I was introduced to tube audio with an Assemblage (a.k.a. Sonic Frontiers) 6L6 PP in the early nineties. That hooked to a pair of nice little Klipsch speakers, a vintage Dual direct drive platter and a Stanton cartridge - been hooked ever since...
Since then, I've modded several P.A./Monaurals to guitar amps; as well as modding salvaged tube stereo "hi-fi's" to updated parts "stand-alones"...in all this I've always maintained the original signature of each designer's circuit. This is with the exception of one very practical dummy add-on. This being this dummy's advice...I put a simple switch (this can even be "hidden" along the edge of the chassis design) to allow "warm-up" on the heaters before adding B+. And this dummy has also learned to design/build or source the chassis first (yes, 1st)...including socket holes filed, finished...
thanks for letting me mostly lurk around such a great forum - it's cool that you guys seem to push out the jive; and bring in the love...
Since then, I've modded several P.A./Monaurals to guitar amps; as well as modding salvaged tube stereo "hi-fi's" to updated parts "stand-alones"...in all this I've always maintained the original signature of each designer's circuit. This is with the exception of one very practical dummy add-on. This being this dummy's advice...I put a simple switch (this can even be "hidden" along the edge of the chassis design) to allow "warm-up" on the heaters before adding B+. And this dummy has also learned to design/build or source the chassis first (yes, 1st)...including socket holes filed, finished...
thanks for letting me mostly lurk around such a great forum - it's cool that you guys seem to push out the jive; and bring in the love...
This is not necessary. I did that with one project I designed, but the reason for that was the use of a solid state PS, and DC coupled stages. Preheating the heaters prevents overvoltage since the DC comes up before cathodes can get hot.
For a different project that uses a 5U4GB as the main power diodes, I didn't bother, since the DC doesn't hit within a second or two.
Yes, 'standby' switches are not necessary. Just one more thing to go wrong, and if misused can do harm. Guitar amps have them because guitarists expect to find them, so they are more a cultural feature than a technical feature.
You are right about finishing the chassis metalwork before starting to build the circuit. However, it would not have occured to me that anyone would think of doing it any other way. As most DIY amps are essentially prototypes (i.e. first in a series of one) it is better to include a few too many tagstrips etc. and end up with some unused tags than to find partway through soldering that not enough tags are available.
You are right about finishing the chassis metalwork before starting to build the circuit. However, it would not have occured to me that anyone would think of doing it any other way. As most DIY amps are essentially prototypes (i.e. first in a series of one) it is better to include a few too many tagstrips etc. and end up with some unused tags than to find partway through soldering that not enough tags are available.
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