Aleph J for Universal Mounting Spec

[henryve]

OK, I just need some advice with the LEDs. There are thousands to select from, so some help just to nudge me in some direction would help. Obviously Blue will be favoured by most.

Not too worry, I will use http://za.mouser.com/Search/ProductDetail.aspx?R=C566C-BFN-CS0W0352virtualkey57280000virtualkey941-C566CBFNCS0W0352

 

[6L6]

Actually, as the LED are there to show proper power to the amp PCB, you will want 2 different colors. Red and Green are the most logical, to show V+ and V-

But some people will want to use at least one of those LED as a 'power on' indicator... So whatever you might find in the way of Pass blue is cool as well...

 

[henryve]

OK, I need somebody else to check my BOM and give feedback. I would like to change it's status from Draft to Revision A.

 

[dimkasta]

After my recent experience with DCB1, I would be really suspicious of clear and super bright leds. Especially blue and white ones.
The cheapest 3mm red ones should be awesome for the job

 

[henryve]

As nobody else besides dimkasta seems interested in giving any feedback on the BOM I am going to make the BOM Revision A. I will allow another 24 hours for feedback.

 

[buzzforb]

Looks good Henry. I would argue gate stoppers are not an option. If interested, I can provide matched fets for GB.

 

[bnorrish]

Agree. Looks great.

 

[henryve]

What would be a good value for gate stoppers? 220R?

PS: Maybe Choky can answer this one since he made the suggestion.

 

[buzzforb]

Thats what i have seen on most IRF amps. You could maybe go as low as 100, but i see no benefit.

 

[didiet78]

I don't think gate stopper needed (if we are talking about J1/J2, JFet gate stopper).
R1 can act like stopper?

Didiet

 

[henryve]

So 220R should be par for the course on the 2SJ74s as gate stoppers as well? Note that the IRF MOSFETs already have 221R gate stoppers as per the standard Aleph J circuit diagram. (R9, R10, R11, R12).

 

[buzzforb]

I think its best just to stick to original numbers. I am sure anything can be tweaked to perfection, but this should happen on individual basis, as all folks builds will be different.

Initial prigin for matched quad will be $12. If using dual output pairs, as I suggest, then $24.

 

[henryve]

OK, the BOM has been updated yet again. Please review. Especially you buzzforb since you have been implicated.

 

[henryve]

Arghhh damn, just after lunchtime and my brain is on siesta. BOM attached.

 

[buzzforb]

Perhaps attach schematic used to BOM, as it will make comparisons and reference easier. there are a couple different ones floating around.

 

[henryve]

I will see what I can do.

 

[henryve]

BOM now Revision A

I have now moved the BOM status to Revision A.

 

[luvdunhill]

For C4, a 10uF/25V cap might fit better: RFS-25V100ME3#5.

I'll look over the rest a bit later.

 

[buzzforb]

Spec wise, Panasonic FM is hard to beat. That says nothing of sound. Ifs it's input cap, I would stick with Elma If possible, but you may not her difference considering bypass mkp. Sorry to be guessing, but I don't know what schematic we are referencing.

 

[6L6]

henryve -- Thanks so much for your work on this! The BOM and notes will be extremely helpful to everybody wanting to build this amp.

As for buzzforb's suggestion of attaching a schematic, I think that's a great idea, it's just that there isn't a really good one yet - the original schematic dosen't have any of the changes, and the eagle schematic that didiet used for making the PCB has a bunch of extraneous bits to facilitate the PCB drilling and pads...

Once we have the PCB tested I will make sure there is an "official" schematic for this. In the time being, didiet's is best.

Question - does anybody know what software Nelson uses for his schematics? Visually it's very appealing, I would love to have the final schematic drawn in that...