MixSID Dual SID Board

While me and couple of hundred other SID fanatics are waiting for the SIDFX units to arrive, a new advanced dual SID board design appeared out of the blue; MixSID by Henning Bekel.

The arrival of MixSID is quite interesting, as feature-wise MixSID appears to be on-par with the SIDFX. Want to install any two SID models to any C64 model? Be able to switch between the installed SIDs on the fly? Choose between mono, dual-mono or true stereo operating modes? Have flexible selection for the second SID address space? Adjustable digi-boost for 8580? Volume level balancing for the installed chips? Reduced noise?

Check.

Both SIDFX and MixSID are capable with the above, and more. Of course SIDFX has even more some interesting features, including software configuration for the settings, and automatic configuration (voltage, filters) for the installed chips etc.

Comparing the two is not exactly the point of this article, but I can’t help myself doing that spec-wise, as both are advanced dual SID boards, with many similar features, and appearing around the same time.

The biggest difference between the two is actually the approach and design philosophy; SIDFX states being a plug and play, solder free solution that automatically detects the installed SID chips and configures itself accordingly. MixSID, in turn, is manually configured, comprehensively documented, open source, and DIY-friendly.

In fact, you can only have MixSID by building one yourself. You can go ahead and order or make your own pcbs, but Henning also sells the MixSID boards as kits, and I was sure to get myself one.

Stereo to C64 with DualSID

I finally assembled one of my DualSID kits. It’s an add-on board for C64 that makes it possible to install an additional SID chip with several different configurations. Detailed description can be found at the DualSID home page or in my earlier post.

Update in April 2018: The DualSID home page is gone, so I add the latest(?) versions of the assembly instructions here, plus link to Lemon64 forums.

• dualsid_assembling_instructions_6581_v3
• dualsid_assembling_instructions_8580_v3
• Discussion, mods and fixes on Lemon64 thread

Note: the transistor orientation is incorrect in the pcb silk screen in pcbs prior to pcb v3. However, letters E, B, C are printed correctly on the board, so check your transistor pinout. Pictures seen on this post have the transistor installed wrong way around. Transistor’s flat edge should face towards edge of the board. I’ve fixed mine since. </update>

I made this one as the 8580 version. Here’s the board – without and with SID chips.

For the convinience of installing it from one C64 to another if needed, I made all external connections and jumper settings using pin headers. When the board is like this, the second SID address selection is done by setting the jumper block in the 2×4 pin header to correct position. Instead of manually changing the jumper block’s position, I’m able to replace the block with 2×4 female pin header that is wired to e.g. a rotary swithch. That way the changing of second SID address can be done externally.

While I’m unboxing my own stuff…

It feels like it’s been ages since my last post. One reason for this feeling is probably the fact that I have moved during this break. Being more specific, I have moved in with my special lady. Who does her best to understand my interest to old computers and other weird stuff including my peculiar electro-analogish taste of music. Wish me luck ;)

Not starting a relationship blog here and still sticking to old computers and weird stuff; Some interesting SID related updates have emerged in the meantime for both SwinSID and 1541 Ultimate projects.

Micro SwinSID has got two firmware updates since my review. The updates have improved the ADSR envelope and filter emulation closer to real SID chip. The latest firmware also introduces 6581 filter emulation that can be selected by e.g. a switch by grounding one of the AVR pins. Unfortunately I haven’t had the change to get first hand impressions of the improvements as I’m lacking the means to program the microcontroller.

New DualSID boards

SID-goodness just keeps on coming. Some while ago Tomi Malinen released his DualSID twin-SID PCB. Depending on how the board is assembled and configured you can add either SID model to any C64 model. Additionally, the second SID address can be configured using jumpers. With DualSID board you can have both SID models in one C64 or configure yourself a stereo SID setup for any twin SID application. Anything goes. It’s probably the best and most versatile PCB design so far for adding another SID chip into C64.

I ordered myself few kits already a good while ago, but I have been lazy with my C64 activities lately and have not yet assembled them. I will have to come back to this topic once I have assembled and installed one.

Meanwhile if you’re interested for such board get familiar with the DualSID web site.

Here’s a picture of the kits I ordered:

Three DualSID boards and components for one 6581 and one 8580 model. While the board is the same there are different ways to assemble it depending on which SID model you are going to have as the second one. The FAQ on the site will help to understand the possibilities, limitations and why there are two different ways to assemble the boards.

Also, HVSC update 54 is out!