Listing is for a set of 6 NEW Analogue Renaissance AR80017A-GS (GRAVITATIONAL SLINGSHOT) Filter/VCA Voice Chips in brand new condition for the following piece(s) of equipment: Juno-106/106S/HS-60/MKS-30.
This is part number GS80017A in the Analogue Renaissance parts catalogue. Having issues with your Roland Juno-106/106S/HS-60/MKS-30, where there is crackling or no sound coming from your synth? The original 80017A chips were coated in an epoxy that is now know to cause the chips to fail. It's not an IF, but a WHEN situation with these. Treating the original chips with acetone CAN save them, but they're not guaranteed to last very long (and there are plenty of stories of them failing because the epoxy wasn't removed from in between all the IC pins). Want a solution that will last 30+ years when installed properly? Get a set of Analogue Renaissance GS80017A's.
These are a new version of the 80017 filter chip (which are still great if you want the 100% faithful sound of a 106), but with a bolder sound than the AR80017A chips. Description of these chips from the Analogue Renaissance website can be found below.
Please note that there is a standard return policy on these, but ONLY if the chips are still intact as pictured. Due to the nature of these types of parts, once the chips have been separated and/or installed, they are no longer returnable. It is highly recommended you have a professional service technician install these.
About the Analogue Renaissance Set of 6 Gravitational Slingshot Filter/VCA Voice Chips:
Introduction: This is a new VCF/VCA combo that replaces the original 80017A hybrid modules in a Juno-106 (or any other synth that uses these). It gives the Juno-106 a much bigger sound without sacrificing the original 80017A's precision which makes the Juno-106 sound so good polyphonically.
The Juno-106 has a lot going for it: Complete hands-on control with one button or fader per parameter, complete midi control for each parameter through SysEx, ultra-stable DCO’s, thundering bass-boost with the HPF in its lowest position and the above mentioned precision of the VCF.
This precision comes in the form of excellent frequency tracking and a very flat resonance response. The former, not only allows playing notes by using the self-oscillating filters as extra oscillators, but also allows several of them to slowly beat against each other, even when separated several octaves apart. The later allows this beating to go really deep and is also fundamental in getting everything summed together without clipping. After all 24 waveforms (Saw, Tri, Sub and Sine, from self-oscillation, multiplied by 6 voices) have to be summed together with chorus on top.
However, this precision comes in part from the filter being virtually distortion-free and this comes at the cost of its sonic character. Or actually, its lack thereof.
And, to my taste, it’s a bit too clean and bright, certainly taking into account that there is only one oscillator per voice. So, I wanted to give the filter a bit more character, let it add some harmonics and move things a bit to the lower regions of the spectrum. I would describe this as a kind of growling quality.
Technical Details: First of all I did not want to take things too far, it still had to be recognizable as Juno-106, not something messed up beyond recognition. So, the filter had to be a 4-pole low-pass filter with all its poles in the real domain and as I consider the Juno-106 a bass-monster its resonance had to have Q-compensation.
As this kind of filter’s sonic character can be entirely defined by the dynamic position of its poles, its non-linearities and where these happen, it is interesting when these parameters are adjustable.
Problem is, that by design, the Juno-106 has few adjustable parameters and for example, gradually distorting the filter by increasing its input level is not possible here as its waveforms are on/off (except for the sub). Adding extra controls for this purpose and making them, like the others, programmable and midi-controllable would be a project of an entirely different magnitude and doing this non-adjustable would mean for it to be impossible to play the pure undistorted waveforms.
To accommodate all this I used a highly modified ladder filter. Its design originates from experiments I did about 2 decades ago with the intention of improving the original 1960’s Moog design. My main beef with it was that it is quite noisy, has low PSRR, and has little headroom: the onset of distortion (1% THD) happens at about 25mV input signal amplitude and it clips (90% of maximum amplitude reached) at only 75mV. Also, resonance disappears at low frequencies and increases a lot at high frequencies.
Noise was reduced by getting rid of all external base resistances: the differential inputs were sourced by low-output-Z buffers and the bias resistors for the ladder were replaced with a stack of bandgap references, the top one also cured the low PSRR.
Headroom was increased by replacing the open-loop differential output amplifier, which also serves as resonance amplifier, with a high-Z instrumentation amplifier that stays linear to almost full-rail signals.
Changing the whole structure to a DC-coupled one, by getting rid of all coupling capacitors and mirroring the exponential converter so that the differential input pair accepts ground-referenced signals, together with the increased impedance of the output/resonance amplifier cured the low frequency limit, so that it can operate and self-oscillate down to the miliHertz range. HF resonance issues were solved by phase-compensating the loop-delay.
My unwary expectation of this improved design, based on the assumption (and popular belief) that most of the magic happens in the ladder, was for its sonic character to be unaltered, but then without the noise and with a much bigger bottom-end. Much to my surprise it sounded entirely different, ultra-clean actually. Something I would rather expect from closed loop OTA based filters than from an open-loop ladder filter.
When doing a Side-by-side comparison of this design with an OTA based 4-pole LPF, both tuned to the same frequency and resonance feedback, I had a very hard time to discern any difference between them. When feeding them sawtooths and squarewaves, I actually couldn’t hear any difference. This was also confirmed by simulations.
Shipping notes:
FAST SHIPPING IS OUR STANDARD SERVICE, WITH SAME DAY SHIPPING & DROP OFF, AND TWO-DAY SHIPPING IS AVAILABLE AS AN UPGRADE ON MOST SHIPPING PROFILES! Saturday afternoon & Sunday sales will be taken to the shipper early on Monday mornings. If you are in the Madison, WI area, a showing can be arranged, and free local pickup is available. In-person cash payment can be arranged to avoid the payment processing fees, but not the Reverb seller fees (those will be reported and the 5% paid to Reverb).
For small and some medium items, the item will be bubble wrapped and well secured in a strong box. For some medium items (sizable drum machines, table top synths) and all large items (keyboards and rack mount devices), item will be double-wrapped and double boxed.
NOTE: We will combine shipping for parts and small items, and often have more in-stock than what is listed (especially replacement keys). Please message us your requirements for multiple parts needed (where multiple items are available, but only one can be purchased at a time), and we will adjust shipping and/or bulk discounts accordingly.