Mini³ Step by Step Build Log - UPDATED 3/20 (56k Warning!)

[Beftus]

Quote:

Originally Posted by timmyGCSE /img/forum/go_quote.gif now..one assumes that I don't have to have the LED's poking out of the case? I've bought them and stuff but looking at the case I'm not sure if it would ruin the asthetics of it, I mean, I don't think I will be silly enough to not realise if its turned on or if I have it plugged into the mains! so surely I could not drill the LED holes in the case and just leave them as 'stumps' on the PCB for diagnostics purposes? I mean technically of course I can do this but in terms of space..

On/off status LEDs are a convenience. It's not required to mount them. A LED draws current, omit the LED and you've got (a bit) longer battery life. There's a bit on Tangent's site regarding power consumption and visibility of LEDs. With a balancing act you can have a LED and maximize battery life. A bit like having your cake and eat it too.

Tweaking the LED Resistor

 

[timmyGCSE]

literally 2 minutes ago finished building my mini3, this guide was so helpful, thankyou so much. Still gotta do the faceplates for the case but will do them on the weekend.

and it sounds AWSOME...only listening with my Portas at the moment and even they sound so amazingly good

 

[rayk]

Nice to see this guide!

I started building mine without looking at it.

How much abuse do opamps take? I had to resolder mine a few times and am afraid all the heating has wrecked them

.

 

[weibby]

Just to share my spoils of war with the face/back plate and a tribute to AMD labs -

 

[gilency]

I have 2 questions:
1-if you buy the high gain mode (the only one at JarAudio), do you just change the resistors to convert it to a low gain or do you have to use different opamps?
2-can you use a digital potentiometer for more symmetric volume control? which one?
Thanks

 

[nattonrice]

Just the six resistors: R1, R3, R4.
 
There is no room left in the stock enclosure for another, even small, pcb.
 

 

[Beftus]

 
"The voltage gain of the amplifier is determined by the ratio of R4L and R3L (as well as R4R and R3R). The default values of 1.5KΩ and 330Ω, respectively, results in a gain of 5, which is a good for a wide array of low and high impedance headphones. The following table shows optimized resistor values for several other voltage gain settings."
 

Gain	R1L, R1R	R4L, R4R	R3L, R3R
2x	470Ω	1KΩ	1KΩ
3x	430Ω	1.2KΩ	620Ω
5x (default)	330Ω	1.5KΩ	330Ω
8x	240Ω	1.8KΩ	240Ω

 
 
"Please do not use other values than listed to maintain low output DC offset and ultrasonic stability."
 
 

 

[reiserFS]

Amazing step by step guide, going to order my parts soon.  The 647-UHE1C471MPD seems to be out of stock at Mouser, any alternatives? Also, which LEDs should I chose?
 
Edit: Actually, I think I'll order the kit from Glass Jar Audio.