I've tried before to create a push-pull amplifier with ECL86 tubes. It was a failure and ended up being an AC-15 type. It turned out to be the power supply there was no good, old cilisium-rectifier and the old-smoothing capacitor could not deliver stable voltage. With a new rectifier and capacitor it came to play just fine. On The Forum 18watt.com I became acquainted with Marshall 1930 Popular amplifier that was just with 2. ECL86 tubes. The official schematic which can be downloaded from the Marshalls website and others are of such poor quality that you can not read component values. I found a schematic at the company "Noice Custom Guitar Systems" where Chris Lowlor have drawen a new schematic and read the actual component values from an original amplifier. I'll try to make a copy of this amplifier. But this time it should be made of new components. Here is the schematic from "Noice Custom Guitar Systems"

I will continuously add new images and text as the project progresses.

After a little searching online I found this picture of an original "MARSHALL 1930 POPULAR".

From the Picture and the schematic I have designed a board layout.

A 2 mm fiberglass plate is drilled after the layout drawing and ready to get mounted turret pipes.

The finished turret board with all components installed. By my previous projects I have learned that it can be a mess with the wires from the transformer to the respective solder terminals, so I've made a little plate with rectifying, the high voltage section and the 2 100 ohm filter resistors for the heat voltage.

The front plate is finished and fitted with potentiometers, jacks, switches and pilot light.

The completed chassis ready for component mounting.

The complete amplifier, front side.

Back side.

The complete amplifier with transformers, tubes and capacitors. With power on, There was sound throug the amp, but there was much noise. This has become much better by switching all the signal wires, in front of the PreAmp tube, out with shielded cables. But the tremolo was not working at all. I found the schematic from the Marshall 18 watt, and with very few changes and replacement of a single capacitor it works quite well now. But it is still a very noisy amp, but it can play quite loud, and full strength, it has a very distinctive Marshall sound.

Schematic change on the tremoloen.

I uploaded a link to my page on www.18watt.com and here I got a reply from a member, probably from the U.S., which meant that there was an error on the schematic around the tremeolo part because the two capacitors in parallel at 47pf and 22nf should be 47nf and 22nf. The value of the original schematic is 68 nf.

I changed the value from 47 pf to 47 nf and then followed the original schematic, and now the tremolo works, it's just very difficult to adjust with the 5Kohm trim potentiometer, so if you turn up the SPEED and INTENSITY, the amplifier begins "motorboating."

Originally MARSHALL made the amp with either 2 pcs. 10" or 1 pcs. 12" speaker. I have found 4 pcs. EMINENCE 10466 10" Classic with Alnico magnet, which has been reconed with new voice coil and Cone. (Look under repair) The amplifier gets 2 of these speakers.

To make it easy for myself. I built the amp into a cabinet from a discarded amplifier that stood in my the basement.

Apart from the noise which reminds me of my childhood's Tube-radio, the amp sounds great through the EMINENCE speakers.

Back to amplifier side.