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 – 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 |
| Super Nintendo (PAL) | 9V DC | 1.3A | 5.5 × 2.1mm | |
SNSP-002E(FRG) |
| Nintendo NES (PAL) | 9V DC | 1.3A | 5.5 × 2.1mm | |
NES-002E |
| 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 2 – 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 3 – 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 4 – 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 5 – 9–10V DC, 4.75mm × 1.7mm, Centre Positive | |||||
| 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 Nomad | 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 6 – 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 |
| Group 7 – 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 8 – 7.5V DC, 4.0mm × 1.7mm, Centre Negative | |||||
| Sony PlayStation (PS1) | 7.5V DC | 2.0A | 4.0 × 1.7mm | |
SCPH-113 |
- Sega Mega Drive 1 vs 2: opposite polarity — swapping PSUs will fry the console ⚠
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 |
5.5 × 2.1 mm barrel
| System ▶ PSU ▼ |
ZX Spectrum +2/+3 | NEC PC Engine Duo | Sega Saturn | Nintendo NES (PAL) | Nintendo Super NES (PAL) | Atari Jaguar | Sega Master System | Sega CD | 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 Super NES (PAL) | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ |
| Atari Jaguar | – | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ |
| Sega Master System | – | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ |
| Sega CD | – | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ |
| Sega Mega Drive 1 | – | – | – | – | – | ✓ | ✓ | ✓ | ✓ | ✓ | ✗ | ✗ | ✗ | ✗ |
| NEC PC Engine | – | – | – | – | – | – | – | – | – | ✓ | ✗ | ✗ | ✗ | ✗ |
| Nintendo Famicom | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ | ✓ | ✗ | ✗ |
| Nintendo Virtual Boy | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ | ✓ | ✗ | ✗ |
| Neo Geo AES | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ | ✓ |
| Neo Geo CD | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ | ✓ |
| Header colour | Voltage / Polarity Group |
|---|---|
| 9 V DC, centre-negative | |
| 10 V DC, centre-negative | |
| 5 V DC, centre-positive |
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 |
4.75 × 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) |
4.0 × 1.7 mm barrel
Only the Sony PlayStation (PS1) uses this connector. No cross-compatibility with other systems.
Notes & Warnings
- Mega Drive 1 vs Mega Drive 2 – opposite polarity; swapping PSUs will damage hardware.
- Sega 9V centre-negative group – Mega Drive 1, Master System, Saturn, Sega CD (cross-compatible).
- Nintendo PAL vs NTSC – PAL NES/SNES use 9V DC; NTSC variants use 9V AC (not compatible).
- Famicom & Virtual Boy – 10V DC centre-negative; only safe with each other.
- Game Boy DMG – 6V DC centre-negative; not compatible with 9V systems.
- 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) |
| 9V 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) |