Hammond 812A 150 Ohm Mic or Line to Grid Audio Transformer
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Create Free Business AccountKey Features
- Line or 150 ohm mic to 1 or 2 grids: 125/500 (150/600) to 10K/40K (12K/48K) ohms
- Max. primary D.C. unbalanced current: 0.4 mA
- +15 dBm maximum power level; +/- 0.5 dB from 50 Hz to 15 kHz
- Deep-drawn tin plated steel case with two 6-32 mounting studs and hardware
- Wire leads, 4" minimum length; 1.75" W x 1.25" D x 2.56" H max
- Humbucking construction with balanced split windings
- Electrostatic shield between primary and secondary
- RoHS and REACH compliant
The 812A is an 800A Series broadcast-quality input transformer that takes a line-level feed or a 150 ohm microphone into one or two grids. The primary is a nominal 125/500 ohms (150/600 ohms also listed) and the secondary 10K/40K ohms (12K/48K ohms also listed), which suits tube input stages fed from standard line or microphone impedances.
The primary accepts up to 0.4 mA of unbalanced D.C. current. Frequency response is +/- 0.5 dB max. from 50 Hz to 15 kHz, insertion loss is approximately 1 dB, and the maximum power level is +15 dBm with the specified characteristics, or higher with reduced low frequency performance.
Humbucking construction helps reject stray magnetic fields, and balanced split windings on both primary and secondary give circuit versatility; the primary may be used as the secondary and vice versa for impedance matching. An electrostatic shield sits between the primary and secondary windings.
It is housed in a deep-drawn steel case with a tin plated finish and fastens with two 6-32 mounting studs, supplied with hardware. Connections are made by wire leads of at least 4" in length. Maximum overall dimensions are 1.75" (44.5 mm) wide x 1.25" (31.8 mm) deep x 2.56" (65 mm) high. The 812A is RoHS and REACH compliant. Its listed shipping weight is 0.5 lbs (0.23 kg), and it is identified by UNSPSC 39121301.
Ideal For
- Line input to tube grid
- 150 ohm microphone to grid
- Driving one or two grids
- Tube preamplifier input stages
Overview
| Series | 800A Series (Audio Broadcast Quality) |
| Application | Line or 150 ohm MIC to 1 or 2 Grids |
| Product Type | Audio transformer, broadcast quality, with wire leads |
| Short Description | AUDIO TX B-CAST W/ LEADS |
Dimensions
| Overall Dimensions (Max) | 1.75" (44.5 mm) wide x 1.25" (31.8 mm) deep x 2.56" (65 mm) high |
Electrical
| Impedance Note | Below nominal impedance, power capability is lower and the frequency spectrum shifts downward; at higher impedances both shift upward |
| Frequency Response | +/- 0.5 dB max. from 50 Hz to 15 kHz |
| Maximum Power Level | +15 dBm with specified characteristics (higher levels with reduced low frequency performance) |
| Primary Nominal Impedance | *125/500 (150/600) ohms (* electrostatic shield between primary & secondary) |
| Secondary Nominal Impedance | 10K/40K (12K/48K) ohms |
| Max. Primary DC Unbalanced Current | 0.4 mA |
Identifiers
| UPC | 623980607153 |
| UNSPSC | 39121301 |
| Part Number | 812A |
Packaging & Shipping
| Shipping Weight | 0.5 lbs (0.23 kg) |
| Series Shipping Weight (Spec Sheet) | 0.5 lb. (0.2 kg) |
Construction & Finish
| Case | Deep-drawn steel case, tin plated finish |
| Leads | Wire leads, minimum length 4" |
| Mounting | Two 6-32 mounting studs with hardware |
| Windings | Balanced split windings on primary & secondary; primary may be used as secondary and vice versa for impedance matching |
| Construction | Humbucking |
| Electrostatic Shield | Between primary & secondary |
Compliance & Certifications
| RoHS Compliant | Yes |
| REACH Compliant | Yes |
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Frequently Asked Questions
What does the 812A connect?▾
It is listed for line or 150 ohm microphone to 1 or 2 grids.
What impedances does the 812A have?▾
Primary 125/500 ohms (150/600) and secondary 10K/40K ohms (12K/48K).
How is the 812A mounted?▾
The 812A has a deep-drawn tin plated steel case with two 6-32 mounting studs, and the mounting hardware is included. Connections are by wire leads with a minimum length of 4".
What is the frequency response of the 812A?▾
Frequency response is +/- 0.5 dB max. from 50 Hz to 15 kHz with approximately 1 dB insertion loss, at up to +15 dBm with the specified characteristics.
What are the dimensions of the 812A?▾
Overall dimensions are 1.75" (44.5 mm) wide x 1.25" (31.8 mm) deep x 2.56" (65 mm) high max.
Is the 812A RoHS compliant?▾
Yes. The 812A is listed as RoHS compliant and REACH compliant.
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