Quote: Yes, solder should remain under the pin connecting it to the pad. Whether or not it's enough for a secure long-term connection depends on how much you removed. Personally I've never had anything but disastrous results with the flood and wick method. A bridge always ends up...

The Grub only draws ~50ma. At least for me, it seems to be that the Carrie is drawing over 450ma (at least at startup), which the MBP detects as a fault and shuts down power to that port. If yours acts the same as mine, there is no DAC that will solve this problem. You'll either need a dual-USB...

I've had problems with my 13" MBP no matter where I tap power from, but that was with the latest prototype version (not the current semi-production version). I'll have to build up the latest board sometime and see if that improves.

The Grub doesn't technically supply the Carrie. The Grub voltage input is directly from USB, and the Carrie piggybacks on that USB power source. So it's a question of what current the computer supplies both the Grub and Carrie over the USB cable (max for most computers is 500ma, which is...

Quote: This is a good idea. 3.2ma might be visible but not much, depending on the LED. You can connect both LEDs to one resistor/pot - that's how the SSMH kit did it.   I'm not sure which tubes are enclosed and which aren't, or if you can tell by looking at them. I suppose the easiest...

Quote: Yes, this might be the better idea. Set up a switch to switch between open circuit, one resistor, and a higher resistor. That way you can use any standard 2W+ resistors and still have control over brightness.

Yeah, that's what I initially tried but no luck. When I get back to school next week I'll pop in those 3.15A fuses and see if that configuration works. I'm willing to bet it was simply that the TX was pulling right around 2.5A, some fuses couldn't take it, and the configuration at the time of a...

For grounding - basically what you want to avoid is actually passing current through the case. Therefore, you want circuit ground to touch the chassis at really only one point (if it connected at two points, there's a possibility some current would flow through the case, which may or may not be...

The Grub and Bantam are the same size and both will work (the Carrie was designed to fit with the Bantam, and then the Grub was designed to fit with the Carrie). As far as quality, I've listened to both and they're both great. By looking purely at the specifications, the Grub might have an edge...

Here's the picture of the transformer/PSU as requested:     A quick explanation of what's going on: the black/white pair connected to the IEC socket w/fuse is the primary winding. Red/yellow and grey/blue are the two 22V secondary windings which go into the gainclone PSU. The...

Yes that's what I was planning but I grabbed some fast blow too just to see what happened.

The SSMH kit that I have isn't easily modified into a 12SR7 or similar (given the socket difference), but it's not really a big deal since I don't use the amp on my desk much. As soon as I have time I'll try modding it a bit.

Quote: My cellphone can do this. When we moved apartments and I had room to put the amp on my desk, I suddenly noticed more interference. Turns out my wifi router (2.4GHz and 5GHz channels) was causing interference, and only in the tubes (if I blocked the tubes with my hand, all was...

Quote: Ordered! Thanks again Tom!

As soon as I get back to LA (I'm home for the weekend) I'll throw up a pic. It's a SumR 300VA 2x22V unit, customized with shielding/potting and an extra 7V secondary. There's a couple pics of potted units on the SumR website that are similar (the ones that are black plastic cyclinders; mine is...

The only thing I can figure is my 2.5A fuse is right on the threshold and that the inrush current was somehow slightly higher one way than the other - maybe 2.45A one way and 2.55A the other, for instance. Or maybe some fuses were slightly different than the others, and the polarity of the...

Double post

Yes, the TREAD is running off of another set of secondaries on the single transformer (hence why I can't just switch the primary on and off). I could use a second transformer exclusively for the TREAD 5V supply but this transformer is shielded (building everything in a single case) and I don't...

Ah, so it's more a problem of surge current when the amp is flipped on if the PSU already was on, rather than having the amp come up a little more slowly with the PSU?   Would it be preferable to switch the secondaries before the PSU, so the PSU and amp powered up together?

Yes, I wasn't sure either. I asked a question about a month back about whether it was prudent to switch the secondaries or to switch the DC supply after the PSU and there wasn't much consensus. To me it makes more sense to switch the DC, so that the PSU is always on and thus always presents at...

From the one course I took that dealt with transformers, I remember that the polarity isn't terribly important (being AC) as long as you line up the "dots" (start of the winding) on primary and secondary. So it makes sense that it works this way, but I'm not sure why it didn't work the other...

After blowing a couple more fuses I'm glad to report that the TX is fine and the PSU is working again. In the end, a simple reversal of the polarity on the IEC socket fixed the issue. I has assumed that "hot" should go to the start of the primary winding (which is the black wire, according to...

In my application (building a GainClone) I'm going to be turning the amp on and off by switching the +/-Vdc supplies with two relays - one for +Vcc, one for -Vcc, ground will remain connected. The relays will be placed after the transformer/psu and before the amp modules they power. I would...

Quote: Yes, I wasn't suggesting using the case as a conductor. The circuit should only contact the case at one point, hence adding a larger mass of conductive metal to ground (but no real current should be flowing through it). The ideal way to build this is to either use a very large...

The strips will tie everything together, but I worry that it's not enough metal to act effectively. The PCB/kit from Beezar essentially used the whole case as a ground, with good results for noise rejection. Depending on your application, case, and environment those strips might be ok. In a...