Midi Synth, oneUP! Custom Atari TIA Chiptune, put a CO104444 inside!

Midi Synth, oneUP! Custom Atari TIA Chiptune, put a CO104444 inside!



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  • Handmade
  • Materials: Controller device, Aluminum enclosure, Authentic Atari TIA IC CO10444D, Funk

Find more finely-crafted boutique devices at:


*Items Purchased after November 30th may or may not arrive before December 25th.

*This unit may or may not temporarily ship in a silver powder-coated metal enclosure rather than the pictured black powder-coated metal enclosure depending on the availability of supplies. However, this unit will be among the last ten to feature a metal housing of this type in either color.

*I'm temporarily out of the normal chipboard product packaging for these two midi instruments, so I'm taking an additional $10 off. The items will still ship securely, with ESD protection.

This midi synth now comes in three variations. You're currently looking at the reduced-cost version that comes with a socket for you to install your own Atari TIA IC. Please also see the shop for versions that come with the TIA IC installed.

Why you want this instrument instead of software or more delicate electronics:

- Reliability: You want an instrument that doesn't crash in the middle of a performance, so choosing hardware over software is a good idea.
- Durability: This is a device that can easily survive drops, spills, weather or crushing (unlike many small synths, notebooks or laptops).
- Rarity: You'll be the owner of a boutique instrument that's carefully built only in limited quantities, helping you to stand out from other acts.
- Compatibility: If you're using a controller with MIDI-out over USB, you're ready.

This is a new version of oneUP!, with a board redesign, adopting the form factor used for the Pocket Pokey synth; they're now a matching set. This is a midi-controlled TIA audio IC from an Atari 2600 and various classic arcades of the late 70’s and early 80’s. The TIA IC installed in this unit is new-old stock, meaning that it wasn’t pulled from a used game system; it was warehoused and the first time it made sound was when I tested it here. The video linked on this page contains a short audio demo. This instrument can do allot more, but the demo should whet your appetite. The oneUP! midi synth connects to your usb-capable midi controller or DAW by a common mini USB to USB A cable. The audio out is by eighth inch jack.

An audio demo can be found using this link.


Here's what my customers are saying about the electronic musical instruments that I build:

"I mentioned the Pocket POKEY on episode 31 of ANTIC The Atari 8-Bit Podcast, which will be published soon."

"...great products."

"Hey man, this thing looks awesome!"

"...it looks like a solid build, and I will def have some fun with it."

"Really neato noiz weapon!"


"Incredible seller, highest tier of excellence. Packaged carefully & beautifully!"


CC1: CH1 Tremolo, CH2 Tremolo, CH3 Volume, CH4 Volume, CH5 Volume, CH6 Volume

CC2: CH1 N/A, CH2 N/A, CH3 Bend Range, CH4 Bend Range, CH5 Bend Range, CH6 Bend Range

CC3: CH1 Decay Mode, CH2 Decay Mode, CH3 Decay Mode, CH4 Decay Mode, CH5 Decay Mode, CH6 Decay Mode

CC4: CH1 N/A, CH2 N/A, CH3 Arpeggiator On/Off, CH4 Arpeggiator On/Off, CH5 Arpeggiator On/Off, CH6 Arpeggiator On/Off

CC5: CH1 N/A, CH2 N/A, CH3 Arpeggiator Speed, CH4 Arpeggiator Speed, CH5 Arpeggiator Speed, CH6 Arpeggiator Speed

CC6: CH1 Polynomial Select, CH2 N/A, CH3 Polynomial Select, CH4 N/A, CH5 Polynomial Select, CH6 N/A

CC20: CH1 N/A, CH2 N/A, CH3 Portamento Speed, CH4 Portamento Speed, CH5 Portamento Speed, CH6 Portamento Speed

Pitch Bend: CH1 N/A, CH2 N/A, CH3 Glissando Bend, CH4 Glissando Bend, CH5 Glissando Bend, CH6 Glissando Bend

When connected to my Windows PC, my DAW recognizes oneUP! immediately. The midi synth has been tested on Android, with an OTG cable and works perfectly. The device was also tested with a hardware USB midi controller (without a computer) and it works well. Some musicians have used this instrument with a Mac device as a host; it should be fine if you already know your setup works with a USB midi output device. The device is small enough to fit in the palm of your hand or your pocket. The work was very much ‘by hand’, aside from the custom PCB which I designed and had made at a board house. The build is solid and durable. The audio output is nice, loud and clear.

The design is based off of Brian Peter’s TIA chip synth under the MIT license. Besides the provided demo, it’s capable of everything in Brian’s demo, too. This unit includes a socketed CO10444D “Atari TIA” audio IC. After the first twenty units, I will most likely be out of TIAs. The customer will then need to source his or her own TIA audio IC to plug into the provided socket.

Returns are usually fine with me, providing there’s no evidence of dissecting the item. I can also service this device for you in the future, if you stay in touch. Shipping will be insured, of course, and tracking will be provided.

Thanks for looking! If you like this product, you might also like the version that uses an Atari Pokey IC:


*If purchased before December 10th, this item should still arrive before Christmas.


Estimated arrival

The estimated delivery date is based on your purchase date, the recipient's location (actual or inferred), the seller's processing time and location, and the shipping carrier.

Other factors—such as shipping carrier delays or placing an order on weekend/holiday—may push the arrival of your item beyond this date.

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Feb 2-5

Jan 26

Order placed

After you place your order, Chocolatchips will take 3-5 business days to prepare it for shipment.

Jan 29-Feb 2

Order ships

Chocolatchips puts your order in the mail.

Feb 2-5


Estimated to arrive at your doorstep Feb 2-5!

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Ships from Virginia Beach, VA


Owner of Chocolatchips


20 reviews

5 out of 5 stars

erik amerika Sep 4, 2020

5 out of 5 stars

I actually have all my old game consoles from the 80s, but for performance I prefer dedicated hardware purpose built for audio. a few companies have made some accessible MIDI synth-boxes for SID, AY3, and other notable chips; but I tell ya, Chocolatchips is the first maker I have encountered that decided to engineer a road-worthy plug&play USB MIDI control interface for the TIA chip. it feels like this box was made just for me. if the window to your youth does not open as far back as Combat and Pitfall, maybe you won't get as excited. The oneUP! Synth by Chocolatchips has returned me to 1982, except this time I am armed with the sequencers of 2020. amazing build. amazing seller. I stumbled across these synths completely by accident while searching for something else MIDI related... thanks universe.

Blaine Buxton Mar 18, 2019

5 out of 5 stars

Fast shipping. Great service. Device came exactly as described. I love it. If you love the old sounds of video games from the past, this will put a smile on your face. Worked and sounded great out of the box.

Casey A. Childers Aug 6, 2020

5 out of 5 stars

This thing sounds incredible. Great communication.

Mark Feb 5, 2020

5 out of 5 stars

Happy to have this unit! Great seller communication and support!

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