Modular Tube Preamp System

[Winston OBoogie]

Yes, the pins are from Harwin, Mouser # 855-H3161-05

Thank you sir.  Again, nice work

 

[Holger]

I've got the final front panel for the PSU today, so here are some more details:
I've designed two PCBs for the required voltages. Here is the HT PCB that bases on a schematic Michael Kingston published some time ago. It can supply up to 300V regulated. I've added a voltage divider for the elevated heaters I use in this project. The little toroid transformer is custom wound, it'a 28.8VA 240V transformer.

Next is the PCB that holds two SMPS, the large one is a MW LRS for the heaters, the small one is for 48V.

The two cards co into a large Fischer cassette that is able to hold several euro cards. Special rails for the cassette are required.

Assembly

Assembled

Complete

Rear view

Bottom

I started in 2017. Still one module to build...

 

[jensenmann]

Wow, Hoger, I´m impressed. That´s a lot of parts crammed into little space. Does it heat up a lot?
In particular I´m interested if the heat transfer through these small tube pins to the PCB is a problem.

 

[ruffrecords]

Wow, Hoger, I´m impressed. That´s a lot of parts crammed into little space. Does it heat up a lot?
In particular I´m interested if the heat transfer through these small tube pins to the PCB is a problem.

Tubes get a bed press for producing a lot of heat, probably due the that fact that the power tubes in guitar amps do get very hot. But mic pres are completely different. One of Holgers modules will probably consume less than 10 watts.  Its front panels will probably rise about 5 degrees above ambient. 10 of these in a 19 inch space is 100 watts.

Cheers

Ian

 

[Holger]

I've measured the temperature in another 3 tube device
https://groupdiy.com/index.php?topic=72114.msg914634#msg914634
As mentioned there the temperature is at 39° C. So I think it will not go above 40/42°C, depending on the room temperature.Using the Harwin pins is safe. The entire Krässemaschine is build around them.