Transformer - Hammond, Tube Driver Interstage

Transformer - Hammond, Tube Driver Interstage

No image available
In Stock

Audio watts: 4
Impedance: 5k ohms
D.C. Resistance: 178 ohms
Inductance: 44 henries
Rated D.C. Bias Current: 30 mA


  • Designed for driver use ONLY in single ended tube output amplifiers. These units replace coupling capacitor circuits for improved sound.
  • Closed style with minimum 8" long leads.
  • All models use bifilar wound windings for exceptional coupling and bandwidth.
  • Minimum frequency response 20 Hz. - 20 Khz (± 1db max. ref. 1 Khz.).
  • The core is gapped to support the specified D.C. bias current.
  • Maximum working voltage - 400 VDC
  • Units are Hi-Pot tested at 1,000 VDC
  • Core uses Hi grade silicon laminations (29M6).
  • Units weight - 3 lbs. 2 oz.
RoHS Compliant
Item ID:
Hammond Part Number:
Product Measurements by Type
Audio Watts4 W
Frequency Response20 Hz - 20 kHz
Inductance44 H
Item Height3.12 in.
Item Length2.50 in.
Item Width3.12 in.
Lead Length8 in.
Mounting Hole Center to Center A2.0 in.
Mounting Hole Center to Center B2.25 in.
Mounting Hole Length0.38 in.
Mounting Hole Width0.20 in.
Primary D.C. Resistance178 Ω
Primary Impedance5 kΩ
Rated D.C. Bias Current30 mA
Secondary D.C. Resistance178 Ω
Secondary Impedance5 kΩ
Working Voltage, maximum400 V
Packaging Information
Packaging Dimensions2.5 in. × 3.12 in. × 3.12 in.
Weight (Packaging)1.2 lbs.

My Project Lists

You must be logged in to add items to a project list.

Specifications, Files, and Documents

PDF: Specification Sheet Specification Sheet231.84 KB

Questions and Answers

No questions have been asked about this product.

Product Reviews

5.00 out of 5 based on 1 reviews
- October 15th, 2020
5 out of 5

These little gems are the best kept secret for interstage transformers. Don't be put off by the Hammond brand name. Has Hammond made some duds in the past? Absolutely, but these are not. I made a driver circuit for a 211 tube with the 126B and it performs wonderful. If you frequent DIYAudio and Audio Karma, only believe about 25% of what you read from the "experts". These are as good as any other interstage out there in my opinion.