New Millett Hybrid Maxed Amp - Page 425

Out of curiosity, I noticed you used a nylon nut to support the screw through the center hole. Is there any reason not to just let the case touch the screw and ground the case through that?

Quote:

Originally Posted by scootsit 

TomB, let me reiterate my last posting - your patience and help is spectacular. Thanks so much. A Millett Mosfet lives and sounds INCREDIBLE! I couldn't have done it without your help! Thanks!

Great!  Another MOSFET-MAX lives!
 

Quote:

Originally Posted by scootsit 

Out of curiosity, I noticed you used a nylon nut to support the screw through the center hole. Is there any reason not to just let the case touch the screw and ground the case through that?

It's only a spacer and nylon was just what I had on hand.

Keep in mind, though, that you need more than just the screw and spacers of some type are absolutely recommended - even if it's just a stack of washers to make up the total space.  It's not grounding so much at the center standoff as much as structural support for the tubes.  The PCB will undergo a huge amount of flex - perhaps a damaging amount - if there's nothing to support the board when you plug and unplug the tubes.  Those sockets can be awfully tight sometimes. 
 

Quote:

Originally Posted by jdkJake 


Pics?
It is not official without pics!

Yeah, you're right.  I suppose I was jumping the gun because we've had a fairly lengthy discussion with scootsit.
 

I will take some tonight. I'm still biasing the tubes/mosfets and finishing some last minute casework. My output caps are the KZ 100uF, so I had to use a grinding wheel to grind the top of the case down a little bit to make them fit better. I've been listening to it, but it's not quite pretty enough yet. A day or two more and I'll be ready to take some pictures.

Regarding the screw, my PCB is bowed slightly (which is good, otherwise those caps would NEVER have fit). I used a screw, put a few washers and a nut under the head, and then a nut underneath. It just barely scrapes the bottom of the case when you push the board in/take it out. I'm tempted to put grommets right under the tubes, just to disperse the force a little better, but we'll see about that.

I've been using these feet for audio stuff, and really like them, so I'll probably use them on this. They're exactly the same as the expensive audio-purposed ones, but are made for household use (hence being somewhere in the vicinity of 1/4th the price)

http://www.amazon.com/Sorbothane-Hemisphere-Non-Skid-Adhesive-Durometer/dp/B003IMSIBA/ref=sr_1_3?ie=UTF8&qid=1329880811&sr=8-3

Quote:

Originally Posted by scootsit 

I've been using these feet for audio stuff, and really like them, so I'll probably use them on this. They're exactly the same as the expensive audio-purposed ones, but are made for household use (hence being somewhere in the vicinity of 1/4th the price)

http://www.amazon.com/Sorbothane-Hemisphere-Non-Skid-Adhesive-Durometer/dp/B003IMSIBA/ref=sr_1_3?ie=UTF8&qid=1329880811&sr=8-3

Those look great, although a bit expensive, I think.  When you case it up, it helps to have cooling slots in the bottom and tall feet will allow the air to come from underneath.
 

They are cheap relative to IsoNodes, which are about twice the price for 8. They work really, really well. Anyway, I'm just about done. When I was biasing the power supply, my V+ lead slipped and shorted to the grounding plane, I want to clean off the char marks...

What size is required for the screws to support the PCB in the center & four corners?

4-40 or 3mil.

Hey all, sorry for the delay, it's been a crazy week. I wanted to post pictures of my build.

So, here's the board/view from above. I chose to route the biasing contacts above the board, instead of below because of how low in the case the Mosfet board sits.

I actually got this as a kit from Glass Jar Audio, which I then modified with parts from Beezar.

Here it is from the outside:

I'm not 100% on those tube protectors. I'll probably spray paint them black, if I decide to keep them, I may just lose them, I haven't decided.

I also need to cut the shaft on the pot just a little bit. Finally, in this picture, the back plate is not screwed on.

I also intend to add a grubDAC. I built it, but bridged a bunch of contacts, which someone is helping me fix.

Awesome build that yields an awesome amp! TomB is perhaps the most patient, helpful human being on the face of the planet, and I highly recommend that anyone interested give it a shot.

TomB,

I don't want to suggest that there is anything wrong with the website, but I think there are some minor tweaks to the Mosfet webpage which might make it a bit easier to use, if you'd be interested in hearing them, let me know.

Quote:

Originally Posted by scootsit 

TomB,

I don't want to suggest that there is anything wrong with the website, but I think there are some minor tweaks to the Mosfet webpage which might make it a bit easier to use, if you'd be interested in hearing them, let me know.

 

Yes, I know - the MOSFET-MAX website has been neglected.  There are a lot of things I wanted to put up there but just never had time.  I welcome your comments.  If you can PM me with a "Do-List," I'll do my best to get them up there.

Many thanks for the kind words, by the way.

Oh - I almost forgot: Another MOSFET-MAX lives!