6.3VAC to 6.3VDC LDO supplies MIC5156 based tube amp upgrade.

[tubelectron]

Hello @v4lve lover !

Can you give me the dimensions of the unit (HxWxL mm) ?
Could it be converted to 7.5VDC / 4A ? Or otherwise 7.5V 2.5A ?
My transformer can provide 12.8VAC / 7A

Thanks to let me know

T

 

[snapper]

@platon.rado​

1N5407 is no SCHOTTKY, e.g. SB360 / SB560 is !

 

[platon.rado]

Yes, you can use anything there.

 

[snapper]

Hello to all self-builders!
I created a modified PCB, partial use of SMD components possible (also for MIC5156),
cutouts for better air circulation SK129 heat sink, use of normal circuit board connection terminals.
When ordered via JLCPCB, 10 boards including worldwide shipping cost approx. €4.50 or $5.00!
Have fun DIYing

 

[matejsirk]

snapper, this is great. Could you provide BOM?​

 

[snapper]

 

[snapper]

small changes

 

[v4lve lover]

very nice work, dont forget that C1 and C2 must be unpolarized electrolytics uvp series panasonic

 

[snapper]

yes, thanks for the tip, now that you say it it's actually clear!
I took it from the (unfortunately incorrect) Eagle circuit diagram.
I know that you can edit the Eagle LBR but I'm having a hard time with that too!
I found the bipolar type Panasonic SU-A at my parts dealer and it should fit!

 

[v4lve lover]

i use these capacitors:UVP1E101MPD-ND for C1 and C2

Perhaps we could arrange a group buy for the 5156BN at a later date

 

[snapper]

IC MIC5156 DIP8 or SMD SO8 available at Aliexpress
https://www.aliexpress.com/item/1005003083351535.html
https://www.aliexpress.com/item/1005004026584777.html

 

[v4lve lover]

I wouldmt take chances on aliexpress components

 

[platon.rado]

I bought it, it works well. Yet!!!

 

[Bas Horneman]

When using these for heaters of an indirecty heated tube. Do you guys ground one leg? Or can/should one use it floating?

 

[m17xr2b]

Don't you have hum without grounding? I do ground one side for safety.

 

[grovergardner]

When using these for heaters of an indirecty heated tube. Do you guys ground one leg? Or can/should one use it floating?

I use these in my Aikido preamp build and reference the negative side to a voltage divider from B+ to raise the supply . Otherwise I would ground the negative side, yes.

 

[Bas Horneman]

I've grounded it. But I still have some hum. I think it is from being connected to 6,3vac taps on the same transformer as the HT supply. (Sort of the rattling of the rectifiers of the LDO supply) reflecting into the other windings.

It only draws 1A though (2*6v6) Salas pre.

 

[grovergardner]

This is a 6V6 preamp you're working on? I played with that for a while, and it is hard to get them quiet. Possibly heater-cathode leakage? Some 6V6's were quieter than others. You might try raising the supply with a voltage divider off the B+. Or even reference the negative to the cathodes of the 6V6s, so they're floating at, what 18 volts or so?

I'm using a separate toroid for the filaments in my scratch-built Aikido and it's dead quiet, but it took some fiddling. ;-)

 

[Bas Horneman]

You might try raising the supply with a voltage divider off the B+.

Thanks I will. That is really standard when I build amps. But since this used DC heaters I did not do it.

This is a 6V6 preamp you're working on?

Yes. Really love it. But built 2 different power amps recently that brought to the fore this issue. So now I'm doing some tweaking on it.

 

[Bas Horneman]

Anyone have an issue with c1 and c2 exploding? I asked about the purpose of the caps. Since I'm building a few of Koifarm's boards that I ordered from jlcpcb.

Knowledgeable members mentioned that the polarity was reversed. Perhaps this was mentioned somewhere but I've never read it that I can remember.