My KT88 Build
Posted: Wed Jun 22, 2022 7:23 am
Here is my take on the Blueglow et. al. SE KT88 Amp.
As you can see it deviates slightly from Mark's design in that I have a separate chassis for the power supply and have used a pair of 872A's instead of the 5AR4. I bread-boarded the 5AR4 and it worked perfectly, I just like the mercury vapour rectifiers better - much more interesting to look at. I also tried a pair of 866A's and a quad, they also worked perfectly - but I'm keeping the 866A's for my next project.
Here is a snap showing the inside of the power chassis.
I'll add a reply to this post with more pics of the signal chassis internals and audio analyzer plots of THD and frequency response.
The amp is everything Mark said it would be, it sounds great, zero hum and it was great fun to build.
Phil Davies.
- Up and running.
- kt88_up_and_running_small.jpeg (181.27 KiB) Viewed 729 times
- Rear view.
- kt88_chassis_rear_view_small.jpg (188.52 KiB) Viewed 729 times
As you can see it deviates slightly from Mark's design in that I have a separate chassis for the power supply and have used a pair of 872A's instead of the 5AR4. I bread-boarded the 5AR4 and it worked perfectly, I just like the mercury vapour rectifiers better - much more interesting to look at. I also tried a pair of 866A's and a quad, they also worked perfectly - but I'm keeping the 866A's for my next project.
Here is a snap showing the inside of the power chassis.
- Power chassis internal.
- kt88_power_chassis_internal_small.jpg (199.47 KiB) Viewed 729 times
I'll add a reply to this post with more pics of the signal chassis internals and audio analyzer plots of THD and frequency response.
The amp is everything Mark said it would be, it sounds great, zero hum and it was great fun to build.
Phil Davies.