• Item: 150W power amp Holton inpsired  
  • Type: retro-thermionic “fiih”  
  • Posted: 3 January 2020  
  • Builder: mwhouston  
  • Country: Australia  
  • Comments: 0  


This is my fifth Holton (assieamps) build. Riding on the success of two 150W and lately two 300W (500W into 4omhs) I have built another 150W amp. The last two builds (300W) are with Holton's latest amp modules which use dual die lateral FETs. These were specifically designed with hifi in mind. Each FET will handle 250W or 220V or 16A. In the 300W versions there are eight power devices in this build only two per channel.

Once more a beefy PS (the absolute heart of any amp) with 300VAC tranni and 80,000uf of filter/storage caps. Snubbers this time are X2s but still with a 47uf first ploy cap. Diode bridge is soldered directly to the first cap to ensure high current delivery. All soldering is with WBT silver solder (4%). Extra heavy speaker binding posts and quality RCAs used. An over-size heatsink and two 80mm silent fans (running low voltage) provide cooling. Enclosure is steel and AL 3U and with the PS mounted on a sub-chassis the whole amp is very stiff but not too heavy. Power switch is rated 16A and the enclosure is earthed and fused.

The overall sound is extremely smooth and natural from top to bottom. Bass again is the signature of a Holton amp. Deep, powerful and articulated bass with a linear delivery of mids and treble make for a very "listenable" amp. At this point, having compared the 300W "Precision" and this amp Precision has the edge when it comes to absolute transparency. Of course it always comes down to total synergy and personal taste. Either amp is a winner.


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