AMB Laboratories DIY Audio

[jtostenr]

Well, I've finally managed to get this thing 95% complete. Got 4 S22 boards built and tested and now encased and wired up. Before I power this thing up I wanted to post some pics and see if there are any stupid mistakes that I made (and didn't catch and have to redo and redo... ) that you guys could point out.

Here is what I know still has to be done:

- switch wired to E24
- outputs from S22/S25 wired to connectors (2 Speakon 8-pole connectors, not shown)
- TRS ground return wire
- front/rear panels
- much of the wiring will be redone once I get the correct size techflex. A couple of wires need to be longer/shorter as well.

It feels pretty good to make it this far, even if it hasn't turned out quite as well as I had hoped. I'm just a little apprehensive about powering up 4 toroids and 6 boards for the first time, all at once lol.

My B22 is a little further behind. I have 4 boards built and tested, but all of the casework has yet to be done. Figured I would get this done first. Anyway, please let me know what you think. I welcome any constructive criticism/feedback (and yes, I know, 2 boards is probably enough )

Jeff

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[jtostenr]

Ugg....3 pic limit. Here's the rest:

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[jtostenr]

1 more...

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[amb]

That's a very impressive and complex build. You said that you've already tested the amp boards, and I assume you have individually tested the PSU boards as well, and verified that all the basics are working. So what's left is the overall wiring. The photos don't show everything, but my suggestion is to draw a diagram of everything that need to be connected, convince yourself that the diagram is correct, and then compare what you've done to the diagram. Check the connections by testing the continuity with your DMM, and also make spot checks to make sure there are no short circuits where there shouldn't be. Pay special attention to the AC mains wiring, the transformers' primaries and secondaries, and the PSU outputs and ground.

[bssanders]

jtostenr, that is going to look like a lot of fun! Looking forward to hearing your results.

[Nebby]

It doesn't look like you have vent holes underneath the heatsinks? Depending on how hard you are planning to drive the amp you may want to consider drilling/milling holes underneath. Perhaps I'm being too cautious, but that center channel of heatsinks concerns me since the heatsinks are right next to each other.

Of course, if there are indeed vent holes below and above, disregard my comment

[jtostenr]

Thanks for the comments guys. I'm going to wire up the switch tonight and perform the checks that Ti recommended. As far as ventilation is concerned, I am hoping that the heatsinks are not going to get hot enough for it to be an issue, but we'll see.

Jeff

[jtostenr]

Well, I got the switch wired in and powered everything up...works almost perfectly The biggest thing I notice is that the trafos are buzzing. If I loosen up the nut or wiggle them around a little, I can get the noise to go away a little, but never completely. I may try some additional padding, or as a last resort I may have to enclose them in something. I really hope I don't have to do that.

One thing I realized once I powered up the S22s is that the S25 I have is always on. This is for the LCDuino, I guess this should be switched, unless there is a good reason to leave always on and have the LCDuino switch the B22 on/off...I don't know. There is an extra pole on my switch in the S22, so I could just use that as well.

One comment about the switch I bought (a 16mm Bulgin), it is a little smaller than the standard one, so I noticed that sometimes I would not press the button in all the way, resulting in the S22 being temporarily turned on then off, then I would have to turn it on again. Probably not a good situation to have. I may end up getting another switch, or just make sure I press the button all the way

Jeff

[amb]

Sometimes a little transformer physical vibration is unavoidable, but you could indeed try additional padding (rubber, neoprene, maybe felt) and tighten the mounting bolt a bit more.

The LCDuino-1 is normally intended to be always on, so that it (along with a momentary pushbutton and a solid state relay) can be used to control the power of the amp. No ε24 would be needed.

[jtostenr]

ok, I'll mess around with some padding and see if I can improve it a bit. As for the E24, I guess I will leave it as is for now and change things as necessary when the LCDuinio is released.

Thanks!

Jeff