A-5000 DHT Power Amplifier

The A-5000 DHT monoblock, like all Allnic Audio products, uses Permalloy (iron and nickel alloy) for its transformer cores. Allnic is grateful to Mr. G.W. Elmen of Western Electric for inventing Permalloy for transformer core use, and in so doing, providing an enormous service to recorded music listeners everywhere.

The A-5000 DHT has the following features:

• All Direct Heated Triodes : The A-5000 DHT monoblock amplifier is a pure direct heated triode, tube rectified power amplifier. It uses only direct heated, single ended tubes from input to output. The first stage is a new old stock Marconi HL-2; the second is a new old stock STC 3A110A (or equivalent); the third is the famous 300B. This is an ideal combination of pure direct heated triodes, resulting in unparalleled faithfulness to the incoming signal, incredible musicality and detail, and quick, articulate bass.
• Real power drive : The driver tube is the 3A-110A (or equivalent). Allnic uses this direct heated triode 3A-110A tube to drive the 300B to its correct specifications via a choke plate inductor. The choke inductor (with a 100% permalloy core) has very low power loss and an infinitely high load impedance. This configuration is an ideal drive stage for the single ended 300B and produces 10 watts of pure class A, extremely low distortion, high power output.
• Nickel alloy output transformer : Allnic uses sophisticated ratio mixed nickel permalloy PB cored output transformers. Because of their extremely high initial permeability, it is possible to use lower turns on the primary winding while retaining very high ‘open circuit inductance”. That means a resulting very wide frequency range and low distortion bass response. This is another reason why the A-5000 DHT excels over other 300B power amplifiers. Allnic also uses a very big nickel core, so as not to be magnetically saturated at a igh current of level of 200mA.
• Fixed bias control grid : Allnic prefers to use low distortion and high output “fixed bias” rather than the relatively higher distortion and lower output “self bias” method. That way, it is possible to eliminate the use of cathode resistors and their associated heat production.
• Natural negative feedback -:The A-5000 DHT applies about -6dB of negative feedback. This is a very complimentary amount of negative feedback that differentiates the Allnic 300B single ended amplifiers from the standard, which have a very coloured and weak speaker driving force. With this natural feedback, the A-5000 DHT has a relatively high “damping factor’, very low distortion, and a higher S/N ratio, without losing the signature, single ended natural sound quality.
• Hard wiring : The A-5000 DHT is all hard wired; circuit boards are not used.
• Beautiful 20kHz square wave response.