxes, you must ensure to pinch inside their areas to make not disappear these automatically. a tap outside will automatically hide any open modal box. this was a requested user feature and we won't change that again. C. improved contrast behavior modal boxes now also support the contrast feature with their own semi-transparent background. we also improved the entire contrast to get really more visual difference. it is done by just inverting the main color in relation to the background color. this should optimize usage with extreme lighting and give entirely more contrast. this also affects all the main labels. D: labels made bigger all the labels of the user interface were made 1 point larger for better readability. this is maximum as it already looks quite clumsy now. ^^ E: removed Bluetooth MIDI connectivity We decided to remove MIDI connectivity features from our releases completely. the reason is, that we always have to provide videos for the app store staff with each update release to demonstrate this iOS system feature with our distribution apps. we have not the time to endlessly capture videos of basic iOS system features, as these system functions are merely invoked by the app, not coded. it is not our code, nor do we even have influence to these mechanisms, so we do not see the logic in the demands of the app store review staff, notoriously asking for demonstrating sub features of our apps, that are in fact features of the OS. So Bluetooth MIDI cannot be established any longer with our distribution apps. it is also not a requirement for the operation of the audio units, b.t.w. F. audio improvements and extension delayed again some audio issues (like hot signals, loudness adjusting, additional comb effects) will come with the next update, as far there is even any interest for that. ### 1.3 — 2019-08-05 1.3 (third maintenance update) A: newdescriptor names the Audio Unit and distribution host app descriptors were changed. the naming of the audio units caused much confusion, as some users were not able to find our plugins after installation. the naming convention of formerly "Filter Model One" and "Filter Collection" are now - "DGST: JAF Model One (AU)" and - "DGST: JAF Collection (AU)" the "DGST:" prefix always marks ALL of our audio units with the unique company identifier. IMPORTANT NOTE : we highly recommend to deinstall the previous version and do a new install therefore! existing projects possibly must be updated with the new instances. B: parameters in AUM especially for AUM, we implemented the "exotic" but ("required") flag for exposing the parameters. otherwise AUM will not publish any parameters, that are not flagged with a special "kAudioUnitParameterFlag_IsWritable" flag. This is somewhat "willful', because other hosts actually listed our parameter tree for automation correctly. ( more info on that in the version history on our product website ) C: several UI fixes the new model selector menu, that came with update 1.2 introduced some new UI discontinuities. sometimes the selector was still (silently) active but visually disappeared. we fixed that. D: toggling the contrast control overlay the contrast button and the adjustor slider can be temporarily toggled with a long press gesture, making it disappearing/appearing again. we hope the new feature will improve user experience. E: the 'pinch2zoom&move' can be locked now we implemented a new 'freeze' button aside the contrast feature, that temporarily disables zooming and moving the interface. this button will also appear/disappear with the long press gesture. F: there was a (possible) problem, using multiple instances with differing zoom adjustments. we fixed that. G: gesture recognizer slightly changed the previous implementations required to touch exactly inside the visible area of the user interface to be recognized. now all gestures are recognized on the entire window area of the audio unit's interface, which is much more logical and intuitive to use. H. audio engine update delayed some audio issues (like hot signals, loudness adjusting, additional comb effects) will come with the next update. ### 1.2 — 2019-07-27 1.2 (second maintenance update) this update fixes mainly functional issues with the Audio Unit application programming interface. A. exposing AU parameters we implemented an extra function to (additionally) expose main parameters to the hosts. notes: there are unclear issues reported with some host apps, not exposing our audio unit parameters at all. this is quite strange due to the fact, that any audio unit per default implements a so-called 'parameter tree', that can ( and actually * must * ) be iterated by any host app to receive all that parameters of a designated audio unit. our units did and * still do * implement this parameter tree. the distribution app even uses this internally, because this app is basically a minimal Audio Unit host, nothing more and nothing less, working with ... guessing what? ... well the ominous parameter tree. So basically, we do not understand, why some hosts are not able to just expose our published audio unit parameters. However, we now use an additional interface function to expose at least the main parameter to the host application with this release. AUM for instance exposes this published "main parameter" of the unit successfully (with 'aufx' types at least), but on the other side, it FAILS to list our parameter tree !? that is absolutely un-logical and must be an issue in that host apps. B. AU parameter automation (which by the way, depends heavily on the bespoken 'parameter tree' above) our JAF and JAX series were initially planned to behave and be used like classic external hardware devices, so we concentrated to MIDI implementation but ... parameter automation should now be possible. there was a missing link, that prevented our units to pass thru parameters from the host inside the rendering block. such usually happens, if the hosts do so-called "parameter automation". Although, many different host applications do implement this feature obviously differently and as long this is the case, we cannot guarantee the functionality of our plugins with these hosts right now. so try, before you buy! The simple fact, that our units can receive MIDI messages and translate these to parameter changes in realtime proves, that the parameters actually can be automated with the internal mechanisms successfully and out of the box. we tested the new parameter automation with Cubasis very successfully. all parameters were recorded and also shown with their correct names from the parameter tree! playing back with parameter automation actually was moving (remoting) the designated controls visually as expected! C: UI corrections and extensions the push buttons are somewhat bigger now but not much. we felt, it tends to become very ugly if these buttons are much bigger. the button labels are also somewhat lighter now. (but wait, for what the heck, did we actually implement pinch2zoom&moving for you, User ???) if you can't read it, just zoom it! the 'modal 'boxes' (which by the way are vector graphic overlays and not 'views') will now automatically disappear, if the user does not us a control inside them actively. So there is no need to click the button again to make this (dis)happen. but these will now also disappear, if a user accidentally passes to hit a controls area inside these boxes, which now may produce just other confusion ... we will definitively not implement any popup menus or similar for the model selector slide button as seen so often in audio apps. theses will lock the screen and the access to the u! that is an unacceptable behavior while working with plugin- and audio interfaces in general. if you want this, so please look for such things anywhere. there are loads of apps that implement this (dis)functionality for you! ... the full list was cut here due to insufficient space ... (you may read the full list of changes on the product/support website.) ### 1.1 — 2019-07-23 1.1 (first maintenance update) A. we changed the touchscreen behavior to be much more intuitive and obvious. - resetting the view with double tapping requires now 2 fingers (previously 1). it was too easy to accidentally reset the view, when doing fast tapping - causing confusion to the users. - moving the view now works as expected with 1 finger (previously 3 fingers were required), if no control is touched, the view will be ready to be moved freely, but touching controls will lock the view moving automatically. this behavior is entirely much more "intelligent" and natural. - pinch 2 zoom works as before, but we optimized the performance with all the moving and zooming. - for performance reasons we disabled any easing animations (eye candy :: versus app and audio performance) B. the background color layer was not resized correctly, when the audio units were loaded into several hosting apps. - we changed this behavior but we are still not sure, whether this will work with all possible hosting apps. please report! note: our audio unit views are self resizing. additionally you can zoom and move the internal views inside the container view freely. We certainly cannot test all available audio unit host apps, to check this behavior everywhere. if a view seems to be disappeared suddenly, so please use double tapping with 2 fingers to reset the view to default state. this should center and size-fit the view to its defaults (fitting view width to screen). C. the maximum view width for zooming is now limited to 2048p, minimum is 256p. - larger scaling does not improve the usage and has a deep impact on the graphics performance and also it is obviously merely confusing to the user. note: view positions are no longer saved as user defaults. we discovered that loading the audio units in to different host apps, produces massive problems with the saved view positions. all possible hosts have different view sizes and container 'window' behavior, that may conflict with any such saved user defaults. D. re-enabled the bluetooth publishing with the JAF Collection and JAF MODEL ONE. - we switched this feature temporarily off, because of some problems and unacceptable delays with the app store review process. the (additional, optional) feature was carefully tested by us and works without any problems. E. the emphasized color for the last filter type (pass thru) was grey. we changed this to green, because the control positions were not easy to recognize the other way. F. the contrast of some knobs was slightly changed. G. the auto-scaling of the parameter changes was changed, especially the filter type selector. - parameter change speed is now more intelligently connected to the current zoom value, that means, the smaller the view is, the faster the controls will change and vice versa. this may be very handy with parameter automation and live performances, where users may optimize the access to selected controls. H. the contrast button was placed more on top of the screen to not to conflict so much with the user interface. I.the documentation and the website resources were reworked. an official email support link is now available. J. New modulation destination was added (exchanged) on both JAF versions (paid and free version). instead of an amp modulation (which basically was a modified form of ring modulation), now a (Bode-alike) frequency shifter was added. this complete new effect can be used without the filter in "pass thru" mode as some of the other modulation destinations and the saturation unit, which are connected serial prior the final brick-wall limiter. K: the frequency labels of the cutoff wheel did show wrong values, we corrected this. next update will concentrate more to the sound. we highly encourage you to contact us, if you've found any issues. ## More apps by Jens Guell - [GM MIDI Player](https://appshunter.io/ios/app/gm-midi-player/id1445780869) - [MIDI SWEET : Clock Sync (AU)](https://appshunter.io/ios/app/midi-sweet-clock-sync-au/id1454284852) - [JAF Collection](https://appshunter.io/ios/app/jaf-collection/id1472896422) - [JAX Stereo Tool (AU)](https://appshunter.io/ios/app/jax-stereo-tool-au/id1473390302) - [JAX !Make Louder (Audio Unit)](https://appshunter.io/ios/app/jax-make-louder-audio-unit/id1474614677) All apps by Jens Guell: https://appshunter.io/developer/1195004865 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-26.*