Regular readers (hahaha…. I kill me) will remember that I bought two Gibson Skylarks. One of which I fixed immediately and the other sat waiting. This is a story about the other.
This is a Gibson Skylark in the “Crestline” series. It is one of the many amps released with the GA-5T model number. This [...]
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Sorry to both of you who read this.. I’m keeping busy :-)
So where are we ? I built out my McTube clone and it actually worked. Here are a couple of pictures :
So yeah, she’s nice looking .. I’m a fan of the clean look. The back has the instructions / names of the controls. [...]
I have purchased the best amp I have ever heard. This is a 2006 Gibson GA 20 RVT. It’s not perfect, I might have to mod it, but I am definitely in love. My strategies about building the Songbird and other things are all up in the air now.
Let see why..
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The Real McTube II was designed with rectified filament voltages because Fred found that the original McTube could be noisy if not done impeccably well. The original McTube (appearantly) had the 12 V AC from the transformers going directly to the heaters on the tube.
That is the way it’s always done on the old amps [...]
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Ok.. finally got off my ass and wired up the transformer and finished the power section. That little transformer was cheap and is dead on spec. The rest of my components .. eh.
So the B+ voltage is expected to be around 140V with load and 150V unloaded. I got 173V unloaded so I might be [...]
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So.. with a transformer on the way, it’s time to start fooling with the calculations. The article by Fred Nachbaur gives you a lot of info, but not a full analysis.
I’m not gonna do a full analysis either, but I want to cover some of the basics, and then measure once we are built. I’ve [...]
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At some point recently, I realized that my transformer for the Real McTube had not yet arrived. Why I needed a new one is chronicled here. A bit of looking around showed me that the reason I was not in possession of the transformer was because I never ordered it.
I was talking about the Hammond [...]
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As I alluded to earlier, there are a thousand options that I want to try with the Songbird. I only got through a third or so of them before I stopped writing and this is nearly the smallest simplest amp you can make (although I have a plan there too!)
Now many of the options that [...]
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Ok, so clean power and rectified heaters and some other stuff were covered in the previous requirements post.
Tube Biasing – 1st Stage
As I understand it from my readings, the standard way of biasing, self biasing, is a complex reaction. Essentially as the power drawn from a tube increases, the bias goes more negative, somewhat [...]
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If you aren’t familiar with the real McTube, it’s a one tube foot pedal type pre-amp. It was designed by a guy named Fred Nachbaur and is by all accounts a very cool device.
It uses a 12AX7 as a two stage pre-amp in much the same way that many other guitar amps do. The [...]
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