The Amp Garage

Practice amp/door stop, fine

Studio amp, no

The resistors are just to balance the voltage across the diodes.

The resistors, and the caps for that matter are not really needed. With the nice production modern diodes we have now you don't need the extra parts.

Looks good Mark!

Do you also use JustRadios for caps?

Matt D wrote:Amazing build! Excuse my ignorance, but what are the 220k resistors off of the screen grids for?

Voltage divider at the screens to lower the screen voltage about 7V.

There is a big thread in the technical section about it.

Colossal wrote:Chris,

Did you use a capacitor just after the rectifier tube, but BEFORE your VRM circuit?

It went

Rectifier-->Stand-->VRM-->Cap

http://i1.wp.com/pdfelectronics.com/wp- ... ematic.jpg?

Check this amp out. Browsing my favorite local vintage shop and came this.
http://www.folkwaymusic.com/vintage-ins ... 1965-0313/

Thanks for all the compliments! That is a remarkably well-constructed amplifier. A couple of questions about the circuit: 1. Should there be a resistor from the grid of V2a to ground? Without it there is no voltage divider and SW1A would have no effect. 2. A very minor point: in the Normal Channel, ...

Over the last few months I have been putting together, building and recording a new amp. The amp is derived from the classic Marshall 1974x (18W) design and shares much of the same elements. It is however modified and voiced to be more of a 20W Plexi ala JTM45/JTM50/1959. Think small package Plexi t...

tribi9 wrote:What is the reason Fender tied the cathode to pin 1 on some octal sockets? Was it just because??

Probably an after market mod to run EL34s.

Saw this the other night, it was very well done. I really enjoyed it.

When I watched it there was no commercials so it was just 2 hours of electronics goodness.

[IMG:856:1024]http://img.photobucket.com/albums/v610/ ... ES-335.jpg[/img]

ic-racer wrote:

Reeltarded wrote:I would be very uncomfortable going over actual 130VAC. Very. I am fairly uncomfortable with some amps at 120, hence my variacs.

At 140vac input, here are some values:
Plates = 515v
V1 = 221v and 212v
Heater = 7.56vac

Those numbers make me a bit nervous!

[IMG:640:480]http://img.photobucket.com/albums/v610/ ... CF0323.jpg[/img]

The tank fit by mm's! It was very close to the OT, no extra noise though.

alvarezh wrote:Jelle, the schematic I am showing is supposed to be from the Small Special, if so, there should be a cap right before the Master Volume. Do you recall the value you have used?

Thank in advance.

NFB resistor sure looks wrong.