Building the PINT

[theory_87 0]

btw, anyone noe wen will Mini^3 be available?

[squalle 0]

btw, anyone noe wen will Mini^3 be available?

 

erm that question, who in sgh can tell u that?

haha

ask amb urself I guess would be your best bet

[theory_87 0]

haha.. wan to get an amp.. but pint is discontinue le.. den Miin^3 still nt out.. haiz...

[thedoctor 0]

and i still can't understand why people would wanna mess with the unstable AD8397..

you guys are so dying for a portable, good sounding amp i presume?

[heady 0]

and i still can't understand why people would wanna mess with the unstable AD8397..

you guys are so dying for a portable, good sounding amp i presume?

 

man, thedoctor, you are right!!

 

[Zephyron 0]

The AD8397's good on the PINT, quite aggressive yet still manages to be open sounding IMO.

 

However, I'm thinking of making the switch to an AD8620 or an AD8066 (Chances are AD8066).

[thedoctor 0]

and i still can't understand why people would wanna mess with the unstable AD8397..

you guys are so dying for a portable, good sounding amp i presume?

 

man, thedoctor, you are right!!

then maybe something like this, perhaps?

not exactly a PIMETA, and even closer resembling a PPA, implementing a discreet diamond buffer at each output.

all channels, including the ground channel are buffered, and biased into Class A with Toshiba Low Noise JFETs.

have an integrated TREAD power filter/regulator within the amp itself.

and still, portable enough to be run with batteries. sucking less than half the current drain of the PINT/Mini3.

 

but really, the amp does draw less than half the current. which should means twice the runtime.

 

The AD8397's good on the PINT, quite aggressive yet still manages to be open sounding IMO.

 

However, I'm thinking of making the switch to an AD8620 or an AD8066 (Chances are AD8066).

i would really suggest otherwise.

the AD8397 is used in the first place because it has huge output current and don't require an output buffer to work wonders. this allows the whole buffer section to be dropped since the single AD8397 could output 200mA of current, which is about the same as what the BUF634 is capable of.

 

swapping the AD8397 to AD8620 or AD8066 means that you're back to a maximum of 40mA-something of current output. there's been talks about swapping the AD8397 with LM6172. and it helps in stabilizing the whole circuit. and that it sounds better than the AD8397. but by then the LM6172 only have a maximum of 50mA of output current.

^ which still negates the original purpose for the use af AD8397 in the first place.

[Zephyron 0]

Hmm okay, that's interesting

 

Do ya think the current draw would still be the same though?

[thedoctor 0]

Hmm okay, that's interesting

 

Do ya think the current draw would still be the same though?

using what chip?

each Opamp draws different current. if it's the AD8620 and AD8066, it should draw about a quarter of the AD8397. well, theoritically. but i do think it will be about 1/4.

the PINT when running with 2 X AD8397 draws 50-55mA.

[siriuz 0]

my pint has never given me oscillation issues

of course, there are other people who have experienced such issues, but what i can say is that:

if properly built, there should not be any problems with instability

[Zephyron 0]

Come to think of it, mine hasn't either.

 

Its operation's been pretty smooth at a near continuous 47mA - 50mA+ current draw.

 

Granted, that kind of current draw is an issue with battery life and storage space n.n;

The AD8397's sound signature is more towards the balanced side from what I tested, so I was thinking of trying out different op-amps using the PINT board purely out of curiosity.

Hopefully, if the sound is still good (to my ears at least) and current draw issues enable me to switch down to a smaller sized casing + AAA batteries.

Hmm, what about mixing and matching the op-amp and ground with different op-amp chips?

 

Oh yes, thedoctor, with regard towards the amp you have above, I'll presume that the current draw is about 24-28mA then? What about the power output and compatibility with regard to different op-amps and its current output with regard to the op-amp you're using on board.

[thedoctor 0]

my pint has never given me oscillation issues

of course, there are other people who have experienced such issues, but what i can say is that:

if properly built, there should not be any problems with instability

maybe some unlucky ones. because some do built it with good soldering and all and still it goes haywire. tried plugging all sorts of different impedence to it? some find it acting quite differently when driving different loads.

and sometimes it goes sideways being given different voltage. for the instability issues it might have with different cans and voltages, i'm just not *very* interested in it.

 

Come to think of it, mine hasn't either.

 

Its operation's been pretty smooth at a near continuous 47mA - 50mA+ current draw.

 

Granted, that kind of current draw is an issue with battery life and storage space n.n;

The AD8397's sound signature is more towards the balanced side from what I tested, so I was thinking of trying out different op-amps using the PINT board purely out of curiosity.

Hopefully, if the sound is still good (to my ears at least) and current draw issues enable me to switch down to a smaller sized casing + AAA batteries.

i reckon the AD8397 is THE lowest Opamp that could be used with low voltage. something like 3V minimum i think. and if you're looking for even smaller case and AAA batteries, then you can't use AD8066 and AD8620 since those needs around 9V to work.

 

Hmm, what about mixing and matching the op-amp and ground with different op-amp chips?

one way to solve the oscillating ground channel is to swap the ground channel Opamp with some other chip. though i would say the difference from doing that ranges somewhere from NONE to MINUATURE, yet some golden ears seems to say otherwise. some seems to say it's even more musical and the such. so YMMV.

but since your unit seems to have no stability issues, i'd say don't bother with it.

 

Oh yes, thedoctor, with regard towards the amp you have above, I'll presume that the current draw is about 24-28mA then? What about the power output and compatibility with regard to different op-amps and its current output with regard to the op-amp you're using on board.

the current draw is about 27mA when driving my 32 Ohm cans. idles at 25-26mA. yet there's a few miliamp difference when using different chips.

the power output of the amp are limited by the buffer section. the use of the discreet diamond buffers allows for something about 800mA max. the Opamp used have NO effect to max current output since it's a buffered design.

[heady 0]

the current draw is about 27mA when driving my 32 Ohm cans. idles at 25-26mA. yet there's a few miliamp difference when using different chips.

the power output of the amp are limited by the buffer section. the use of the discreet diamond buffers allows for something about 800mA max. the Opamp used have NO effect to max current output since it's a buffered design.

 

thedoctor, not all of us are able to do P2P as well as you can. How about doing a pcb of your design for us? Btw- what is the schematic of your design?

 

 

[thedoctor 0]

thedoctor, not all of us are able to do P2P as well as you can. How about doing a pcb of your design for us? Btw- what is the schematic of your design?

er erm.. the truth is, all the schematics are all in my head.

i've built quite a number of new amps, and the ones that you see above is one of the completely new design.

i'm still trying to learn Eagle, so please bear with me. but even with a PCB, i doubt we could make it as small. since the amp is cramped into a very small space, use of jumpers cannot be avoided.

well unless we go with 2 layer PCBs that is.

[heady 0]

er erm.. the truth is, all the schematics are all in my head.

i've built quite a number of new amps, and the ones that you see above is one of the completely new design.

i'm still trying to learn Eagle, so please bear with me. but even with a PCB, i doubt we could make it as small. since the amp is cramped into a very small space, use of jumpers cannot be avoided.

well unless we go with 2 layer PCBs that is.

 

I must say, having seen your projects, you are amongst the top DIYers in SE Asia. Even if you have to use a hand drawn schematic, shoot a pic and post here, it is still most welcome. After you learn to do Eagle, you can replace the pics.

 

So, can I persuade you to launch a thread for each of your projects here? You will be sharing your knowledge and ideas and at the same time also helping this site to gain viewership. What do you say? Say yes!!