Re-entering amp design mode has meant having to generate schematics, which has never been something I could do well in freehand. When I was still at Logitech, I could use my OrCAD license for tube projects as long as I could provide the vacuum tube (valve) library, but those days are gone and I’ve had to look for an alternative.
A little searching led me to KiCad — a totally free EDA tool suite (from folks at CERN!) that even has library parts for a few common tubes/valves. It’s easy to use, and has library parts for most anything you’d need in a tube amp. The weakest library (for tube stuff) is the transformers, but there are reasonable ways to get around that (see my next Beamer schematic).
Now I’m trying to make myself plan a proper layout, but since I don’t use PCBs that’ll be in a 2D mechanical CAD program. I’ve just started to get serious about it, but LibreCAD looks promising…
Here’s that schematic I referred to.
(Looks like WordPress makes *some* things more complicated…)
I’m not crazy about “Beamer” as an amp name (derived from the push-pull 6BM8 design), but that’s all I’ve got. Suggestions are welcome!
The more I look through my schematics & notes from 15 years ago, the more I realize that my Beamer project really wants to be a stripped-down Verberator II: no reverb or tremolo (we have boxes & software for that these days), just a wide tonal range, from clean to dirty.
Today I dug out my old Verberator II prototype (grrrr: link not working) chassis and immediately realized that I’d already done much of the work toward a Beamer. I suspect I gave up on it (and amp building) because the tremolo was more than I could master. With all the crazy shit you can do with software these days, it makes sense to leave that to post-production and concentrate on the core function (TONE) with electric guitars. So we’re talking about a gain pot, a foot-switchable ‘boost’ stage, and a master volume, with one or two tone stacks (or single-pot controls).
The rest is left as an exercise for the builder…
Fifteen years ago(!) I built the Highway 86, my last tube amp project that made it all the way to finished. I put in a little time on prototyping Verberator II / Murgatroid ideas after that, and ended up bailing when the amp ideas and life both got too complicated.
The point is, the Highway 86 is good enough that a friend offered me $700 for it! I couldn’t let it go, but it sold me on simple amp designs. We’ve got plenty of great hardware & software available for reverbs & effects, but the sound & response of real tubes are what keep me playing guitars.
Enough about me; what about tube amps?
I may someday get back to the Verberator II or the Murgatroid concepts (or combine them), but recent garage cleaning uncovered a trove of old tube amps I had acquired for parts on eBay over 10 years ago, which required me to think about which parts are worth keeping.
Two of the old amps are stand-alone hi-fi stereo jobs from the 60s with push-pull 6BM8 output stages, which means I have 4 output transformers that should be pretty similar. So naturally I’ve got this crazy idea of building a short run of 4 amps with the same design. I’m thinking maybe a preamp like the Decimator and a power amp along the lines of the Highway 86.
But first … I have to clean up my man cave enough to make space for tube stuff again!
The Alaska & Paris-to-Poughkeepsie tours were scheduled partly on the assumption that I would be starting chemo in Nov., but my recent CT scan & oncologist visit have changed everything.
The CT showed no change in my cancer from 3 months ago (excellent!), but it also showed that I had walking pneumonia (less excellent). I’ve already taken the precautionary course of antibiotics, but my onc says the pneumonia could take 2 months to clear up.
So … since the lack of change in the cancer could mean that my body is more sucesssfully defending itself, and no one wants me to start chemo before the pneumonia is definitely gone, I get to put chemo off until at least next year, when I’ll get scanned again.
I just might have a few more lives left in me…
I’m happy to report that my absence from posting the last 10 months has been due to an excess of excellent experiences with my wife.
In March we went to Death Valley for several days, simplified by flying to Vegas and renting a car.
At the end of August/beginning of September we hit Sitka & Juneau, AK for 6 nights each. Highly recommended, especially if you’re into the temperate rainforest vibe.
Then, in honor of our son’s 30th birthday, we took both of the ‘kids’ to a Paris B&B for two weeks and all got to know each other as adults.
The “Paris to Poughkeepsie” tour continued through Basking Ridge, NJ (jamming with old band mates) and Warwick, NY to the fabled Hudson River town of Poughkeepsie. That was home base for the out-of-town relatives attending a wedding across the river
Now I’m home & recovering from all the excitement.
Next: the cancer situation (not bad!)
P.S.: I do read comments, but am too paranoid to open the site to outside accounts. Keep those cards and letters coming!
Have I neglected my site?
Is anyone paying attention?
In case anyone actually does read this, I offer a brief report on 2018:
I got to celebrate my mom’s 90th birthday with all my sibs.
Not so great on the lung cancer front: This year brought metastases to both lungs and slow tumor growth that has me aiming to start chemo as late as possible, but before the cancer causes me any signifiant breathing problems (or ???). I’m hoping to make it through 2019 before firing the chemo starting gun, but anything unexpected could change that in a flash.
Musically, I’ve got a tune idea or two percolating, as well as stuff from two of my brothers that’s ripe for development.