Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › A mini PPA v2,my first portable attempt.
New Posts  All Forums:Forum Nav:

A mini PPA v2,my first portable attempt. - Page 7

post #91 of 103
Quote:
Originally Posted by Avro_Arrow View Post
 


I could design one, if there was enough interest.

If you start a interest thread I would be in for a few boards...

post #92 of 103
Quote:
Originally Posted by vixr View Post
 

If you start a interest thread I would be in for a few boards...

 

Likewise.

post #93 of 103

 

The first thing we have to decide is what we want this amp to be.

 

Is it to be battery powered or mains powered?

 

I can assume it will be a three channel amp.

 

We have to come up with a new name, I asked Tangent a while ago about

continuing development of the PPA and he said he was fine with is as long

as we did not use the name PPA. My suggestion is "Trident".

 

Opinions?

post #94 of 103

Since I have really loved diamond buffers in portable amps I'll definitely be in for a couple of boards and can help with any prototyping that happens for this project.

 

I'm thinking ultimately this should be the most insane portable amp we can DIY. Battery powered for sure; but a discussion into NiHM vs LiPo batteries would be useful. Not sure how comfortable people are working with LiPo chargers.

 

3 channel amp would be a safe assumption.

 

Using rail-rail opamps would be a good idea here, and for stability and simplicity, going with a JFET input opamp is probably easiest.

 

Trident sounds like a cool name, though the first thing it makes me think is Poseidon. :)

post #95 of 103

 

So, three channel and battery power.

 

Physically how big? Battery in the same case as the amp?

post #96 of 103

As with all portable amps, the aim should be that it's not much bigger than the DAP used - 3" x 5-6" and not incredibly thick.

Battery inside the case is pretty much a given.

post #97 of 103

 

PPA buffer vers LME49600

 

I don't mind doing a diamond buffer...it keeps in spirit with the original, however...

I think the PPA buffer would limit op amp choices.

LME49600 with it's higher bandwidth and slew rate would allow the use

of higher performance op amps.

 

Also..."mini" seems to have been mentioned...

post #98 of 103

 

Discussion on the "Trident" continues here.

post #99 of 103
Thread Starter 
Hi guys, it's me the op, I apologize for not keeping up on this, I have been so swamped at work and with other projects that I have not had much time to get back on this project.
There appears to be some interest in this after all, so I think I will dust the mothballs off of it and start again in Ernest.

There are a few issues that need to be adressed on this little amp, first and formost being the power supply, my current amp has 3 lipo cells and a controll board, these barely fit in the case, and in fact are so snug that I think it's a safety issue. And to further complicate this, 3 cells really is not enough. It works fine with some op amps, but is not enough ( it seems ) for the 627/37 combo that I have in my full sized PPA.

The other issues are minor in comparison, mainly finding enough room for good quality bypass caps ( mainly for the opamp power rails) , I have a board layout that should allow for a for some whima surface mount film type, but I have. No idea if they will be a good or bad cap in that spot.

As far as putting a 1/4 trs plug on this thing, that would require a much larger case, and that may be the end all fix for it anyway, if a larger case could be found then a larger battery might also be implemented. I will look at all my old designes, and see if I can track down a good case and a reliable battery supplier.
post #100 of 103

I think it's cool both projects are going on. Honestly, I'd love the chance to A/B the two final products since they are so close in spirit. Will be following this.

post #101 of 103

Somehow I missed this earlier, but it's a very interesting project. Definitely interested in a board or two when available. 

post #102 of 103
Good to see you back here again H22 - and I am still interested in your project :-)
post #103 of 103
Thread Starter 
I'm considering a whole new re-design, using a larger case. Right now I'm testing a power supply option, using a boost converter to get 24 volts, going to test it out on my full sized PPA, then hopefully scale it down. The case I'm looking at is the y2 case, it's a bit bulky but not terribly large. Should allow enough room for good quality bypass caps and lots of battery reserve.
New Posts  All Forums:Forum Nav:
  Return Home
Head-Fi.org › Forums › Misc.-Category Forums › DIY (Do-It-Yourself) Discussions › A mini PPA v2,my first portable attempt.