Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › DIY Portable Amp <120$
New Posts  All Forums:Forum Nav:

DIY Portable Amp <120$

post #1 of 17
12/10/10 at 10:28pm
Thread Starter 

What are my options for portable amps at this price range ?

 

I'm looking for

 

Size: About the size of an iPod 5G/5.5G

Power: Rechargable or Not ?

Bass: Bass boost is a big plus

IEM Ready: I'm gonna be mostly using the amp with IEMs but maybe the occasional low oHm cans(<50)

 

I'm a big fan of DIY so I know how to solder and do custom work.

Reply
post #2 of 17
12/10/10 at 10:56pm

Mini^3 is the standard recommendation - easy to build, stable design, lots of docs, etc.

 

Personally, I really like the Sijosae designs, the Class-AB portable amp is awesome and I've really enjoyed it.

Reply
post #3 of 17
12/11/10 at 9:28pm

If you're looking for bass boost I'd recommend a cmoybb

Reply
post #4 of 17
12/18/10 at 12:52am
Thread Starter 

I'm not looking for a a bass boost, I'm looking for an improvement in sound quality. I have a pair of Studio.Fi 3s and without amp they sound okay, but when powered by a semi decent amp with subpar cabling the gain bass, clearer and smoother sound and greatly improve in their soundstage.

 

I understand I am aiming for 2x gain since IEMs don't need power. Any recomendations for the rest of the parts ? This is my first DIY Amp. I understand that 470uF capacitors are good and the higher the uF the better ?

 

It would be really nice if someone could list out what I need and what I want in each part and why. I know you will say to go read Mini3 official website but I can't seem to find what I need on there and I want it in laymans terms.


Edited by iLovPieNCake - 12/18/10 at 1:25am
Reply
post #5 of 17
12/18/10 at 4:52am

mini3 beats a cmoy for sure..

 

http://www.amb.org/audio/mini3/   if you read that page carefully it has everything you need to build a mini3, including a parts list..

 

Quote:
I know you will say to go read Mini3 official website but I can't seem to find what I need on there and I want it in laymans terms.

 

 

so you have read the mini3 website?  what information can't you find??


Edited by particleman14 - 12/18/10 at 4:53am
Reply
post #6 of 17
12/18/10 at 11:00pm
Thread Starter 

I've been looking at their website for a while and I'm putting forth a lot of effort to understand it all.

 

Does anyone know how to raise the mA charge rate ? I don't want it to take 17 hours to charge, I'm looking for 11 hours (~23mA). Also, how does battery current affect output (8.4 v 9.6) ? And has anyone seen a 350mAH 9v ?

 

Anyone have any higher quality recomendations for the capacitors, potentiometer, and etc ?

 

I'm almost dead set on the Mini 3 but how much better and how portable is a Pemeta(Sorry If I get the spelling wrong) ?


Edited by iLovPieNCake - 12/18/10 at 11:02pm
Reply
post #7 of 17
12/19/10 at 12:43am

R8 would need to be about 60ohms. See the Notes on R8 on the parts list page. Not sure what you mean about battery current but that battery is probably 7 cell (8.4V) and I would be suprised if it were a true 350mah.

 

I guess you could try something like some elna capacitors but I'm sure all the parts AMB recommends are top quality. I think that the recommended alps pot is the only one that would fit. You could buy a few and test them and use the best one if you like. The only thing I would do if building another mini^3 would be using one of these http://www.radioshack.com/product/index.jsp?productId=2062219&CAWELAID=107597874 instead of the clips AMB sells that you have to modify to get most batteries to fit.

 

Not sure on the pimeta but I'm sure a search would find some useful info.

Reply
post #8 of 17
12/19/10 at 10:45pm
Thread Starter 

I'm sticking with the Mini^3

 

I think It would be a lot better if I did use a Li-Polymer battery(520mA) but did not use the NiMH charge circut they have. Has anyone built their Mini^3 with a removable battery ?

 

Anyone have anymore part recomendations or has anyone built their own enclosure for the Mini^3 ?

Reply
post #9 of 17
12/19/10 at 11:20pm

umm, just use the recommended parts in the parts list. :)   You're going to have a headache plus extra cost if u order something else and its the wrong size or spec..

I haven't seen any other enclosures other than the hammond ones that these boards are designed to fit into... were you thinking of using a different case?  If so you project will definitely no longer be <$120.

Reply
post #10 of 17
12/20/10 at 12:09am
Thread Starter 

DIY case. Any Ideas ?

Reply
post #11 of 17
12/20/10 at 12:20am

Not really, the board was specifically designed for that hammond case.  It seems like quite a bit of extra work for no reason (unless you just want to be different or something)

Plus, using a different case would make your amp less portable as you will be hard pressed to find a similar size to the hammond... and again you'll most likely be going over your price range, unless this has changed? 

 

my mini3 cost me almost exactly 120 with amb face plates.  so any mistakes or modifications will be more $$.

Reply
post #12 of 17
12/23/10 at 3:58pm
Thread Starter 

Any part recommendations if I go above 120$ ?

 

I'm thinking about removing the charge circuit for NiMH batteries since I am most likely gonna use my own li-poly battery charged externally.

Reply
post #13 of 17
12/24/10 at 1:10am

I doubt you will find a high voltage (10.8V) li-po battery that is small enough to fit in that hammond case.

 

Quote:
Originally Posted by iLovPieNCake View Post

Any part recommendations if I go above 120$ ?

 

I'm thinking about removing the charge circuit for NiMH batteries since I am most likely gonna use my own li-poly battery charged externally.

Reply
post #14 of 17
12/24/10 at 7:28am

Do also remember that the OPA690 has a maximum voltage rating of 12V

Reply
post #15 of 17
12/24/10 at 9:45pm
Thread Starter 

What if I remove the charge circuit, will that make enough room ? 

 

How do I change the gain(3X) when building ? I don't want 5x gain because I will mostly be using this with IEMs through my DIY iMod.

Reply
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › DIY Portable Amp <120$