Oh no...not another Baby Huey EL84 build.

[Bas Horneman]

To prevent me from soiling the GB thread GB for Baby Huey PCB I'll be posting assorted pics here regarding my build.

The rounding of the board and the thickness makes for a very nice looking board.

 

[Bas Horneman]

I've decided to use schottkeys for at least the bias supply diodes. Perhaps also for the main psu rectifiers.

https://www.st.com/resource/en/datasheet/stpsc2h12.pdf

They do need some bending to fit. And I'll have to devise something so they don't touch each other. Should be no problem if I check after assembly if they don't touch.

 

[Bas Horneman]

Power supply capacitor under the board done because of proximity to one of the output valves....too close for comfort regarding heat.

 

[prasi]

Hello Bas, Pl check the pins of tube against schematic.
I am not sure if marc (bandol83 ) intended to populate them from bottom side .

regards
prasi

 

[Bas Horneman]

I am not sure if marc (bandol83 ) intended to populate them from bottom side .

Hi Prasi,

I populated the sockets from the top.

You gave me a big fright now.

I used this picture as my guide. But looking at the pcb I have in my hand....and the sockets....and the pcb tracks.... all looks good.

 

[prasi]

That looks good! Extremely Sorry to have given you a fright.

It was for the EL34 MK2 that marc intended to fit the tube from bottom.

All the best for build and listening.

 

[Bas Horneman]

No worries Prasi. I could have made the mistake...and then it would have been great to know before....

Kind regards,
Bas

 

[Bas Horneman]

Almost done. Just waiting for my coupling caps. One cleaned. One to go.

 

[Bas Horneman]

My bias schottkey rectifier assembly just to prevent them from shorting...Just to be safe.

 

[Ketje]

My bias schottkey rectifier assembly just to prevent them from shorting...Just to be safe.

Nice solution
But couldn't you find any bigger diodes for 10mA rectified current ?
Mona

 

[Bas Horneman]

But couldn't you find any bigger diodes for 10mA rectified current ?

I tried. But mouser said the ones I ordered would be too heavy for airmail

 

[Bas Horneman]

First test. Just the bias and powerdrive circuit.

Test was successful.
No smoke. No explosions. Led lit up.
Bias was easily set by the little potmeters. 53VDC on the tabs of the powerdrive mosfet. Got confirmation from Gingertube that this is sufficient for the EL84 version.

 

[Bas Horneman]

With regard to the discrepancies between the board 1.6 and the schematic 1.6. I used these values.
For
R16=15K
R17=10K
as per Schematic 1.6.

R18=1K
as on the Rev. 1.6 pcb.

Ofcourse the proof of the pudding is in the eating. I'll follow up on this.

R13 is 33k now but will be doubled up with another 33k after listening so I'll end up with 16.5k. (Just so I can hear the change for myself)

 

[Francois G]

Of course the proof of the pudding is in the eating.

Thanks Bas, hope you pudding is superb!

 

[Bas Horneman]

Thanks Francois!

 

[Bas Horneman]

d1, d3 with a wire. Since I want to try different power supply options. Like the 21st century maida regulator.

 

[Bas Horneman]

Voltage across r18 is 1.056 volts. Perfect.

From member Planet IX

Hi Bas,
if we assume Uled=1,7V and UbeQ2=0,6V then
Isink= (Uled-Ube)/R18
= 1,1V/560R
= 2mA

Regards, Boris

1,1/1000R=1.1mA

Measured is 1.056mA. So that each half of the triode is 0,5mA. Which is the target set by the designer.

 

[Bas Horneman]

21st century maida regulator:

21st Century Maida Regulator

21st Century Maida Regulator: A modern B+ voltage regulator – Neurochrome

 

[cogsncogs]

I tried. But mouser said the ones I ordered would be too heavy for airmail

Try this one.

1200PIV 100(160)A

 

[Bas Horneman]