[imran27]

I know, but in a previous post we spoke about the O2 and NJM4556A I guess and per O2's creator this "slow" op-amp is able to rise a 10kHz square signal with12.65 volts in 3.51 uS, so this means a slew rate of 3.6 V/uS; basically V/uS is what defines the ability of an op-amps to rise or fall a signal.

What indeed can change the "flavor" of an op-amp used in output buffer would be the pre and post ringing and usually faster op-amps might have trouble with some capacitive longer cables of the headphones. However, this is something that can be checked with a scope with a resistive load in parallel with a small non-polarized cap. Some people do prefer the sound that has lot of pre/port ringing because this creates sort of a better soundstage under some circumstances.

No no.

I am not talking about slew rate at all.

I am talking about large signal step response.

OPA1652 has a slew rate of 10V/uS and OPA2209 has a slew rate of 6.4 V/uS

But look at the large signal step response, OPA2209 is faster by a factor of more than 2. Rise time is ~0.4us for OPA2209 vs ~1us for OPA1652 even though OPA1652 has a higher slew rate.

Pick any opamp which has comparable CMRR (to any reference opamps for comparison) but a lower rise time, faster settling time and low overshoot. You will consistently see that it has higher fidelity, especially with IEMs.

 

[raoultrifan]

I understand, but OPA1652 is able to rise a 10V square signal in less than 1uS, so that means is able to reproduce a 1MHz signal properly: https://www.edn.com/electronics-blo...-The-bandwidth-of-a-signal-from-its-rise-time.

I still think the pre and post ringing makes more of a difference of the output sound, also the harmonics higher than -90dB (again scope and FFT analyzer tests need to be conducted).

 

[Rroff]

usually faster op-amps might have trouble with some capacitive longer cables of the headphones.

That is a good point actually - I'd not thought about cable length, though the Sennheiser ones are pretty decent - my HD600s normal stereo cable (I've a shorter one for balanced use) is the 3m one - all my other headphones are "normal" length around 1m - its possible the cable length is upsetting certain opamps (some are more susceptible to it irrespective of speed depending on the design goals) and a rough correlation with the slew rates is just coincidence maybe.

 

[SpudHarris]

Ordered a few adapters and Opamps (OPA1652, 1692, 2172 and LME49723) but thought I would rekindle my liking of the ADA4610-2 and think it could be a late night. I completely forgot how great this is... To be truthful I think I only ever tested previously in mobile applications but did rate it then. Now I have the Lycan test bench to test with full sized phone I am appreciating it more.

I know this was/is a favourite of Mad Max, I haven't used any caps on this yet so potentially more to be had in terms of performance.

 

[Mad Max]

Still is a fave.

 

[imran27]

Ordered a few adapters and Opamps (OPA1652, 1692, 2172 and LME49723) but thought I would rekindle my liking of the ADA4610-2 and think it could be a late night. I completely forgot how great this is... To be truthful I think I only ever tested previously in mobile applications but did rate it then. Now I have the Lycan test bench to test with full sized phone I am appreciating it more.

I know this was/is a favourite of Mad Max, I haven't used any caps on this yet so potentially more to be had in terms of performance.

Interesting.

I have some sort of voodoo or bad omen one me whenit comes to OPA1642 and ADA4610-2

I ordered them twice, multiple pieces, soldered them and all of them didn't work. I tried different boards, different soldering temperatures, let them cool for quite some time, no luck.

Maybe I will order them again and try. ADA4610-2 at least looks quite interesting, Aol is low, CMRR is decent, step response in particular looks very promising. I believe it sounds very resolving and detailed with a good amount of air and silence between instruments?

 

[Mad Max]

It indeed does in whatever I use it in as buffer.

 

[SpudHarris]

OPA1692, 1652 and 2172 plus LME49723 all arrived today.

1692 and 2172 are VSSOP, oh lordy how the hell to peeps solder them? They are tiny! I'm ok with SOIC but now and again make mistakes. Anyone on here have any advice or tips?

I can't do anything with them yet as the adapters are on route and I will do some research but please chime in if you can...

Thanks in advance.

 

[Rroff]

To solder anything that small I usually use a tiny bit of either silicone PCB glue (make sure its non-acidic/not plumbing stuff, etc. which will corrode electronics over time) or failing that superglue to hold the part in place rather than try and hold it by soldering one pin initially. The rest is just practise and steady hands really :| you can get adaptors that are slightly channelled and solder plated so you just heat the contacts but they tend to be 10-100x the price of normal adaptors.

Having some flux paste (the gel kind) makes it a lot easier to not accidentally bridge pins - I won't even attempt anything below SOIC without some.

Having the right soldering iron bit helps a lot as well - ideally a tapered point that is at most 1mm - ideally slightly smaller than that.

Could try drag soldering but I find that only really works with like SSOP-28 chips, etc.

 

[dumbears]

I received OPA1692 today, and I was eager to solder them to the adapter boards right away. However, I failed. I fried 3 of them, and I don't know why. Everything looked right in appearance, but when they put into test, there's a lot of background noise. One of them even got heated up and ended with nothing just noise. Before I put them to test, I checked the connectivity of each pin to the SSOP to DIP adapter board.

I know there're many of you being much more experience, please advise what can possibly went wrong. My solder is too hot? I tried 3 temperatures: 300C, 250C and 230C, according to the thermostat. I have soldered tens of SOIC with only 3 failures (if my memory serves me), but this is the first time I dealed with SSOP.

Pls help. Thanks in advance.

 

[Rroff]

I usually solder at 350C and try to be fairly quick and precise. Pretty low failure rate.

I've grabbed some OPA1692s but in the middle of some house renovations at the moment so probably won't get to trying to solder them before Monday at the earliest.

With SSOP especially if you don't use flux paste it is very easy to accidentally bridge pins and not necessarily be easily noticeable if its pushed up against the housing of the IC.

 

[skwoodwiva]

I am ready to order chips.

Can you guys ID the op amps here?

I assume they can be bettered

My "dealers trash" brand new batch of 6 Meizu sp 6s

 

[SpudHarris]

I received OPA1692 today, and I was eager to solder them to the adapter boards right away. However, I failed. I fried 3 of them, and I don't know why. Everything looked right in appearance, but when they put into test, there's a lot of background noise. One of them even got heated up and ended with nothing just noise. Before I put them to test, I checked the connectivity of each pin to the SSOP to DIP adapter board.

I know there're many of you being much more experience, please advise what can possibly went wrong. My solder is too hot? I tried 3 temperatures: 300C, 250C and 230C, according to the thermostat. I have soldered tens of SOIC with only 3 failures (if my memory serves me), but this is the first time I dealed with SSOP.

Pls help. Thanks in advance.

Is it possible you blew them handling them?

Are your Opa1692 SSOP or VSSOP?

 

[dumbears]

Is it possible you blew them handling them?

Are your Opa1692 SSOP or VSSOP?

Thanks foe the reply. Oops! You're right. It's actually VSSOP.

I don't know. I store my soldering iron and other equipment in a tin box, so to kind of decharging myself. I put the opamp in a tin can too after opening it out from the package. It's too small, so need tweeters to handle it. I don't think I over heated the chip since I used flux to solder the pins. It just needs a quick slide of the iron to solder each side.

I still got 2 left though. However, I might kill them as well, since I haven't had a clue what I did wrong. Perhaps, I should let things rest for a couple of days before my next trial.

 

[imran27]

Thanks foe the reply. Oops! You're right. It's actually VSSOP.

I don't know. I store my soldering iron and other equipment in a tin box, so to kind of decharging myself. I put the opamp in a tin can too after opening it out from the package. It's too small, so need tweeters to handle it. I don't think I over heated the chip since I used flux to solder the pins. It just needs a quick slide of the iron to solder each side.

I still got 2 left though. However, I might kill them as well, since I haven't had a clue what I did wrong. Perhaps, I should let things rest for a couple of days before my next trial.

Once you have enough flux (not a lot), and right amount of solder on your tip (if it is more than what's required, you'll have a hard time resolving the solder bridges) it is pretty quick.

You do need tweezers to handle these tiny parts.

I too destroyed one of mine due to not enough flux and solder bridges. Will try to remove bridges and see if it still works.