Back at the 45 SET
Back at the 45 set, It's been a while since I have been able to build, Hospitals just won't let you go home to play...
I have breadboarded my first attempt, and it sounds wonderfull!!
Rectification with an 83V
An 0D3 to regulate B+ on input stage
A pair of RCA Globe 27 mesh plate for input
A NOS Stancor power tranny
James JS 5-200 Choke, Choke input from rect for smoothing
And James JS 6113 HS for OPT
All is working quite fine, with absolutely ZERO hum at the speaker.
I borrowed a few ideas from http://nullspace.us/45.html
I used the 53V instead, and 27's since I have many NOS
The Topology that I used is similar, but changed many things due to parts at hand.
I will have to put togather a schem to share, as I assembled my revisions off the top of my head. Thinking as most of us do, "I'll remember what I did".
I am no expert here, but am proficient enough to get it done.
Here are a couple pics as it's running...
I changed the 0D3 regulator to a 0C3 to regulate the input B+ to 105vdc
and the Globe 27's really shimmer.
I have been listening to smooth jazz for the last couple hours, and now with the B regulated at 105v the sound is just sooo sweet.:D
I'm in the process of designing a SET 45. Having built a EL34 PP, now I'm keen to try the SET madness. I'm interested to see your schematics when you can share them. What is the current operating point of the 45 in your design?
I am running the 45's which are NOS ratheon at 267 VDC plate at 37ma
and -44dc on the grid. I also have a set of NOS matched pair of kenrad's.
I could run them harder, but with only 2 sets of 45's I want to conserve their life.
I have center tapped 100 ohm resistors mounted at the filaments to provide a point for cath bias connection. At the center tap I have mounted a 10w 1500 ohm ww resistor bi-passed with a 100uF 100v cap.
I will draw up a schematic today and get it posted with explanation throughout the build from input to output "at least the best than I can explain". I have been building for the last 7 years and things "just make sense". I always breadboard amps first to debug everything within ratings and at times above, if it makes things sound better.
This is all I do everyday, retired and enjoying music.:D
Good day, Mike (mltube)
Winter is here...
Awoke to this white stuff all around...
Will be posting schematic soon.
Hey, d to the g
Snow melted on pavement, but grass still has 1". Sounds like more to come soon.
Have to get back to the 45set build now. :))
Have a great day, Mike
45 set circuit starter
Here are a couple circuits to get started. They are safe, but may want to tweak the 100 ohm 1w resistor in PS to get the B+ desired and you could go capacitor input for a little more B+, but I went with choke input for better regulation and lower B to start it off. I always start on the low side then bring things up a little at a time for desired effect. ** Note forgot to show ground on neg side of the PS caps. And circuit for amplifier next post. Sorry, going on almost zero sleep here...
Here is the amp section...:o
some reason pic didn't upload.... :(
2nd attempt circuit upload...
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