The word b_u_g_g_e_r had been automatically moderated in my post above. How uptight can you be to be offended by that particular word?!? 
That is simply rediculous... 
And this is the same place where post this 'funny' smiley:
IMNSOHO, that's pretty *****ed up
Excuse the OT talk, just had to get it off my chest...
That is simply rediculous... And this is the same place where post this 'funny' smiley:
IMNSOHO, that's pretty *****ed up
Excuse the OT talk, just had to get it off my chest...
The trick is not so much thin solder tips but thin solder! I can solder a normal SO8 device with a 2mm tip and 0.5mm pitch parts with a 1mm tip.
For clean SMD work, get 0.4mm solder.
Desoldering an SOIC is a bit tricky. I'm presuming you don't have a controllable small hot air gun.
If you want to keep the part you're removing, use solder wick. The best type I've used so far is "soder" wick with "rosin" from chemtronics. Not the no-clean type. It's so good you can get virtually all of the solder from the pad. Sometimes you can pull off the IC cold after doing that but I don't recommend it as the chance of pulling off a pad is significant.
Then, gently wedge a thin screwdriver under the IC and apply some twist while reheating the pins (slide the iron along a row of pins repeatedly working away from the screwdriver side). Be careful you don't lift the part to far when the first row of pins comes off. Then reheat the other side.
If you don't want to keep the IC (e.g. it's broken) flood both pin rows in solder so it's got some thermal mass and all pins are connected. Then, alternatively heat both sides with the iron in quick succession. After 2 or 3 times the IC will come off. Clean off the solder from the board.
Once you've got the hang of it you can rework boards so you don't even see there's been any hand soldering going on (after cleaning off the flux that is).
For clean SMD work, get 0.4mm solder.
Desoldering an SOIC is a bit tricky. I'm presuming you don't have a controllable small hot air gun.
If you want to keep the part you're removing, use solder wick. The best type I've used so far is "soder" wick with "rosin" from chemtronics. Not the no-clean type. It's so good you can get virtually all of the solder from the pad. Sometimes you can pull off the IC cold after doing that but I don't recommend it as the chance of pulling off a pad is significant.
Then, gently wedge a thin screwdriver under the IC and apply some twist while reheating the pins (slide the iron along a row of pins repeatedly working away from the screwdriver side). Be careful you don't lift the part to far when the first row of pins comes off. Then reheat the other side.
If you don't want to keep the IC (e.g. it's broken) flood both pin rows in solder so it's got some thermal mass and all pins are connected. Then, alternatively heat both sides with the iron in quick succession. After 2 or 3 times the IC will come off. Clean off the solder from the board.
Once you've got the hang of it you can rework boards so you don't even see there's been any hand soldering going on (after cleaning off the flux that is).
Thanks Bruno! That seems to be a very good recipe for succes. What a great tip to flood the rows in case you just want to remove a part. Makes perfect sense.🙂
Dipole Subwoofer driven by UcD
Hello all,
in the last days I built up a Linkwitz style dipole subwoofer using these woofers and tried to measure its frequency behaviour and its
impedance curve.
It is clearly to be seen, that the impedance maximum of 60 Ohms of the paralleled chassis will require a high voltage to drive them appropriately at low frequencies around 20Hz. The ~27Vrms out of the UcD180 will result in 12W @ 60Ohms - not quite much.
I think of driving the UcD in a bridged configuration to double the voltage and increasing power by a factor of 4.
I also want to experiment a bit: driving the speakers by a current instead of a voltage, coming out of the UcD. Does anybody know an appropriate way to realise this, especially, if the UcDs are bridged? I hope to flatten the frequency dependent output power curve by compensating the impedance effect.
Thanks in advance!
Regards, Timo
Hello all,
in the last days I built up a Linkwitz style dipole subwoofer using these woofers and tried to measure its frequency behaviour and its
impedance curve.
An externally hosted image should be here but it was not working when we last tested it.
It is clearly to be seen, that the impedance maximum of 60 Ohms of the paralleled chassis will require a high voltage to drive them appropriately at low frequencies around 20Hz. The ~27Vrms out of the UcD180 will result in 12W @ 60Ohms - not quite much.
I think of driving the UcD in a bridged configuration to double the voltage and increasing power by a factor of 4.
I also want to experiment a bit: driving the speakers by a current instead of a voltage, coming out of the UcD. Does anybody know an appropriate way to realise this, especially, if the UcDs are bridged? I hope to flatten the frequency dependent output power curve by compensating the impedance effect.
Thanks in advance!
Regards, Timo
Driving with current source rather than voltage source will result in a frequency response that mirrors the impedance curve, i.e. massive peak at resonance.
I don't think it's even important to have constant power as efficiency will change through the band.
I don't think it's even important to have constant power as efficiency will change through the band.
Re: Dipole Subwoofer driven by UcD
Hello Timo,
Sound pressure is not directly related to the power you put in the woofers but it is related to the voltage you apply to them. Around the resonance frequency, the impedance is high, this mean you are lucky since you need not that much power, just voltage, to get a certain amount of sound pressure out of the woofers.
On the other hand, dipoles drop off with 6dB/Oct, so you need more voltage at lower frequencies to keep the same sound pressure level. Because of that, using bridged amps maybe beneficial. In fact I want to try to bridge two UcD400 modules for my dipole woofers.
Best regards
Gertjan
tiki said:
Hello Timo,
Sound pressure is not directly related to the power you put in the woofers but it is related to the voltage you apply to them. Around the resonance frequency, the impedance is high, this mean you are lucky since you need not that much power, just voltage, to get a certain amount of sound pressure out of the woofers.
On the other hand, dipoles drop off with 6dB/Oct, so you need more voltage at lower frequencies to keep the same sound pressure level. Because of that, using bridged amps maybe beneficial. In fact I want to try to bridge two UcD400 modules for my dipole woofers.
Best regards
Gertjan
Also consider a bigger amp and doing some EQ on the dipole. I have an Infinite Baffle sub which is also supposed to drop off at 6dB/octave, I am using a serious amount of digital EQ to even out the bottom end and it's staggeringly effective.
Check out the "Cult of the Infinitely Baffled" mailing list. These guys advocate EQ on the designs as a matter of course and you can seem some IB stuff discussed ocassionally.
http://f20.parsimony.net/forum36475/
I will be writing up more about my system here:
http://www.duffroomcorrection.com
By the way, do note that you don't necessarily need to go down the serious EQ route to improve performance. Linkwitz's transform circuit is a really good start. Or add on a Behringer "Feedback Destroyer".
However, if you want to see just how good room correction can get, check out the graphs from the DRC readme:
http://drc-fir.sourceforge.net/doc/drc.html#htoc190
For me DRC is a huge change with stereo imaging exploding out and filling the room. Bass boom disappears and small details suddenly become much more obvious.
Check out the "Cult of the Infinitely Baffled" mailing list. These guys advocate EQ on the designs as a matter of course and you can seem some IB stuff discussed ocassionally.
http://f20.parsimony.net/forum36475/
I will be writing up more about my system here:
http://www.duffroomcorrection.com
By the way, do note that you don't necessarily need to go down the serious EQ route to improve performance. Linkwitz's transform circuit is a really good start. Or add on a Behringer "Feedback Destroyer".
However, if you want to see just how good room correction can get, check out the graphs from the DRC readme:
http://drc-fir.sourceforge.net/doc/drc.html#htoc190
For me DRC is a huge change with stereo imaging exploding out and filling the room. Bass boom disappears and small details suddenly become much more obvious.
Some stuff to learn for me, thank you for that!
Gertjan, I would like to hear from your experiences, bridging the 400s for the dipole.
Because this is my first subwoofer, it is easy to say, I like the sound of my audio equipment much more than before, irrespective of the non-optimum behaviour until now. 😀
Regards, Timo
Gertjan, I would like to hear from your experiences, bridging the 400s for the dipole.
Because this is my first subwoofer, it is easy to say, I like the sound of my audio equipment much more than before, irrespective of the non-optimum behaviour until now. 😀
Regards, Timo
tiki said:
Hi Timo,
I'm quite sure you will like the dipoles. Maybe you need a bit of time to get used to them as you will have far less booming bass than with conventional closed systems or basreflex system. So initially you may think there is less bass. What is less are the resonances. This is because dipoles excite less room resonances, bass is much faster. I apply a 6dB/oct equalization in between the pre-amp and power amp to compensate for the roll-of. Besides that, I'm using a DEQX PDC unit as my active crossover and speaker correction system.
I don't know when I can have the first results with the bridged UcDs, I'm still working on optimizing the SMPS supplies and don't have that much free time. However, I'll keep updates related to that supply in the following thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=55338
Best regards and good luck with the dipoles, hope you like them
Gertjan
JP,
Just received the UCD 180's. How small they are
.
Is there anything to watch out for when I replace the 5532 for different opamps like OP's? Do they run on 2x15V? Could not find the thread anymore where some DIY'ers modded their UCD 180's.
Thanx, Bert
Just received the UCD 180's. How small they are
.Is there anything to watch out for when I replace the 5532 for different opamps like OP's? Do they run on 2x15V? Could not find the thread anymore where some DIY'ers modded their UCD 180's.
Thanx, Bert
Cute aren't they 😉Bgt said:JP,
Just received the UCD 180's. How small they are
Is there anything to watch out for when I replace the 5532 for different opamps like OP's? Do they run on 2x15V? Could not find the thread anymore where some DIY'ers modded their UCD 180's.
Thanx, Bert
You can find what voltage another opamp needs/can handle in datasheets from the manufacturer.
Search for posts, not threads and these keywords: 8620, diode, ucd
That should do the trick.
There is also a huge thread somewhere with the 2604 opamp in the subject. A lot of opamps get reviewed there.
The J511 Tweak
Hi !
Does someone tried to add a J511 on his module like it was said earlier on this thread ? Does it sound better ?
thanks..
PA
Hi !
Does someone tried to add a J511 on his module like it was said earlier on this thread ? Does it sound better ?
thanks..
PA
On desoldering opamps, I have had good success using a pin (needle) and desoldering (bending) one leg at a time. Add a bit of solder/flux to each leg before doing that and it should come out clean and nice. Legs can be rebent into position and the opa reused if needed.
Add flux, and use soldering braid after doing this to clean up the pads. Next, use a cotton swap dipped in solvent (isopropylic alcohol or other solvent - I use paint thinner) to clean up the PCB from flux/rosin residue.
Most improvement in SQ on the UcD 180 comes after changing the OPA (to say OPA2134 or OPA2107) and removing the two (22uf I think) coupling capacitors. Check for DC offset on the UcD output after doing that (smaller than 100mV should be OK). Do not remove the coupling caps using the stock opamps!
A relative good thread on another forum on how different OPAs sound:
http://www6.head-fi.org/forums/showthread.php?t=84519
Another link: http://tangentsoft.net/audio/opamps.html
Add flux, and use soldering braid after doing this to clean up the pads. Next, use a cotton swap dipped in solvent (isopropylic alcohol or other solvent - I use paint thinner) to clean up the PCB from flux/rosin residue.
Most improvement in SQ on the UcD 180 comes after changing the OPA (to say OPA2134 or OPA2107) and removing the two (22uf I think) coupling capacitors. Check for DC offset on the UcD output after doing that (smaller than 100mV should be OK). Do not remove the coupling caps using the stock opamps!
A relative good thread on another forum on how different OPAs sound:
http://www6.head-fi.org/forums/showthread.php?t=84519
Another link: http://tangentsoft.net/audio/opamps.html
he guys, thanx for the answers. I am getting more and more convinced that the OPA 627's are just it. Now to find a type(=OPA627) that will fit on the UCD?
Bruno Putzeys said:
Hi Bruno,
when will this happen? Ie. if I order now, do I get 180ST with 12V or 15V zeners?
If 15, when will it for certain be 12 V's?
Re: The J511 Tweak
More details can be found earlier in this thread (use search), but adding a current source does improve the sound IF you make sure to tie it between the output and the op amp supply at which it has worst PSRR (check the op amp data sheet for that).pa said:
magils said:
Not sure when, but I think if you're up to the task of changing the op amps, changing the zeners shouldn't be a problem either...
The 627 is not available in duals. The op amp on the UcD modules is a dual type.Bgt said:
(I like the 8620 better anyway. The 627 can really get too dry to my taste.)
