SE 300B amplifier

[popa marius]

The construction of the amplifier is in progress, the interconnection of modules and the wiring of the sockets follows

 

[grataku]

Woo! Well done! Tight fit.

 

[hooman]

I like the protection cage for the 300B.

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the most protection cage ever made😍

 

[hooman]

😳

 

[popa marius]

GND

 

[huggygood]

I really like the set 😎, including the seresto flea collar box cover, I use it too 😀

 

[popa marius]

The sides of the amp will be covered with oak wood, but basically the amp works perfectly and I've already done some auditions with it

 

[popa marius]

The amplifier is completed and the last harmonic distribution measurements with fundamental frequencies at 100Hz, 1Khz and 10Khz in addition oscillograms with SQW signal at 20 Hz, 30 Hz and 10 Khz. All measurements are made at a sine output power of 7w

 

[popa marius]

and oscilogram

 

[popa marius]

The amplifier has come to an end and together with a pair of Klipsch R 820 F speakers make a good team

 

[zenzen]

Nice work, congratulations.

 

[grataku]

Where do you get the perforated 300b sockets and the meters from?

 

[popa marius]

The sockets for the 300b are recovered from an old PP amplifier with OT100 and despite their age are more robust than the one found now. I monitor the current and anode voltage in both channels by successive switching with simple milliammeters also obtained from recoveries

 

[alex mm]

Hi,
Have started, to collect components, to build this SE amplifier. Also layout PCB's , it seams, the power supply board is more complicated, then amplifier itself .
Best regards,
Alex

 

[alex mm]

Hi, just arrived from China, my PCB's and planted few components . Are missing components , next week will come .

Best regards
Alex mm

 

[alex mm]

Have the power supply tested, everything works correctly, I'll test the amplifier maybe tomorrow .

 

[alex mm]

Hi,
Tested power supply PCB but seams heat sinks are under necessary requirements . Have ordered a second PCB's revisited rev.1.1 , split in two boards , one for HV and negative voltage , the second one for filament supply of 300B .

Beautiful sound , next step to do some measurements and the case .

 

[alex mm]

Hi, I redrew schematic of power supply and amplifier .
Cheers,
Alex

 

[pieter t]

Common mistake: too high value for grid resistance in case of fixed bias.
WE300B datasheet:

 

[popa marius]

I think this recommendation for the 300b refers to the situation for which the tube was probably used in RF. It is difficult for a driver to work on a load of 50K equivalent to grid resistance