n_maher

The first brand that I used cut a pretty nice hole and with a correctly sized pilot seemed to track really well. I'm sure if I'd taken my time and fussed with it even more I could have gotten really good results. The second, HD branded bit was a serious POS and did nowhere near as good a job. That's exactly what I'm hoping to find. I just want to be able to find a data sheet first and confirm electrical insulation/isolation. [edit] Like this:

All good suggestions but as usual time and availability are the limiting factor. Fabrication of the amp chassis absolutely has to be done by the end of the weekend and really I'd like to be wiring before Monday night. I'm going to head to the local HW store at lunch and see what I can find. I like the idea of using some sort of caulking-type product since the size/shape of the bottom of the socket isn't perfectly round so I'd have to use a glue of some sort anyway. I don't think you're seeing the hole picture (no pun intended), the sockets sit on top of the chassis so the contacts on the bottom run through the hole in the chassis and there's less than 1/16" clearance which makes me nervous. The Johnson tube sockets that I'm using (second guessing this choice big time) are a pain to work with for this reason, there's no way to bottom mount them and be able to use the output tubes that I want to. The socket pictured below is pretty similar:

I'm investigating a product right now called pyrosealant. And we were thinking the same thing with the silicon caulking. There's no room for washers since anything that has an I.D. of 1-1/2" is going to have a huge O.D. and not fit in the hole. I'm working on some hand filing to slightly enlarge the hole that I drilled but I definitely want a physical layer of separation between the socket and the bare metal edge of the hole.

I've used that trick before. Thankfully this one wasn't that deep and didn't want to open up so I was able to leave well enough alone and treat it later with just a band-aid. My real challenge for the weekend is figuring out how to isolate the tube sockets so there's no danger of them trying to short on the chassis. I don't think that hot glue will hold up to the temps that these things will be running at...

It might be hot enough to make gravy on top. The cathode resistors for the output tubes look like this... Well, it's a limited run show so enjoy it while you can. I'm hoping to make big progress this weekend although my wife has other plans for my time.

I like sleep way too much to ever go without it for no good reason. But to answer the question I don't think I've ever gone more than 36hrs or so without at least a couple hours of shut eye.

Well between last night and tonight I'm beginning to question whether or not the amp gods are on my side. Last night's snafu is already documented but get this - so I duck out of work 10 min. early so I can run by the hardware store (which closes at 5) and pick up a replacement hole saw. Any guesses as to what size they're currently sold out of. SONOFABITCH! And the pisser was that I had 20 minutes to deal with this before I had to be at another meeting. So I run to Home Depot aka the friggen devil to see if they have anything. Ok, so they've got pre-packaged craptacular looking hole saws so I grab a 2-1/2" set and then look twice. "Dang, that looks smaller than 2-1/2", but it has a label and everything." Not wanting to be f'ed twice in one day I crack open the package and low and behold it's a 2-1/8" bit. I cannot begin to imagine how angry I would have been if I'd gotten it home and found that out at 9pm. So, I go back to the isle and select the right bit and drive pieces separately and I'm headed back to the register with 2 min. to spare. Fast forward to 9pm and the resumption of my hole cutting activities from the previous night. The third hole in the chassis, which was 90% done when the first bit gave out finishes up just fine. The fourth hole, yup, this HD bit sucks ass, fights me all the way. I manage to get it done but it leaves a slightly larger hole than the other three. Oh, and the burr that it leaves around the inside of the hole proceeds to slice my thumb, awesome. So for the rest of the evening I get to fight with trying not to bleed on the amp and bits since the cut is about the equivalent of a nasty paper cut and not worth doing anything about. Anyway, enough pissing and moaning from me for one night. All of the large diameter holes are now drilled and the front four output coupling cap positions have the mounting holes as well. The tube socket holes are going to require some manual enlarging to ensure that they don't short against the case (more on that another night) but that shouldn't be all that time consuming. But no one cares about any of this, show us the pics man, show us the pics!! Blank Canvas Real Nerds Do Full Scale Cad Drawings Mock Up As of 9:30 (more mock up) As of 11:00 (output caps provisionally mounted)

Happy Birthday Ethan!

The only issue I ever had with that approach is that a) you have to supply your own material for the panel and anodizing is your responsibility as well.

Well it did and didn't go well last night. Chassis fab = bad, Pete's review of the power supply wiring = good. Just a couple minor tweaks and that part is essentially functional if not done. I think the PS can live without the chassis stiffening for now although that'll be the first thing that I do after finishing the Amp. I'm hoping that the hardest decision that I have to make next weekend is what sets of output tubes I'm going to bring with me to CanJam. Oh, and I'm really hoping that I'll have actually gotten to flip the power switch before shipping it to Florida.

I haven't found any and when I've asked other folks about it the answer has always been that outside of FPE things get really expensive, really fast.

I think I was just pushing it a little to hard and should have allowed more time for the bit to cool. It cut the first two holes fine and then died. The second bit was a cheap POS so I wasn't really expecting it to do anything. A big amen on that one and I appreciate the low parts count more and more every day.

Yeah, we need a pissed off dog or cat smiley. perhaps: but somehow it loses something when it's that small... Regardless, I made myself somewhat productive tonight and cleaned the adhesive off of all of the caps and mounted them in their clamps so that's one less thing that I have to worry about tomorrow night. I just hope the next bit can make it through the last two holes. With all the bits and such it's almost to the point where having a panel fabricated might not have been a bad idea. I'm pretty sure I torched at least $40 tonight.

Ugh, an hour and half in and things were going well. An hour and 31 minutes, not so much. Both 2-1/2" hole saws have cooked themselves, the first one after just two holes, the second couldn't cut for shit from the get go. So not much progress will be made tonight, which sucks because at this point I don't nights to throw away and there's no going to get another bit at this point. I guess we'll give it another go tomorrow night when I get home at 9...

Yeah, that's the idea for sure. Can't say that I'll be shipping this around the country like I have the DAC though.

Bwaaaaaaaaaaaaahahahahahahahahaha - - waaaaaaaahahahahahaha!

Funny thing, I'm actually not feeling particularly great but I'm behind at work as it is so no leaving early for Nate tonight. And mini meets will be decidedly difficult for a while, but I'll do what I can.

corduroy?

Well, here's to hoping that my hand is as steady with this chassis as it was with the first. And hopefully it'll be picture time some time before midnight tonight.

Funny you'd ask that, they just pulled up outside so we'll see if they've got anything for me... [edit]amp chassis has arrived, won't get to check it till I get home but should be ok.

Just go preparing to have to calmly explain what it is, what it does and why they should treat it the same as an Ipod. It may be aggravating but I think your attitude about it will go a long way towards whether or not there's a problem. My guess is that if it's in carry-on luggage they may take a look at it but that's about it.

Heh, wait till you see the amplifier section, not as much iron but bigger caps.

So tired, so very tired, but the power supply wiring is done. I haven't reviewed the wiring yet with a clear head so no embarrassing pictures yet, just this teaser with the tubes installed. And with the wife out at meetings tomorrow night I hope to launch into chassis fab for the amp. That is of course assuming that UPS does their job and delivers the chassis tomorrow, I have great luck with shippers so I don't know what I'm worried about... Oh, and one more detail about the power supply. I got some good news from the trafo designer today, provided that some other calculations are done and proper precautions taken to avoid overstressing the low-voltage secondaries I should be able to run 5U4 rectifiers so that the tube compliment of this amp will be the same as the original HA-2. That's good news on two fronts, one 5U4's cost less than half of what 5AR4's do and there are a ton more options for good NOS tubes, two it's just so fracken cool that they can be the same that it makes me go .

Even though I make my own cables I feel compelled to go buy something from BJC right now. And I'd love to hear Moster's reply to the letter.

Yeah, cry me a river Mr. K1000 x 2.