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Boss Boss PQ-4 Hi-Fi Plus Mod Kit


WARNING! — The OPA2134PA opamp, of which are included in many of my kits, is currently extremely hard to find. Mouser and Digikey are currently out of stock with none expected until 2023. I have hundreds in stock. BE CAREFUL BUYING THE OPA2134PA ON EBAY. THE MAJORITY ARE FAKE! Manufacturers in China are rebranding cheaper opamps and selling them as OPA2134PA opamps. I test all my OPA2134PA opamps I buy. You can easily test whether a OPA2134PA has been rebranded. Do this, take some Acetone on a Q-tip and rub across the lettering of the opamp. If it is Fake the ink used to print the labeling will dissolve into the Q-tip.

These are highly sought after. Bringing top money on eBay. Stock they are really great tone shaping pedals but are rather noisy. This mod reduces noise and adds clarity to an already good circuit. With this mod we replace the cheaper noisy op-amp chips with low noise higher quality chips.

Lower quality capacitors are also replaced reducing noise even more and also adding a more focused Hi-Fi tone to the circuit. Noise is substantially reduced and the signal is passed through preserving the original tone of your guitar. You’ll be shocked at the improvement this mod will make on this.

I am unsure if there are different versions of this circuit so before you order make sure your pcb looks like this.

Mod Options

For Guitar, For Bass


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Boss Boss PQ-4 Hi-Fi Plus Mod Kit
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