Barrel Power Supplies
Using Barrel Power Supplies Safely
Warning: Using the wrong PSU can irreparably damage your hardware.
Many retro consoles and computers used simple barrel-type power connectors, but voltages, currents, and polarity standards varied widely between manufacturers. While some systems can safely share power supplies, others use opposite polarity or different voltage requirements that can cause permanent damage if mixed.
The compatibility matrices below group systems by connector size and clearly show which combinations are safe, underpowered, or dangerous. Always consult the tables rather than assuming compatibility.
Power Adapter Information
| System | Voltage | Current | Barrel Size | Polarity | Official PSU Model |
|---|---|---|---|---|---|
| Group 1 – 5V DC, 5.5mm × 2.1mm, Centre Positive | |||||
| Neo Geo AES (later PRO-POW-3 / E) | 5V DC | 3.0A | 5.5 × 2.1mm |  |
PRO-POW-3 / PRO-POW-E |
| Neo Geo CD (Front & Top Loader) | 5V DC | 3.0A | 5.5 × 2.1mm | |
Neo Geo CD PSU |
| Group 2 – 6V DC, 4.75mm × 1.7mm, Centre Negative | |||||
| Nintendo Game Boy (DMG-01) | 6V DC | 0.7A | 4.75 × 1.7mm |  |
DMG-03 / MGB-005 |
| Group 3 – 7.5V DC, 4.0mm × 1.7mm, Centre Negative | |||||
| Sony PlayStation (PS1) | 7.5V DC | 2.0A | 4.0 × 1.7mm | |
SCPH-113 |
| Group 4 – 9V DC, 5.5mm × 2.1mm, Centre Negative | |||||
| ZX Spectrum +2 / +2A / +3 | 9V DC | 2.1A | 5.5 × 2.1mm | |
Sinclair PSU (various OEM) |
| NEC PC Engine Duo / TurboDuo | 9V DC | 1.5A | 5.5 × 2.1mm | |
DUO-AC |
| Sega Saturn | 9V DC | 1.5A | 5.5 × 2.1mm | |
MK-2103 |
| Nintendo NES (PAL) | 9V DC | 1.3A | 5.5 × 2.1mm | |
NES-002E |
| Nintento SNES (PAL) | 9V DC | 1.3A | 5.5 × 2.1mm | |
SNSP-002E(FRG) |
| Atari Jaguar / Jaguar CD | 9V DC | 1.2A | 5.5 × 2.1mm | |
PA-1400 / MK-4120 |
| Sega CD (Model 1 & 2) | 9V DC | 1.2A | 5.5 × 2.1mm | |
MK-1602 |
| Sega Master System | 9V DC | 1.2A | 5.5 × 2.1mm | |
MK-3025 |
| Sega Mega Drive / Genesis (Model 1) | 9V DC | 1.2A | 5.5 × 2.1mm | |
MK-1602-05 |
| NEC PC Engine / CoreGrafx / TurboGrafx-16 | 9V DC | 0.85A | 5.5 × 2.1mm | |
HES-ACA-01 / Turbo AC Adapter |
| Group 5 – 9V DC, 3.5mm × 1.35mm, Centre Negative | |||||
| ZX Spectrum (16/48K) | 9V DC | 1.4A | 3.5 × 1.35mm | |
Sinclair PSU |
| Atari 7800 | 9V DC | 1.0A | 3.5 × 1.35mm | |
C018187 |
| Atari 2600 (VCS) | 9V DC | 0.5A | 3.5 × 1.35mm | |
C017945 |
| Group 6 – 9V DC, 4.75mm × 1.7mm, Centre Negative | |||||
| Sega Game Gear | 9V DC | 1.2A | 4.75 × 1.7mm | |
MK-2103 (shared PSU with Saturn in some regions) |
| Group 7 – 9–10V DC, 4.75mm × 1.7mm, Centre Positive (see note) | |||||
| Atari Lynx (Model 1) | 9V DC | 1.0A | 4.75 × 1.7mm | |
PA-1400 |
| Atari Lynx (Model 2) | 9V DC | 1.0A | 4.75 × 1.7mm | |
PA-1400 |
| Sega 32X | 10V DC | 0.85A | 4.75 × 1.7mm | |
MK-1633 |
| Sega Mega Drive / Genesis (Model 2) | 10V DC | 0.85A | 4.75 × 1.7mm | |
MK-1633 |
| Sega Nomad | 10V DC | 0.85A | 4.75 × 1.7mm | |
MK-1633 |
| Group 8 – 10V DC, 5.5mm × 2.1mm, Centre Negative | |||||
| Nintendo Famicom (HVC) | 10V DC | 0.85A | 5.5 × 2.1mm | |
HVC-002 |
| Nintendo Virtual Boy | 10V DC | 0.85A | 5.5 × 2.1mm | |
VUE-002 |
- Sega Mega Drive 1 vs 2: opposite polarity — swapping PSUs will fry the console ⚠
- 9V vs 10V PSUs: Many vintage power supplies were unregulated — a “9V” adapter could output 10–11V off-load.
- For this reason, Atari Lynx (9V) and Sega 32X / Nomad / Mega Drive 2 (10V) supplies are effectively interchangeable. They are grouped together as 9–10V to reflect this safe cross-compatibility.
PSU Cross-Compatibility
Compatibility Key
| Symbol | Meaning |
|---|---|
| ✓ | Safe – barrel fits, voltage/polarity correct, PSU current ≥ system requirement |
| – | Underpowered – fits & matches, but PSU current too low |
| ✗ | Dangerous – wrong voltage and/or polarity |
3.5 × 1.35 mm barrel
| System ▶ PSU ▼ |
ZX Spectrum (16/48K) | Atari 7800 | Atari 2600 (VCS) |
|---|---|---|---|
| ZX Spectrum (16/48K) | ✓ | ✓ | ✓ |
| Atari 7800 | – | ✓ | ✓ |
| Atari 2600 (VCS) | – | – | ✓ |
| Header colour | Voltage / Polarity Group |
|---|---|
| 9 V DC, centre-negative |
4.0 × 1.7 mm barrel
Only the Sony PlayStation (PS1) uses this connector. No cross-compatibility with other systems.
4.75 × 1.7 mm barrel
| System ▶ PSU ▼ |
Sega Game Gear | Atari Lynx | Sega 32X | Sega Mega Drive 2 | Sega Nomad | Nintendo Game Boy (DMG-01) |
|---|---|---|---|---|---|---|
| Sega Game Gear | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ |
| Atari Lynx | ✗ | ✓ | ✓ | ✓ | ✓ | ✗ |
| Sega 32X | ✗ | – | ✓ | ✓ | ✓ | ✗ |
| Sega Mega Drive 2 | ✗ | – | ✓ | ✓ | ✓ | ✗ |
| Sega Nomad | ✗ | – | ✓ | ✓ | ✓ | ✗ |
| Nintendo Game Boy (DMG-01) | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ |
| Header colour | Voltage / Polarity Group |
|---|---|
| 9 V DC, centre-negative (e.g., Sega Game Gear) | |
| 9–10 V DC, centre-positive (e.g., Lynx, MD2, Nomad, 32X) | |
| 6 V DC, centre-negative (e.g., Nintendo Game Boy DMG) |
5.5 × 2.1 mm barrel
| System ▶ PSU ▼ |
Neo Geo AES | Neo Geo CD | ZX Spectrum +2/+3 | NEC PC Engine Duo | Sega Saturn | Nintendo NES (PAL) | Nintendo SNES (PAL) | Atari Jaguar | Sega CD | Sega Master System | Sega Mega Drive 1 | NEC PC Engine | Nintendo Famicom | Nintendo Virtual Boy |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Neo Geo AES | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ |
| Neo Geo CD | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ |
| ZX Spectrum +2/+3 | ✗ | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| NEC PC Engine Duo | ✗ | ✗ | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| Sega Saturn | ✗ | ✗ | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| Nintendo NES (PAL) | ✗ | ✗ | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| Nintendo SNES (PAL) | ✗ | ✗ | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| Atari Jaguar | ✗ | ✗ | – | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| Sega CD | ✗ | ✗ | – | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| Sega Master System | ✗ | ✗ | – | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| Sega Mega Drive 1 | ✗ | ✗ | – | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ |
| NEC PC Engine | ✗ | ✗ | – | – | – | – | – | – | – | – | – | ✓ | ✗ | ✗ |
| Nintendo Famicom | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ | ✓ |
| Nintendo Virtual Boy | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ | ✓ |
| Header colour | Voltage / Polarity Group |
|---|---|
| 5 V DC, centre-positive | |
| 9 V DC, centre-negative | |
| 10 V DC, centre-negative |
Notes & Warnings
- Mega Drive 1 vs Mega Drive 2 – opposite polarity; swapping PSUs will damage hardware.
- Nintendo PAL vs NTSC – PAL NES/SNES use 9V DC. NTSC NES uses 9V AC; NTSC SNES uses 10V AC. AC units are not compatible with DC supplies.
- Game Boy DMG – 6V DC centre-negative; not compatible with 9V power.
- Atari Lynx, Mega Drive 2, Nomad, 32X – 9–10V DC centre-positive; not compatible with centre-negative groups.
- Neo Geo AES (later) & Neo Geo CD – 5V DC centre-positive; not compatible with 9V/10V systems.
- General rule – PSU must meet or exceed system’s amp requirement; lower amps = underpowered.
Common Dangerous Combinations
| Mistake | Why it’s dangerous |
|---|---|
| Mega Drive 1 PSU → Mega Drive 2 | Opposite polarity (centre-neg → centre-pos) |
| Mega Drive 2 / 32X / Nomad PSU → Mega Drive 1 | Opposite polarity (centre-pos → centre-neg) |
| Any 9V PSU → Game Boy DMG | Wrong voltage (needs 6V) |
| Any DC PSU → NTSC NES/SNES (AC) | Wrong type (AC vs DC) |
| 9V PSU → Neo Geo AES (later) / Neo Geo CD | Wrong voltage and polarity (needs 5V centre-positive) |