Sorry, you were wrong, in general, in regard to any aspect of superiority of through hole metal film resistors compared to SMD thin film resistors. Other than being more eye and soldering tool friendly, I can't think of any other advantage of through hole resistors. Even for the same power dissipation requirements, SMD resistors are better, since they dissipate power much better (being in contact with the substrate).
A very interesting presentation:
Bruce Hofer - Designing Analog Circuits with Ultra-Low THD - YouTube
regards
George
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I would remind you that the rated power dissipation of the 0805 SMD that we DIYers commonly use is only 0.1 watt, as compared with an ordinary through-hole that is rated at 0.25 watt. You have to go to a 1210 to get 0.25 watt.
Do you have any factual data on distortion of an 0805 SMD metal film as compared to a 1/4-watt through-hole metal film resistor? That would be more valuable in the context of this discussion.
Do not misconstrue my comments here to favor one or the other of SMD vs Through-hole. I just think it is appropriate that the readers get the right impression so that they can knowledgeably choose for themselves in the context of a given application.
Cheers,
Bob
Do you have any factual data on distortion of an 0805 SMD metal film as compared to a 1/4-watt through-hole metal film resistor? That would be more valuable in the context of this discussion.
Do not misconstrue my comments here to favor one or the other of SMD vs Through-hole. I just think it is appropriate that the readers get the right impression so that they can knowledgeably choose for themselves in the context of a given application.
Cheers,
Bob
Hi Bob 
The logical solution if you need the extra power for the smt resistors is to use more than one in series, as Bruce showed in his presentation. Takes up more area but you can’t have it all.
Btw thanks George for the link to the presentation. I would have liked to hear the discussion on opamps as well.
The logical solution if you need the extra power for the smt resistors is to use more than one in series, as Bruce showed in his presentation. Takes up more area but you can’t have it all.
Btw thanks George for the link to the presentation. I would have liked to hear the discussion on opamps as well.
Thanks for the reminder. Not sure where you got the information about 1210 format for 0.25W rating, but a quick look at DigiKey shows no less than 62,566 thin film resistors in 1206 format (which was suggested here), with a power rating of 0.25W. If Bruce Hofer uses the 0805 5ppm Susumu thin film resistors, I would assume he's considering the power dissipation spec (which is 0.125W, BTW) and uses them everywhere it is possible.
I suppose Google would help, but until somebody cares to do a deep search, I guess Bruce Hofer's testimony is good enough.
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On my build of Victors Osc I used Wima FKP for the Wein bridge. He did not disclose to me what passives he spec’d, I just went with what I saw in the pics and what was the logical choice, available at Mouser. All standard parts I use in other designs. I noticed on a earlier version, he was using a few MELF 1N4148 diodes, later replaced with SOD-123, fine by me I can only assume, based on Bruce’s presentation that a NPO MLCC would be as good or better than the MKP’s. 10nF NPO’s are expensive. Could do something like Bruce showed in the small pcb that replaced the axial PP. use ten 1n’s. If I design a pcb like Bruce showed, to replace Mkp2, would anyone be able to measure the differences?
I can only assume, based on Bruce’s presentation that a NPO MLCC would be as good or better than the MKP’s. 10nF NPO’s are expensive. Could do something like Bruce showed in the small pcb that replaced the axial PP. use ten 1n’s. If I design a pcb like Bruce showed, to replace Mkp2, would anyone be able to measure the differences?
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There's an interesting chapter on cap linearity in AoE the X-chapters, Horowitz & Hill. They are very firm that C0G caps meet or exceed linearity of the best film caps.
I have used them in an all-pass filter that delivered better than -150dBc performance.
BTW I know that Hofer prefers Susumu 5ppm, not sure which size, probably the larger.
Jan
I have used them in an all-pass filter that delivered better than -150dBc performance.
BTW I know that Hofer prefers Susumu 5ppm, not sure which size, probably the larger.
Jan
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I remember scooping smt parts off the floor under neath the pick n place machines when I was servicing them, as a young green tech. Still have them in my parts bins Motorola forced the MLCC mfg’s to print a value code on them, for inspection reasons. The mfgs still to this day, do not print value codes. some simple things are just stuck in the mud. All you can go by is colour, size, meter/fixture, Mouser did not mix them up
Syn08, I am a cheap Canuck yeah, Caught me, I did not even look at current prices, good, they have come down a lot since last time I looked. One less pcb for me to do, thanks. Easy to solder across 5mm lead space. Still like to use the highest V MLCC I can afford.
Motorola forced the MLCC mfg’s to print a value code on them, for inspection reasons. The mfgs still to this day, do not print value codes. some simple things are just stuck in the mud. All you can go by is colour, size, meter/fixture, Mouser did not mix them up Syn08, I am a cheap Canuck yeah, Caught me, I did not even look at current prices, good, they have come down a lot since last time I looked. One less pcb for me to do, thanks. Easy to solder across 5mm lead space. Still like to use the highest V MLCC I can afford.
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"For surface-mount technology (SMT) resistors, only use the 1206 size. Smaller resistors exhibit increasingly larger dynamic thermal impedances, thus exacerbating signal-dependent nonlinearity for ultra-low THD+N audio."
From "Designing for Ultra-Low THD+N" by Bruce Hofer himself.
If nothing else, 1206 sized devices are easier to pick up with tweezers than smaller parts.
(http://hifisonix.com/wordpress/wp-content/uploads/2017/11/Designing_for_Ultra-Low_THD_N-1.pdf)
From "Designing for Ultra-Low THD+N" by Bruce Hofer himself.
If nothing else, 1206 sized devices are easier to pick up with tweezers than smaller parts.
(http://hifisonix.com/wordpress/wp-content/uploads/2017/11/Designing_for_Ultra-Low_THD_N-1.pdf)
Amen!
I would assume that this suggestion by Bruce mainly applies to SMT resistors that may contribute to distortion, such as feedback resistors, degeneration resistors and load resistors. It may apply less (e.g., use of e.g. 0805) to resistors not passing any or a very small amount of signal-dependent current and/or in the signal path. Nevertheless, you probably can't go wrong using 1206 if you are not concerned about the extra space.
Cheers,
Bob