BassMaster 85

[Hammer]

Hello, ixtern!

I will post here some of my tested cirsuits. Now I see, that it will be two more versions of BassMaster:

- BassMaster 74, TL074 based synth, +/- 12V;
- BassMaster 69, CD4069 UBE based synth, +/- 6V;

All of them will have the cheapest MT3608 DC-DC step up converter.

ATTiny 85 tested with exponential V/Oct table, and it's working fine. I only still can't make any good sounding LPF. It's possible to replicate Moog's transistor ladder LPF, but it's not my goal.

Here are some new circuits of BassMaster 69:

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BassMaster69_PowerSupply.jpg
Description:	Dual power supply
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BassMaster69_VCA.jpg
Description:	VCA
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BassMaster69_SAWVCO.jpg
Description:	Saw VCO
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[Hammer]

I got carried away with sodering... BassMaster 69 is fully analog, with CV/Gate interface.

Video: https://www.youtube.com/watch?v=enAQWEEOE9k

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BassMaster69_Circuit_Diagram.jpg
Description:	BassMaster 69 circuit diagram
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Popcorn_BMS69.mp3
Description:		Download
Filename:	Popcorn_BMS69.mp3
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[Blue Hell]

Nicely simple electronics - I love that thyristor osc thing .. that must be about as simple as it can get

nice tune too

[Hammer]

[Hammer]

I've recode ATTiny85 USB -> CV/G converter to make glissando. Is it not necessary to have ADSR envelope driven LPF for saw bass?

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sawbass_BMS69.mp3
Description:	BassMaster 69 saw bass	Download
Filename:	sawbass_BMS69.mp3
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[Hammer]

First attempt to make eurorack case:

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[Mynasru]

Amazing sound! I may be able to design some PCBs in eagle if your interested

BTW do you know this website:
http://robstave.github.io/acs/
It has many lo-fi attiny85 examples.

[Hammer]

Mynasru, thank you a lot!

I'm very interested in PCB, but I still not sure with circuit design.

I've already made new version of expo conerter, and some changes in power supply circuit. And I want to use iPhone as MIDI source. Now I've tested ESP8266 WiFi module as CV/G source for Korg Monotron, and it's working good with no audiable latency. Also BassMaster should have some another filter.

I'm wating for parts to solder and test new version of BassMaster, and then it will be great to help me with PCB.

[Mynasru]

[Hammer]

[Hammer]

Eurorack case still is too expensive for me. So, I decided to make 'tiny' rack for testing new circuits for BassMaster. Height of modules is 100mm, width 10X mm.

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_DSC2798.jpg
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[Hammer]

BassMaster 85 with glide feature + Sallen Key LPF in tiny rack:
https://www.youtube.com/watch?v=0ASOCZw-jrE

[Hammer]

Hi again!

Two microprocessors are twice more fun than one!

I have tested several filters, even tried diode half ladder one. But I don't have enough knowledge to set them up well. Trials and errors...

Later I will return to the development of the diode filter (it sounds like boiling mercury, but I have still no success with resonance), and so far earned only Buchla-syle LPG.

But it works great!

First ATTiny85 is still used as signal source, and the second one is for vactrol LED controlling.

500Hz of Arduino PWM is not affect LDR. Now you do not need linear LDR because its possible to correct envelope by microprocessor. And I want to make sine modulation.

But vactrol must be fast. I ordered these vactrols: https://ru.aliexpress.com/item/FREE-SHIPPING-5PCS-LOT-VTL5C1-L5C1-DIP-4-IC-NEW-Original/32651474669.html

Are there any cheap fast nonlinear LDR or vactrols?

Also, you can just replace vactrols with 100k stereo pot, and it will be very useful for continuous saw bass like in my previous post.

Additional SYNC output is for a drum sequencer. It have its own MIDI channel.

There is still a lot of work, but it is already possible to design a PCB I think.

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BassMaster85VX.jpg
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BMS85_VX.mp3
Description:	BassMaster 85VX SAW test	Download
Filename:	BMS85_VX.mp3
Filesize:	711.93 KB
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[Mynasru]

[Hammer]

Nice!

[Hammer]

Tell me please, can I use CA3080 with 5V single supply?

[Blue Hell]

[Hammer]

Thanks, I will think.

[JovianPyx]

The two schematics found here:

http://electro-music.com/forum/post-436089.html#436089

are my design and I never tested them. Psyingo wanted to try them and found some weirdness for which he made modifications and said he made it work better. I don't know what he did and didn't get a copy of his schematic, so be warned, it may take some fooling around to get it to work. If I were to try it, I'd start with the upper and then the lower.

[Hammer]

I've tried this schematic: http://www.experimentalistsanonymous.com/diy/Schematics/Filters%20Wahs%20and%20VCFs/4007%20Based%20VCF.pdf

CV range occurred to be quite unuseful(

The last attempt will be to use digital potentiometers. And if the attempt turns out to be unsuccessful, then I will more accurately select the vactrols.

[Hammer]

[JovianPyx]

I designed with 4007 and 4069 in non-digital mode just to see if it will work, did several things that didn't work perfectly but were useful anyway, like saw to triangle with BS sine output (for a Fatman). I view the 4007 as a CMOS transistor array with 3 of each P and N types, sorta connected usually conveniently.

[Hammer]

I understand that, and it's great! And I always check such schematics. And I often sketch what I have checked. That's why I've been doing my synth for so long

I tried the second circuit with a stereo pot. instead of transistors, but I really did not like the sound of resonance. I have little experience, perhaps the input signal was high amplitude...

That's what I got:

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4069_SK.jpg
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[Hammer]

I checked the digital potentiometers. I have only x9c103, it is 10k. It's not cover full cutoff range. Need to use x9c104 I think:
https://www.intersil.com/content/dam/Intersil/documents/x9c1/x9c102-103-104-503.pdf

I can't hear any audiable clicks from fully breadboarded circuit. Maybe some hiss sound, but this is breadboard...

Using two analog oscillators it is possible to make an ADSR circuit without using a microprocessor. On the contrary, you can use a very small microprocessor, such as Attiny 10 for decay circuit.

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BMS85_VX9.mp3
Description:		Download
Filename:	BMS85_VX9.mp3
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BMS85_VX9_2.mp3
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Filename:	BMS85_VX9_2.mp3
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[Hammer]

JovianPyx, I've tested the 4069 state variable filter with k3446 MOSFETs. Filter closed at ~3V on MOSFETs gates, and opened on ~3.5V

I think it is possible to use level shifting op amp to get CV range closer to 0-5V.