McCurdy AU300 clone - development thread

[punk]

option 2 will work for me.

 

[thomasdf]

Ok what if i did a footprint for the carnhill- but then brought a parallel set of connections to solder pads at the edge of the card?

Is the general preference for all connections (including gainswitch, i/o, etc…) to be on one card edge?

That's the best option, for me !

 

[My3gger]

Ok what if i did a footprint for the carnhill- but then brought a parallel set of connections to solder pads at the edge of the card?

Is the general preference for all connections (including gainswitch, i/o, etc…) to be on one card edge?

Parallel sets of connections close to trafo holes would be good to have. Holes in the traces (often seen for different cap wire lengths) with wire links could allow modifications mentioned previously.

 

[amplexus]

Parallel sets of connections close to trafo holes would be good to have. Holes in the traces (often seen for different cap wire lengths) with wire links could allow modifications mentioned previously.

Yes, that seems to be the best idea. Because of the variations in strapping for different potential trafos, I think I will just provide parallel connections for Primary hi/lo, and Secondary hi/lo//CT and allow the user to strap out windings as required or not.

 

[amplexus]

Ok I'm diggin into this this weekend.

What would the preferences generally be for the connections positions on the pcb. I am going to do the layout for 2.54mm header connectors so they can be hand soldered or use pin header connectors, or use 2.5mm euroblocks. Unless anyone has suggestions there

The connections are as follows:

1) Input from Phase/Pad/XLR - 2p
2) External input transformer connection - 6p
3) PSU (Fil, B+, Chassis) - 5p
4) Output Transformer connections (In+CT, Out) - 5p
5) Signal Output to XLR - 2p
6) Gain adj. - 2p

So a total of 22p for all the connections. My thoughts are

1) Throw everything on one side which may allow for a cleaner layout in chassis, at the expense of more wire waste and less direct routing of flying leads.

2) Input From Phase/Pad PCB, and Gain Adj on the 'North' side; External IPT on the North East/West; Output, output TX connections, and Power on the South side

Thoughts?


Also In terms of the cap mounting footprints, I was thinking just to do a 15mm footprint that would allow for a wide range of Panasonic/WIMA/TDK radial box caps- does anyone have strong feelings about doing a multi-spaced footprint to allow for Axial caps (like 150's, Dijons, MKT1813 etc..)?

 

[amplexus]

Ok two rough layouts The IO sits on the one side on door number 2 because the intent is to have an output attenuator on the front panel. So the physical XLR in and out would route to the front panel first regardless.

 

[JMan]

Looking at these, would the front panel side be the left end?

 

[amplexus]

Looking at these, would the front panel side be the left end?

Yes. The left side would go to the front of the chassis (i mean you could orient it however you wanted for your wiring pleasure....)

 

[amplexus]

I've also added the 12 and 36V filament options. via on board jumper. At 12V each board will draw nearly half an amp in heater current. If you're only doing one or two that's manageable, but any more than that and the 36V option makes much more economical sense when it comes to the power supply.

150mA versus 450mA is a big difference.

 

[JMan]

I think my preference would be for the second layout option above, especially if the I/O connections from the xlrs will be visiting the front panel before hitting the board.

I've also added the 12 and 36V filament options. via on board jumper. At 12V each board will draw nearly half an amp in heater current. If you're only doing one or two that's manageable, but any more than that and the 36V option makes much more economical sense when it comes to the power supply.

150mA versus 450mA is a big difference.

Woof, I'm imagining running that 8-channel version from your initial post at 450mA/channel. Yikes.

 

[amplexus]

I think my preference would be for the second layout option above, especially if the I/O connections from the xlrs will be visiting the front panel before hitting the board.


Woof, I'm imagining running that 8-channel version from your initial post at 450mA/channel. Yikes.

Yuuup. That's why they defaulted to 36V strapping and the OEM PSU was 36V. So just a little over 1A for 8ch... Versus almost 4A.

I agree about the second layout. I've rolled with that one- executive decision ;-)

 

[amplexus]

Refined the positioning, added the heater strapping jumper.

I went with 3.5mm spacing on the connections. They will fit standard 3.5mm euroblocks, as well as those phoenix pluggable blocks, as well as be easy to hand solder wires to board.

 

[My3gger]

Refined the positioning, added the heater strapping jumper.

I went with 3.5mm spacing on the connections. They will fit standard 3.5mm euroblocks, as well as those phoenix pluggable blocks, as well as be easy to hand solder wires to board.


View attachment 104103

Any news about this project?