[ruZZ.il]

yeah, Tangent has done an outstanding job, I, and I'm sure many many other people, really appreciate it (Thanks Mr. Young!). which means you basically have to read through the the PIMETA pages a bit then focus on the parts list and the parts selection.. you should print out a checklist and make comments for yourself while you're doing it all, like, who you ordered from, what value you ordered, etc. What I did was open 1 tab with the parts list, another tab with the selection guide and for every part I just read what flexibility I had and worked from there.. then I had another 2 tabs, digikey and mouser.. plus the few bits from tangents shop. you'll need to look at the schematics and s.guide thoroughly for the resistors.. mouser had all the ones I needed. In retrospect, I'd have ordered slightly different values for some, like gain, but I'll tweak it soon enough.. and I've learnt!

I suggest doing something similar.. cant go too wrong.. also, I suggest socket mounting all your stuff so you can play around in the future! the opamps may need little mounting boards depending what you get.. you can get them at tangents. the build guide is really put together well too, and when you're done, you'll find plenty info around here for adding a charging circuit (thanks tomb!) which I found useful. (maybe you should find it first and order the parts.. you'll want it later, anyway.. they're pretty standard, I picked up similar parts at some local electronics bits shack here)
I found the STEPS to be a nice build too. I built mine for my future projects and its busy charging my pimeta right now

enjoy!

 

[vixr]

---------

 

[Soymilk]

yeah i'll probably use sockets for the opamps and the gain resistor; are there any others that change stuff?

for powering the circuit: is it such that if you want battery powered, you just wire batteries in, and if you want wall power, you wire in whatever plug you need? so if you wanted to do batteries + wall power, you'd need to have another circuit in there so that when it's plugged into the wall it'll draw power from the wall / charge the batteries?

edit - o ya, i dropped by fries. they dont have crap.


edit again: i just remembered about diamond buffers, so i'm going to be making three of those instead. not gonna bother with batteries, just gonna do wall power, dont want a portable amp anyways

will the jameco wall wart still be good enough to drive the pimeta well? does the maxed pimeta mentioned by you (tomb) entail a triple diamond buffer + crossfeed?

 

[ruZZ.il]

check out the trickle charger that tomb helps out with. even if you don't plan on transportability, batteries are an extreme convenience.

for another few bucks, you could socket all the resistors if you'd like since you may want to add R8 for some noise later, or tweak your bias current.. I didnt use any sockets for my resistors though maybe I should have socketing the buffers may be convenient too. I found myself playing with stackability a bit and am glad I socketed them. I ended up with what most do, stacked left and right, single ground.. i started with all stacked though but I'm budgeting current.. kinda.

regarding crossfeed.. Jan Meier explains it and theres more info on that here.

also, make your own bill of materials, post it for comments if you like. you'll learn more.

-ruZZ

 

[1nf1n1ty]

Ya...that doesnt help me...I want someone to fill out the checklist...i should leave this for tomorrow morning before i say shomesing i schoildnt...

but ya...baby me please...lol...if u dont get why im like that..read my last post in my thread....sorrieze...agains

 

[Soymilk]

Quote:

Originally Posted by ruZZ.il /img/forum/go_quote.gif check out the trickle charger that tomb helps out with. even if you don't plan on transportability, batteries are an extreme convenience. for another few bucks, you could socket all the resistors if you'd like since you may want to add R8 for some noise later, or tweak your bias current.. I didnt use any sockets for my resistors though maybe I should have socketing the buffers may be convenient too. I found myself playing with stackability a bit and am glad I socketed them. I ended up with what most do, stacked left and right, single ground.. i started with all stacked though but I'm budgeting current.. kinda. regarding crossfeed.. Jan Meier explains it and theres more info on that here. also, make your own bill of materials, post it for comments if you like. you'll learn more. -ruZZ

thanks for the links

i'll consider socketing them all if it's really that cheap

where's a good place to get sockets? i know for the buffers (and opamps too, right? do they use the same socket?) you can get those off tangent's site, but what about resistor sockets?

i didnt look at the trickle charger that closely, but is it set up so that while the wall wart's plugged in, the amp will draw power from that, and when it's unplugged then it'll draw from batteries? or is this just a battery charger that you can plug the wall wart into to charge the batteries? if it's the latter, i dont really want to bother doing it. even if it's the former i may end up not doing it anyways, since i really don't see myself ever needing to run it on batteries. also, since this will be maxed out with everything, wouldn't the battery life suck anyways?

and yes, i was planning on making my own bom, posting it and asking questions about which pieces are more important to get high quality parts than others. i just discovered the part selection guide on tangent's site for the pimeta (i'd never really looked at it before), and wow it really goes in-depth. i havent read it all yet; does this cover every part?

 

[ruZZ.il]

1nf1n1ty:

there always has to be some element of 'y' in DIY. Fortunately, most of the work has been done, we just have to go the last mile. Anyway man, share the good stuff

Soymilk:

no probs.. I was talking about the "DIP-8 IC sockets, gold contacts" mentioned in the parts list.. p/n's are there. they fit on the pimeta board but you'd need 2.5 (chop chop, I guess) though I see Mill-Max at mouser have some dip sockets that look right

(note to self).
Tangent has the adapters for mounting surface mount chips to the socketed ones.. useful if you get so-8 op amps. (I overlooked this and ended up soldering my o.amps directly.. whoops though I kinda like the 8610/20 sound... will be a bitch when I want to roll o.amps though.. )

the charge circuit is pretty cool.. by the use of the diodes it selects the highest voltage source automatically and the LM317 controls the charging current, so when its plugged in the amp runs on external DC and charges simultaneously and when you unplug it it seamlessly switches to the batts.
I've been using 2x8.4v batts for a good couple hours, above 5 at least and my amp is rather current hungry, about 60ma while running (I got rather cheap 8.4v's.. stacked L/R buffers, biased(I need to tweak this.. my headphones are low impedance, so they need more current..)).

 

[Soymilk]

ah, the sockets are in the parts list. i havent gone through that yet lol. i've just glanced at it and said "ok theres capacitors, resistors, diodes, and some other stuff. that's enough for today!"

for the charger: hmm... i guess i'll give it some thought. i've got enough on my plate as it is though, and i really don't see myself ever using / needing to use battery power. what i'll most likely end up doing is casing my pimeta in a case that has some extra space inside so if i want to add the charger circuit + batteries in the future i can.

 

[1nf1n1ty]

haha...sorry about last night...I was out late with friends...and did stuff...

So ya...i know there is that element...But Question about the Pimeta...there is the single opamp and the dual op amp...do you need both? or just one?

 

[1nf1n1ty]

K...I was about to buy parts...but I cant read schematics to understand what resistors and diodes I need...and I cant find them outlined anywhere but that...

Would it be possible for someone to just List them?...I really just dont know...how about ill offer an incentive...of some sort....but you wont know untill you get it.

 

[ruZZ.il]

I'm not sure the PIMETA is best if you cant quiet read the schematics yet... anyway, you just need to go through looking at all the zigzag things (resistors - R) and list their values. you need to double up for L/R.. so.. (bog standard options

R1 4.32k x3 (1 L, 1 R and 1 G...)
R2 1M x2
R3 1k x2
R4(l/r) 10k x2
R4(g) 4.32k x1
.
.
.

also, 0 ohm means jumper, inf means leave open.
although you should read the parts selection guide.. cause.. you use these to set gain and stuff.. like, gain=(1+r4/r3) so, the standard is 11. you may want it lower for low impedance headphones.. as for the op amps, a dual opamp is used for L/R and a single is used for G. there are adapters to use 2 single ones for the L/R, which supposedly work better. I'm yet to try this.

I suggest reading through the build docs thoroughly before asking anymore questions though, since most of this is greatly detailed there.

 

[vixr]

the single channel opamps on a browndog sound waaaay better than dual ICs... uses a lot more battery power though...

 

[tomb]

Quote:

Originally Posted by 1nf1n1ty /img/forum/go_quote.gif K...I was about to buy parts...but I cant read schematics to understand what resistors and diodes I need...and I cant find them outlined anywhere but that... Would it be possible for someone to just List them?...I really just dont know...how about ill offer an incentive...of some sort....but you wont know untill you get it.

A fellow by the name of Sanaka created this very elaborate spreadsheet for the PIMETA:

PIMETAparts.xls

Hold on to your wallet as you check through this, though - it's pretty much an ultimate PIMETA.

 

[Soymilk]

Quote:

Originally Posted by vixr /img/forum/go_quote.gif the single channel opamps on a browndog sound waaaay better than dual ICs... uses a lot more battery power though...

when you say this, do you mean two single channel opamps on the browndog adapter that converts two single channel to a dual channel? so you're doubling up on the L/R opamps, right? do you double for ground too, or is a single one good enough?

Quote:

Originally Posted by tomb /img/forum/go_quote.gif A fellow by the name of Sanaka created this very elaborate spreadsheet for the PIMETA: PIMETAparts.xls Hold on to your wallet as you check through this, though - it's pretty much an ultimate PIMETA.

wow that is an awesome list. thanks! also, is the jameco you listed earlier still powerful enough for an ultimate pimeta? triple diamond buffer, possibly 2x single channel opamps on the adapter for each opamp, crossfeed, the works?

on a side note, wow those opamps ramp up the cost pretty damn fast. i'm gonna have to see / hope i can get some samples from work

probably not going to work though...

 

[WSikorski]

I put mine in the smallest case i could get away with, that would also hold the tread PS.