EL51 amplifier

	electron Tube Data sheets
	electron Tube Data sheets
	EL51 amplifier

2007-08-24
Here I will report a bit about an amplifier I'm building.
It may take a long time because I'm in no hurry to finish it ;-)
The main goal is to make an amp with 1930's side contact tubes without any semiconductors.
There will be the following tubes: 4x EL51, 7x AZ4, 2x EE1, and the rest EF6 tubes probably.
As you can see, the main transformers and the p-sockets are already mounted.
For the AZ4's I will add some small transformers at the bottom side, which is still completely empty.

2011-07-28
Here you can see that I made some aluminum pipes for the wires to the top connections of the tubes. It took a while to find a good solution. Glue was not working so I had to find something else. A friend of me suggested using a jack plug socket which is 6.35 mm while the aluminum pipe is 6mm. So they skew a bit but that is ok for me. Most mechanical work has been done so now I can add some electronic stuff.

2021-05-10
I decided to do something again ... Maybe finish it this year :)
One output stage is built and i'm tuning the circuit. I added a 4699 tube to reduce ripple voltage on the driverstage. The output transformers are replaced with 5k Raa types.

2024-08-25
Also this year I did some stuff work on the EL51 amp. I found an old schematic for tonecontrol which I wanted to try. The ECH4 is used for this. Heptode with g3 is 0V is input tube. The Triode is used for active control. The outout (at 100k resistor) goes to the volume control potmeter and then to the EEP1 phase converter.
It works quite well. Though the ECH4 is microphonic and the 50Hz from te filament is a problem. That is why I placed the volume potmeter between the ECH4 tone control circuits and the EEP1. It is still humming a little bit by the output stage. Needs work or maybe I leave it.

	2007-08-24 Here I will report a bit about an amplifier I'm building. It may take a long time because I'm in no hurry to finish it ;-) The main goal is to make an amp with 1930's side contact tubes without any semiconductors. There will be the following tubes: 4x EL51, 7x AZ4, 2x EE1, and the rest EF6 tubes probably. As you can see, the main transformers and the p-sockets are already mounted. For the AZ4's I will add some small transformers at the bottom side, which is still completely empty.
	2011-07-28 Here you can see that I made some aluminum pipes for the wires to the top connections of the tubes. It took a while to find a good solution. Glue was not working so I had to find something else. A friend of me suggested using a jack plug socket which is 6.35 mm while the aluminum pipe is 6mm. So they skew a bit but that is ok for me. Most mechanical work has been done so now I can add some electronic stuff.
	2021-05-10 I decided to do something again ... Maybe finish it this year :) One output stage is built and i'm tuning the circuit. I added a 4699 tube to reduce ripple voltage on the driverstage. The output transformers are replaced with 5k Raa types.
	2024-08-25 Also this year I did some stuff work on the EL51 amp. I found an old schematic for tonecontrol which I wanted to try. The ECH4 is used for this. Heptode with g3 is 0V is input tube. The Triode is used for active control. The outout (at 100k resistor) goes to the volume control potmeter and then to the EEP1 phase converter. It works quite well. Though the ECH4 is microphonic and the 50Hz from te filament is a problem. That is why I placed the volume potmeter between the ECH4 tone control circuits and the EEP1. It is still humming a little bit by the output stage. Needs work or maybe I leave it.