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20220214

Built an Arradio module over the weekend with a new friend I met trough muusikoiden.net/tori. I posted a prompt to borrow an Arradio module to study its circuitry which led to a process where we managed to source parts and pcbs to build a few units. To confirm my earlier notes, the tda7088 pin1 to 3,3v power line via 33k on a switch (currently 30k) does indeed work as a channel latch mechanism and toggling it changes the tuning behaviour. We changed the original design by adding polarity protection diodes 1N5817 (instead of the ferrites, but still including them) and I added a 1k resistor to the output (cut the trace on the pcb and soldered a 1k smd resistor as a bridge). Neither additions might not be necessary but I feel more confident exploring the circuit with these changes. I’ll proceed to test the unit with different radio sub-modules and possibly designing a new pcb layout. The current unit also has a I/O switch which I’ll need to study too… It cuts the power from the FM receiver sub-module and I’m not sure if it has (or needs) surge protection circuitry.

Updates:

Drilled a hole to the faceplate to accommodate a sub-mini switch hooked to toggle the latching mechanism. I tested if the circuit “Scan” feature could be activated with a button (3,3v to pin15) but this only produced glitches. I think the tuning potentiometer control voltage should be squeezed with a resistor for it to work (or even disengaged). The Conrad “UKW Retro Radio” schematics which the sub-module is based on show a 200k resistor between the tuning pot(s) and the RE2 trace which lead to the “Reset”/pin16 (perhaps serving as a voltage divider?). The “Reset” also works for manual tuning. The new “retro radio” board wiring examples show a 1m resistor after the tuning pot(s). I should test the minimum voltage the chip needs for manual tuning and add a voltage divider accordingly. The “Scan” is on pin15 and I think a constant voltage at at “Reset”/manual tuning prevents it from working. I’ll test having 0 voltage present at the RE2 trace will enable the “Scan”.

I don’t have any radio reception in the basement I work in, which defeats the purpose of having a radio. Spend a few days building antennas. I had most luck with a 2x 75cm dipole antenna made from insulated scrap copper but I’d have to set it up 10-15 meters out to our housing companies backyard, which might cause suspicions. Touching base with the radio-hobbyist scene.

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20220130

Agroecology and the Survival of Cuban Socialism (2021) Aidan Ratchford offers a glimpse to how Cubas modern (monoculture) sugar farming industry was developed into a pluralistic farming praxis. Interesting to note that the development they underwent rid the country of the binary division between urban and rural.

The resilience of maintaining its socialist principles has been crucial to this experience of degrowth; only an economy which prohibits landlordism, structural inequality, and the accumulation of private wealth and means of production, can strive for genuine degrowth. In this sense degrowth as a real life experiment has necessarily a socialist character, given that the fundamental principles of capitalism are incompatible with the above. This is not to say that capitalism will not have its own “degrowth” given the threat of climate change but this “degrowth” will be the forced underconsumption of use values by the Global Poor, not Cuba’s sundering of social wealth (i.e. use values) from capitalist valuation.

Ethics & Epistemology (1998) a nice extract from a discussion exploring  the different understandings of freedom which Hegel, Engel and Marx deployed. Particularly how Engels statement “freedom is the recognition of necessity” can be understood. The analysis investigates how the thinkers approached nature and I like the definition that of our freedom can be measured by investigating how well we achieve in the projects we undertake: Ecological sustainability is freedom! The text explains that some mistakes of the Soviet Union where a result of a misfortunate process where the Second International chose to revive Hegel’s notion of freedom as an internal state which does not demand an engagement with the world. This enabled the state to limit individual freedom so that it could compete in overall productivity with capitalist societies, so that history would complete itself – Instead of deepening an investigation to what productivity, progress and history actually are.

For both Marx and Hegel human beings realise their essence through recognising themselves in the world beyond. For Hegel this takes place in the realm of the Mind, of thought, and is essentially an act of contemplation. For Marx however, it is through activity, through interaction with the external world outside themselves that human beings realise their own nature. This involves not only work, production, that is the moulding of nature to human design, but also social interaction where people recognise in each other their own selves.

The practice of the International was to submit to ‘historical necessity’ – ‘scientific’ laws that determined the movement of society – which would of their own accord pave the way for socialism. This was the opposite of Marx’s approach, who argued that the fact that social relations could be analysed scientifically, as governed by laws that acted independently of humanity, was itself precisely the state of affairs that needed to be overcome through socialist revolution.

Working towards an Arradio FM receiver module. Sourced schematics & the pcb layout and investigated the circuitry thoroughly. The Arradio hosts a sub-module from an FM radio kit which is no longer available but there seems to be an alternative to the sub-module Steckmodul mit TDA7088 which has the same components and the 70nH & 78nH inductors, which the tda7088 schematics call for are designed into the pcb. The varicap/capacitor diode 1SV101 which handles the voltage based tuning is a rare component but not completely lost yet. There is also an AM circuit which, if I understand it correctly can piggybacks on tda7088 tuning mechanism (or CD9088CB which is the same chip).

The previous schematic also shows a 33k resistors attached to the pin1 which is defined as a “mute” toggle on the chip datasheet (other sources I’ve spotted show a 10k resistor in the same arrangement). If I understand it correctly the “mute” can be understood as a channel latching mechanism, which enables the radio to lock to strong FM signals when the chips “scan” feature is used. A post by Lui Gough defines the mute as “a frequency locked loop with internal muting of weak signals”. Disabling this “tuning lock/mute” might enable a FM receiver unit build around the chip to linger in-between channels for unbeautiful static noises. I will investigate this further as I don’t actually know how the current circuitry behaves. This post offers a thorough breakdown of the chip. I know that the mute switch on the Arradio only cuts the device power input. If my experiments are successfully I will propose n³ (Arradio developer) that that I’d update the design so that it would support the newer fm sub-module and that the submodule control & audio amplification circuit tl074 would be made using smd components.

I’d also like to change the pot and jack-in footprints to match more common components, include reverse voltage circuitry and possible switches for the “mute” and “scan” features (while reducing a hp or two).  Eventually I’d like to try building the submodule could be build straight to the pcb. Learning KiCad!

Sourced two 1SV101s and I’m hoping to test them with the mini-FM transmitter. No idea if it would work thou.

Posted on

20200531

Muzak: On Functional Music and Power (1992) Simon C. Jones & Thomas G. Schumacher. A straight to the bones text on the ideology of functional music. The text offers a good overview on how Muzak is designed and how it effects people who are subjected to it. There are even some statistics on how it effects worker efficiency.

For Adorno, one of the functions of popular music was to distract workers from the monotony of increasingly rationalized and mechanized work. It treated the symptoms of alienation and subordination, alleviating boredom and fatigue but without removing their causes. Popular music was, in the end, little more than “social cement,” reinforcing existing social relations and power structures – entertainment as containment […] The stylistic regularity and harmonic simplicity of Muzak suggests a secure, private, domestic world that signifies the comfort and security of home in terms of a particular, bourgeois conception of domestic well-being. Its aim is precisely to make one “feel at home” whether in an office, factory or airplane.

I remember reading that Muzak is used in shopping-centers to make the violent experience of moving with an elevator from a level of where fur-hats are sold to the floor where butchered meat is sold more coherent. Muzak removes the post- from modern. A contemporary application of the text would be a critique of ambient-music and earphone-culture as processes were individual wellbeing is build by enforcing technologically segregated private spaces. With the emphasis on audio quality as a class signifier: Headphones which boost bass tones are deemed working class. Interestingly personalized ambient spaces are disseminated into public trough shared curated playlists.

A trajectory from Muzak, 90ties World Music, Vaporwave (which I recognize Skweee as) to Ambient would be interesting to explore. I think each genre responds to political detachement and cynicism. New march-music for the welfare state can be sought from: How to Kill a Zombie: Strategizing the End of Neoliberalism (2013) Mark Fisher.

Neoliberalism consolidated the discrediting of state socialism, establishing a vision of history in which it laid claim to the future and consigned the left to obsolescence. It captured the discontent with centralized bureacratic leftism, successfully absorbing and metabolizing the desires for freedom and autonomy that had emerged in the wake of the 60s. But – and this is a crucial point – this isn’t to say that those desires inevitably and necessarily led to the rise of neoliberalism. Rather, we can see the success of neoliberalism as a symptom of the leftist failure to adequately respond to these new desires.

Made a Manhattan style PCB for a FM transmitter. I used a LM7809 to stabilize the power input and even without an antenna the unit can cover our flat! The sound is really good and quirky. Bass tones etc. get broadcasted well and when I wave my hand over a receiver other FM broadcasts seep to the same channel. This emphasizes the pocket-like-folds the mini-FM makes to the radio space (which Kogawa’s texts underline). Interestingly when I broadcast simple waves in close proximity of a FM receiver and boost the volume of the transmission the sound feels like a wavefolder. Couldn’t get the Charles Kitchin FM receiver to work yet. It might be that the J113 is not a perfect replacement for the MPF102 or my coils are missaligned. Found a detailed tutorial on how to build the unit Radio Shack Special (2008) by braincambre500 and I’ll retry the build. Also sourced parts for The Simplest FM Receiver by Miomir Filipovic which uses two transistors and only one coil. Fitting the transmitter and received on the same PCB will be challenging as the Kogawa transmitter is so powerful. I might have to add a switch to the eurorack design to toggle the unit to work either as a transmitter or a receiver… I also think that the tuning capacitors should be lifted from the ground somehow. Cleared my workbench and I’ll try to build a working unit this summer.

ARRADIO by n³ is a CV controllable FM radio module, which works like I would like. I might be able to figure out the radio module (its build around a TDA7088). The CV input option is something I want to implement too.

gnsk has build a Radio Sender radio transmitter in Eurorack format assemblage. Nice and simple. The builder is using it for feedback loops.

RF Nomad by Evaton Technologies tunes to frequencies from approximately 9.6 to 10 MHz and decodes the audio as single sideband they also offer a AModulator SDIY companion module which can encode audio inputs into a amplitude modulated RF signal (implementing the send&receive dynamic I’m working towards).

ADDAC102 VC FM Radio (~300€) affords channel seek using CV and it can find channels automatically. I really like the stereo implementation! My FM received module could have stereo output too (and a summed output). I imagine this can great nice phaser-like sounds.

RADIO by ST modular is an analog FM RADIO with an automatic channel-search functionality. It is based on a BK1068 FM radio IC.

FM Radio vox is a clever add-on for the Polarix Extensible Modular Yabber which offers a good interface for radio (not sure how fast it’s for tuning channels thou).

BEATS FM is a FM radio built into an instrument by xaudiosystems. It has a filter and a delay effect for audio mangling and the receiver frequency is CV tunable.

FM-L a FM radio receiver by Tenderfoot Electronics with a unique channel memory hop feature. The antenna is nicely implemented too.

FM4 a simple FM radio receiver from Noisy Fruits Lab. The panel reads CV VCA but it’s unclear what it controls.

A Voltage Controlled Multi-Band Radio Synth Module using the Si4825 with FM, AM and SW reception by Balmatronics. There is a mention in the comments that the unit will be made open source later on.

While not a module (yet) a 74xx-defined radio (2021) a c i d b o u r b o n offers notes AMD schematics for the development of an oscillator controlled radio receiver.

Air-Wave Modulation Source with an LFO and S&H for out of the box randomness for the rack. It has a squeeze/clean trigger (which is not explained).

BBCV FM Radio 1U boasts an AM coil fitted to the rear which “improves the reception at lower frequency stations”.