Multi pattern U47 schematic

[kojoboadi]

Just remembered, it was because I had used turrets on mic pcb and a turret wasn’t connecting on the back!
Made sure all connections were working then worked like a charm.


Haven’t used it in a while but after holidays will test again and see if it still works!!!

Thank you so much—I really appreciate it! I’ve used many of your posts as guidance while building my own setup. I think I need to rewire the grounds on the T.Bone STC 7000 PSU because I’m getting some hum. However, with the Takstar PSU, it works great with no issues. I just need to bring the heater down to 5 volts.

What values would you suggest for the B+ voltage and R1/R2 resistors? Currently, I’m at 105V with 1G for both.

 

[Spencerleehorton]

As this multi pattern mic should essentially work at 120, 60, 0, I use mine at 120v rather than 105v
Heaters at about 5.2v seems about right, have a play and see what suits you.
Merry Xmas bud.

 

[kojoboadi]

As this multi pattern mic should essentially work at 120, 60, 0, I use mine at 120v rather than 105v
Heaters at about 5.2v seems about right, have a play and see what suits you.
Merry Xmas bud.

I need some advice—I’ve assembled what appears to be the same PSU as yours, the TPSU_2xFIL in the Tbone Retro PSU. Everything is set up, and the voltages have been adjusted accordingly, but my heater doesn’t seem to have enough current, causing a significant voltage drop when connected to the microphone.

Would you mind sharing the values you used in yours? I’d really appreciate your help!

Thanks in advance!

 

[Spencerleehorton]

i'll take a look in a few days and get back to you

 

[kojoboadi]

i'll take a look in a few days and get back to you

thank you much appreciated its driving me nuts.

 

[Spencerleehorton]

I will check my psu but I think I changed the mains txf as I think that was the issue from memory!

 

[kojoboadi]

I will check my psu but I think I changed the mains txf as I think that was the issue from memory!

ahh okay thank you

 

[Spencerleehorton]

as you can see from this image, i removed the transformer and made my own PSU pcb, pretty sure the problems you are having are what i had with the 6.3v not having enough current due the transformer not providing it!!.
The tranformers are available on ebay or aliexpress, its a 170v with 6.3v.
if you need anymore info please just ask.

 

[kojoboadi]

View attachment 145286
as you can see from this image, i removed the transformer and made my own PSU pcb, pretty sure the problems you are having are what i had with the 6.3v not having enough current due the transformer not providing it!!.
The tranformers are available on ebay or aliexpress, its a 170v with 6.3v.
if you need anymore info please just ask.

Thank you! Yes, you're correct! I don’t have enough current on the heater. Would you mind sharing the values you used in the heater circuit? Thanks again—this has been bugging me all week!

 

[Spencerleehorton]

as you can see from my scribbles i started with 1.8R resistor into the LM317 but ended up with a 5R 7W (you can see it in the above photo), you should be able to see i have 2 x 2200uf and a 10000uf cap on the heaters. Also on the adjust leg ive got the 22uf to gnd with a 5k trimmer and 5k in parallel with it giving 2.5k trimmer, the other is a 220R to the output leg and make sure you put a diode across from input to output, i then adjusted to about 6.45v and that gave me the required 6.3v at tube.
hope this helps and you get it sorted.

 

[kojoboadi]

View attachment 145289
as you can see from my scribbles i started with 1.8R resistor into the LM317 but ended up with a 5R 7W (you can see it in the above photo), you should be able to see i have 2 x 2200uf and a 10000uf cap on the heaters. Also on the adjust leg ive got the 22uf to gnd with a 5k trimmer and 5k in parallel with it giving 2.5k trimmer, the other is a 220R to the output leg and make sure you put a diode across from input to output, i then adjusted to about 6.45v and that gave me the required 6.3v at tube.
hope this helps and you get it sorted.

Thank you so much!! will order the trans and give it a go !!