Mayer-inspired 4P1L

[EvilMose]

I am very much impressed by Thomas Mayer's designs and try out filament bias. His implementations use a lot of iron at considerable expense. My goal is to build a filament bias amp on the cheap (relatively speaking). Got the idea after reading this post.

The 4P1L, triode strapped, has considerably more gain than most DHTs (mu = 11ish), which considerably cuts down on the power required and dissipated by the filament bias. I am using six of Pete Milett's DC filament power supplies, which will allow biasing the tubes individually.

B+ is fed by Tubecad PS-2 supplies, one per channel. Using ASC motor runs as the ultrapath caps. Thinking the CCS for the driver stage may be overkill and that a 4k resistor would suffice. Probably also need a small cap to bypass the VR tube.

Going to have a ton of heat inside the chassis will all of those regulators and the filament bias - not sure how I will approach this yet.

[ratbagp]

Perhaps you could use that perforated orange material that Wavebourn uses to get rid of the heat. I presume it is metal of some sort.

One more 4P1L SE

ray

[Jaime]

I like this amp Sakuma style.
1 .- 4L1P tube is cheap.
2 .- Good power output. Same as 2A3 tube, 3wpc.
3 .- The same tube as the driver and output.
4 .- All DHT.
5 .- interstage transformer.
Do you see any downside?

[Wavebourn]

Originally Posted by ratbagp

Perhaps you could use that perforated orange material that Wavebourn uses to get rid of the heat. I presume it is metal of some sort.

One more 4P1L SE

It is perforated aluminum. I painted it using a fluorescent can spray.