Pin count
Sets the number of winding taps and the board footprint. Parts with different pin counts are not drop-in replacements for each other.
Transformer products
4 PIN Audio Transformers
A four-pin package brings out both ends of each winding and nothing else, which suits a straightforward isolation or impedance-matching stage. Compare AC impedance, turns ratio and dielectric strength, then confirm the pin pitch and height against the board before ordering samples.
Part number search & selector
Find 4 PIN Audio Transformers part numbers
The table uses the current English-site product records, published selection fields and part-specific technical-file links.
* Frozen Image and Part Number columns · drag horizontally to review all specifications
| Image | Datasheet | Compare | Downloads |
Pins
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L/W/H(mm*mm*mm)
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AC impedance PRI:SEC(Ω)
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DC resistance PRI:SEC(Ω)
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Turn Ratio(PRI:SEC)
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Mounting Method
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Hi-Pot(AC)
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Insertion Loss（dB）
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Insertion Loss (dB)
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| Image | Part number | Datasheet | Compare | Downloads | Pins | L/W/H(mm*mm*mm) | AC impedance PRI:SEC(Ω) | DC resistance PRI:SEC(Ω) | Turn Ratio(PRI:SEC) | Mounting Method | Hi-Pot(AC) | Insertion Loss（dB） | Insertion Loss (dB) | Sample |
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WHATC-05-042AR | SPEC | 4 PIN | 14*8*4.4 | 600：400 | 105：105 | 1±1% | SMD | 1250V | 2.3 | — |
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WHTT4205 | SPEC | 4 PIN | 20.5*8.5*4.5 | 20000：20000 | 2370：2820 | 1±1% | SMD | 1250V | 1.3±0.5 | — |
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WHTT4203 | SPEC | 4 PIN | 20.9*8.5*4.5 | 600：287 | 155：144 | 1±2% | SMD | 1650V | 3.5 | — |
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WHTT4204 | SPEC | 4 PIN | 18.2*8.5*4.6 | 600：290 | 141：171 | 1±1% | SMD | 1250V | 3.3±0.2 | — |
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WHTT4202 | SPEC | 4 PIN | 18.2*8.5*4.6 | 600：287 | 180：160 | 1±1% | SMD | 1650V | 3.5 | — |
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WHTT4201 | SPEC | 4 PIN | 18.5*5.08*4.6 | 600：287 | 155：144 | 1±2% | SMD | 1650V | - | — |
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WHTT4103 | SPEC | 4 PIN | 15.2*8.2*5 | 600：600 | 62：3.2 | 6±1% | SMD | 1250V | - | — |
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WHTT4102 | SPEC | 4 PIN | 15.6*8.5*5 | 600：400 | 118：140 | 1±2% | SMD | 1500V | 3.85 | — |
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WHTT4101 | SPEC | 4 PIN | 15.2*8.2*4.9 | 600：600 | 160：133 | 1±3% | SMD | 1250V | - | — |
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WHTT4100 | SPEC | 4 PIN | 15.2*8*5.08 | 600：301 | 150：150 | 1±1% | SMD | 1250V | 3.3±0.25 | — |
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WHTT4V150 | SPEC | 4 PIN | 11*8.2*5 | 600：600 | 73：73 | 1±1% | SMD | 1250V | 1.5 | — |
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WHTT40013 | SPEC | 4 PIN | 14*8*4.4 | 600：346 | 157：146 | 1±1% | SMD | 1250V | 2.9±0.1 | — |
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WHTT4009 | SPEC | 4 PIN | 11*8.2*5 | 600：600 | 160：135 | 1±2% | SMD | 1000V | - | — |
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WHTT4006 | SPEC | 4 PIN | 14.5*8.2*5 | 600：600 | 48：42 | 1±2% | SMD | 1250V | 1 | — |
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WHTT4005 | SPEC | 4 PIN | 11*8.2*5 | 600：600 | 160：135 | 1±2% | SMD | 1250V | - | — |
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WHTT4002 | SPEC | 4 PIN | 15.2*8.2*5 | 600：400 | 62：3.2 | 6±1% | SMD | 1250V | - | — |
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WHTT4001 | SPEC | 4 PIN | 14*8.15*5.08 | 600：600 | 140：170 | 1±2% | SMD | 1000V | - | — |
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No matching part numbers
Broaden the selected filters or clear the current search.
By pin count
Choose an audio transformer by pin count
Pin count sets the winding taps and the board footprint, so start from the circuit you have.
How to select
Selecting an audio transformer in four steps
Work from the source and load impedance outward to the mechanical constraints.
- 01
Fix the impedance on both sides
State the source impedance, load impedance, signal level and frequency range, and whether the stage has to convert balanced to unbalanced.
- 02
Derive the turns ratio
The impedance ratio is the square of the turns ratio. A 600:600 part is 1:1; stepping 600 down to 150 ohm needs a 2:1 turns ratio.
- 03
Check level and isolation
Confirm the maximum signal level the core can carry without saturating, then confirm the dielectric strength the safety case demands.
- 04
Confirm the footprint
Match pin count, pin pitch and height against the board, then verify insertion loss and frequency response on your own hardware.
Parameters
What the audio transformer datasheet values mean
Each figure is measured under stated conditions; read the conditions with the number.
AC impedance
Quoted for a stated frequency, commonly 1 kHz. Read the test frequency with the value; the same part reads differently elsewhere in the band.
Turns ratio
Fixes the impedance transformation and the voltage relationship between windings. Impedance ratio equals turns ratio squared.
DC resistance
Winding copper loss. It adds to insertion loss and matters most when the winding also carries a bias current.
Dielectric strength
The isolation the barrier withstands under the stated test. Choose against the safety requirement, not against the working voltage alone.
Insertion loss
Signal lost through the transformer at the stated frequency. Compare candidates at the same frequency or the numbers do not mean the same thing.
Compare
Audio transformer families side by side
Pin count and impedance separate the families more than package size does.
Return to the selector ↑| Pins | Parts | L/W/H(mm*mm*mm) | AC impedance PRI:SEC(Ω) | DC resistance PRI:SEC(Ω) | Turn Ratio(PRI:SEC) | Mounting Method | Hi-Pot(AC) | Insertion Loss（dB） | Insertion Loss (dB) | Action |
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| 4 PIN | 17 | 11*8.2*5, 14*8*4.4, 14.5*8.2*5, 14*8.15*5.08, 15.2*8.2*5, 15.2*8*5.08, 15.2*8.2*4.9, 15.6*8.5*5, 18.5*5.08*4.6, 18.2*8.5*4.6, 20.9*8.5*4.5, 20.5*8.5*4.5 | 600：287, 600：290, 600：301, 600：346, 600：400, 600：600, 20000：20000 | 140：170, 105：105, 48：42, 160：135, 157：146, 73：73, 150：150, 160：133, 118：140, 62：3.2, 155：144, 180：160, 141：171, 2370：2820 | 1±1%, 1±2%, 1±3%, 6±1% | SMD | 1000V, 1250V, 1500V, 1650V | 1, 1.3±0.5, 1.5, 2.9±0.1, 3.3±0.2, 3.3±0.25, 3.5, 3.85, -, 2.3 | Not specified | Filter → |
| 5 PIN | 5 | 14.5*8.2*5, 14.5*8.2*4.8, 14.5*8.5*5.08 | 600：600, 600：365, 600：460, 300:600, None | 120：250, 138：130, 90.5：112：102, 45：55, 65：75 | 1±1%, 1±2%, 2±1% | SMD | 500V, 1000V | 2.8, -, Not specified | 1.3, Not specified | Filter → |
| 6 PIN | 6 | 13.2*8.2*5, 13.5*9.5*7.5, 13.5*10.0*7.50, 14*8*4.4, 15.2*9.0*7.5 | 600：316, 600：412, 600：430, 10000：10000, None | 155：150, 115：115, 30：38, 50：50, 170: 170, 1620:1620 | 1±1%, 1±2%, - | SMD, DIP | 1200V, 1250V, 1500V, 3750V, 3880V, 4600V | 2, 3.0±0.25, 4.5, - | Not specified | Filter → |
Application review
Where audio transformers are used
Confirm line level, balanced wiring and the impedance ratio the circuit expects.
Professional audio and broadcast
- Confirm line level, balanced wiring and the impedance ratio, then check insertion loss and frequency response across the audio band.
Intercom and paging systems
- Long runs pick up ground noise. Verify the isolation rating and that the core handles the maximum drive level without saturating.
Industrial and instrumentation audio
- Check the dielectric strength against the safety case, and confirm the operating temperature range covers the enclosure.
Consumer audio interfaces
- Height and footprint usually decide. Confirm the pin pitch and that frequency response holds at the levels the interface actually uses.
Documents
Audio transformer datasheets and drawings
Datasheets carry the tested impedance, frequency response and recommended footprint.
Showing representative available file sets. Search to find a specific SKU.
- 17
- PDF datasheets listed
- 17
- 3D file sets listed
- 16
- PCB footprints listed
VOOHU’s published product content is reviewed by its engineering team. Specifications, downloads and technical support information are tied to specific part numbers, so you can verify them before requesting samples or a quotation.
Category overview
What an audio transformer does, and why 600 ohm
Two questions come up on almost every audio transformer enquiry: what the part is actually for, and why so many datasheets quote 600 ohm.
Discuss a new design
Contact FAE for a replacement assessment.
Already have a part number? Request samples or a quote.
What it does
An audio transformer couples a signal magnetically between two windings. Nothing conducts across the barrier, so a ground loop between two pieces of equipment cannot push current through the signal path. That is what removes hum. The second job is impedance matching, so a source drives a load it can actually deliver power into.
Why 600 ohm keeps appearing
600 ohm is a telephone and broadcast line convention rather than a law of physics. It became the reference impedance for balanced audio lines, so parts and equipment were built around it. A 600:600 transformer is a 1:1 isolation part; a 600:150 part steps impedance down by four, which is a 2:1 turns ratio.
How to wire and verify it
Identify the primary, secondary and any centre tap from the datasheet pinout, not from the physical symmetry of the package. Keep the balanced pair symmetric on the board. Then measure insertion loss and frequency response on your own hardware, because the published curve is taken under the datasheet's stated source and load.
FAQ
Audio transformer questions engineers ask
Answers cover function, the 600 ohm convention, wiring and interchange limits.
What does a 4 PIN audio transformer give me?
Four pins bring out both ends of the primary and both ends of the secondary, with no centre tap. That covers the common case: isolate two stages, or match one impedance to another. If your circuit needs a centre tap for a balanced feed or phase splitting, you need a part with more pins.
When would four pins not be enough?
When the circuit needs a tap partway along a winding. Centre taps are used for balanced drive, phase splitting and some bias arrangements. Those require five or six pins. Decide from the schematic which nodes you have to reach, then pick the pin count that exposes them.
How do I identify primary and secondary?
Read the pinout from the datasheet for the specific part number. Do not infer it from the package outline, because a four-pin body is usually symmetric and gives no visual clue. Getting primary and secondary the wrong way round inverts the impedance transformation.
Are 4 PIN parts with the same impedance interchangeable?
Not automatically. Compare turns ratio, DC resistance, maximum signal level, dielectric strength and insertion loss, and check the pin pitch and recommended footprint. Even when two parts share an impedance figure, they may be specified at different test frequencies, which makes the numbers hard to compare directly.
How do I request samples or a quote?
With a complete part number, send the part number, quantity, delivery region and the date you need it. If you are still selecting, send the source and load impedance, signal level and frequency range, and a sales engineer will confirm candidates before samples are arranged.
Engineer support
Continue after product selection
Send the candidate part number and the condition you need reviewed. Sample support can be added after the selection is clear; commercial questions may be discussed in the same engineering conversation.
- 1Selected part numbers
- 2Engineering review
- 3Sample request
- 4Commercial discussion
For a replacement review
- Original part and datasheet
Include the document revision
- Operating conditions
Temperature, isolation voltage and PoE current basis
- Package constraints
Pin count, pitch and spacing between pin rows
- Project stage and annual volume
To help prioritize samples and evaluation
- Target review date
When you need candidates and a comparison of differences
Engineering review identifies candidate parts and explains the differences.
For samples and a quotation
- Candidate part numbers
From the selector or engineering review
- Quantity and project stage
Prototyping / pilot build / production
- Required delivery date
Specify sample and production timing separately
- Required documentation
Compliance documents, material declarations or third-party reports
Samples are free of charge. Sample quantity and lead time depend on the part number and project stage. Sales will respond on business days.
Published replacement reviews
Push-Pull Transformer Selection Comparison: VOOHU WHST06Q02E0 vs. Würth Elektronik 750316819
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