The Amp Garage

If it can run on batteries, it can probably run of a MAX1044 (or LT1054)

Check it out here - then you'll just use your usual 9V wall wart with it.

http://www.geofex.com/circuits/+9_to_-9.htm

PS: Thanks goes to R.G. Keen!

LeftyStrat wrote:So I started looking into building something with this, but the biggest problem is how to mount it. If I mount it outside the chassis, the HT will be exposed. But putting it inside the chassis takes up a bit of real estate.

A DIY Fender-style "dog house" might do the trick!

It looks fantastic, but may be a b*tch to service. I go for the middle route - if it works, is stable and easy to work on, it's all good. That means that I combine PCB with eyelets and turrets in some cases. But so be it - best sound and lowest noise, as well as being a respectable build is my focus...

Sure. But look at the code. 4378 - week 43 in 1978. That's a 34 year old capacitor. I'd probably build it with something new.

Find the datasheet and sum it up, ad 50% for good measure and there you go.

The usual small DPDT-relays people use, are at around 60-75mA each @ 12V. Then add 10mA for diode an dropper resistor. 300mA should do fine for two relays. But use a 12V primary and a rectifier bridge, not the voltage doubler.

FWIW I solved problems like this by putting two or more caps in series to get the right phase of the NFB. You have to get larger values of course.

I skipped it, and didn't use the 150K bleeder, and it sounded fine!

Looking good! Is the metal caps isolated by a transparent film of some kind? I cannot see it on the picture. If not, be careful that the case isn't shorting out the resistors.

Very few circuits require those specific properties. A 100 on / 5 M off might work fine too. A 1K on 500K off might also. Depends on the circuit.

Here's a good way to implement it. You probably want to change the fixed bias from a balance-type to an adjustable type.

[img:600:778]http://www.londonpower.com/GRAPHICS/pwr-fig1.gif[/img]

Hey, leave Ben Franklin alone! He merely supplied us with a simple "rite of passage" that we must understand to do this stuff. Those who don't are better off not working with high voltage

Everything is suspect - from the PT not delivering enough juice, to the diodes having (perhaps partly) failed, to the filter capacitors needing replacement.

Try to view the amp as modular, and start from the "entrance" of power.

Before you totally rebuild the amp:

What is B+? What does the bias measure?

Is the 15" speaker loud connected to one of your other amps?


It could be the speaker - the tubes - the power supply.

h = hours