The Hundred-Buck Amp Challenge

[Printer2]

Yes cost. An extra tube, socket, bigger transformer to supply the heater and the static power drop of the rectifier. Also a tube rectifier rules out a bridge rectifier and some inexpensive transformer options can not be used.

[Printer2]

Not a hundred buck amp but the above schematic partly came out of the ideas developed here. I laid out the part arrangement for the tone controls (remember, I am using dual pots), basically it is a 5E3 Fender Deluxe board with the input cathodes split with the tone control components mounted point-to-point on the top panel. This reduces the amount of wires running back and forth if the parts were on a board. I also wanted to stay away from a design with a custom board (although I will make one for myself) so anyone could take a standard 5E3 and modify it to also do the Blackface tone control. I am mulling over a switched PI for a LTP but I have not decided on it yet. So anyway, here is the layout.

[djgibson51]

Re Tube Rectification:
My current project uses a psu similar to ones I previously posted on this thread.
But...two of the silicon diodes in the rectifier are replaced by 2 cheap 6AL5 double diode tubes with both internal diodes paralelled.. Filaments wired in series across the 12vac for a total draw of 300mA. Each diode in the 6AL5 has a max of 9mA. Should be safe for a design using up to 27mA continuous.
Cheers
JimG

[Cassiel]

Greedy, greedy Fender: they want to cover every market niche! So they did their 100 buck challenge too but with some profit of course. Anyway, funny specs: 2W RMS into 8 Ohms - 45% THD. I'm guessing it's a 1W push pull (12AT7).


Pawn Shop Amplifiers

[hushpuppy]

Originally Posted by Printer2

You missed it? That means you have to go back and read from the beginning again.

well that kind of reply is not what i was expecting here..

[Wavebourn]

Originally Posted by hushpuppy

this is driving me nuts - Who Won !?

Friendship won!

[Wavebourn]

Originally Posted by tubelab.com

It is possible to get significant sag in a small watt amp. Many small watt amps are class A SE designs. It has been said that sag doesn't exist in a class A amp. In theory this is true, but many Fender Champ players will state otherwize. Why? It's because that amp left class A as soon as you plugged in the stomp box and dimed the volume control. Given a little wimpy power transformer, small power supply caps and OPT with 400 ohms of DCR, the plate voltage drops nearly 50 volts when you hit it hard.

Also, Champ introduced sag by control grid of an output tube that regulates B+ for the preamp. I made this effect more pronounced in the "World Champion" amp in this thread.

[tubelab.com]

I'm guessing it's a 1W push pull (12AT7).

They likely just copied the firefly.

[Printer2]

Originally Posted by hushpuppy

well that kind of reply is not what i was expecting here..

Just a bit of humor. No real winner in the ordinary sense.

[hushpuppy]

thank you. I did eventually read the rest of the thread .
i was am looking for a amp I can afford with the tone I'm looking for ..
If there is such a thing .. that I can afford .
considering I dont know a thing about building a amp Im also going to have to have it built.
I really thot this might lead to a workable solution for me and I really had my hopes up .

still looking