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
Audio Transformers
Audio transformers match impedance and provide galvanic isolation on audio lines, breaking the ground loops that cause hum. Filter by pin count, AC impedance, turns ratio and withstand voltage, then check insertion loss, frequency response and the mounting footprint before you commit to a part.
Part number search & selector
Find 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.
- 28
- PDF datasheets listed
- 25
- 3D file sets listed
- 26
- 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 an audio transformer actually do?
It couples an audio signal magnetically between two windings, so the two sides share no electrical connection. That breaks ground loops, which is the usual cure for hum between two pieces of equipment. It also transforms impedance, letting a source drive a load it can deliver power into, and it can convert between balanced and unbalanced wiring.
Why do so many audio transformers say 600 ohm?
600 ohm is a convention inherited from telephone and broadcast line practice, not a physical constant. It became the reference impedance for balanced audio lines, so equipment and parts were designed around it. A 600:600 part is a 1:1 isolation transformer. If the datasheet quotes a different pair, read the test frequency alongside it.
How do I work out the turns ratio I need?
Impedance ratio is the square of the turns ratio. To go from 600 ohm to 150 ohm the impedance ratio is four, so the turns ratio is two to one. Fix the source and load impedance first, then derive the ratio, then confirm the part carries your maximum signal level without the core saturating.
Does pin count tell me anything useful?
Yes. Pin count sets how many winding taps are brought out and therefore how the part can be wired: whether a centre tap is available, whether both windings are fully accessible, and how it sits on the board. Parts with different pin counts are not interchangeable even when the electrical ratings look similar.
Can I swap in a transformer with the same impedance?
Not automatically. Matching impedance is necessary but not sufficient. Compare turns ratio, DC resistance, dielectric strength, maximum level and insertion loss, and check the pinout and footprint. After any change, re-measure frequency response and distortion on your own board rather than relying on the datasheet curve.
Will an audio transformer affect sound quality?
It will have some effect. Every transformer has insertion loss, a finite bandwidth and a level above which the core saturates and distortion rises. How audible that is depends on the part and on how hard you drive it. Compare candidates at the same test frequency and level, and verify on your own hardware.
What isolation rating should I ask for?
Choose against the safety requirement that applies to the equipment, not against the normal working voltage. The datasheet dielectric strength is measured under a stated test condition, so read the condition with the number. If the design has to meet a specific standard, tell us which one and our engineers will confirm which parts qualify.
How do I request audio transformer samples or a quote?
If you already have 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, frequency range and any isolation requirement, and a sales engineer will shortlist candidates before you commit to samples.
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
Sample quantity, lead time and cost depend on the project stage and part number. Sales will respond on business days.
Published replacement reviews
Push-Pull Transformer Selection Comparison: VOOHU WHST06Q02E0 vs. Würth Elektronik 750316819
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