Boss PSA-100

The power brick that fed a generation of Boss pedals, and a model-name minefield that makes buying one today a research project.

Overview

The Boss PSA-100 is an AC adapter, a 9-volt wall wart built to power the company's compact effects pedals. That much is clear from the sources. Almost everything else is not. "PSA-100" is not a single, cleanly documented product in the available record. Sources reference the exact name "BOSS PSA-100" in listings on Blue Guitars ONLINE, Mercari, and notice-facile.com. The same research also turns up a swarm of lookalike designations: PSA-100S, PSA-100S2, PSA-100G, PSA-120S, PSA-120T, PSA-220S, PSA-230S, PSA-230S2. No source confirms whether any of these are the same product, related products, or entirely different ones. Treat that ambiguity as the defining fact about this adapter.

The clearest documented use of the PSA-100 comes from notice-facile.com. It lists the PSA-100 as a compatible power accessory for the DS-2 pedal. The pedal runs on either a 9V battery (6F22/6LR61) or a Boss PSA-100 AC adapter sold separately, with a current draw of 20 mA. So whatever else the PSA-100 is or was, it was the mains-power option for at least one documented Boss pedal, and it didn't come in the box. Beyond that, the research thins out fast.

Here is the honest problem with writing a spec sheet for this thing: manufacturer document excerpts state "9V DC" for the PSA-100, but beyond that single figure, almost no specification in the research is explicitly attributed to the model "PSA-100" by its exact name. Almost every other number that turns up belongs to something else. Third-party compatible adapters marketed under the PSA-100 name carry their own figures — a Joom listing for a "Punasi" compatible adapter claims 9V at 1A output, 100V–240V input, center-negative polarity, a 5.5mm outer / 2.1mm inner barrel, and a 1.5m wire. A separate Joom listing for a "PSA-100S2" adapter lists 1A, negative center, 5.5 × 2.1mm, and a 200 cm cable. An Amazon listing for a "Bgojot" adapter cites 9V DC while advertising compatibility with PSA-100S, PSA-120S, PSA-120T, and PSA-220S. None of these are the genuine Boss PSA-100, and the research does not permit treating any of their numbers as the real thing's specs. The genuine unit's output current, polarity, input voltage, and connector size are simply not documented in the sources available — a genuine gap, not a hidden value.

In practice, anyone hunting a PSA-100 today is buying on the Boss name and the model number, not on a published datasheet. Compatible adapters have filled the gap. Mercari listings for third-party "BOSS PSA-100 互換" (compatible) adapters are common, priced around ¥1,840 for a 9V 1.0A unit, with multi-packs also appearing. These are not genuine Boss products, and the listings say so.

Collectibility & Value

The market is dominated by third-party replacements rather than original units. A Mercari listing for a compatible "BOSS PSA-100 互換" AC/DC adapter rated 9V 1.0A carried a price of ¥1,840 at the time of the snapshot, and a three-piece set of compatible adapters also appeared in Mercari search results. No confirmed price for a genuine, original Boss PSA-100 appears in the research, and no original MSRP or launch price was found either.

On failures, the one concrete reliability data point concerns a sibling model, not the PSA-100 itself. A YouTube video documents a BOSS PSA-100G that had been in use for over twenty years before its wire broke (断線), prompting a tip replacement. That is a PSA-100G and should not be read as a PSA-100 failure report. It does suggest that cable breakage at the plug end is the kind of wear these Boss adapters pick up over long service. No capacitor replacement procedures, repair guides, or spare-parts availability information for the PSA-100 were found in the research.

Verify the exact model designation before buying, because the PSA-100 family naming is muddled and the sources do not resolve it. A listing that says "PSA-100 compatible" is selling a third-party adapter.