[BoilermakerFan]

 
Quote:

Here is image of a dial I was thinking of...
 

 
I think the set screw holes would look better on the inside
 
 
 
You all are killing me with the kindness ...
 
 
I have no plans of building any amps right at this moment..
I am thinking about a Beta 22 but since SkyLab thinks its not a whole lot better than a Dark Voice and same price and no labor I just my buy Dark Voice amp but nothing in stone yet... 
 
I may make a rack and some of those pointy brass feet for my equipment  that they use on high end amps? Is the purpose? Or is it just to get air space under the case or some other high tech reason?
 
ENJOY

 
A RK27 shaft will be long enough to accommodate that design.  It will work fine. 
 

Skylab has auditioned more equipment than most guys can dream about, he's well respected, and a friend, so I respect his opinion though I haven't heard a Dark Voice.  The big point of contention with a B22 is that they go up in smoke so easily.  Even very experienced builders have had a B22 go up in smoke while commissioning a new build.  Even if you buy one already assembled and tested, there is a risk of damage occurring in shipping.  Then just forget to turn off the power to your B22 just once before unplugging your headphones and you'll never forget again as you'll be pulling bad parts off the boards, then chasing down the ones hiding after you think you have all the badly charred parts replaced.
 
The cone feet concentrate the weight and make the amp or rack very stable and minimize vibration.  If the rack is designed correctly to distribute the weight properly, a 3-point tripod is a better base than 4-points, but if too much weight is on one side, it will tip over.  If your making  them, why not use bronze?  It's a much denser metal and less brittle than brass.

 

[TBomb06]

Well, one thing I can say after listening to my MOSFET Max for a few days is that it sounds just incredible with my SR225's. Slightly more bass than my BJT version (which was built with parts known for good bass), and the highs seem to be a little more pronounced than with my BJT version. This is just my take, and is definitely not scientific. I just know it sounds so good I have to stop myself from turning it up so loud that I end up damaging my ears . I love the way this amp sounds with my Grados for the music I listen to. Guitar riffs are right there in your face, the drums are so tight and clear, and the bass punches through really well. One other thought on the aesthetics of the amp...the BJT build with the 1" heat sinks and the Muse ES caps looks downright puny compared to this one with the 1.5" sinks and the big Silmic II caps. It looks like it means serious business, which I love. Great work Tom, Colin, and all the others who have helped make this project so awesome!

 

[rarebear]

I was looking at some systems and really liked the racks as I never seen one..
They seem to be all square with a X shape I guess so there is lots of air around systems
 
I just finished SkyLabs review of the Beta 22 and for the money almost you can buy a Dark Voice and not have build it.. Thanks for the info on the Betas burning..
 
Oh what size is the shaft?

 

[jdkJake]

* sigh*



Look up the part number from the BOM. There are multiple distributors. Their web sites will give you the exact dimensions.

 

[the_equalizer]

 
Quote:

 
SNIP

Then just forget to turn off the power to your B22 just once before unplugging your headphones and you'll never forget again as you'll be pulling bad parts off the boards, then chasing down the ones hiding after you think you have all the badly charred parts replaced.
 
SNIP

Hmmm.. not good       I was thinking about building a B22, but if it requires such delicate treatment, I guess I'll pass for the time being.
 
cheers!

 

[BoilermakerFan]

Quote:

 

Hmmm.. not good       I was thinking about building a B22, but if it requires such delicate treatment, I guess I'll pass for the time being.
 
cheers!

Dig into it, they might have come up with a fix, but I know of two B22s that went up in smoke at meets because cans were unplugged from powered up amps.  TBH, for the money, I think other amps can be built that would sound as good and deliver more power or they are cheaper to build for the same amount of power.  A PassDIY F5 comes to mind.  It will need resistors on the headphone jack to protect it from the shorts too, but it should be more robust than the B22. 
 

 

[rarebear]

I need to finish a small lathe job and will have time to make some knobs next week..
 
I have some 1 3/8" brass and was thinking of making a rare wood and antiqued brass knob or just something quick out of aluminum to get some opinions..
 
I'll up up the shaft size but I guess its a 1/4"
 
Anyone know if there are any designs styled like this I might use as a reference?
 

 

[TBomb06]

Quote:

Dig into it, they might have come up with a fix, but I know of two B22s that went up in smoke at meets because cans were unplugged from powered up amps.  TBH, for the money, I think other amps can be built that would sound as good and deliver more power or they are cheaper to build for the same amount of power.  A PassDIY F5 comes to mind.  It will need resistors on the headphone jack to protect it from the shorts too, but it should be more robust than the B22. 
 

I believe AMB said that as long as you turn the volume all the way down before you unplug them, it shouldn't be a big deal. I think it's a safe practice to turn the volume all the way down when you plug/unplug headphones on a powered up amp anyway. And it's only if you use a TRS jack,  not if you're using something like XLR.

 
Quote:

 
I'll up up the shaft size but I guess its a 1/4"

 

Close. It's 6mm.

 

[jdkJake]

So, you know the old adage? Measure twice, cut once? Learned that one again today.
 
I built my grubdac for my MOSFET-MAX today. The build went fine (documented on the grubdac thread). Works well, sounds good so far.
 
When I went to install it into my MOSFET-MAX, I learned something, very, VERY important. While the BantamDac and GrubDac are the same size physically, the placement of the USB connector differs between the builds (DOH!). I had drilled my MOSFET-MAX panel to the template that matches the BantamDac, as such, the USB jack does not line up correctly. So, fair warning to everyone else, determine which DAC you want to include (if any) and cut appropriately.
 
No bitterness, this is my mistake. I have not yet decided how to fix it. I am hoping for divine guidance or some inspiration. Feel free to jump in!   Normally, re-drilling the back panel would be no problem, but, I used those cheap-ass voltage monitoring jacks, which, are one time use. So, removing the back panel to re-drill is a royal pain as I will have to replace those jacks as well. I'll figure something out. Probably have to use a pig-tail though the existing hole. We shall see. Not optimum, but, it will work and avoid rework at this point. I want to live with the DAC for a while and see what I think of the sound as compared to my Keces and y1.
 
Anyway, here is a shot of the test configuration (which I do not condone, open voltages and such).
 

 
The front panel switch is set to switch the input and power up the DAC at the same time. The switch is in place of the L1 ferrite, which I actually had in line until the bead itself cracked under the physical stress. I ended up removing it for now until I can get a replacement. Not sure what the effect will be overall on the sound beyond lessing the total amount of noise reduction on the +5 input. I will fix it on my next mouser/digikey order (maybe).
 
How does it sound? At first, the bass was WAY big and sounded out of balance. As the amp warmed up and the DAC got a bit of burn-in, that seemed to change. The bass is still big, but, the upper end is opening up. I need to listen to it more. I also need to get it off the netbook that is providing the signal and see how it sounds on the main rig. So far, it sounds like a Wolfsen. I am partial to Burr-Brown, so, time will tell. Got to love the packaging though! This AMP is ready for ANYTHING. Bring it on...

 

[tomb]

Well, I'll have to take credit for some of this mistake.  Obviously, the templates I've provided on the MOSFET-MAX website do not take the grubDAC into account, yet.  I thought they were in relatively the same position as the BantamDAC, just MiniUSB on one and USB-B on the other, but I guess you're saying it's not that simple.

 
Colin is re-designing the BantamDAC for a Mini-USB and the same PCB planform as the grubDAC, so maybe that will simplify things in the future.  Sorry, I know that doesn't help you now.

 

[BoilermakerFan]

Use a cheap Harbor Freight nibbler tool and cut out a small rectangular area of the mistake and the area where the correct hole should be.  Head to your local hobby shop and buy a piece of 0.083" aluminum sheet.  Trim it at least 3/16" over size or more and carefully rough up the back, inside edge of the Hammond panel and the edge of the insert.  JB Weld it in place or better yet, use the Magnum Steel putty and clamp it in  place so the magnum Steel oozes out of both sides.  Filet or chamfer the inside edge of the cutout so it looks more finished and fold it over the back side of the insert.  If you do it correctly, you'll have a thin layer of Magnum Steel between the chassis and the fill plate, plus it over laps enough to bond on the edges of the Hammond back and the over lap locks it in place.  The Magnum Steel is strong.  I used it to encase the cracked oil drain on my cheap DeVilbiss "7HP" air compressor to keep it running for as long as I could.  That was in '04 or '05.  It's still going strong and has yet to crack further.  Air compressors are subject to extreme heat and cooling cycles and vibration, so if it holds a compressor block together, I think it will serve your needs well. 
 

 

[BoilermakerFan]

You have one other option...
 
Use said nibbler to cut out the back for a L-Conn USB B connector and mount it up.  Remove the miniUSB jack from the Grub and drop the leads into the PCB on the Grub.  You'll have to use the 8" deep chassis though so it will fit, but you can more than likely salvage the rear panel and connectors if you have at least 2" of play in the leads.  If you cut them short, SORRY!
 
Here's my AudioSector NOS USB DAC in the 6" deep Hammon case for reference:
 

 

 

[jdkJake]

No worries TomB!
 
It is always on the builder to double and triple check these things. Sleep well. I will figure it out. Worse comes to worse, I will just re-drill another back panel. I want to move some things around anyway and maybe add a bypass out to allow me to chain to another amp. 
 
It is all good. Part of the adventure!

 

[jdkJake]

Thanks for the tips BoilermakerFan.
 
I am leaning to a combo of the two approaches. In other words, remove the jack, wire to a panel mounted version. Clean up the back panel.
 
I bought a second grubdac to build another switch box that would allow me to use it across multiple devices. I may just re-build that one for the MOSFET-MAX and re-purpose this one for the switch box (which I have yet to build). So, in any case, I should be good to go. They both need similar switch controls.
 
Where did you source that L-Conn USB connector? 
 
 
BTW, Nice work on the AudioSector. What do you think of the sound? I am always pining to try a NOS design.

 

[tomb]

"L-com" is the actual name:
http://www.l-com.com/productfamily.aspx?id=1393
 
I've bought several of them, but never used them.  It's a great suggestion by BMF, but be forewarned: these things are about three times bigger than you think they are.