M³ amplifier build discussions thread
Mar 6, 2005 at 8:28 AM Post #31 of 828
pabbi1, if you must use Vishay-something (although I am not sure why that is important), there is Vishay-BC PR02 series 1 ohm 2W metal-film resistors for R9. Mouser #594-5083NW1R000J

z2trillion, do not change R9 to 10 ohms. If you do you won't be able to properly adjust the bias of the MOSFETs without also changing the value of R7. Changing R9 to 10 ohms will increase the output impedance somewhat, but more importantly it will reduce available voltage swing because of the voltage drop across them will be 10x compared to 1 ohm given a particular quiescent current setting.
 
Mar 6, 2005 at 4:39 PM Post #32 of 828
Thanks, AMB, just trying to be consistent... otherwise, I'd always have that nagging feeling, especially as no one ever *recommends* Xicon.
 
Mar 6, 2005 at 6:14 PM Post #33 of 828
Quote:

Originally Posted by MisterX
No... in fact i prefer the green ones but try dispelling the myth that Wimas are the best 5 times a day and it gets old real fast.
biggrin.gif



My bet is that the myth started in the US because they're made in Europe and they're hard to get
biggrin.gif

Over here where even "ye olde electronics shop around the corner" has them, no one seem to think much of Wima caps (except me, but that's because I'm a fashion victim who likes the color
tongue.gif
)

/U.
 
Mar 6, 2005 at 8:23 PM Post #36 of 828
Here's a look at mine in progress:

m3.jpg


I've done everything except the output transistors and bass boost, I need mounting hardware for the heatsinks before proceeding.

Next step is to mount the output transistors, check things out and do the biasing, check the offset, then do some listening tests and measurements.

At that point, I may adjust the gain, and when that's set, I'll figure out what to use for the bass boost.

Thanks to morsel and amb for another great project!
 
Mar 6, 2005 at 8:40 PM Post #38 of 828
Quote:

Originally Posted by amb
jamont, looks great!
smily_headphones1.gif



Thank you!

BTW, do you think it matters if the heatsinks are attached with self-tapping screws or is it preferable to tap the heatsinks and use machine screws? My thought offhand was that self-tapping screws would be easier and should be fine since I won't be disconnecting the heatsinks after final assembly.
 
Mar 6, 2005 at 9:01 PM Post #39 of 828
jamont said:
Here's a look at mine in progress:

m3.jpg


I've done everything except the output transistors and bass boost, I need mounting hardware for the heatsinks before proceeding.

ouuuu, ahhhh!!! I like the blue
lambda.gif
What parts did you order to get blue, also what caps did you choose if one might ask?

Thanks
DigiPete
 
Mar 6, 2005 at 9:16 PM Post #40 of 828
Quote:

Originally Posted by jamont
do you think it matters if the heatsinks are attached with self-tapping screws or is it preferable to tap the heatsinks and use machine screws?


Either is fine as long as it's mechanically secure.
 
Mar 6, 2005 at 9:47 PM Post #41 of 828
Quote:

Originally Posted by DigiPete
ouuuu, ahhhh!!! I like the blue
lambda.gif
What parts did you order to get blue, also what caps did you choose if one might ask?



Resistors are Xicon MF 1/4 W and MO 2W, trimpots are Bourns 3296W, small caps are BC 370 and BC 416, electrolytics are Nichicon UPW. I wasn't trying to get everything blue, it just came out that way.
 
Mar 6, 2005 at 10:21 PM Post #43 of 828
Quote:

Originally Posted by jamont
Here's a look at mine in progress:


jamont,

And idea what the total parts cost was? I know that there are a bunch of us waiting to see how much this is going to hurt.
600smile.gif


Thx,

Nate
 
Mar 6, 2005 at 10:29 PM Post #45 of 828
Quote:

Originally Posted by n_maher
And idea what the total parts cost was? I know that there are a bunch of us waiting to see how much this is going to hurt.
600smile.gif



I had most resistors, caps, and opamps on hand already, so I've spent under $100 so far, mostly on the board and related parts. If you're starting from scratch it should be comparable with the PPA, maybe a bit less.
 

Users who are viewing this thread

Back
Top