If we are into fine tuning -- the discrete R's have lower THD. I have a problem with smd when I cant read/see the part number or its value, it is a b**ch. smd is great for small spaces and automation. For me, I'll stick to the best parts (lowest distortion). Even if I have to lay out my own pcb artwork. Thx - RNM
i'd like to see an apples to apples comparison that proved that. by that I mean there are several metal film SMD, even Zfoil and Sfoil if you want to go that far. even thin film is fine i'm sure, given thats what all the resistive elements inside high performance opamp dies are made from I would think.
this is what I mean by equipment though, good tweezers and a good illuminated loupe
this is what I mean by equipment though, good tweezers and a good illuminated loupe
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Considering there is virtually no voltage change with signal over anything but the external feedback resistors, I'll buy you dinner if it proves to matter.
Be careful Mr. Wurcer. Mr. Marsh is building his from tubes and running +/- 400V rails. His application is a low output moving coil cartridge preamp
...I was off doing some other stuff and 10-15 pages whooshed by, much to my amazement.
it seems that a design has been seized upon?
but I have returned sort of like Rip Van Winkle (of American legend) to find that the design has 26 transistors (if I counted right)?
I don't mind.
but, what, no error correction circuitry?
inquiring minds want to know?
_-_-bear
it seems that a design has been seized upon?
but I have returned sort of like Rip Van Winkle (of American legend) to find that the design has 26 transistors (if I counted right)?
I don't mind.
but, what, no error correction circuitry?
inquiring minds want to know?
_-_-bear
Its all right there in Linear Audio on testing resistors. Seems the Dale (Vishay) were best to my view of the data/graphs.
Does it matter? I just use the best I can find.. why not? they all cost about the same so when one finds better parts I use those. But thats up to each to decide for themselves...
Still find smd not useful to me when i want to know what it is-- I have to measure them. Tiny is cool. But not for a one-off that I have to make and play with. IMUVHO.
Whats for dinner? - I'm having Pad Thai tonight- RNM
Does it matter? I just use the best I can find.. why not? they all cost about the same so when one finds better parts I use those. But thats up to each to decide for themselves...
Still find smd not useful to me when i want to know what it is-- I have to measure them. Tiny is cool. But not for a one-off that I have to make and play with. IMUVHO.
Whats for dinner? - I'm having Pad Thai tonight- RNM
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Like diamond buttons for tailored suit made from a cloth blend of silk, cashmire and mink?
wood or diamond for same cost?
If they cost the same as wood buttons why not? If you had the choice for the same dollars which would you go for. I thought so.
ADC and DAC are so good that the resistors may be the limiting factor... as their thd was at or near what the linearity of the converters are. Compare the levels of thd of converetrs to the discrete and smd resistors. I am assuming this SW-OPA is at least as good as the best converters out there.
-RNM
If they cost the same as wood buttons why not? If you had the choice for the same dollars which would you go for. I thought so.
ADC and DAC are so good that the resistors may be the limiting factor... as their thd was at or near what the linearity of the converters are. Compare the levels of thd of converetrs to the discrete and smd resistors. I am assuming this SW-OPA is at least as good as the best converters out there.
-RNM
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no it doesnt matter, I find the best way is simply to only take out what you need from the strip as you go, many still have the value printed on there even at 0603 size. those reasons of frustration however are all good, though I do wonder what you will do in years to come as such parts become extinct one by one.
I bet they didnt test metal foil such as, the VPG VF series, or even if you want to go another step for this application and price doesnt matter, the VFCD1505 Zfoil chip dividers. Actually the Vishay group parts are strangely priced waaay above the made to order ASMP/ASM series custom value parts from Texas components (they supply the Sfoil version for a bit less as well).
if you want the best you can find, test the best you can find. I dont believe the differences found will have anything to do with being SMD, more likely the material used for the element.
if you are here Jan, I havent got that particular linear audio, late to buying the mag but very interested in this current edition. did you test any MELF types at all, or just thin film? I gather the results you got were thermally based, which are a complete non-issue with the vishay parts and as Scott pointed out, unlikely an issue here
apples to apples
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Just noting the results and what I will use and why. To each his own. BUT and IF I can buy this thing from a vendor in taiwan with or without smd, I'll try it at least. Making it myself is not the great fun it is for most over here in the DIY category.
That reminds me -- how is the pcb coming along?
Got my Audio Precision brought over and doing some work (as thier ex -CEO) and play.... Got a lot of software to buy while still in S.E.Asia... -RNM
That reminds me -- how is the pcb coming along?
Got my Audio Precision brought over and doing some work (as thier ex -CEO) and play.... Got a lot of software to buy while still in S.E.Asia... -RNM
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They call that feedback resistors, fiendishly cunning designers ...
But, the intrinsic design has remarkably good distortion figures, performs excellently even at very high gains ...
Frank
vishay precision group (VPG) I think you will find is still just the one company. there are simply not that many factories geared up to make this stuff. besides like I said, better to buy from Texas components unless you need very large production quantities
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SW-OPA FFT's -
Got FFT's on a working prototype ??
They call that feedback resistors, fiendishly cunning designers ...
But, the intrinsic design has remarkably good distortion figures, performs excellently even at very high gains ...
Frank
Got FFT's on a working prototype ??
agree totally!
me too, but at least at this stage it seems not to be the BF862 version? myself I still love building though, mainly so I can make idiosyncratic parts choices =)
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Nope, this is purely from sim fiddlings ... I'll be keeping entirely out of the building game, my interest in the exercise at this point is to see how closely sim behaviour can match up with real componentry working, and to investigate whether the sim mechanism can help to refine the design in any areas. Also, I enjoy understanding how circuits tick by looking at the waveforms at various points through the beast ...
One thing that is intriguing, is that the distortion figures hardly vary if different BJTs are used, but the PSRR figures change dramatically ...
Frank
Warning to No More Deadline Scott..... I am suppossed to be retired... but a company i was CEO for several years had its president die and now I am back here in Bangkok helping with product development. Seems there is only one way out.
My main interest was to have SW (by hook or by crook) to put his immense knowledge and talent for analog design out and up and running for the benefit of all -- before he retires (?)
besides C of high C jFEts and its affect on PSRR - are there any other factors you found to make a big difference in PSRR. That is interesting to me as it gets little attention elsewhere.
BTW - I find the same thing re transistors make a minor difference in an audio designs' THD where the topology dominates and why symmetrical/balanced topologies are so important. Thx - RNM
My main interest was to have SW (by hook or by crook) to put his immense knowledge and talent for analog design out and up and running for the benefit of all -- before he retires (?)
besides C of high C jFEts and its affect on PSRR - are there any other factors you found to make a big difference in PSRR. That is interesting to me as it gets little attention elsewhere.
BTW - I find the same thing re transistors make a minor difference in an audio designs' THD where the topology dominates and why symmetrical/balanced topologies are so important. Thx - RNM
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Tsk, tsk ... everyone has their own approach and ideas on things, I enjoy playing with other people's ideas, to see where that can lead, since I'm coming from a completely different perspective.Sure Frank. When Scott knows what to SIM and feels how to tweak, it can help to refine the design.
For example, I feel the +ve PSRR figure could go a bit better at high frequencies, trying a few things to see what makes a difference, but apart from extra cascodes haven't come with anything significant so far ...
Still a lot to explore; as I've mentioned before I have very little instinct for how such circuits work, so this is a journey of discovery for me ...
Frank