Switchcraft A4FB 4-Position XLR Circular Connector Plug - Equivalent & Substitute Parts

Part Overview

The Switchcraft A4FB is a 4-position circular connector plug with female sockets, designed for audio and instrumentation applications. This connector features solder cup termination, stainless steel construction, and a keyed orientation for secure mating. The A4FB is classified as obsolete, making identification of equivalent and substitute parts essential for ongoing system maintenance and component procurement.

Substiute Parts

A4FB

Switchcraft Inc.In Stock: 815A4FB Datasheet

Current PartRFQ

A4FBX

Switchcraft Inc.In Stock: 1221A4FBX Datasheet

DirectRFQ

AC4FB

Amphenol AudioIn Stock: 787AC4FB Datasheet

SimilarRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitute parts for the A4FB are identified based on strict electrical and mechanical compatibility criteria. The following parameters must match or remain within acceptable tolerances for direct substitution:

• Connector type (Plug, Female Sockets)
• Number of positions (4)
• Shell size (XLR)
• Termination method (Solder Cup)
• Mounting configuration (Free Hanging, In-Line)
• Fastening mechanism (Latch Lock)
• Current and voltage ratings (10A, 125VAC minimum)
• Keyed orientation for mating security

Two substitute parts meet these criteria: the Switchcraft A4FBX (direct manufacturer equivalent) and the Amphenol Audio AC4FB (cross-manufacturer alternative). Both maintain the core electrical and mechanical specifications required for functional equivalence in audio and instrumentation circuits.

Parameter Comparison

Engineering Selection Recommendations

Switchcraft A4FBX is the primary substitute for the obsolete A4FB. Both parts are manufactured by Switchcraft Inc. and share identical electrical and mechanical specifications, including cable opening dimensions, shell material, and contact finish. The A4FBX is currently in active production status with ROHS3 compliance, making it the preferred choice for new designs and direct replacement applications where Switchcraft components are specified.

Amphenol Audio AC4FB serves as a cross-manufacturer alternative when Switchcraft A4FBX availability is constrained. The AC4FB maintains core XLR 4-position plug configuration with solder cup termination and 10A current rating. Differences include a narrower cable opening range (0.118" ~ 0.256" versus 0.210" ~ 0.300"), zinc die cast shell construction instead of stainless steel, and tin contact finish instead of silver. The AC4FB includes IP40 ingress protection and specified operating temperature range (-25°C ~ 75°C), features not documented for the original A4FB. ROHS3 compliance is confirmed for the AC4FB.

Selection between A4FBX and AC4FB depends on cable diameter requirements and environmental specifications. The A4FBX accommodates larger cable diameters and maintains material consistency with the original design. The AC4FB is suitable for applications where cable diameter falls within its specified range and environmental protection rating is beneficial.

Frequently Asked Questions (FAQ)

Q: Can the A4FBX directly replace the obsolete A4FB without circuit modification?

A: Yes. The A4FBX maintains identical electrical ratings (10A, 125VAC), mechanical configuration (4-position XLR plug, female sockets, solder cup termination), and cable opening specifications (0.210" ~ 0.300"). No circuit or mechanical redesign is required.

Q: What is the primary difference between the A4FBX and AC4FB substitutes?

A: The A4FBX is a direct Switchcraft equivalent with identical specifications. The AC4FB is a cross-manufacturer alternative from Amphenol Audio with a narrower cable opening range (0.118" ~ 0.256"), different shell material (zinc die cast versus stainless steel), and tin contact finish instead of silver. Both maintain 10A current rating and XLR 4-position configuration.

Q: Is cable diameter compatibility a concern when selecting between A4FBX and AC4FB?

A: Yes. The A4FB and A4FBX accept cables with 0.210" to 0.300" diameter. The AC4FB accepts cables with 0.118" to 0.256" diameter. If your application uses cables larger than 0.256" diameter, the A4FBX is required. For smaller cables within the AC4FB range, both options are mechanically compatible.

Q: Are there RoHS compliance differences between these substitutes?

A: Yes. The original A4FB is RoHS non-compliant. Both the A4FBX and AC4FB are ROHS3 compliant, making them suitable for applications with RoHS requirements.

Q: Does the AC4FB's IP40 rating affect compatibility with the original A4FB application?

A: The original A4FB does not specify an ingress protection rating. The AC4FB's IP40 rating provides additional environmental protection but does not prevent substitution. If your application requires specific ingress protection, verify that IP40 meets your environmental specifications.

Q: What contact finish differences exist, and do they affect electrical performance?

A: The A4FB and A4FBX use silver contact finish; the AC4FB uses tin. Both finishes are standard for audio and instrumentation connectors. Silver provides slightly lower contact resistance, but both are acceptable for 10A applications. Contact finish selection should align with your existing connector inventory to maintain consistency in mating pairs.