Tag: circuit

5E3: Schematics and Ideas

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5e3_schem
I’m hoping this will clear things up for the night. Practical matters have brought about the decision to build a tube amplifier. In this case, I’m going to get a WeberVST kit as not to go it solo on the first attempt. The winner of much debate as to which circuit to start with is the ever popular 5E3, a Fender ’57 Tweed Deluxe circuit.

Unfortunately, this circuit isn’t quite ideal. The goal for our prototype is going to be about balancing loudness with clarity and transforming its bluesy rock tone into something a little smoother and less aggressive. We’re going to attempt lowering the gain in the preamp by using tubes with a lower gain factor and increasing wattage in the output stage which will include substituting some 6L6 variety for the standard 6V6s. The use of two separate volume controls seems to be pointless for our purposes as well. I think I’ll probably wind up setting up a treble and bass tone stack by dumping one of the volume pots.

Anyone care to buy a Marshall 2×12 4102?

the final layout

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final circuit layout with pre-printed PC board

She’s big and bulky, but you can’t ask for too much when you’re dealing with pre-printed PC boards. The 22k resistor in the gain path makes for extremely high output (in terms of headphones). The 100k stereo potentiometer on the output side should make the noise floor a lot lower unless the knob is cranked. That’s what I was going for here since the application of this device will be mainly for when other loud instruments are being played in the room. A short trip to the electronics store should yield three more of these guys. After that, it’s onto the chassis.

the first of four…

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IMG_1400

This was my first attempt at building the circuit on the PC board. Unfortunately, I think I’m going to have to get a different board since this one isn’t quite big enough with two opamps. Soldering it is also a bitch considering it’s tiny and my iron tip isn’t as small as it should be.

The 1/8″ plug is the output soon to have a pot attached to it for volume control. I’ve been thinking about attaching an light meter to each channel, but I still need to know what the dimensions of the chassis will be before I jump that far into it.

two ears. two channels.

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stereo headphone amplifier circuit

Double the circuit for stereo. This is a breadboard representation of a single “channel.” Each channel will have its separate PCB with controls. This one lacks a volume pot, but the output was more than enough. 750mW after hooking up the gain path resulted in ripping the ear buds out of my ears in order to avoid total deafness. Sadly to say, I have about as much luck avoiding electrocution as I do cutting myself with knives. I’ll keep to the low voltages for a little while longer.