STATUS ARTIS -

// RESEARCH PERIOD: 2004-2023 //

** ORIGINAL ALL-ANALOG fx CIRCUIT DESIGNS **

BFP #1 … HARDWARE SIMULATOR

Without any doubt this BFP hits the guitarist at a primal level, by pushing the world’s most notable vintage dirt boxes into a new upper territory of gain, dynamics, and versatility … all while maintaining the signature vintage charactereir …

The idea can be used in any vintage design that used Germanium devices specifically for their particularly strong dynamic characteristics

BFP #2 … HARDWARE SIMULATOR

The Arbutus Booster has proven itself great as an on-all-the-time non-linear DC-shifting booster in front of vintage low-gain (not hot) tube amplifiers – turning the combo into a breathing beast … other players seem to use it the same way with their favorite amplifier.

Beyond the jFET based Triode-response emulator shown here I have discovered the existence of two other methods for hardware-simulating the large signal “soft-clipping” action associated with class-A Triode signal transfer.

BFP #3 … HARDWARE SIMULATOR

By sandwiching my Triodifier stage between preamp and EQ stages then feeding a 60watt power stage I can get a realistic set of tube-like power dynamics that holds up to a drum kit.

BFP #4 … HARDWARE SIMULATOR

A 5-way parametrically variable high-headroom/high-drive linearization of the Kushner-Plunkett 2-transistor classic WAH circuit; with full replication of (un-buffered) input network loading. The same transfer function can be produced two ways, in both cases a physical (Fasel) inductor is used.

BFP #5 … HARDWARE SIMULATOR

One of the important targets in this tube-vibrato emulator is getting the HP/LP cross-over frequencies just right // one way is to match it to an accurate simulation of the original Fender tube circuit (I used my 12ax7 SPICE modelling). The final way is to verify that the zero-depth response sounds identical to straight signal when bypassed – which the audio clip below demonstrates.

As with some of my other phasors, trems and sine modulators the design features an extended range Univibe LFO circuit, which imparts a very natural analog feel. Notice the almost-phasor like response in anti-phase mode!

Dedicated to the memory of good friend Roly Roper (RIP)

BFP #6 … HARDWARE SIMULATOR

After years of building refined clones of the Acoustic 360 preamp I came up with a linearized “modern” equivalent that uses the same 1.5Hy Cinemag inductor and producing a somewhat stronger/sharper EQ response. Same 12-position (single-band) cut/boost EQ function with Treb/Bass shelves but augmented with my optical-based ENVELOPE-LOCK limiter block. Features super low-noise and super low-distortion – with hugely versatile controls.

BFP #7 … HARDWARE SIMULATOR

The BIAS MODULATING TREMOLO BFP … Hardware Emulation

Producing high headroom “bias modulating” Tremolo similar in quality to the gain-modulating effect found in the output stage of 6G16 brown-face Fender tube amplifiers (labelled there as Vibrato – not to be confused either with Harmonic Tremolo (see above) appearing in other brown-face models).

The “Unitrem” features an adapted Univibe LFO circuit, which helps impart a strong analog feel to the effect. Version III only uses three transistors in total and easily goes into heavy chop territory without distorting the signal.

UNI-TREM-III (c)2019 // status: MANUFACTURABLE

First discovered in 2005 … here’s what version II from 2011 sounded like:

OPTO-VIBE-II (c)2014 // status: LIMITED MANUFACTURABILITY

I wanted to see how close to the response of a bulb-based Univibe I could get using instead matched opto-couplers and a current-drive approach – with the same LFO of course. But Cadmium Sulfide based opto-LDR’s are slowly getting banned everywhere. So, R.I.P. “Silonex/Luna NSL-32” … my favorite opto for the last three decades

Presented below: two examples demonstrating improvements of the common types of ALL-PASS filters found in many commercial phasor pedals.

IMPROVED-STD-OTA (c)2014 // status: MANUFACTURABLE

The key to making OTA phasors sound more focused and swirly in the high range.

IMPROVED-STD-2STAGER (c)2022 // status: MANUFACTURABLE

AUTOMATIC GAIN CONTROL BFP’s

The final frontier, an obsession …

the outcome: finally (for me anyway), a more-complete theory of AGC Circuit Design

“ENVELOPE LOCK” FLOATING-GAIN-COMP/Limiter (c)2014 // status: EXPERIMENTAL

LA-2A style minimalist opto-limiter (c)2019 // status: LIMITED MANUFACTURABILITY

LA-2A style “fast” non/opto-limiter (c)2017 // status: MANUFACTURABLE

minimalist OTA style limiter (c)2017 // status: MANUFACTURABLE

Having had success in other forms of non-linear Cv control this is something I had to try – and the feel of this thing is truly amazing. In the process it suggests, or confirms, how the human psycho-acoustic mind seems to prefer one type of response over another (my subjective interpretation here).

This easy to build design provides two of the four main AGC processing responses, and they are the usual kind. Essentially a feed-fwd/back switch-able design that doesn’t require any specialized IC’s. See the not-a-Limiter design below which provides the two other AGC modes.

Incidentally, this design has nothing at all in common with the Dyn-a-comp (including the signal path structure) other than using an OTA as controlled amplifier // exhibitng much better noise figures in the process …

shows how there’s still room for “new” approaches to these old design problems!

Broadcast-Limiter with 7uS ATTACK/RELEASE times (c)2018 // status: MANUFACTURABLE

This circuit chops up the signal at 140khz and applies the Riemann integral limit in reverse. There is no localized time averaging performed by charging/discharging a capacitor …

NOT-A-LIMITER (c)2022 // status: MANUFACTURABLE

This easy to build design provides two of the four main AGC processing responses, and they are not the usual kind. Essentially a pro-compressor designs from the 70’s adapted to instrument level use but without requiring specialized IC’s.

For example, in the clip below notice the near-infinite sustain produced in one mode!

All I can say is this, Signetics had the right idea in getting rid of the noisy op-amp that was included in the NE570/NE571 chips but had they (including cool audio) put out an NE572 version with all sections decoupled – even if only including one compander circuit per package – they would possibly be widely used today. Unfortunately they decided to go for low outside parts count and package density over extended performance potentiality.

RECTIFIER BFP’s

MAXIMIZING RING … AND PRESENTING A NEW APPROACH

FULL-WAVE RECTIFIER WITH “LOW-BUT-NOT-TOO-LOW” THRESHOLD (c)2019 // status: MANUFACTURABLE

SPLIT-WAVE FREQUENCY DOUBLER (c)2019 // status: MANUFACTURABLE

WAVE-SHAPER BFP’s

Pure Electronic Design Non-Sense …

1-BIT A/D FUZZ of DOOM (c)2019 // status: MANUFACTURABLE

NYQUIST ALISIER (c)2005 // status: MANUFACTURABLE

NEW-TOPOLOGY “GAINY CMOS-INVERTER FUZZ” (c)2017 // status: MANUFACTURABLE

“GLOTTAL WAVE” CONVERTER (c)2018 // status: MANUFACTURABLE

“HARD-MODULATOR” WITH HIGH CARRIER REJECTION (c)2018 // status: MANUFACTURABLE

“SUB-MULTIPLIXER” WITH WIDE-OPEN CHANNELS (c)2018 // status: MANUFACTURABLE

ODD’S and ENDS

Things that don’t fit elsewhere …

ORIGINAL HI-FI COIL DRIVER APPLIED TO “JENSEN JT-DB-E” TX (c)2018 // status: MANUFACTURABLE

ZERO-DEGRADATION OPTICAL STAGE/LIVE MUTE FOR (k&k) PASSIVE PICKUPS (c)2019 // status: MANUFACTURABLE

EPILOGUE // THE “BBD” BFP … re: Analog Delay, Chorus and Flanging

So far, I’ve steered well clear of anything BBD related …

That changed recently after talking to a friend in Germany who delids IC’s, helping clear some of my mis-conceptions about BBD behavior. Which lead to a nice discovery //

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