Links are working now bichi
post #1351 of 2194
9/30/07 at 7:36pm
SOIC8 to DIP8 Carrier
- made from spare surplus parts
- still needs epoxy "potting" for added mechanical strength
- SOIC socket installed on SB0460
- allows DIP8 opamps to be tested with SB0460 and SB0550
Intial test of adapter/carrier, plugged in an old Texas Instruments TL082, DIP8, circa 1980, JFET frontend.
- surprised by audio quality and did RMAA tests, out of curiosity.
- seems to be a nice match with Line-Out caps, Panasonic S, SMT, 33uf @ 25vdc
- short audition with "Put Your Records On," Corinne Bailey Rae, source 48/24
- firm bottom, accurate image, clean highs, very pleasant overall...
SOIC to DIP8 Carrier:
SOIC to DIP8 installed on SB0460:
RMAA Results: 48/24/48 and 96/24/96
Texas Instruments TL082-CP:
EDIT: reloaded eSnips stuff with new links
The 5 volts for the mic is injected between the flexijack & the line in coupling caps & if you don't use the flexijack for a mike then the 5 volts is not injected.This voltage is injected on the right channel, in other words the ring on the tip ring sleeve 1/8th inch plug. In Windows Vista you can actually disable individual inputs so they don't show & can't therefore be selected. For those with Windows XP I'm not sure if that can be done so I no longer recommend shorting the line in coupling caps on XP machines. If you short them on a Windows Vista machine make sure you disable the mike input for the flexijack first.
Update, tried to find where to disable inividual inputs on XP but was a no go.
For those with Windows Vista to disable the mike inpute for the flexijack right click on the speaker icon in the taskbar & select recording devices then right click on micrphone & select disable.
There are two other coupling caps in the line in circuit after the line in opamp. These are 47uf caps on the other side of the ADC & very very close to those 4 large caps above the ADC.
I'm waiting on a new board as I was probing around on the board when it was live & accidently shorted the power supply to the relays to the left channel line-in. When there is no plug in the flexijack the left channel is shorted to ground. When I accidently shorted the relay power to the left channel line-in ther was no plug in the flexijack & I ended up blowing the left channel trace & seems like all of the opamps that lead to the ADC may have been fried as well, even the ones behind the second set of coupling caps. I will be getting new Elite pro card on tuesday if all goes well. The output section on the old card still works so I'm still able to listen to music on old card, just not able to do anymore RMAA tests on this card.
The other caps other than the ones I mentioned to bypass with metalyzed film caps are for the line-in & have no bearing on the sound you hear at the speakers though they may improve the specs as read by RMAA & help if you plan on doing any recording with the line-in.
Oh, it's a pity to hear the first card is malfunctioning,, you can render it to a repair man, great chances it can be repaired!~
For the other 2 coupling caps for Line-in "These are 47uf caps on the other side of the ADC & very very close to those 4 large caps above the ADC",
1. do you suggest to short them in addition to the former 2 ones you mentioned before?
2. The 5v injection to the mike right channel can be offsetted by shorting these 2 additional ones? Or do you know how to get rid of the 5v injection for mike?
3. I need to always connect the line-in to the output of a winradio advanced radio. After I did the first mod to short the 2 line-in caps, I didn't try to connect it to the radio, do you think there is a risk to destroy the cards? If you suggest to do the additional 2 caps, I'll do that too. I think it will only impact mike not line-in, right?? I can't affort to destroy the $750 radio
4. Can you suggest which caps need to be bypassed to let a better recording results?
Thanks in advance!!
I would like to know too. Been hearing mixed results. And regarding the power filter cap, can it use 6.3V caps?
So, I've read through but am still unsure of what the verdict on shorting the 4 caps by the opamp is?
1. Have not tested new card yet but from what I remember there is D.C. voltage there that needs to be preserved on the second set of coupling caps. This voltage offset probably is needed for the ADC to work properly as the ADC has only plus voltages powering it , no minus voltages. so do not direct couple there.
I need to get better probes for my volt meter before testing voltages as it was a simple slip of my current probes as they are not sharp enough to dig in to the solder & not slip that damaged my old card.
2.No the 5 volts going to the mike cannot be offsetted by shorting the two additional caps & could be damaging.
3. never activate the microphone when connected to anything else but a microphone as the 5 volt D.C. is always there at the input jack when microphone is activated but not when line-in is selected. If you have Windows Vista I suggest disabling the microphone if connecting to anything but a microphone. If you don't have Vista make very sure that line-in is selected before connecting to any other source than a microphone. On Vista you can still remove it from the disabled list if you need to use it for a micrphone input later.
4. Waiting to get better probes before further testing of voltages to prevent the costly replacement again. 300 dollars is not chump change to me.
The new card stock does measure slightly better than the old modified one did but still don't like the sound of it. In particular piano sounds stripped of some of its harmonics & sounds dead as a result. There are high frequecies there on cymbles & synths but piano sounds lifeless on new stock card.
It depends. Are your amps DC coupled? If so, keep them. If not, short them if you like You can replace them with some OSCONs. I use 47uf FM, as I don't have OSCON at the moment.
6.3V, yes, even with a 20% voltage tolerance. It's regulated down to 1.2V, apparently.
Benefit of D.C. coupling is clearer sound & better soundstage but slightly worse specs. Very very slightly worse, not durastic at all. .0002% worse distortion & .3db worse signal to noise & about the same dynamic range. better frequency response in the bass especially by .02-.04db depending if you also direct couple the line-in to the first line in opamp. The worse THD distortion is strictly the second harmonic as all other THD componants are better. Do not connect to a D.C. coupled amp though unless you have less than 10mv D.C. offset at the output of the card.
Note you have to have a pretty resolving system to hear much of the differences. Also when I was comparing befor I was using creatives own tests as I had not run stock tests on the previous card which are far worse than mine. On my system it tests considerably better than creatives tests even stock but even my modded card outshined the creative tests by a wide margin. This is testamony to good powersupply selection as my computer powersupply is very clean.
Aye, my Seasonic is pretty clean , and the path on my motherboard uses Rubycon so I'm good to go there.
Were the earlier notions that coupling the caps could cause dc to leak into the headphones/speakers proven false or am I safe with that since I have an amp? If the latter, would shorting the line in caps hurt my mic?