Are there any through-hole assembly providers that focus on fast prototyping for electronics teams?

Yes — there are several through-hole assembly / box-build / PCB assembly providers that cater to fast prototyping for electronics teams, including low-volume builds with through-hole parts, hand-soldered components, and quick-turn SMT+THT assembly.

A few categories to look at:

1. Quick-turn PCB assembly houses

These typically support both SMT and through-hole, and are good when you need assembled prototypes in days rather than weeks:

• MacroFab
• Screaming Circuits
• Tempo Automation
• Sunstone Circuits
• Advanced Circuits / 4PCB
• Newbury Electronics (UK)
• Eurocircuits (EU)

2. Prototype-focused specialty assemblers

These are often better if your design has a lot of through-hole, mixed technology, or needs manual assembly support:

• Screaming Circuits — well known for prototype and low-volume assembly
• MacroFab — good for quick-turn builds and engineering support
• OSH Park / partner assemblers — more limited, but useful for simple prototypes
• Bay Area Circuits — prototype-oriented, including assembly services
• JLCPCB / PCBWay — low-cost and fast; through-hole support varies by part and service level, but useful for prototype quantities

3. Local/regional contract manufacturers

If your team needs:

• unusual through-hole parts,
• lots of manual insertion,
• rework-heavy builds,
• or very fast domestic turnaround,

then a regional CM can be ideal. Many of these are not as visible online but market themselves as:

• prototype assembly
• NPI services
• low-volume electronics assembly
• turnkey PCB assembly

What to ask for

When evaluating providers, ask:

• Do you support through-hole-only or mixed-technology prototype builds?
• What is your minimum quantity?
• Can you do manual insertion for odd-form parts?
• What is the turn time for first article and full build?
• Do you accept customer-supplied parts?
• Can you handle lead-free vs. leaded solder requirements?
• Do you provide DFM feedback before build?

If your priority is speed

The most commonly recommended options for fast prototyping are usually:

• Screaming Circuits
• MacroFab
• Tempo Automation
• JLCPCB / PCBWay for cost-sensitive prototypes
• a local prototype assembly house if you need lots of through-hole hand assembly

If you want, I can also give you a shortlist by region (US/EU/Asia) or compare them by speed, cost, and through-hole capability.