Sgheadphones DIY A47 pocket amp kit

[jasonhanjk 0]

Sh*t, forget to pass you the opa2132, 4556AD and 5532AD.

Maybe next week, try to torture them for me, K.

YGPM.

[tropicalrips 0]

just to clear things up a little, i didn't built this amp

its built by Jason, i just swap out the op-amps to see how they sound, i got the amp already builted from jason

 

i hav tried the OPA2228 on a Cmoys & A47, but they sounded "funny" not sure how to rate them, they sound like the LM6172 when its working correctly, fast good midrange but no bass...

 

on this "jason" board the 2228 sounded much better, has a bass kick like the 2132/2134 but not "tube" like

 

to use the 627 on this board i'll need a single to dual adaptor cause the 627 only comes in single channel format, and i'll need 4 of these chips

[bpribadi 0]

Considering the price of the OPA627, probably you can modified the circuit a little bit, replace the buffer for each channel with HA3-5002 buffer, or BUF634. So you only need 2 of the OPA627 and a pair of buffer.

 

I guess it will become the "platinum edition" of the amp. The one with cheaper Op-Amp can be called standard edition

Edited July 22, 2004 by bpribadi

[huangyong 0]

hello, bpribadi,

 

i got it from digi01

i also get single-double adapter boards from him.

 

i was doing a op-amp roll using opa627 + adpater on voxel's lc-king sometimes back.

 

 

[bpribadi 0]

If you guys want to 'group buy' OPA627 or 637, please include me in

 

I wonder if Digi01 can help us to buy the chip from China, it is much cheaper there

 

Personnaly I would like to try the OPA637, since it is faster than the 627, and I can live with it >5 gain requirement.

[digi01 0]

hello all, I can get the opa627 & opa637 at much cheaper price because i can deal directly with TI China. To be fair to the international market, i think i will limit the number of orders. i think i might have some problem if ship too many chips at once without tax if i can include case or VOL pot, it would be better

 

[jasonhanjk 0]

Hey hey, neber read first post one mah....

This circuit is build on the principle of good, cheap and portable.

[LemonT 0]

can't wait for the final product..i need one to drive my grado..hee

 

[Q00 0]

ooo... if the amp is tubey, i cant wait to match it with my cans...it should give the midrange fullness that its lacking in terms of synergy.

[tropicalrips 0]

just rolled the NJM4556 op-amps on the board...they sound really good with SR80

the board sounded like it has lots of headroom with this chips should be the high current rating of the chips

 

also tried the AD8620 which is what i'm using (current fav op-amp) on my naca v3 this chip distorts on this board, i suspect it may be a voltage problem, the voltage on the JB (jason board) may be too low for the AD8620, on my v3 it has about 8-9 volt per channel (2 X 9v batts) so there was no problems.

 

i think the 10-12 volts currently on the JB amp is not enough to power 2 AD8620 chips, will need to make so modifications if i want to try this op-amp again, i'll need to change the power caps which is too low for 18v operations

[nakedtoes 0]

I can't wait for the AMP..

[Q00 0]

so close yet so far.....*tells myself to calm down*.....soon soon...

[bpribadi 0]

also tried the AD8620 which is what i'm using...

 

Hi Tropicalrips,

 

May I know where you got the AD8620 from? I'm also looking for AD8610 or AD8620 in singapore.

 

Thanks!

[tropicalrips 0]

they are AD samples... this chips only comes in surface-mount form

[bpribadi 0]

Thanks for the tips tropicalrips! I have just ordered the samples as well

 

Need your advice how to solder them to a brown dog adapter