Transformers.
After a lot of research into many different brands of both OEM and after-market transformer manufacturers including Hammond, Heyboer, Mercury Magnetics and DeYoung Manufacturing, I decided to go with
O'Netics transformers.
Since these are the single most expensive part of any amplifier and have a huge impact on their sound, this is not where I wanted to cut any corners. Bud Purvine's transformers are a work of over engineered art.
The power transformer has primary taps for both 120VAC and 240VAC.
The secondary taps are as follows;
1) B+ 700VAC @ 400mA center tapped
2) Bias 100VAC @ 20mA
3) Heater 6.3VAC @ 10A
4) Rectifier Heater 5VAC @ 6A (Will feed pilot light)
5) Switching 15.3VAC @ 500mA
This transformer is severely underated, it
is capable of delivering up to 600mA on the B+ tap and is tested and guaranteed stable at 130° Celsius for up to an hour.
The output transformer is a 100W 'Hi-Def' model and has a primary of 2K2Ω and secondary taps of 4, 8 and 16Ω.
It boasts a flat power bandwidth and passes transients quickly, a perfect match for a modern high gain amplifier.
Again it is conservatively rated. Bud has assured me that it is safe for up to 300W and has the same thermal rating as the PT.
While on the subject of iron, the choke I chose was a 10H one from O'netics as well, it was designed specifically to be used in a tube amp.
The total cost for the three pieces was $512 USD plus taxes and shipping.
Package received.
First thing i did was to sand the laminates to prep them for painting.
Next using the end bells as masking I applied 5 coats of high temperature flat black paint.
I then removed the end bells and sand blasted them.
I chose to replace all the stock fastening hardware with all stainless steel barrel headed machine screws with Nylock nuts.
Chasing the threads after having to trim a few shorter.
I took the sandblasted end bells to Dragon Powdercoating and had them done in a light blue to follow the colour scheme of the build.
The end bells for the 10H Choke I decided to apply a baked enamel finish on them. Again they were sandblasted, 3 coats of primer, two coats of blue enamel and then baked in a rod oven @ 200°F for two hours.
Here is the finished product.
Here are the re-assembled PT and OT.