Regulated B+ ?

[Delta Sigma]

Has anyone used a Maida-ish design to regulate B+ for a tube mic's power supply?

I want to be able to order a batch of PCBs and then transformers from a single source and be able to use them on any tube mic project. I played with some different B+ voltages and loads (100VDC - 220VDC) with passive filtering and with a Maida regulator. The Maida adds some parts cost, but it's easy to get 100 to 220 from the same transformer.

In other words, I could buy multiple transformers like this one, without knowing what project requirements would be:
https://sklep.toroidy.pl/en_US/p/TSTA-0015001-Mains-transformer-for-tubes/632

Same transformer and same PCB for multiple different projects with a few different components.

Started thinking of this after reading the @rock soderstrom thread with an already quite versatile PSU design:
https://groupdiy.com/threads/diy-pr...ps-like-preamps-buffers-or-microphones.84324/

Passive (for B+, regulate heater) might be the smartest way to go, but I do like the idea of using the same transformer for all future projects.

 

[Drosselmeier]

I ordered 20 transformers. They cost less than $15 each. B+ was made using a passive filtering. Suitable for M251 (+120V) and U67 (+230V) circuits.

 

[Delta Sigma]

View attachment 143343
I ordered 20 transformers. They cost less than $15 each. B+ was made using a passive filtering. Suitable for M251 (+120V) and U67 (+230V) circuits.

View attachment 143344

Where did you order them from?

 

[Drosselmeier]

Where did you order them from?

Russia
Rostov-on-Don city
"Tortrans" LLC
tel. +7(863)22066602

 

[rock soderstrom]

Passive (for B+, regulate heater) might be the smartest way to go, but I do like the idea of using the same transformer for all future projects.

Here is a thread about your topic with quite good info. Check the @Kingston PSU for an active regulated B+ version.

https://groupdiy.com/threads/regulated-b-solutions.71122/#post-906408

 

[gyraf]

The Polish company "Toroidy" mentioned/linked in OP are very competent people.

They are my main supplier of power transformers - their "Audio" type designs are among the quitest I've found.

You'll want to talk to Tomasz

/ Jakob E.

 

[Delta Sigma]

Here is a thread about your topic with quite good info. Check the @Kingston PSU for an active regulated B+ version.

https://groupdiy.com/threads/regulated-b-solutions.71122/#post-906408

Awesome. This is a lot simpler than the Maida, and I'd still achieve the wide range of loads from the same transformer. I really gotta start paying more attention to the Drawing Board.

 

[rock soderstrom]

Awesome. This is a lot simpler than the Maida, and I'd still achieve the wide range of loads from the same transformer. I really gotta start paying more attention to the Drawing Board.

I always wanted to build this circuit and merge it with my doubler heater-PSU linked above and then compare it directly in a microphone or preamp.

Here is my first draft for a PCB, what do you think? Sorry for the rough sketch. Diodes are UF4007, most electrolytic capacitors are 33uF/450V because I have a lot of them. I would like to install the LED as drawn, any cons?

How many dB ripple rejection would such a circuit have? We need Ian (@ruffrecords), I still can't work it out


R1,R2 = 1K for 10mA total current

 

[Delta Sigma]

I always wanted to build this circuit and merge it with my doubler heater-PSU linked above and then compare it directly in a microphone or preamp.

Here is my first draft for a PCB, what do you think? Sorry for the rough sketch. Diodes are UF4007, most electrolytic capacitors are 33uF/450V because I have a lot of them. I would like to install the LED as drawn, any cons?

How many dB ripple rejection would such a circuit have? We need Ian (@ruffrecords), I still can't work it out

View attachment 143437
R1,R2 = 1K for 10mA total current

I haven’t had a chance to look closely (film enlargement night tonight), but for a PCB, I think it’s worth having the option of a C12 style bias. Jumper instead of resistor when not needed.

I also had the thought of adding a ‘PTP’ like section to the PCB. Pads for components and wires to allow for resistors for relay switching, polar pattern voltage dividers, and switchable filters for cathode followers.

 

[rock soderstrom]

I think it’s worth having the option of a C12 style bias. Jumper instead of resistor when not needed.

I also had the thought of adding a ‘PTP’ like section to the PCB. Pads for components and wires to allow for resistors for relay switching, polar pattern voltage dividers, and switchable filters for cathode followers.

That sounds like an interesting project, I'm looking forward to seeing how it is implemented.

I'm going to make my PCB very basic for now, for use with small preamps, buffers and also microphones.