This Product Selection Guide contains information to help select products in the Audio Transformers category on DigiKey.com
Like most other transformer products, audio transformers consist of two or more magnetically coupled coils of wire, usually wound around a magnetic core. They are distinguished from other transformer types by being adapted and characterized for use at frequencies across all or a significant portion of the human audible range spanning roughly 20 Hz to 20 kHz, and are used for isolation and transformation of information in analog format, as contrasted with transformers designed for transmission of information encoded using a digital signaling protocol. Examples include output transformers for vacuum tube amplifiers and voice coupling transformers for traditional telecom applications.
SelectionCharacteristics
Turns Ratio - Primary:Secondary: Indicates the ratio between the number of turns on a device’s primary winding and it’s secondary winding, as designated by the manufacturer.
Impedance - Primary (Ohms): Nominal characteristic impedance of the primary winding, also indicating if a primary winding center tap is provided.
Impedance - Secondary (Ohms): Nominal characteristic impedance of the secondary winding, also indicating if a secondary winding center tap is provided.
DC Resistance (DCR) - Primary: The DC resistance of the primary winding.
DC Resistance (DCR) - Secondary: The DC resistance of the secondary winding.
Transformer Type: Indicates typical application or product attributes as described by the manufacturer.
Frequency Range: The span of output frequencies supported.
Frequency Response: Describes the limits of variation in a device’s transfer characteristic over the frequency range indicated.
Voltage - Isolation: Indicates the level of electrical isolation provided between the primary and secondary windings of the transformer.
Insertion Loss: Refers to the amount of signal power or amplitude reduction that occurs when the audio signal passes through the transformer.
Return Loss: Characterizes signal loss due to reflection of a portion of an incident signal, expressed in dB as the ratio of incident signal power to reflected signal power.
Power Level: The rated power transmission capacity of the transformer.
Operating Temperature: Recommended operating temperature, typically given in a range or as a maximum. Exceeding these temperatures may affect performance or damage the device and other system components.
Approval Agency: An indication that the product meets the minimum safety standards of an approving agency. These agencies are either government entities or private third-party labs that protect consumer safety.
Mounting Type: Indicates how the device is attached.
Size / Dimension: The physical dimensions of the device. Typically length X width.
Height - Seated (Max): Indicates how far the device will extend above the surface to which it has been attached.
Termination Style: Selection of termination style used to connect the device to a system, such as flat lead, PC pin, and solder lug.
ProductExamples
| MFR PART # | 107B |
|---|---|
| DIGIKEY PART # | HM2368-ND |
| MANUFACTURER | Hammond Manufacturing |
| DESCRIPTION | 150CT Impedance Primary Ohms 12 Impedance Secondary Ohms 3.53:1 Audio Transformer 300Hz ~ 50kHz Through Hole |
| DATASHEET | Click Here |
| MFR PART # | TY-250P |
|---|---|
| DIGIKEY PART # | TY-250P-ND |
| MANUFACTURER | Triad Magnetics |
| DESCRIPTION | 1kCT Impedance Primary Ohms 1kCT Impedance Secondary Ohms 1:1, 2:1 Audio Transformer 20Hz ~ 20kHz Through Hole |
| DATASHEET | Click Here |
| MFR PART # | 117K4 |
|---|---|
| DIGIKEY PART # | HM2412-ND |
| MANUFACTURER | Hammond Manufacturing |
| DESCRIPTION | 8 Impedance Primary Ohms 25V Impedance Secondary Ohms Audio Transformer 100Hz ~ 9kHz Chassis Mount |
| DATASHEET | Click Here |
MediaLinks
Videos
What are Transformers? How Do They Work?
Switchcraft Pro Audio - RMAS1 3-Way Mic Splitter
Articles
Classic Tube Output Audio Transformer Overview