The SLB (Smooth Like Butter) Active Rect/CRC/Cap Mx Class A Power Supply GB

[Kokanee]

Happy Days,
I reflowed the solder joints on the entire board and powered it back up. Everything worked as it should, and dialed in the BJT drop to 2.3V and output was a touch over 31V. I also hooked up my SFP to the transformers on a separate test and the board seemed to work OK. Next step is to start installing components into the chassis.
MM

 

[AKSA]

Excellent, Myles, you are cooking with gas.......!
I try to set 2.8V across Vce of the series output transistor on the SLB; there is a small adjust you may be able to set.

HD

 

[Kokanee]

Hugh,

Nice to hear from you, I have to laugh about this. I will have to go back in and adjust the pots to read 2.8V. I do not know why my old brain thought that 2.3V was the magic number. Thanks for the heads up.

Anand, thanks for the help

MM

 

[Kokanee]

Hugh, Anand,

With no load, the pots max out at 2.35V drop on the BJT's. I expect that when attached to the amp it will drop more and can be adjusted at that time. Am I correct and can continue to move forward.
Thanks,
MM

 

[xrk971]

Yes, drop still be more with a Class A amp load attached.

 

[Kokanee]

Thanks for all the help, I shall continue with installing components.

 

[Blowmymind]

Kokanee,
Please, will you do fallow ups on your build. I am fallowing. 👍

 

[Kokanee]

@ BMM, yes I will. I am a slow and methodical builder. I am in the process of installing the SFP/trans/SLB's/fans/HS/amp module into the chassis for an actual load test. Will post some pics when this happens.

@ xrk971: Is it recommended to test the amplifier with a load attached ?. I have some 100W/8ohm resistor's, will they be OK for this ?

Thanks,
MM

 

[xrk971]

If you have 8ohm power resistors they will work well for dummy loads. Do these require heatsinking?

 

[Kokanee]

Probably yes to be safe, I have a 6' x 6" x 3/8" alu block to use for the testing. I have a question about the hook up, but I will post in the Alpha Nirvana thread.
MM

 

[Blowmymind]

I’m going to be starting a soft start and SLB for the first time. What size fuse do people recommend?

Thnx,
BMM

 

[poseidonsvoice]

Fuse size is based on the size of your transformer in VA and your mains voltage + a small fudge factor.

Try (VA/Mains voltage) * 1.5

Best,
Anand.

 

[Blowmymind]

Hey there,
I’m going to direct solder the transitors on to the board. Q10 And 12. Just to be sure, the square pad is where the base goes?
Thnx,

BMM

 

[Kokanee]

I believe you are correct. The Q10 and Q12 are designated BCE when looking at the face of the transistor reading the lettering. If you are attaching to the chassis base or a heat sink this would ensure that the base goes to the square. You can check also by looking at the schematic or by using your DMM. I attached mine with flying leads but no molex cable, and I traced the base on the transistor back to the square pad on the slb board.
MM