The Amp Garage

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The shield is not really needed, since no signal is going through those wires, but on the other hand, it can't hurt, as it keeps those wires from becoming really good antennae (for hum, RF, etc.). just ground the shield at the chassis.

--mark

Why 6-11-16 ohms? Will 4-8-16 work or 2-4-8.. Just curious. You have to take into account the parallel resistance as well. Ideally, the total load presented to the amp remains roughly consistent, and the attenuation steps are 3-4db each. Ohm's law will let you work this out, and a spreadsheet makes...

chief mushroom cloud wrote:hey... Sgt OD/TubeTramp has an Elgen

Tracy, his was the rave I was speaking of.

chief mushroom cloud wrote: I have schematics of both Lead100 and Bass100, if interested

I'd love to see them.

--mark

Although I've seen video with them using Orange amps, I think the Elgen amps are seen most often. This was a weird, almost unknown brand that some folks rave about.

--mark

I use a butcher block table top I got at Ikea, mounted on a sturdy home made wood frame. Lots of parts drawers.

--mark

[img:800:600]http://mhuss.com/images/Bench.jpg[/img]

Almost any JFET is fine, as the cathode will only ever get 2-3 volts max across it, and 1-2mA of current through it.

--mark

That *is* pretty. I've often thought about poplar (for its nice weight/strength combination), but shied away because of the trouble to finish it.

--mark h

This is an old audiophile (phool?) trick. All electrolytic capacitors start to get higher in impedance as the frequency gets higher (at some dog-hearing-only frequency). The small value bypass ensures that the impedance of the combination stays low up to close to RF. Also, you'll sometimes see this ...

I think it would be better to leave that largest value of cathode resistance in place at all times, and just parallel (much larger than normal) resistors to get the various values you want. As drawn, if all transistors are open (for even a microsecond) the cathode voltage will fly up towards the pla...

...better late then never... Mark Huss 50, married, no real kids, ten 'fuzz kids' (cats, dog and ferret). Lots of builds and mods. Day job: Ethical hacker for a large international bank. Used to teach electronics in a previous life (including vacuum tubes :wink:). Other former jobs include playing f...

chief mushroom cloud wrote: anything that written around designing guitar amps specifically is a waste of $$

That's true in many cases. but KOC's and Gar Gillies' books are very useful IME.

--mark h

*Any* 3-terminal regulator out of Mouser or DigiKey that provides enough current is fine. They still make the good 'ol 7812, which is good for up to 1A.

Note that you'll likely need to heat sink whatever regulator you use.

--mark h

The location on the buss bar is not critical, as long as the bar itself is chassis-grounded at a distance from the power grounds. The underlying idea behind all the successful grounding schemes is to keep the "noisy" ground currents, e.g., between the center tap of the PT and the (-) side of the ear...

In keeping with the 'constellation ground' idea, I just connect all the grounds of a given stage (including the front panel controls) to the buss at roughly the same location (near that stage), and then connect the buss to the chassis at or near the input jack. This also makes it fairly easy, no sol...