After watching all of Uncle Doug videos on vintage guitar amplifiers, I decided to design my own. It is based on Fender Tremolux and Deluxe Reverb tube amplifiers. To keep it simple my amplifier has one input and tremolo but no reverb. I used 2 x 12AX7 and 2 x 6L6GC. The amplifier has volume, tone, tremolo intensity and speed adjustments on its control panel. Within the amplifier chassis the bias of the output tubes can be adjusted by a pot.
My design's main difference from Fender is the tremolo circuit. I tried to modulate the audio signal on the volume stage of the amplifier. This has not been done before. I used an opto-coupler to adjust the volume level using a single triode.
Another difference of my design comes from the use of standard transformers instead of special transformers used on tube amplifier. Tube amplifier transformers are expensive and are hard to find. However, AC step up transformers are cheap and easy to find. I use one to generate the B+ voltage for the amplifier. I use silicon bridge rectifiers instead of tube rectifiers. For the filament voltage I use a standard 12V transformer. I also convert the output of the filament transformer to DC and filter it. This reduces the hum of the amplifier. 12AX7 use 12V filament voltage. 2 x 6L6GC filament inputs are connected in series to be powered by 12V as well. The output tubes are fix biased for higher output power and low distortion. The negative bias voltage for the output tubes is generated using a voltage doubler circuit from the output of the 12V transformer.
The values of the components are yet to be determined.
No comments :
Post a Comment