[Greeny24]

Hi, I have an STX with no mod's powering the K702's. I really need better amplification for these phones, and was wondering if it would be a good setup to have the STX (with line out/rca) to a headphone amp. Or would I just be amping a crap audio feed? I was also going to maybe upgrade the opamps, but I've read for the K702's the default ones are good enough.
 
Gah it gets so confusing, every time I come onto head-fi I end up going to bed at 4am. Too many options. 

 

[Jd007]

The STX line out to a headphone amp setup would work like a charm, as the strongest part of the card is the DAC section. Also upgrading opamps always helps, as the stock ones (in the I/V section especially) are pretty bad (after you've heard some better ones).

 

[dex85]

i'm using STX->amp->K701. no complaints here, but i did have to change the buffer to get the K701 going. imo JRC2114D in I/V works very good with K701.
Quote:

Hi, I have an STX with no mod's powering the K702's. I really need better amplification for these phones, and was wondering if it would be a good setup to have the STX (with line out/rca) to a headphone amp. Or would I just be amping a crap audio feed? I was also going to maybe upgrade the opamps, but I've read for the K702's the default ones are good enough.
 
Gah it gets so confusing, every time I come onto head-fi I end up going to bed at 4am. Too many options. 

 

[gwillys]

 
Mastech HY3003D power supply arrived a couple hours ago. burson opamps are happily singing away @ 16v, drawing .18 amp.

i'll keep it there until i find out if 18v is safe. the caps on the card are 16v.

external psu + & - connected to output & ground where the original 7812 regulator had been. in other words, i replaced the 7812 regulator with the power supply, leaving the input pad vacant.

molex connected to card as normal.

no smoke or fire. no anomalies with the computer so far. seems rock solid.

only problem is, the fan of the new psu is LOUD. gotta sort that out the rest of the system is pretty much silent.

anyway, this opens the door for a less drastic (& quieter) approach.

 

[jalyst]

Quote:

@ jalyst,
dots show regulators 7805 & 7812. best to leave them unless you learn some soldering tech and develop
a strategy for replacement.
 

 
http://www.newclassd.com/index.php?page=70
 
http://bursonaudio.com/burson_super_regulator.htm
 
(the guy thats 'tweaking' his card by rewiring the grid would do well to check the above links
 
in any event, if you mod the card, the first thing i'd do is recap. cheap & easy - instant gratification & improves with burn-in.
i'd recommend recapping/burn-in before rolling opa's. the silmic II's change the character of the card pretty dramatically &
you'll then have a very good foundation for other mod's. can't stress this enough - recap!!
 
i used the dexa 7805 because it's fixed and compact, and the burson 7812 because it's adjustable and better suited for analog.

 
So the two links are for the two OPAMPS you're soldering onto those two regulator points?
So Silmic II's are just some type of high quality capacitor that I'd replace all my existing capacitors with?
I don't get why you have solder the dex and burson onto those two points when there's already sockets specifically for opamps.
Is it just to increase the overall resistance/opamp count?

 

[jalyst]

Quote:

here's my st mess. if it survives the power supply phase, i'll tidy it up, in a utility fashion.
don't care much about how it looks, the sound is very, very good. night & day difference from stock.
 
if you think that looks bad, you should see the crossovers (hi pass/low pass) for my polk monitor 30's. Obbligato gold & copper, erse pulsex, solens, claritycap sa, duelund resistors, jantzen 15ga coils. mounted on clipboards, bigger than the speakers pretty funny looking. just 2 of the caps cost more than the speakers. but they sound great with a sub.
 
 my plan at the moment is to use a variable 0-30v regulated bench psu to power pins 4 & 8 of the 3 opa's.
hopefully, this wont upset the card or mobo. the goal is to get 18v to the opa's.
 
i really dont know what i'm doing. it would be really helpful if someone would chime in here before i blow something up

LOL, serious franken-ST!! 

I'd love to offer some advice but I'd definitely cause someting to blow-up if I made any suggestions!
I don't suppose you could use mspaint or similar to highlight your mods and they're name/function in that picture?

 

[jalyst]

Quote:

 
Mastech HY3003D power supply arrived a couple hours ago. burson opamps are happily singing away @ 16v, drawing .18 amp.

i'll keep it there until i find out if 18v is safe. the caps on the card are 16v.

external psu + & - connected to output & ground where the original 7812 regulator had been. in other words, i replaced the 7812 regulator with the power supply, leaving the input pad vacant.

molex connected to card as normal.

no smoke or fire. no anomalies with the computer so far. seems rock solid.

only problem is, the fan of the new psu is LOUD. gotta sort that out the rest of the system is pretty much silent.

anyway, this opens the door for a less drastic (& quieter) approach.

Ah now I see (basically) what you're using the 7812 mount pt for.
Essentially another feed point for power.....  It all seems rather scary LOL.

 

[gwillys]

@ jalyst - you got it
 
external psu is silenced

ok, so far:

1. recap - replace nichicon fg with elna rsf

2. install burson opamps

3. replace smt 7805 with dexa +5v regulator (if you dont go the external psu route, you could also use the dexa +12v in place of the smt 7812)

4. remove smt 7812 and connect external psu (regulated! - you can use a burson regulator here) at that point for 16v to analog section. exceeding 16v will shorten lifespan of 16v caps. on the other hand, i've read that the closer you get to a caps voltage rating, the less distortion they produce.



looks like around $525usd invested so far. that includes the card and $100 for the mastech hy3003d. but i've had $500 worth of fun, so no question i got my moneys worth.

it sounds great - losing track of time. thats a pretty good gain considering that out of the box, the st hurt my ears. literally.

so now, i'm going to look into the xo/clock, which i know absolutely nothing about, except that its hard to remove no hurry on that.

i'll put up pics when i get some.
=======================
btw, as far as powering the bursons: heres my power supply, more or less
 

see the knob second in from right? just a little turn takes it from 16 to 18v, or anywhere 0 to 30v. now...you would'nt think that someone such as myself would be engaging in such careless action, would you?

 

[beeman458]

Today I received and replaced the computer power supply and it made a "huge" difference in the sound quality and the emotional impact of the music being ported over to the HD-650's.
 

 
(And I don't give a snap what the anti-cable crowd has to say on the matter, so don't bother as I'm sharing for those who care.)
 
I also replaced the power cord today with a ten foot, Audioquest, NGR-3 and it sucked the life out of the music and left it flat and emotionally lifeless.  I plugged the original three foot, two dollar and ninety-five cent computer power cord back in and the life was immediately restored back into the music.
 
Go figure, a three dollar power cord whipped on a two hundred dollar audiophile grade power cord.  Well, I now have a new ten foot Christmas tree light, extension cord.
 
In about two weeks, I should receive the custom HD-650 headphone cables that I ordered from Double Helix Cables so it's time will tell on if these cables will provide an emotional uplift over today's emotional uplift.

 

[jalyst]

Quote:

@ jalyst - you got it
 
external psu is silenced

ok, so far:

1. recap - replace nichicon fg with elna rsf

2. install burson opamps

3. replace smt 7805 with dexa +5v regulator (if you dont go the external psu route, you could also use the dexa +12v in place of the smt 7812)

4. remove smt 7812 and connect external psu (regulated! - you can use a burson regulator here) at that point for 16v to analog section. exceeding 16v will shorten lifespan of 16v caps. on the other hand, i've read that the closer you get to a caps voltage rating, the less distortion they produce.



looks like around $525usd invested so far. that includes the card and $100 for the mastech hy3003d. but i've had $500 worth of fun, so no question i got my moneys worth.

it sounds great - losing track of time. thats a pretty good gain considering that out of the box, the st hurt my ears. literally.

so now, i'm going to look into the xo/clock, which i know absolutely nothing about, except that its hard to remove no hurry on that.

i'll put up pics when i get some.
=======================
btw, as far as powering the bursons: heres my power supply, more or less
 

see the knob second in from right? just a little turn takes it from 16 to 18v, or anywhere 0 to 30v. now...you would'nt think that someone such as myself would be engaging in such careless action, would you?

Excellent!!
If you ever have time you should start a dedicated thread which documents your progress in detail.
It would encourage others to follow in your footsteps, or at least adopt many similar approaches.
 
Good-luck with the xo/clock, although I'm not sure how much modding it will affect overall SQ.
No doubt what you've done so far would've already had a big impact!

 

[gwillys]

@ jalyst
 
that would be the blind leading the blind
this set up could crash & burn. i'll tell you one thing, i dont leave the system powered and unattended.
 
i dunno about this whole digital thing. probably the sound i'm after can't be had in the digital realm. the input to my amp is greatly improved, but no doubt, it sounds digital.
oh well, i still have a decent turntable, cartridges & lp's. thank god, emotionally speaking, the turntable has a cheap 3' power cord.
 
now i'm trying to figure out if i should use a decoupling cap where the ext. psu connects to the card. and then, what kind of cap & value.
or maybe run the juice thru the burson regulator, which i'm told, provides a type of decoupling. and then theres the two 470uf caps i put on the card - maybe that wasnt such a good idea. a little knowledge is a dangerous thing. & theres so much bad info out here, not to mention posers.
 
man, this stuff is not easy for a dummy to sort out. about the time you think your getting a handle on something, some little tidbit of reality enters the equation and shoots the whole thing down
 
wish i could go back to my stereo 400 & maggie 2.5r's.

 

[gwillys]

i just implemented the burson  regulator.
 
external psu to burson to card at the original 7812 position.
ext psu + to burson input, - grounded to burson board. burson output & ground to card.
 
i was careful to adjust things to get 16v output on the burson. right now, 22v input and the heatsink is slightly warm.
 
as far as i can tell, it takes at least 22v input on the burson regulator to get 16v out.
 
big improvement, really cleaned up hf/mids. much easier to listen to.
i think i can live with this.
 
so, the external psu is not a solution in itself. burson to the rescue.
 

 

[shimm]

gwillys, now you're ready to upgrade XO. I'll show you some pics (and other info) from russian forum if you wish.

 

[gwillys]

shimm, that would be great!

 

[shimm]

First, you should carefully remove this quartz:
 

 
1. one guy used this XO:
24576 кГц........"FXO-BCF"...................."FULL".............. ; T/HC 5В.................-40~85C 50ppm 10T/HC30pF 45/55%
 

 
2. other guy used (i think) this XO:
http://ru.farnell.com/fox/fxo-hc736r-24-576/osc-5x7mm-smd-cer-24-576mhz/dp/1641004?Ntt=FXO-HC736R-24.576
 

 
pin1 - not used, pin2 > GND, pin3 > OUT, pin4 > +3,3V
 
Benefits in both cases: more detailed sound (thats why need PS washed out first), SS wider.