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

[xrk971]

Amazing work by JPS64 in progress for the new Alpha Big Boy with Buttah (ABBB) 52w Class A amp.

All external power actives (2 MOSFETs and 2 BJTs) connected with high current Molex quick disconnect PCB mounted connectors.

All one needs to do to connect amp are 4 Faston spades from transformer secondaries, two Faston spades for speaker, audio input 2-pin JST, and chassis/earth GND Faston spade. OCB can be mounted anywhere (on floor of amp, etc).

 

[md_Stryker]

Are you sure that's a JPS64 design? Where are all the thru-holes?

 

[xrk971]

Laboriously hand applied one by one - so saved for last step.

 

[md_Stryker]

X,
I think you know I was kidding.
I can tell from the symmetry and regionalization of the power that this is a JPS64 design.
Amazing work.
The alignment of all the individual thru-holes must be a nightmare!

-Michael

 

[Mark Johnson]

When shipping PCBs, I wrap them tightly in photocopier paper and use cellophane tape to hold the wraps in place. Usually two complete wrap+tape operations per board, to guard against surface scratches. If it's an expensive board, next comes a bubble "sleeve", held in place by several rubber bands, to guard against drops and rough handling. Then, tightly bundled in a Tyvek tear-resistant envelope and more rubber bands. Put the whole thing in a standard #0 bubble mailer, affix lots of Scotch brand clear shipping tape (cheap at Costco), out it goes.

_

 

[douggoldberg]

I'll take a 1 PCB please

 

[xrk971]

It’s a monobloc - you might need 2.

Or are your referring to the SLB, or SLB DR? Please specify.

Thanks,
X

 

[slk23]

For an M2X build, for example, I understand that's optimal to have a separate PSU for each channel, each with its own transformer and SLB-DR. If I don't go with that approach is there any advantage in using two SLB-DRs with one transformer (e.g. Antek AN-3222) compared to one SLB-DR?

 

[xrk971]

No, you might actually generate more ground loops by connecting two SLBs in parallel from a single set of secondaries. Just use one SLB and it’s GND as the star hub. I am using just one and it works fine on my M2X. Never been quieter. No ground loops. I have Antek AS-3222.

 

[slk23]

No, you might actually generate more ground loops by connecting two SLBs in parallel from a single set of secondaries. Just use one SLB and it’s GND as the star hub. I am using just one and it works fine on my M2X. Never been quieter. No ground loops. I have Antek AS-3222.

Thanks, good to know. This is my first amplifier build and I've got some questions that are pretty basic. For instance, with one AS-3222 and one SLB, how do the wires from the AS-3222 connect to the SLB? Does one pair of wires from the first xfmr secondary go to AC1 on the SLB and the second pair to AC2? And what about the AS-3222 purple ground wire?

 

[xrk971]

I’ll post a schematic diagram later. For now, connect secondaries of the Antek to the AC input of the SLB. Two pairs (the wires from Antek are grouped blue green per pair by proximity). The purple is a static shield that connects to earth ground/chassis ground - the same as the chassis/return pin on SLB (one separated by NTC 8D-20). From SLB positive and negative those go to amp +ve and -ve spade terminals. The ground from the amp goes to ground of SLB. The speaker return goes to GND of SLB. And I have found that the ground of the RCA input of you send to to GND of SLB, is whiter than letting it go to GND of the M2X board. Basically, all GND connection go radically to the SLB star hub. The star hub then connects to the chassis and earth GND via the NTC 8D-20 and 22nF 2X safety cap. The iEC inlet should have a fuse and GND from there goes to chassis GND and earth GND bus that SLB pin connects to. Chassis GND should never inadvertently touch the clean 0v star hub GND except through the NTC. The mains from IEC should go through an NTC 8D-20 or CL60 NTC before going to the red/black primaries of the Antek. This is to prevent turn in surge and it reduces hum somewhat. That should get you started.

 

[gary s]

Hi X, you certainly are tempting all the members with your offerings so far, what with the Apha 20, Yarra pre and chassis, Melb DB, BA18 DB, SLB and now the ABBB, you will be leaving yourself with no where to go. Unless of course you guys have an amazing new design up your sleeves.

Anyway if the ABBB becomes a GB, then I will take 2 off boards for a future project. By the way are you intending to supply the 2 off ABBB 52watt class A channels with just the one SLB power supply?

Regards,

Gary..

 

[xrk971]

The ABBB has built in dual rail SLB on board. It’s a one-board solution - just connect trafo and speakers. Connect audio source and you are making music.

If you have the gen 1 Alpha BB, you need 1 SLB per BB.

Indeed we have something up our sleeves but it’s not for DIY

 

[gary s]

A very elegant solution then for the ABBB - will definitely put my name down for 2 of these for a future project.

Have the Alpha 20 with the SLB as my next project (apart from the Yarra pre that is with both Melb and BA18 DB's)

 

[gary s]

Looking forward to seeing the schematic and parts list for the new ABBB, when you are ready to release these.

I like to get all parts together and ordered well and truly before starting on a project, but I gather all documentation and tid bits of info as they appear here for future reference, it helps a lot with the build and testing phase.

At this stage do you know the dimensions of the ABBB single channel PCB?

 

[gary s]

Hi again X, one more point - I assume you will be starting a new thread for the ABBB and its GB when it comes to that point?

 

[xrk971]

Hi Gary,
Yes, new GB thread all in good time. We are still pretty early stages and working out overall functionality still. Trying to fit in a compact SSR protection circuit and startup delay. This amp will be pretty full featured.
Regards,
X

 

[gary s]

Certainly fully featured - in fact everything but the kitchen sink it seems.

Maybe the other functions you newly mention on a separate snap apart PCB or two, or are you looking to add all of them to the single channel amp board. I would look at start up delay to be separate if it has mains voltage on the PCB at least.

 

[xrk971]

The delay is effected through a solid state relay (a very low RDSon FET - probably same one used in active bridge portion of PSU) that connects the amp to the speaker output. AC power from secondaries is always applied. Mains stays on primary side of trafo so never touches the board.

 

[xrk971]

I’ll post a schematic diagram later. For now, connect secondaries of the Antek to the AC input of the SLB. Two pairs (the wires from Antek are grouped blue green per pair by proximity). The purple is a static shield that connects to earth ground/chassis ground - the same as the chassis/return pin on SLB (one separated by NTC 8D-20). From SLB positive and negative those go to amp +ve and -ve spade terminals. The ground from the amp goes to ground of SLB. The speaker return goes to GND of SLB. And I have found that the ground of the RCA input of you send to to GND of SLB, is whiter than letting it go to GND of the M2X board. Basically, all GND connection go radically to the SLB star hub. The star hub then connects to the chassis and earth GND via the NTC 8D-20 and 22nF 2X safety cap. The iEC inlet should have a fuse and GND from there goes to chassis GND and earth GND bus that SLB pin connects to. Chassis GND should never inadvertently touch the clean 0v star hub GND except through the NTC. The mains from IEC should go through an NTC 8D-20 or CL60 NTC before going to the red/black primaries of the Antek. This is to prevent turn in surge and it reduces hum somewhat. That should get you started.

I forgot that I already posted this on Melbourne DB for M2X thread:

Melbourne Daughterboard for M2X