[sean-xenos]

Hi,

in theory the use of DIP-8 sockets for opamps instead of soldering the opamps directly on the board might reduce the sound quality.
But I always thought that this effect is negligible and can't actually be heard.

I'm quite surprised that a German audio engineer strongly advised me not to use IC-sockets for better sound quality

Has anybody ever actually heard the difference between opamps soldered directly / used with sockets?

I usually use the gold plated high precision IC sockets that are slightly more expensive.

Thanks for your advice

,

sean-xenos

 

[rreynol]

You should definately be using oxygen free pure silver sockets that have been cryogenically treated for maximum sonic enjoyment. j.k.

Even if it weren't so subjective, I think the benefits of using sockets (not frying chips, rolling op amps, etc) would far outweigh the (highly) debatable sonic degradation.

 

[grasshpr]

I think their was a thread about this topic a few months ago. You might be able to get a more detailed comparison.

 

[ericj]

Sockets increase the parasitic capacitance of the connection slightly.

Unless you are using extremely fast, very wide bandwidth amps, the effect is negligible and nowhere near audible.

The MAX4102 datasheet specifically states that i should NOT mount this so-8 chip on an adapter and shove it in a socket. But it's a broadcast-quality video opamp with a 350v/uS slew rate and 250mhz of bandwidth, which makes even the fastest opamps you'll see people using on this forum look like feeble old grannies with zimmer frames. And it's probably awful for audio. I picked up samples intending to build a video line driver.

If you're having trouble getting rid of oscillation when using a high-speed bipolar opamp, soldering the chip to the board is one thing that might help, but there are other things to try first that aren't so drastic.

 

[sean-xenos]

Quote:

Originally Posted by grasshpr I think their was a thread about this topic a few months ago. You might be able to get a more detailed comparison.

I found this thread: http://www6.head-fi.org/forums/showthread.php?t=93459

As I plan to use OPA2604s in the audio output stage of a CD Player I'm quite sure that neither the slew rate nor the frequency range will contradict the use of DIP-8 sockets.

Thanks for your replies

 

[JahJahBinks]

I always think that socket is for easy of opamp rolling, but if you know which one to use in the beginning, why not solder the chip directly on the board. Note that ICs have lower solder temperature than resistors/capacitors, using socket can eliminate this issue, otherwise just be more careful not to heat it for too long.

 

[Garbz]

I mean common, what doesn't effect sound quality? Silver solder, $200 RCA sockets, 99.9999% solid silver cable, $5 ea resistors, $30 capacitors where does the madness end.

The best amplifier I've ever heard uses none of this boutique crap. The sound is simply attributable to fantastic circuit design. There's got to be a point where even the most stingent of us builders here says NO this has gone to far. And if I'd have to pick it opamp sockets would be that point. I mean they make an electrical connection, a good one at that. What more does one need? It's less then 1mm in the great scheme of STANDARD COPPER CIRCUIT BOARDS, and lead solder connections are bigger.

I say do an objective a/b compairson. If you can hear the difference I will lay down my hifi and never listen to music again!

 

[mono]

At one point using AD843 with +-30V, I observed that it was getting pretty warm->hot and that seemed to be effecting the sound. Knowing that soldered-in chips are 'sunk better, I'd wondered if the benefit was enough in certain (this in particular) scenarios.

 

[Garbz]

Sunk how much better? At lest with an socket it allows airflow under the chip. Drop a bit of thermal glue and a bottletop on it.

 

[mono]

Quote:

Originally Posted by Garbz Sunk how much better? At lest with an socket it allows airflow under the chip. Drop a bit of thermal glue and a bottletop on it.

Typically trying to 'sink heat away through the epoxy case of a chip is a last resort because it is so inefficient. I don't know that this would necessarily mean it didn't help though, especially since I don't have in mind any particular critical temp threshold. Airflow around it can help but is generally not as good as direct pin-PCB solder bonds, presuming the PCB has a fairly sized or thick leads.

I have 'sunk the casings on mosfets, mostly overclocking computer gear but there was a secondary benefit there, that by 'sinking the epoxy it helps avoid longer term heat-induced casing breakdown types of failures. No opamps are getting anywhere near that hot unless implemented incorrectly.

What I am unsure of, is whether the benefit is realized... if the temp reduction would be enough, or if it's just a narrow window of ambient temp and voltage range (on the hotter running chips) in which a small temp drop seen by soldering them down, will matter. Towards the end of heat reduction, some gain would probably be seen by soldering the chip to a removable socket, and plugging that socket into one soldered to the PCB, though this even further raising the inductance.

It should also be mentioned that AD834 runs hotter than many supposed-audio opamps behind a buffer. Running one directly driving a load- I can't recall if I've ever tried it.

 

[JahJahBinks]

If you know how chips are fabricated, you would not say that heat is dissipated better that way, because it doesn't.

 

[mono]

Quote:

Originally Posted by JahJahBinks If you know how chips are fabricated, you would not say that heat is dissipated better that way, because it doesn't.

Which way is "that way"?

There is no question that with chips lacking an integral heat-spreader, soldering the pins does help to cool them. The major manufacturers go so far as to mention it in spec sheets for many chips, though seldom opamps which is to be expected as their temp doesn't even come close to critical. Likewise with many parts, a temp may not be critical yet the temp change does effect part function.

 

[DaKi][er]

Quote:

Originally Posted by Garbz There's got to be a point where even the most stingent of us builders here says NO this has gone to far. And if I'd have to pick it opamp sockets would be that point. I mean they make an electrical connection, a good one at that. What more does one need? It's less then 1mm in the great scheme of STANDARD COPPER CIRCUIT BOARDS, and lead solder connections are bigger. I say do an objective a/b compairson. If you can hear the difference I will lay down my hifi and never listen to music again!

Using crazy fast opamps, the added parasitic capacitance of the sockets could easly be enough to throw the otherwise stable circuit (though sitting on the limit here) into oscilliation and yeild it completly usless that you cant get any audio out of it at all. You can't tell me you wouldn't hear that

Yet the circuit would have to be a quite poorly designed one and probably quite hard to produce this senario

But I would have to say that if it was running stable with the sockets that there would be in my mind no doubt that the sockets were harming the signal in any way at all, there are far too many other factors in the audio reproduction chain that have technicaly far worse in the order of 1000 fold effecting the original sound, yet people love the way they sound more 'musical' (non os, for one)
But lets not get into that argument