cspirou

Power LED indicator has been expanded to 3mm and I moved everything up by a couple mm to give more room under. Unless there's any glaring errors I consider this my final variation. If anyone still wants a case and hasn't ordered one, please contact me immediately.

The corners are already counter-sunk and it seems to work fine. Measured thickness is about 2.5mm or 0.1".

@Flyingsparks - since I am already doing this for Pars it should not be an issue. I haven't heard back on the quote yet but I already know that there is no difference between the Alpha and TKD versions

The original post has updated drawings. Look over it for errors I widened the case to 6.5". Also decided to go brute force with ventilation and added a lot of holes on the top and bottom panels. Diameter for the power button has been widened a bit from 10.5mm to 11mm. Besides the text, the issue I need feedback on is the power LED hole. I have it at 2mm right now, but it seems small and limits the kind of LEDs people can use. Should I keep it at 2mm or go bigger? Sending this in for a quote

Sorry about the radio silence. You guys are right, it's not cool when I'm holding other people's money. I'll just say this. I got a lot of stuff going on and I would have honestly preferred joining a group buy rather then starting one. No one else was doing it, so I did. Yeah, modifying drawings does take time. But not this much time. The current design works. Everything fits and the front and rear panels are accurate. It does get a bit hot, however with the cover off it runs fine. So I'm going to maximize the vents on top and bottom like in the following PDF dynalo_top_plate_15.pdf I'll order this by Monday when they open back up. IF I haven't completed this order by Wednesday, I will refund everyone's money and I'll absorb the cost of the prototype. I'll even have the prototype for sale. The drawings will remain for anybody that wants to go through Enclosures and Cases Inc themselves. They should also work at fine at Context Engineering. @Pars - You will also get your panels with countersunk holes. Just let me know which holes you want countersunk. This goes for anyone else as well.

Just wanted to let you guys know I haven't disappeared. Updating is just taking a little longer then expected with life. I did get in contact with the manufacturer and he said my modifications won't affect the price too much.

Yeah, they don't really need to be there after it's mounted. I do use them to hold the IEC in place for soldering and it takes some pressure off the pins when I was using it without an enclosure, but are otherwise optional.

It's only because of the stud on the side panel for the screw. Which isn't an issue anyway because I need to increase the width for more airflow. The screws I used for the IEC were kinda long too.

Got the amp assembled After cutting some leads and removing the IEC screws, everything fit fine. There's some small gaps here and there, but at this price point I think it's acceptable and you wouldn't really notice unless you look really closely. After running it for a couple hours the case can get pretty warm. Even the potentiometer starts feeling warm. I'll try it without the top cover to see what i get. Either way, the next revision is getting a lot more holes.

Its all on my spreadsheet. 21 TKD and 19 Alpha.

Yeah, you can check. ~40 enclosures. Somewhat doubtful it would be under $100

Enclosure has arrived! Its a raw brushed metal which actually isn't that bad. Good news is the front and rear panel layout is fine. Except for a slight issue with the power switch. And that's only a problem because the way I soldered it makes it tilt slightly up. Because of this the cap rubs a bit with the panel. I can easily fix this by making the diameter 1mm wider or just using a smaller button cap. (Or just solder better) The bad news is that the side panels don't quite fit. Partly because I did not receive a good CAD drawing for the side panel, so I did not take the stud for the top and bottom screws into account. It doesn't touch the PCB, however it does interfere with a screw I use to secure the IEC to the PCB, as well as some pins under the source switch. But this can easily be resolved by making the case wider. I can also use the 3.5" tall case they offer, however that will increase the cost quite a bit and will have a lot of empty space. I'll take the screw off the IEC and cut some pins to post pics of it completely enclosed. Drawings will be updated by this weekend and hopefully we can put a final order in by next week. We could also get another proto but that's an additional 3 weeks and $3 per case. I don't think we will need another proto.

I'd rather wait for me. No point in paying for shipping twice.

Update! prototype is finished and has been shipped! Will post pictures as soon as I recieved it. Prototype price will be updated to include shipping on the spreadsheet. This should only add 37 cents to the price.

Faster then enclosures, thats for sure.

When I initially adjusted the offset I didn't short the inputs. I'll remove the zero ohm resistors and re-adjust with shorting jacks.

I was auditioning some low-z headphones the other day and noticed the left channel was starting to sound a bit distorted through my Dynalo Mini. After I powered down everything and turned it back on the obvious distortion seemed to disappear, but things just don't sound as 'good' as when I first built it. Did some voltage checks the power supply seems normal and DC offset is ~1-2mV on both channels. However I noticed that when I turn the volume pot that the DC offset jumps to 40mV and then gradually comes back down to 1mV after 5-10 seconds. For the balanced output this is +40mV/-40mV or 80mVp-p. This DC while turning the potentiometer seems to explain why I hear some scratchiness when turning the volume while there's no music playing. Anyone else notice scratchiness while turning the volume? Is this sort of DC-offset normal as long as it drops after awhile? Would changing the THAT chips to JFETs do anything to resolve this?

I heard back from the guy and he said it should take another week. sorry about delaying the layout samples. Family stuff

Sent an email a few days ago for an update and didn't get a response. I'm going to call first thing on Monday during business hours. Good thing is no money had changed hands yet. He's usually better with responding to emails so I don't know what the deal is. Still, at this price I'm willing to put up with some issues like this. Been playing around with fonts a bit more and will post more samples this weekend

How is high voltage generated for the tube from a DC power brick?

Don't you mean Input-Ubal/Bal-Volume-Buffers-output? I mentioned something like this earlier but his response was to put it before the Ubal/Bal board https://www.head-case.org/forums/topic/12733-balanced-to-unbalanced-board/?do=findComment&comment=753597 However that's because I have the SMD boards. The through-hole boards have a servo for the buffer so is probably different. The VAS before attenuation is good for low noise since you aren't amplifying Johnson noise. Downside is the Ubal/Bal stage possibly clipping because it is always getting a full signal. This should not be an issue though because the gain is low and the rails are +/-20V

i just came across these regulators on eBay https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F322870941945 much cheaper then the other supplier and I believe comes with a heatsink. If it's pin compatible with the Dynalo Mini then It seems like a great option to the AMB modules.

Prototype should take another week or two. I'll contact him again next week to see how things are going. Too bad Asia and Euro and only in FPE. I'll play around a bit more and post updates.

Paid. Thanks Steve!

Do the totals include the TKD pots?