I guess that some folks have been wondering what I’ve been up to the last month or so. Well, I’ve been trying to take it easy to let a shoulder injury heal. If physical therapy can be considered “taking it easy”. In the last month I’ve learned all about labrum tears. However, today something arrived in the mail and that means it’s time to get back to work.
I placed an order with Matt at Musical Power Supplies for a custom UL transformer with a 20% tap to continue the EL84 optimization study. Today it arrived.
After some discussions, I placed the order on May 1st. It arrived today in the mail, May 30th. This is a great turnaround time for a custom wound transformer. And the transformer is really nice. It has a good size core and the fit and finish is excellent.
I look forward to running it through its paces. Once I’m done with the EL84, I may try it out with a triode stage to see how it stacks up against the Edcor units. It’s always good to have multiple sources available for parts. And transformer availability can be especially problematic.
Now I need to get my desk cleaned off and get the test rig set up with the new transformer. I’m eager to see how this data compares with the data I took with the 40% UL tap. My plan is to use the same bias points to the maximum extent practical to see how operation compares across the operational envelope.
As always, questions and comments are welcome.
I’ve used Musical Power supplies for a few custom power transformers. One was kind of an oddball but after a little emails back and fourth he had nailed it. Very recommended.
Are you thinking SE or PP for an amp.
R
This characterization is for SE operation. I already have all the data for a 40% UL tap position. I need to collect and analyze the data for the 20% UL tap now that I have the transformer.
My wife had a labrum tear…not as fortunate as you were. Excruciating before surgery, unpleasant period after. Such joy, even as the supportive husband. At least I was able to complete my “ghetto” amp. Simple but mostly guessed design and parts laying around. Works better than expected but some weird waveforms at higher freqs. We’ll see if I bother with that….
Be sure to pamper that injury, but curious to see what you find with the alternative UL tap.
Dear Matt,
I am happy to hear you feel better now after the injury. Just take is easy and listen to the music.
How did you get injured?
Would you believe me if I said I was trying to tune up my 97mph fastball and over did it? Yeah, I wouldn’t believe that either.
As near as I can tell I did something to my shoulder while gardening. Specifically while mulching the beds around my blueberry bushes. Evidently shoveling a couple of cubic yards of mulch can do that when you’re not 18 years old anymore. At least that’s what my smart aleck doctor said. Not a big enough tear to require surgery but I am going to be rehabbing it for a few months. Just one of the joys of getting older. 🙂
I have a few years on you, trust me when I say – many more “joys” to come 😞
For a custom transformer that was good timing. I am glad you were able to get exactly what you wanted. Hope you feel better!