diff --git a/vision_toolbox/backbones/darknet.py b/vision_toolbox/backbones/darknet.py
index ccc93ef..d7a85f1 100644
--- a/vision_toolbox/backbones/darknet.py
+++ b/vision_toolbox/backbones/darknet.py
@@ -64,12 +64,12 @@ class Darknet(BaseBackbone):
     def __init__(
         self,
         stem_channels: int,
-        stage_configs: list[DarknetStageConfig],
+        stage_configs: list[DarknetStageConfig | tuple[int, int]],
         stage_cls: Callable[..., nn.Module] = DarknetStage,
     ):
         assert len(stage_configs) > 0
         super().__init__()
-        self.out_channels_list = tuple(cfg.out_channels for cfg in stage_configs)
+        self.out_channels_list = tuple(cfg[1] for cfg in stage_configs)
         self.stride = 32
 
         self.stem = ConvNormAct(3, stem_channels)
@@ -93,7 +93,7 @@ def from_config(variant: str, pretrained: bool = False) -> Darknet:
             darknet53=((1, 2, 8, 8, 4), DarknetStage, "darknet53-94427f5b.pth"),  # YOLOv3
             cspdarknet53=((1, 2, 8, 8, 4), CSPDarknetStage, "cspdarknet53-3bfa0423.pth"),  # CSPNet/YOLOv4
         )[variant]
-        stage_configs = list(map(DarknetStageConfig, n_blocks_list, (64, 128, 256, 512, 1024)))
+        stage_configs = list(zip(n_blocks_list, (64, 128, 256, 512, 1024)))
         m = Darknet(32, stage_configs, stage_cls)
         if pretrained:
             m._load_state_dict_from_url(_BASE_URL + ckpt)
@@ -101,9 +101,9 @@ def from_config(variant: str, pretrained: bool = False) -> Darknet:
 
 
 class DarknetYOLOv5(BaseBackbone):
-    def __init__(self, stem_channels: int, stage_configs: list[DarknetStageConfig]) -> None:
+    def __init__(self, stem_channels: int, stage_configs: list[DarknetStageConfig | tuple[int, int]]) -> None:
         super().__init__()
-        self.out_channels_list = (stem_channels,) + tuple(cfg.out_channels for cfg in stage_configs)
+        self.out_channels_list = (stem_channels,) + tuple(cfg[1] for cfg in stage_configs)
         self.stride = 32
 
         self.stem = ConvNormAct(3, stem_channels, 6, 2)
@@ -129,8 +129,7 @@ def from_config(variant: str, pretrained: bool = False) -> DarknetYOLOv5:
             x=(4 / 3, 5 / 4, "darknet_yolov5x-0ed0c035.pth"),
         )[variant]
         stage_configs = [
-            DarknetStageConfig(int(d * depth_scale), int(w * width_scale))
-            for d, w in zip((3, 6, 9, 3), (128, 256, 512, 1024))
+            (int(d * depth_scale), int(w * width_scale)) for d, w in zip((3, 6, 9, 3), (128, 256, 512, 1024))
         ]
         m = DarknetYOLOv5(int(64 * width_scale), stage_configs)
         if pretrained: