I also made a before/after recording that I can dig out and post when I find the time.
that would be great!
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You need the SOIC-14 package, sometimes just called SO-14. The other version is too small.
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Any recommendations for a good quality SMD station that doesnāt cost the earth? Happy with my through-hole work soldering but keen to get my SMD on.
Thanks in advance.
Can you share a detailed pictures and before/after audio recording?
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Thanks for the info!
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Went ahead and did it but was a jerk and didnāt take pictures (we all owe everyone on the internet something, right?).
It was pretty straightforward. There are really only 3 ICs by the physical outputs, and these are the ones to replace. The are marked LM837 ā itās a little hard to read but this is basically the primary way to identify them. If you canāt read them, you shouldnāt be working with SMT anyway.
My side cutters have pretty sharp angles, so I was able to go along the chip and carefully snip each leg near the casing (away from the PCB). After the chips came up, I took a soldering iron with a flat/screwdriver tip and carefully ran it along the pads ā this acts sort of as a āmagnetā for the remaining leg bits (they stick to the iron by way of surface tension from the solder still present on the tip). After the bits were up I used some solder wick to clean up excess solder remaining on the pads so the replacement chips would sit flush with the PCB. Then I positioned the chips (triple check your orientation here!), added a little flux, and soldered in the new chips. After that I used a toothbrush and some water to scrub off the flux residue, rinsed the area with some water, sprayed a little alcohol on to dissolve and evaporate the water, then set it in front of a fan.
It would be easier to use no-clean solder instead of using flux/rinse/fan. If the thought of running water over your PCB freaks you out, you should go the no-clean solder route. It might also mean you shouldnāt do the mod in the first place.
I didnāt A/B the sound quality. Soldering is kinda meditative for me, so the worst thing that could happen is that it would sound the same and Iād have spent 30 minutes meditating.
Whether its real or not, I do believe I hear an improvement in sound in that it seems more detailed overall. Thatās as far as Iāll go into describing the sound improvement though, otherwise weāll start getting into a strange audiophile sword fight and then we all lose at life.
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thanks @panelist for your input!
I received the chips today and Iāll try it tomorrow. As soon as I finish Iāll upload audio samples for you. I donāt know how many of you are interested, but if I receive 10 likes ore more in this post I will upload a video with the procedure 
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lol, this isnāt Facebook. Iād definitely be interested in some A/B audio files though.
Just upload it! 
hahaā¦ yes, I know. I donāt care to be a popular guy. I just wanted to know if there is enough interest.
Iāll make some audio samples and a short video.
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u past 10 likes already sir 
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I canāt put more likes. Iāll tell my friends to buy OTs and sign in Elektronauts to like @denoise. 
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I prepared a 24 bit 44.1 loop for comparison. Iāll record the audio from the OT main outs directly to a MOTU 1248 line inputs.
Do you have some recommendations for playing the audio out? OT mixer main volume, track level, etc? I notice that for some reason the OT outs are a little low and I have to rise the analog inputs on my interface.
As poor outputstages tend to kill/squash loud peak transients, I recommend using as loud levels as possible before digital clipping occurs. This should reveal the difference best IMO.
even subpar amplifier circuits can sound decent if you keep output levels low (ovbsly noise floor will suffer though). Great amplifier circuits deliver pristine (transient response) sound even when driven close to the max that they can handle before going overly nonlinear.
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thanks for your answer @tsutek ! this thread made me learn more about OT gain stages. So in this case I should increase the levels before clipping in the following order?
1 - input level on the MOTU
2 - OT mixer level (Main)
3 - OT track level (LEV)
4 - OT track volume (in the Amp page)
or is the order of point 1, 2 and 3 irrelevant? perhaps how the OT gains the output digitally before the A/D -> op-amps conversion achieves the same result.
the MOTU input level is the least important one here IMO, as long as you keep the input gain somewhere around 50% it should not affect SNR or transient response in any significant way. IME soundcard inputs can (not saying they will, but theoretically) affect the sound if past 75% of max or very low, something below 25% perhaps? Talking about the input knob range here, cannot say any dB values as I do not personally know the MOTU cardsā¦
As for how the internal OT gainstages work, that should not affect the outputstage either, as those gain operations occur in the digital domain, right? Although I am not an experienced OT ninja, so if I am mistaken, let us know.
Iām doing something wrong then, because I sent a loop peaking at -0.6 db to the OT. I have to rise the Mixer volume to +63 (max), the track level to 127 (max) and the amp vol to +63 (max) to receive a decent volume in the line input (at 50%).
(at this point the admin should perhaps split the forum)
is the MOTU set to line level input? Are you using balanced TRS cables?
yesā¦ line level input and unbalanced TS cables
do you have any spare TRS cables to use instead?
also, make sure you do not have any -10/-20 input pad on the MOTU.
For a 24bit recording, it is generally advised to aim for a rec level of ~ -18dB peaks