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Old 12th October 2012, 11:34 PM   #1621
RNMarsh is offline RNMarsh  United States
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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
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Old 12th October 2012, 11:50 PM   #1622
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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

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Old 12th October 2012, 11:56 PM   #1623
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Quote:
Originally Posted by RNMarsh View Post
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

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.
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Old 13th October 2012, 12:27 AM   #1624
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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
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Old 13th October 2012, 12:53 AM   #1625
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...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?

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Old 13th October 2012, 12:57 AM   #1626
RNMarsh is offline RNMarsh  United States
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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

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Old 13th October 2012, 01:06 AM   #1627
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Originally Posted by RNMarsh View Post
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? But thats up to each to decide for themselves... RNM
Like diamond buttons for tailored suit made from a cloth blend of silk, cashmire and mink?
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Old 13th October 2012, 01:29 AM   #1628
RNMarsh is offline RNMarsh  United States
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Default wood or diamond for same cost?

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Like diamond buttons for tailored suit made from a cloth blend of silk, cashmire and mink?
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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Old 13th October 2012, 01:34 AM   #1629
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Quote:
Originally Posted by RNMarsh View Post
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
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

Last edited by qusp; 13th October 2012 at 01:39 AM.
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Old 13th October 2012, 01:46 AM   #1630
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Vishay today is the common name of the holding that bought many companies, together with their production and techsupport. Hence it's name does not mean high quality.
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