I've spent literally years trying to make a good tube guitar amp for home practice, with mixed success. I never came up with something so good that I could tell myself I was done.
Then two things happened: I realized how much of my time had gone into futzing with the amp rather than the guitar, and the Boss Katana 50 showed up in stores. To my ears, it's the first affordable solid-state guitar amp that sounds convincingly "tubey", and it has output power settings from 0.5W to 50W. That covers everything from the bedroom to a small stage gig.
So I got a Katana 50, and it is not only my home practice amp, it's also the one that goes to every weekly music jam, and I even used it on stage for a guest performance with a friend. I even used it outdoors at a jam held at a local farm this summer, with a bassist with a 300-watt rig sitting right next to me. To my surprise, the Katana 50 held its own.
I'm still tinkering with low-power tube guitar amp designs. But now I have no excuse not to practice guitar.
I may be wrong, but I think that era is pretty much gone for good.
There was a time when North America was swept up in mandolin fever, and there were all-mandolin orchestras, and mandolin stars.
I think the guitar star has now gone the way of the mandolin star.
But I don't think the guitar itself is going away quite yet. It is maybe the most versatile of musical instruments, and one of the most affordable, too.
Personally, I have no interest whatsoever in stardom (and I'm not exactly one of those gorgeously beautiful people that the public wants to elevate to star status.) But I am constantly inspired by the incredible things other guitarists manage to do with their guitars.
-Gnobuddy
There's still more future joy and play in playing the guitar than building the amplifiers.
With the wealth of "workable" amps in pawnshops and new/cheap there's no good reason (as you may admit to your embarrassment) to spend much time slinging solder. Even if you only play your sister's wedding party. (Ever see a solderer at a party?)
With the wealth of "workable" amps in pawnshops and new/cheap there's no good reason (as you may admit to your embarrassment) to spend much time slinging solder. Even if you only play your sister's wedding party. (Ever see a solderer at a party?)
Agree completely that there's no need.
But there's also no need to jump out of a perfectly good aeroplane with a large handkerchief strapped to your back, and yet, quite a few people do it. Repeatedly.
I love playing music, but if that's all I do, eventually the engineer / builder part of my brain gets a little restive. I start wanting to design circuits, calculate things, solder parts, cut metal, saw wood, and build stuff.
And if all I do is design, calculate, solder, cut, and build, then the musician part of my brain gets restless, and I start to miss music.
I guess I just happen to be wired so I'm not fully happy with one or the other. But the combination is pretty good fun.
As I write this, I've started work on a new and slightly weird tube guitar amp project. If it goes well, I'll start a thread about it. If not, it's back to the metronome, guitar, drum machine, music theory book, and MuseScore (notation software)!
-Gnobuddy
If I knew then what I know now I would have stuck to playing rather than building stuff, how long I could go without building is a question never to be answered. I could see a person that is not into electronics building an amp for the personal satisfaction. Won't be much cheaper than buying an amp without some good instruction unless a donor is found.
I'm impressed, too. The sounds are an absolutely enormous improvement over the first generation of THR amps. I didn't like those at all, either the sound quality or the price. (But Yamaha sold a tonne of them, so clearly, lots of people did not share my opinion.)
That said, the new THRs cost more than a Katana 50 - and are also far less versatile, simply because of the tiny powder-puff-sized speakers and limited output power. These THRs will never be more than a bedroom amp, while the Katana 50 and 100 will go from bedroom to stage and back without missing a beat. Roland / Boss really hit it out of the park with the Katana 50.
But the sounds in the new THRs are really good. It will be interesting to hear more clips of the new THRs, to see if they sound better than the Katanas, or not.
-Gnobuddy
The preamp needs a few mA, the power amp tens of mA's. You need a big resistor (in watts) to drop the voltage a large amount. It can be done but just wastes power and you carry more iron in your PS than needed. You could always go to a voltage doubler to get the preamp voltage higher. But generally preamp circuits can operate at lower voltages.
One of my preamps alternated triodes and pentodes. The triode stages and the power amp needed some 230V B+, the pentode stages more like 150V.
This was a low-power amp, about 2 watts to the speaker using a push-pull pair of 6AK6 pentodes. So I didn't need a lot of current at 230 volts, in fact only some 20 - 25 mA peak.
I solved the power supply problem by using a nominally 48V RMS Hammond power transformer. I found it actually produced about 75V DC when half-wave rectified, i.e. it must have been putting out about 55V RMS unloaded with today's (higher) AC mains voltage.
So I used a voltage doubler circuit to generate approximately 150V DC, and a voltage tripler to generate approximately 225 V DC. It worked very well.
-Gnobuddy
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