Rod Coleman DHT Filament Regulator Top view

The Coleman Regulator: Filament Supply for Directly-Heated Triodes

The Coleman Regulator is a purpose-designed Regulator for heating Directly-Heated Electron Tubes. It differs from general-purpose voltage regulators in a numbers of ways:

Adding Coleman Regulators to your DHT amplifier:

"Rod Coleman" DHT Filament Regulators are available as a kit: 2x PCB + all PCB parts. Sufficient to heat 2 Tubes. You assemble the Regulator yourself, using the PCB and components.

The Regulator power transistors are cooled by mounting to a heatsink - or you can use some amplifier-chassis or metalwork for cooling.

Please add your own rectified dc (rectifiers + capacitors) - these components are not supplied. If you need a neat solution for the Raw DC, there is now a PCB and some parts are now available, please find it here:

How to buy Rod Coleman Filament Regulator Kits

You can buy with PayPal. Please send me some email: dht (at) lyrima.co.uk and I will issue a PayPal Invoice - it can be paid from your PayPal account, or with Cards. If you need help choosing the right kits, please write, and I will reply quickly.

To buy Coleman Regulators, Please write to: dht (at) lyrima.co.uk - for a PayPal Invoice, or help with your order.

Paypal Payments are accepted. I can send a PayPal invoice - it can be paid with most Cards, as well as PayPal. Price List below: given in British Pound (GBP).

Price List for Filaments <2.5A

Cost for 2 (stereo) is GBP 32 including signed delivery
Cost for 4 (2x stereo) GBP 55.50 including signed delivery
Cost for 6 (3x stereo) GBP 74.50 including signed delivery

Price List for Filaments 3.5A: GM70, 845, 211, 3C24

Cost for 2 (stereo) is GBP 33 including signed delivery
Cost for 4 (2x stereo) GBP 56 including signed delivery
Cost for 6 (3x stereo) GBP 75 including signed delivery

Price List for Filaments 4.0 .. 6.5A: RCA813, 808, SV811, Eimac 100TL, 75TL

Cost for 2 (stereo) is GBP 35 including signed delivery
Cost for 4 (2x stereo) GBP 58 including signed delivery
Cost for 6 (3x stereo) GBP 77 including signed delivery

To buy Coleman Regulators, Please write to: dht (at) lyrima.co.uk - for a PayPal Invoice, or help with your order.


A PCB and some parts are now available to support the raw dc supply.

Raw DC Supply Kit:

PDF Technical Documents:

General Installation Manual (PDF):

Assembly Instructions (PDF):

Filament Bias - Application Note

- for 4P1L and 26 DHTs, a popular bias-method, eliminating input and cathode capacitors. Application Note (PDF):

V7 PDF manuals