[dsavitsk]

Quote:

Originally Posted by adamus /img/forum/go_quote.gif anyone on using 240k resistors? or shall i pop to the electronics shop and buy some 220k?

240K is fine

 

[scompton]

Quote:

Originally Posted by m0b1liz3 /img/forum/go_quote.gif Why not just wire up the Millet SS to have pre outs with a resistor in line and a switch to go from HP amp to pre?

I want a pre because I want tone controls. Some of my vintage cans are a little light on bass but respond well to judicious use of bass boost.

 

[procalli2007]

I have a aluminium hammon case which I will be soldering the heatsings directly to.

I also have a pot and dc input which are metal and which ground the case sides.

Will this be ok?
The heatsinks are connected to the mosfets using the beezar heatsink kit.

 

[scompton]

My heat sinks are soldered onto the ground plate. I used the Mouser mounting kits and have no problem.

I don't know about the pot and the power jack grounding. The ground pin in the power jack I used is connected to the threaded body, so I'd guess that it wouldn't matter, but that's a guess that I'd want verified, as you do

 

[tomb]

As long as you wire the center pin of the power jack as the "positive" and you use the recommended VOIP power supply, then everything will be negatively grounded - including the metal body of the power jack and the case.

That's the desired way to do it.

P.S. I'm not sure you'll have much luck soldering to aluminum.
I found this excerpt on the Internet:
Quote:

Tin the aluminum under oil, then solder as normal. Aluminum normally won't accept regular solder. That's because of the oxide coating on its surface. By covering the surface with oil, you can scrape away the oxide coating while preventing oxygen getting to the surface and reforming it. You can then tin the surface with an iron, through the oil coating, and get a proper bond. Then you can clean the oil off and solder as usual.

I don't know if you want to try that, though.

 

[TimJo]

Quote:

Originally Posted by procalli2007 /img/forum/go_quote.gif I have a aluminium hammon case which I will be soldering the heatsinks directly to.

I know this has been discussed before, with different folks having different results, but I was able to back out the posts on my heatsinks using a pair of vise grips, and then attached them using 4-40 screws. May be worth a try, but I can't guarantee the results for your heatsinks, just saying it worked on mine without a problem.

 

[scompton]

I tried, but not too hard, so I wasn't successful. Considering what a pain it was soldering them to the ground plate with a 15W soldering iron, I wish I'd spent more time trying to do it.

 

[TimJo]

Quote:

Originally Posted by Chipp /img/forum/go_quote.gif Well I'll be darned.... Indeed I did. Sorry if thats what you were trying to get across earlier, I thought you were saying that it looked like I bridged pin 1 on the mosfets together. Update: Well, those resistors weren't whats keeping the tubes from firing.

It's hard to describe things based on the pics, but looking at the close up of the terminal strip with the yellow power wire, it looks like the gate on the Mosfet (pin 1) is not attached in the correct place. It looks like it is attached to the fourth lug on the terminal strip, but it needs to be attached to the second lug, with a 2K resistor between the lug and the gate.

 

[Chipp]

Quote:

Originally Posted by TimJo /img/forum/go_quote.gif It's hard to describe things based on the pics, but looking at the close up of the terminal strip with the yellow power wire, it looks like the gate on the Mosfet (pin 1) is not attached in the correct place. It looks like it is attached to the fourth lug on the terminal strip, but it needs to be attached to the second lug, with a 2K resistor between the lug and the gate.

Looks like I seriously need to revisit my schematic reading ability - but, in the meantime the amp is alive.

Thanks a ton for the help!

 

[rds]

Quote:

I have a aluminium hammon case which I will be soldering the heatsings directly to.

More like welding if want to try that

But Tomb has a cool suggestion. I've never tried it but it sounds feasible.

 

[adamus]

from parts to sound in 3 hours!

sounds suprisingly good, not on par with my soha + jisbos but still good.

I will post pics in a bit

 

[procalli2007]

Quote:

Originally Posted by tomb /img/forum/go_quote.gif As long as you wire the center pin of the power jack as the "positive" and you use the recommended VOIP power supply, then everything will be negatively grounded - including the metal body of the power jack and the case. That's the desired way to do it. P.S. I'm not sure you'll have much luck soldering to aluminum. I found this excerpt on the Internet: I don't know if you want to try that, though.

Could I glue it to the case?

 

[adamus]

Heres my 3 hr mini millet, making lovely sound. I used 470uf pana fc caps, and wima mkp10 330nf film caps.

good bass, lovely valvey mids, slightly recessed highs which i expect to develop with a bit of burn in.

 

[tomb]

Quote:

Originally Posted by procalli2007 /img/forum/go_quote.gif Could I glue it to the case?

Personally, I wouldn't recommend it. If you do, probably JB-Weld would be the way to go.

However, there's a reason Pete included the copper board in his BOM. The idea is that you're supposed to sandwich the top of the case between the heat sinks and the copper plate. That way, you can solder the heat sink pins to the copper and the case lid is held in place. If you study his very first pic, that's how he attached the whole thing to a wallet tin.

P.S. There's always TimJo's suggestion of pulling the pins and using screws, too - but it won't give you the grounding advantage of the copper plate.

 

[rds]

Another method, which is very similar to Pete's is to get #3 or #4 washers and tin them and then solder them to the pins of heatsink with the washers flush against the case.