Hey everyone,

I'm considering doing a short run of inexpensive replacement boards (fully populated) for people with faulty Say it Again boards / SAD4096 ICs. But prior to even designing a replacement prototype, I wanted to see how many people would be interested in something like this or are in need of one. It is only a matter of time before the remaining SADs out there croak. This would be a plug and play replacement board based on a Digital PT2399 Delay/Reverb IC that has very analog delay/BBD sounding qualities. I've seen others available, but they're usually priced in the $140 range.

EDIT: I see there are already inexpensive boards available. http://www.parts4pinballs.com/product_info.php?products_id=4668

_{Post edited by thedefog : Found replacements}

I'd still be willing to make these boards. Price would probably be about the same, $50+, when all is said and done, plus shipping. The delay design would be a little different than the other approaches I've seen.

If I see more than 10 interested, I'll just etch these and populate them myself, keep the cost down. If there is enough interested past that, I would consider doing a board run and either selling them as kits or populating/selling them myself, but that would up the cost at least $20 or more.

I may need help with some current/voltage readings, as well as a guinea pig eventually as I don't actually own a Centaur to test a design in, but I've built and designed well over 100 guitar effects pedals at this point (10+ original designs), so I'm pretty confident in the audio effect realm.

I think that is enough Ins to perk my interest in building a prototype. I'll start to plan out a design now. I'll post updates as I make progress. I want this to be a community-based thing, so people are completely welcome to etch/build their own. I know not everyone has the time to do so, nor cares to do that sorta thing, which is why I don't mind making a small batch of them. When I have something tested that works properly, I'll post all the BOM and PCB board traces, etc.

Wow, great response.

Honestly it boils down to bucket-brigade Delay ICs not being available anymore. There are clones being made by a company called Cool Audio, however, they produced a different type (Not SAD Reticon, Panasonic MN30XX series). They can be adapted to work with some modifications and many components to plug right into the SAD4096's socket with a daughter-board type adapter. However, the original design is prone to noise regardless, and the amount of components to create a daughter-board adapter works out to nearly as many as just re-creating a new board with modern parts.

I've already made some headway since I posted this. I started laying out the most simple PT2399 delay possible based on the spec sheet for it, I'll have to work on impedence balancing from the original machine, as well as the correct resistor value and wattage to drop the 43v down to around 9v where it can then be regulated by a 7805. Also need to figure out what value filtering caps for the power will be appropriate, when and where it should be filtered, and the right balance of filtering on the delay IC so that it best matches the characteristics of the original without introducting too much noise. I have a decent layout going already, but ended up with 1 jumper already, so will redo once I finish the first version.

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It is good because it is cheap, and for low-fidelity operation has decent signal to noise ratio. It has built-in filtering that rolls off high-end frequency starting around the 2Khz range, so it is a perfect substitute for the SADXXXX chips because they had similar filtering to eliminate noise. And if the PT2399 ever dies, $2 per chip is certainly more affordable than a used/pulled now probably $200 SAD4096 that could crap out at any moment.

I've built several different PT2399 delay designs for effects pedals and one for my analog synth I built. GGG PT delay, Rebote 2.5, Dual Delays, Chorus pedals based off of the PT chip, and some weird/experimental sound mangling devices as well.

I use Eagle if I'm going to do a professional board run. When I'm mocking things up and prototyping, DIY Layout creator is actually a lot easier to work with and allows me to just press-n-peel PCB traces from my laserjet and iron on/etch quickly.

The PT2399 has similar characteristics. It is definitely low-fidelity. If the general consensus is that people want a higher-fidelity delay, that could be done as well, and a filter control added in to roll off the high-end. That may be more expensive though, and would require me diving into some ICs I'm not completely familiar with.

Is he a pinsider? I'd love tocontact him if so and maybe we could collaborate on this. I saw that page as well when I was hunting around to see if it had already been done. The PT2399 wasn't on the market at the time he built that design with the Holtek chip. Unfortunately that IC is not available anywhere. I'm going to need a little design-checking along the way due to the fact I don't physically own the machine. I can re-create all of the voltages though on my bend supply and simulate it in circuit to the best of my ability.

I'm off to breadboard the delay using a 43v power supply to try and figure out just the right resistor drop /wattage to work efficiently with both the 5v regulator/rail needed for the PT2399 and to create a 12v rail for the buffer. And later when I get bored I'll blow up some capacitors.

I got the PT2399 breadboarded and powered on a 45v rail, wirewound flameproof resistor in line to drop the voltage down, then divided for the 12v & 5v regulated section. Probably going to throw a 12v regulator on there as well like the original SIA board did. The tricky part will be isolating the digital and analog ground paths on the board. I'll be slowly working through this and will eventually design and etch a prototype. In the meantime, someone else is reproducing the boards that Clive originally made with his permission that may be able to get them to owners much sooner that I probably will be able to do. I'm guessing it will be a good month before I get a working prototype, time permitting, but I can hopefully fill the remaining need for these boards.

Making more progress here. Got a schematic built that looks good on paper for both the voltage drop/filtering & power regulating without having to use a 12v regulator via a zener diode like on Clive's design. I'm going to begin playing with some layouts incorporating it. Looks like there is plenty of room to allow for a jumper-free design as well while also keeping the board size about 1/2 of the original.

Agreed. I emailed Clive Jones and he didn't seem to have anything to do with the original. However, he seemed like a really nice guy and said when he had a moment he'd take a look regardless.