Official Universal Passive Tube PSU Thread

[Roman Beilharz]

Thank you kinglok, did you order PSU PCBs? Maybe they have run out of supplies - I don't know and Chunger doesn't answer

 

[Roman Beilharz]

3 months now, still no PCBs - still no excuse, no mail, no response, no nothing except my PayPal payment and the initial order confirmation . Has anyone in the forum a good wire to Chunger? Any help highly appreciated, as I have the prepared cases with power transformers sitting on the shelfs ready to go and as I already have the BOM for the parts in place, I can't even switch to a different circuit/offer like the micparts VPS...

 

[johnchantler]

I got a refund 5 weeks after my C12 psu pcb order placed in august with a short 'out of stock' note.

 

[Roman Beilharz]

Wow, thank you for your helpful reply. I looked carefully and: You're right! My order had also been refunded 10 days ago .

So now I have two full blown sets of parts for this project to sell, if anyone was interested. Alternatively: Any spare PSU PCBs would also be welcome

But I didn't even recieve a short notice, well...

 

[johnchantler]

I started laying out a pcb based on the schematics that changer has published, but have not had time to get it finished.

Maybe vintagemicrophonepcb.com has something to get you sorted?

 

[ElSmurf]

Ok, good to know this option is off the table. Contacted Dany about two weeks ago to see if he had any spare PSU PCBs for his D251 but he was fresh out. I think I'll just buy the full set.

I started laying out a pcb based on the schematics that changer has published, but have not had time to get it finished.

This would be great too, if you'd be willing to sell them. Especially since you're in Europe.

 

[johnchantler]

I realistically won't get anything done and certainly not tested before April next year. crazy couple of months ahead alas.

 

[ElSmurf]

I realistically won't get anything done and certainly not tested before April next year.

Thanks for the heads up!

Since this PCB is almost ten years old, maybe they'd consider releasing the PCB layout, or have someone else produce them. There's clearly demand for it, and there's not a lot of other options out there that are this simple to implement.

 

[donivan]

has anyone worked with the 1.5a vrs. of this pcb
c10 is a 5mm cap
but what came with the kit is a 15mm
mouser or digikey doesn't carry a 5 mm 4700uf 25v elec. cap
any ideas?
I've tried contacting chunger

 

[ElSmurf]

c10 is a 5mm cap
but what came with the kit is a 15mm

That looks like a very small footprint for a 4700uF/25V cap. I don't think you'd find that value with a smaller lead space than 7,5mm.
If the leads of the 15mmLS cap fit through the holes I'd just bend them to fit the 5mmLS. For mechanical stability you could put it flat on the pcb, if the cap isn't too long.

 

[Roman Beilharz]

Thanks for the heads up!

Since this PCB is almost ten years old, maybe they'd consider releasing the PCB layout, or have someone else produce them. There's clearly demand for it, and there's not a lot of other options out there that are this simple to implement.

Yeah! If there wasn't a chance of the PCB to be back in stock any time soon, I'd highly appreciate Matachung to publish their data for others to order on-demand PCBs.

 

[Roman Beilharz]

has anyone worked with the 1.5a vrs. of this pcb
c10 is a 5mm cap
but what came with the kit is a 15mm
mouser or digikey doesn't carry a 5 mm 4700uf 25v elec. cap
any ideas?
I've tried contacting chunger

As I see there is a V. 1.5 of 2023 of this board, this project doesn't look like old news, though, indeed, and was great to have available again. Man, I am so stuck with this

 

[Matador]

has anyone worked with the 1.5a vrs. of this pcb
c10 is a 5mm cap
but what came with the kit is a 15mm
mouser or digikey doesn't carry a 5 mm 4700uf 25v elec. cap
any ideas?
I've tried contacting chunger

Apologies for the confusion. This is due to a BOM change between 1.4 and 1.5(a).

The original board was designed to be configurable between a passive heater supply (e.g. simple RC filtering), and an active heater supply (the LM317). After all of the hundreds of people that use the psu, exactly zero of them ever wanted to use a passive heater supply.

Since it took up so much of the board space, I reduced the final capacitor from 4700uF (intended for the passive supply), to a 10uF/25V. However for an active supply, this capacitance isn't needed as the heater load is essentially constant current, and the datasheet recommends an output capacitor "to improve transient response":

C0 improves transient response, but is not needed for stability.

In short, you can just leave it out.

 

[JeffKall]

Apologies for the confusion. This is due to a BOM change between 1.4 and 1.5(a).

The original board was designed to be configurable between a passive heater supply (e.g. simple RC filtering), and an active heater supply (the LM317). After all of the hundreds of people that use the psu, exactly zero of them ever wanted to use a passive heater supply.

Since it took up so much of the board space, I reduced the final capacitor from 4700uF (intended for the passive supply), to a 10uF/25V. However for an active supply, this capacitance isn't needed as the heater load is essentially constant current, and the datasheet recommends an output capacitor "to improve transient response":



In short, you can just leave it out.

Good Morning, Matador …

I have a couple of Universal Tube PSU questions for you …

I recently built a pair of Dan’s D-67’s using your Universal Tube PSU’s (with R1 and R2 changed to 18K) … and it works great !!!

This week … I finished a pair of Dan’s D-EF47’s and also tried using your Universal Tube PSU’s … but I wasn’t sure what value R1 and R2 would need to be changed to get B+ down to the required 105V (the 5.05 Heater voltage was not a problem) …

Also … I don’t know how to address the RS 48V reed relay that Dan uses to switch patterns in your supply …

Dan’s PSU ties a 14K 1W resistor from B+ to the reed relay wiper (com) to keep constant current supplied to the relay and stabilize B+ when changing patterns …

I am unsure how to integrate that 14K 1W into your Universal Tube PSU …

My thought is to string it in between pin 1 (B+) and pin 4 (unused Bias pin) on the Universal Tube PSU 7 pin connector and then just route the unused pin 4 on the 47’s 7 pin connector to the wiper on the RS reed relay … but the RS reed relay wiper connects directly to the rear diaphragm of the capsule … and being a MAJOR tech-challenged Newbie … I just need to confirm that it is okay to connect additional voltage to my capsule …

Any advice you could give me with regard to R1/R2 values for 105V B+ and how to accommodate supplying the RS reed relay wiper it’s constant current voltage would be truly helpful and dearly appreciated …

Matador … thank you for everything you and ‘Chung have done to make this Newb’s DIY life fun and gratifying !!!

My pair of your C12’s remain my absolute favorite microphones !

All the best to you and yours …

Also thanks in advance for any insight other GroupDIY members could offer !

And Happy Holidays to everyone on GroupDIY !!!

Jeff

 

[Matador]

I recently built a pair of Dan’s D-67’s using your Universal Tube PSU’s (with R1 and R2 changed to 18K) … and it works great !!!

This week … I finished a pair of Dan’s D-EF47’s and also tried using your Universal Tube PSU’s … but I wasn’t sure what value R1 and R2 would need to be changed to get B+ down to the required 105V (the 5.05 Heater voltage was not a problem) …

If you need lower B+, then you need higher R1 and R2. It's hard to pre-suppose what the current requirements are exactly: I would swap either R1 or R2 with a 250K pot, then set the trimmer resistor R4 to mid-value, and tweak the pot until you get down to 105. Then add together R1 and the pot value, divide by 2, then you have the required values for R1 and R2.

As for Dany's design, I'm not familiar with it, so you'd have to seek support from him.

 

[JeffKall]

If you need lower B+, then you need higher R1 and R2. It's hard to pre-suppose what the current requirements are exactly: I would swap either R1 or R2 with a 250K pot, then set the trimmer resistor R4 to mid-value, and tweak the pot until you get down to 105. Then add together R1 and the pot value, divide by 2, then you have the required values for R1 and R2.

As for Dany's design, I'm not familiar with it, so you'd have to seek support from him.

Thank you, Matador …
The B+ issue is the most important to me … and your solution is brilliant !

I am sure I will ultimately find a solution for the reed relay … but in the meantime the 47’s “default” to cardiod … and that works 90% of the time for me …

Besides … until your next revision of PSU PCB’s are available at Studio 939 … I am going to give the 47’s a rest !

Thank you again for your help !

Best Regards

 

[LucaN]

As I see there is a V. 1.5 of 2023 of this board, this project doesn't look like old news, though, indeed, and was great to have available again. Man, I am so stuck with this

Hello. I'm also pretty much ready to build my tube mic but was hoping to do it with the Chunger Universal PSU. As I don't see it on the 939 website, I am looking for something else similar so I can get started. I saw you opened a dedicated thread about this where you mentioned that you were able to find a comparable alternative. I was meaning to ask you if you could refer me to it, but the forum says I don't have enough privileges to answer in that specific thread, and I can't figure out how to DM people here. I've been using the forum extensively for research but never actively engaged with anything or anyone, so I apologize if I'm not getting it fully.

 

[Roman Beilharz]

Hi Luca,

I am not sure about rules and privileges so I am not sure you are allowed to PM the user TLRT. He could provide a very well done similar PCB with nicely printed values/part descriptions on top. Try to use this link and mail him.

Good luck, my best

Ro

 

[LucaN]

Hi Luca,

I am not sure about rules and privileges so I am not sure you are allowed to PM the user TLRT. He could provide a very well done similar PCB with nicely printed values/part descriptions on top. Try to use this link and mail him.

Good luck, my best

Ro

Thank you!
I can't find a private message section anywhere on Group DIY . Maybe it's there and I just can't see it, but I doubt so, I looked allover the place. So I'm guessing I'm locked out of the PM function. I understand having to moderate the forum and restrict the influence of new, unknown users, but it's a bit annoying to not even be able to know what I need to do, or how much I need to wait to get a more comprehensive access to the forum, since I've been registered here for 4 years now. I really hope I can solve this soon because I'm finally starting to build my own microphones and being able to interact with the amazing community here would make all of the difference. If anyone has helpful info on this website's rules with permissions and PMs please lmk.
Anyways, I don't want to drift too much off topic. I would really appreciate it if TLRT or anyone who could share a similar PSU PCB could try to PM me, maybe I can't start conversations but I can receive messages if someone else sends first.

 

[Roman Beilharz]

Look, this should explain and cover it all: https://groupdiy.com/threads/private-messages-conversations-permission-update.82401/

You need to complain more and add three more posts doing that