[tomytank]

My hybrid boards turned up Thursday, so far I've completed the resistors, diodes and small signal transistors. I'm going carefully and methodically through the build.

Like sumo-kun says the boards are stunning, much smaller in person than I thought they would be. As I get time, I'll keep working.

 

[paxeaxe23]

I'm looking forward to building my SS amp and have ordered the parts from mouser and sent a PM to runeight about getting the board/s. In the meantime I have a question about the power supply. So far I haven't found much information on the PSU but I live in Germany where we have 240v supply. Has anyone got a schematics and/or board for use with this amplifier. Thanks

 

[macm75]

Quote:

Originally Posted by les_garten /img/forum/go_quote.gif I hate trick questions like this...

I got the point. Actually, I appreciate it.

 

[sumo-kun]

Quote:

Originally Posted by Beefy /img/forum/go_quote.gif sumo-kun - are you doing the hybrid or solid state? I got a custom toroid for my solid state build and it works a treat.

I'm doing the hybrid build. Looks like the R-core looks like a good way to go since small and the minimal flux leakage are good things for my planned small case. I'm curious about the R-core toroids though... sounds like it would be the ultimate transformer haha.

 

[Beefy]

Quote:

Originally Posted by sumo-kun /img/forum/go_quote.gif I'm doing the hybrid build. Looks like the R-core looks like a good way to go since small and the minimal flux leakage are good things for my planned small case.

Probably. The single toroid I used makes more sense when you don't have the heater windings.

*

After listening to my Lambda with my SRD7-SB, my current theory for the 'scratchiness' I am getting is that the noise is coming from the glue on the pads. Sometimes when I move my head slightly , the glue sticks, then separates. I suspect that the reason I wasn't hearing it after the bias was shorted is that I was holding so incredibly still to be able to hear any slight noise.

Though I still need to listen some more with my Exstata to confirm that this is the case, and not something wrong with my bias circuit/wiring. Unfortunately, it in is pieces right now as I will be drilling the bottom of my case today......

 

[BoilermakerFan]

Quote:

Originally Posted by macm75 /img/forum/go_quote.gif I got the point. Actually, I appreciate it.

Yep, when in doubt, throw it out. A $0.50 resistor could have taken out 100X it's cost in other parts or more.

 

[BoilermakerFan]

Quote:

Originally Posted by sumo-kun /img/forum/go_quote.gif I'm doing the hybrid build. Looks like the R-core looks like a good way to go since small and the minimal flux leakage are good things for my planned small case. I'm curious about the R-core toroids though... sounds like it would be the ultimate transformer haha.

They would be if they were easy to get world-wide and in higher VAs. Custom multi-windings in 200-700VA size offer sure would be handy!

 

[pabbi1]

Quote:

Originally Posted by macm75 /img/forum/go_quote.gif Would you use this resistor? It's R1, 1M, on the amp board. It still reads 1M. Maybe just put some heat shrink around it?

Those who forget the PAST are doomed to repeat it.

 

[macm75]

So for C6 on the PS, .1uf - 1kV, I bought the 27mm lead spaced cap instead of the 22mm spaced. Although it will not fit in the spot, I'd like to drill into the board, put it parallel with R23, between the corner hole and Test Point 3.
I just drilled thru a couple junk pcb's and it went thru with ease. Not sure if the eXStata board is the same material as my junk boards and wish to take precautionary measures... is it OK drilling into these boards?

 

[digger945]

I've got a board here in hand, and while it doesn't appear to have a layer in the middle, that would best be answered by Alex.
Looks like the inboard pad of C6 has a trace beneath the mask(on top, connected to 0V), and this is pretty close to another trace on the other side of the board.
The outboard pad for C6 is indeed connected to other traces on the bottom of the board(ultimately ends up connected to "High Bias"). If you drilled one hole about 5mm off center you would have to wire it back to the pad anyway, so why not try to bend each lead of the cap inward about 2.5mm and see if you can make it fit?

What kinda cap, Wima?

 

[tomytank]

I had the same problem with C6 on the PSU and bought the 27mm lead spacing Wima and had to do what Digger945 describes, I bent the legs slight inwards and then downwards. It does fit. Reaches just to the edge of the diode d3 on one side and has a couple of mil on the R23 side.

 

[macm75]

It's a Wima. The cap is also a little wider than the C6 ink outline on the board. I'd have to press fit the cap between the hi bias diodes and the 'lytic.
But thanks, you're right! I can mount it over the diodes, extend the leads a little, and, for extra security, tie wrap the the cap to the 'lytic.
All is well but I'll still check with Alex on the drilling.

Edit: Thanks tomytank!

 

[runeight]

Drilling???? I hate these trick questions.

 

[macm75]

Quote:

Originally Posted by runeight /img/forum/go_quote.gif Drilling???? I hate these trick questions.

Tough Crowd

 

[BoilermakerFan]

Quote:

Originally Posted by macm75 /img/forum/go_quote.gif Tough Crowd

They're just trying to help because you have one of about 60 sets of boards, and in reality one of 35 or sets of hybrid boards. New boards are not going to be available again for some undetermined length of time. So, if you toast a board, you're out of luck unless you built one channel P2P on proto board or buy a complete populated prototype amp from from the builders on the Alpha team...