Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Chip Amps Amplifiers based on integrated circuits

Neurochrome LM3886DR Build
Neurochrome LM3886DR Build
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th September 2020, 04:31 AM   #451
tomchr is offline tomchr  Canada
diyAudio Member
 
tomchr's Avatar
 
Join Date: Feb 2009
Location: Calgary
Yeah. I think step 5 should have been:

5. Electrolytic capacitors: C2, C3, C11, C13, C14, and C15.

Typo on my end. My bad.

Tom
__________________
Modulus-86, 186, 286, & 686: 40-240W (8Ω), <-120dB THD. HP-2 Headphone Amp: 660mW, <-130dB THD. Taming the LM3886.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right
  Reply With Quote
Old 13th September 2020, 05:07 AM   #452
DaveFred is offline DaveFred  Canada
diyAudio Member
 
Join Date: Jan 2018
Location: London, Ontario, Canada
Two boards almost done!

LM3886DR almost done.jpg
  Reply With Quote
Old 14th September 2020, 11:12 AM   #453
DaveFred is offline DaveFred  Canada
diyAudio Member
 
Join Date: Jan 2018
Location: London, Ontario, Canada
Before soldering the chip to the board, I screwed the board and the chip to a piece of plywood so they would all lay flat on the side of the heatsink.

amp on bb ply.jpg

Soldering the boards is the easy part compared to putting it all in the case.

Lots of put the case together/take the case apart, rinse/repeat...

marking holes.jpg

Doesn't help that I have not built any other amp before and don't really know what I am doing.

I marked/drilled/tapped all the mounting holes in the heatsink to mount the boards, chips and a couple of brackets to hold some wires.

marking holes 2.jpg

tapped holes.jpg
  Reply With Quote
Old 14th September 2020, 02:16 PM   #454
asuslover is offline asuslover  Romania
diyAudio Member
 
Join Date: Aug 2016
Looks very good, one thing I would do different ....instead of mounting the chip and the board on a piece of plywood I would use a piece of aluminum flat bar or the actual heatsink.
Can you share with us what brand of the Drill Tap you are using, looks like you did a great job with that.
  Reply With Quote
Old 14th September 2020, 04:23 PM   #455
DaveFred is offline DaveFred  Canada
diyAudio Member
 
Join Date: Jan 2018
Location: London, Ontario, Canada
Quote:
Originally Posted by asuslover View Post
Can you share with us what brand of the Drill Tap you are using, looks like you did a great job with that.
I am using USA made Champion tap and drill bit.

What made the biggest difference was the tapping fluid/oil, it went from hard to turn/lots of torque required/I can see the tap twisting/OMG will this snap? to, easy to turn with massively lower resistance.
  Reply With Quote
Old 15th September 2020, 12:11 AM   #456
DaveFred is offline DaveFred  Canada
diyAudio Member
 
Join Date: Jan 2018
Location: London, Ontario, Canada
Quote:
Originally Posted by tomchr View Post
Yeah. I think step 5 should have been:

5. Electrolytic capacitors: C2, C3, C11, C13, C14, and C15.

Typo on my end. My bad.

Tom
Why do you use a clip to hold the chip against the heatsink rather than directly attaching it with a screw?
  Reply With Quote
Old 15th September 2020, 12:20 AM   #457
454Casull is offline 454Casull  Canada
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Quote:
Originally Posted by DaveFred View Post
Why do you use a clip to hold the chip against the heatsink rather than directly attaching it with a screw?
Not Tom, but one reason is that you'll never lose screw tension through heating and cooling cycles. You also get a bit more wiggle room if the screw is improperly located.
  Reply With Quote
Old 15th September 2020, 01:05 AM   #458
tomchr is offline tomchr  Canada
diyAudio Member
 
tomchr's Avatar
 
Join Date: Feb 2009
Location: Calgary
Quote:
Originally Posted by 454Casull View Post
You also get a bit more wiggle room if the screw is improperly located.
The wiggle room is the biggest reason.

Quote:
Originally Posted by DaveFred View Post
What made the biggest difference was the tapping fluid/oil, it went from hard to turn/lots of torque required/I can see the tap twisting/OMG will this snap? to, easy to turn with massively lower resistance.
Always, always use cutting fluid when cutting threads. I use Relton A-9 Aluminum Cutting Fluid (not to be confused with A-1 Steak Sauce ).

Tom
__________________
Modulus-86, 186, 286, & 686: 40-240W (8Ω), <-120dB THD. HP-2 Headphone Amp: 660mW, <-130dB THD. Taming the LM3886.
Neurochrome : : Audio - www.neurochrome.com - Engineering : : Done : : Right
  Reply With Quote
Old 15th September 2020, 04:19 AM   #459
DaveFred is offline DaveFred  Canada
diyAudio Member
 
Join Date: Jan 2018
Location: London, Ontario, Canada
I added the volume knob to the front plate tonight.

There is a very common volume knob extension available online and I bought one, but I didn't like how much play there was between the bushing the the shaft.

So instead, I bought a linear bearing from a 3D printer that rode on a 6mm shaft and mounted it to the front plate from behind. The picky me wanted to tap blind holes for the screws that held it, but the practical me won and I did through tapped holes knowing the front knob would hide the holes.

Much less play with this set up.

volume1.jpg

volume 2.jpg

volume 3.jpg

volume 4.jpg

volume 5.jpg

volume 6.jpg
  Reply With Quote
Old 15th September 2020, 02:34 PM   #460
454Casull is offline 454Casull  Canada
diyAudio Member
 
Join Date: Jan 2004
Location: Toronto, ON, Canada
Very clever. I probably would've gone with a ball bearing myself but your way seems to require less work. How does it "feel" in rotation?
  Reply With Quote

Reply


Neurochrome LM3886DR BuildHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Neurochrome LM3886 Done Right - 45 W, 8 Ω, 0.002 % THD+N; 80 W, 4 Ω, 0.004 % THD+N tomchr Vendor's Bazaar 32 31st August 2020 05:49 PM
Neurochrome Parallel-86 Group Buy tomchr Group Buys 55 23rd August 2019 09:14 AM
Neurochrome Differential preamp build IanLenco Analog Line Level 39 10th March 2019 06:08 PM
FS: 4 channels of Neurochrome Mod-86 amp kits tubesguy Swap Meet 4 7th April 2017 04:46 PM
FS: Full set of Neurochrome PCBs (Parallel-86, Power-86, THAT Rx) FJHookah Swap Meet 5 7th July 2016 08:15 PM


New To Site? Need Help?

All times are GMT. The time now is 10:30 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki