DHT tube Headphone Amp

In this blog page I will describe the DHT headphone amp I built.

I decided to base my amp on this design,

Tubelab TSE

I bought their PWB
TSE PWB

But made some changes to it, which I will describe in the following.

This was kind of a long, complicated project. A "standard" build would have been much simplier, but there were some things I wanted to try and do.

Here is a list of the main decisions

Seperate chassis for the Power Supply
Coleman DHT Heater
300b tubes
Wooden chassis with G10 fiberglass top
upgraded "premium" parts

I bought pieces of g10 fiberglass from these guys

http://www.alphaknifesupply.com/zdata-ordering.htm

They had olive drab, 0.052 thick on sale for $2 each, so I bought a four of these to play with.

I bought a sheet of olive drab/forest green at 0.118 thick, and earth/coyote/tan at 0.128 thick.

All pieces are supposed to be 11.5 by 8.5, but some are not perfectly square, and they are a little longer, more like 11 5/8 by 8.5.

These six pieces were about $40 with shipping, they have a $25 min order.

I also ordered these

http://www.amazon.com/gp/product/B000HE86L4/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1

I used them to make the holes for the tube sockets in the g10 sheet.

Heatsinks: I have to make some adjustments for the heatsinking because I am bottom mounting all of the heatsinked parts, and I want to use larger heatsinks

I have a bunch of these I bought a while back from http://www.surplussales.com/Heatsinks/HeatSink6.html for $1 each(HSK) 401-67502
Heatsink. Spacing - Tapped holes for four TO-247. Tapped mounting holes on edge. Dimensions: 3-13/16" x 1-1/2" x 1/4"H.
Basically just a flat, thick bar.

I drilled new mounting holes in the PWB, and then drilled and tapped holes in these guys to hold them to the board.
For TBD, I mounted this heatsink to the bar(HSK) 401-27211
12 fin, flat bottom, 1 surface heatsink. Heavy 0.2" thick bottom plate. 4-3/16" x 2-9/16" x 11/16"H. Six #8 threaded base holes. Six #6 threaded base holes.

Sept 4. Went to Rockler and bought Padouk pieces. They sell as ¾ x 3 x 24 and ¾ x 3 x 48. I bought one of each, and got the guy there to cut them to two pieces 13 1/8 long (width of box) and two pieces 13.5” long (length)

Sept 30

I bought 1x6 African Mahogany, which is actually ¾ x 5 1/2, for $3.73 a foot at Home depot, I need about 4 feet but I bought 5 to have a little extra to play with.

I also bought a piece of this decorative perforated aluminum, to use as a cover for my PS box, so I can get air flow through the top.

http://www.homedepot.com/p/MD-Building-Products-1-ft-x-2-ft-Aluminum-Mill-Union-Jack-Sheet-56008/100250804

Tools

I own this jigsaw. Found it cheap on ebay a while ago. BTW, the quick change system for blades is very nice, can swap out blades in a few seconds with no tools. It uses t shank blades, I have been using Bosch blades for it.

http://www.amazon.com/Hitachi-CJ110MV-5-8-Top-Handle-Variable-Speed/dp/B000BS3LU2

I also have this little Bosch “Pony” router, which is also known as a laminate or trim router.

I bought this little router table top for it

http://www.rockler.com/product.cfm?page=30716&site=ROCKLER

I also bought this sander

http://www.homedepot.com/p/Milwaukee-5-in-Random-Orbit-Sander-6021-21/100609940?N=c28sZzv

I needed hook and loop sandpaper, so I bought this

http://www.ebay.com/itm/Mirka-Abranet-9A-232-AP-5-Mesh-Grip-Discs-Variety-Pack-/271094270881?pt=LH_DefaultDomain_0&hash=item3f1e7a4ba1

And this to hold the sandpaper, so I don’t wear out the pad when I change sandpaper.

http://www.ebay.com/itm/230446553866?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649