Hey friends!
I was wondering if any of you guys had go-to brands for clearly above average silicon transistor sounds.
Generic 2n5088/89... do their job, no doubt but are there any models with a real audiophile quality (like a JRC's has an edge over standard TL's) without sacrificing output of course.
Thanks!
GM
(https://media.giphy.com/media/pUeXcg80cO8I8/giphy.gif)
Here we go!
Hello. Welcome to the forum.
Honestly, I lack experience with Hi-Fi transistor circuitry, but according to TAoE (https://en.wikipedia.org/wiki/The_Art_of_Electronics), lowest noise bipolar transistor is ZTX851/ZTX951, supposedly because the die inside them is larger (collector current up to 5A), but the best performance is achieved at low source impedance (less than 1k) and low collector current (around 0.1mA). At higher source impedance (100k), high Beta 2N5962 outperforms ZTX851 at any collector current. I suppose it's a matter of particular application, so the choice depends on whether you use it in a gain stage, or output stage, or as buffer, or a mixer...
Both of these are not officially endorsed as "low noise"/audiophile parts, by the way. It was a research done by the book authors.
I've read elsewhere that BC337 is also a fine low-noise transistor.
Indeed. Low noise is great but "texture" is greater as for audiophile quality in stompboxes.
My main focus is for transistors used in gain stages (fuzzes etc).
Are tere any 2N type NPN trans/brands around which could sound more "open" than regular ones?
The openess of a pedal is probably more circuit based than transistor based, particularly when you're clipping that transistor on purpose. Good news is, transistors are pretty cheap, buy a bunch, throw them in a breadboard, and find the ones you like!
I haven't really seen RG in a while, I suppose this is a good place to wait for him.
For your average fuzz pedal, noise performance from a silicon transistor would be really hard to hear.
Coupled with the noise floor of a typical guitar amp? Even harder to hear.
My ears aren't the greatest, but I've never been able to hear the difference between 2 brands of NPN's.
OTOH, I've never set up a formal test. I'm more of a "build it, hear it, apply it" pedal builder.
As opposed to designing/building towards a specific end goal. That's too complex for me.
Yes, sili NPN's are pretty hard to differentiate soundwise, hence my question.
I've built tons of mosfet projects and so far I've been able to single out the type of mosfet trans I really like to work with, as those have very different character and behave differently in a gain stage(s) configuration (ex: J201 are very meaty, 2N7000 are much tighter etc...)
But when it comes to silicon trans, apart from the output there's not much difference.
I know that the general circuit design does the heavy lifting in terms of texture but still, I wonder is there's a brand/nos type trans that adds something to the sound, just like a JRC is better than a TL opamp...
Quote from: thermionix on July 31, 2018, 07:26:34 PM
Quote from: Gainmonger on July 31, 2018, 05:34:04 PM
JRC is better than a TL opamp...
Says who?
I was wondering that too. TLxxx ain't great, but JRC are cheap and old just the same.
<dons tin hat and jumps into trench>
Quote from: ElectricDruid on July 31, 2018, 08:02:33 PM
Quote from: thermionix on July 31, 2018, 07:26:34 PM
Quote from: Gainmonger on July 31, 2018, 05:34:04 PM
JRC is better than a TL opamp...
Says who?
I was wondering that too. TLxxx ain't great, but JRC are cheap and old just the same.
<dons tin hat and jumps into trench>
says me.
I can't be the only one to notice a difference between JRC and TL opamps, am I? It might be subjective but still.
I've made a lot of circuits with cheap generic TL's and they sounded pretty good but circuits with JRC 4558 or 4580 just sound a lot better, tighter with more definition (and less prone to hiss)
Socket them and use an oscilloscope I guess.
I don't f%#@ with op amps so this is kinda outside my wheelhouse, but I remember seeing a video a couple years ago of a lecture in a studio where they basically did a double blind test with several ICs, including vintage and current JRC, TI and even a video op amp. There was no discernible difference.
I reckon if you try hard enough, you could find a specific situation where a small detail will be different between same spec chips from different manufacturers, but I am highly skeptical of that difference being enough of a factor that one would advocate for one chip in detriment of the other. Probably easier to hear the difference between film/foil and silver mica capacitors. It just smacks of cork-sniffing audiophile snake oil to be quite honest.
I'm only going to say this once. Well, I'll try.
@Gainmonger: you're on the slippery path to hifi tweako hell. Today, it is quite difficult to know if the brand stamped on the transistor is actually the brand that it was supposed to be, due to counterfeiting. Then there's the fact that transistors are now a "jellybean" item, too inexpensive and too low a profit margin item for many companies to waste their MBAs' time on, and the dillema that wafer fabs to make transistors are too expensive to be owned by one company. You see the problem - the brand imprinted on a transistor may not mean much from lot to lot.
So hunting for ever-tinier, subtler differences between transistor brands may well be fooling yourself.
Squinting subtle "texture" differences between parts is a good way to get hooked on Cork Sniffer's Disease, the malady that searches for hyper refinement in changing out one part for another. It's a common misapprehension that by taking a circuit and changing out parts for "better" brands recommended by other self-proclaimed experts is a good way to get lost. Humans are famous in psychology circles for self deception on many levels. For instance, how do you know that the PCB material and quality of the copper on it are not a bigger factor than the transistors? Can you hear the difference in tin-lead solder and tin-lead with a percent or two of silver in it? Does the circuit sound better when oriented to magnetic north under a pyramid?
I know it's tempting to believe that the magic is in getting magic brands of parts. Don't get sucked in.,
Quote from: Gainmonger on July 31, 2018, 05:34:04 PM
Yes, sili NPN's are pretty hard to differentiate soundwise, hence my question.
I've built tons of mosfet projects and so far I've been able to single out the type of mosfet trans I really like to work with, as those have very different character and behave differently in a gain stage(s) configuration (ex: J201 are very meaty, 2N7000 are much tighter etc...)
J201 isn't even a mosfet, it's a Jfet. J201 and 2N7000 won't normally even operate in the same circuit (DC source follower being an exception), J201 is depletion mode (normally on), 2N7000 is enhancement mode (normally off), so they have entirely different biasing requirements.
Similarly, when you reference "JRC" and "TL" op amps, I assume you mean the common RC4558 and TL072? JRC is a brand, they make hundreds of different op amps, and Texas Instruments make thousands. You could mean JRC1458 and TLE2074 for all we know.
Anyway, they're both quite different op amps. The 4558 is a general purpose bipolar op amp, most at home dealing with medium to low impedances, and has relatively poor noise performance if used as a front end input for a guitar effect due to this. Quite at home after the guitar has been buffered though. The TL07x series is BiFet, with fet inputs and bipolar output, it is designed for high impedances, and has much better noise performance than the 4558 when dealing with guitar impedances.
So one does not sound "better" than another, at least not universally. It's entirely dependent on the circuit it resides in whether one will have better performance or "sound" better than the other.
Something I've been wondering since I revisited Analogman's tube screamer page the other day, what's the difference between a Texas Instruments RC4558P and a Texas Instruments TL4558P?
Quote from: Gainmonger on July 31, 2018, 03:07:45 PM
Indeed. Low noise is great but "texture" is greater as for audiophile quality in stompboxes.
My main focus is for transistors used in gain stages (fuzzes etc).
Are tere any 2N type NPN trans/brands around which could sound more "open" than regular ones?
Well, I think the only instrument to measure "openness" is human ears, but unlike noise measuring, readings from ears vary greatly from unit to unit. :icon_biggrin: You'll have to use your own to find out.
Quote from: thermionix on July 31, 2018, 07:26:34 PM
Quote from: Gainmonger on July 31, 2018, 05:34:04 PM
JRC is better than a TL opamp...
Says who?
Datasheet for NJM4558 (made by JRC) shows a slightly lower noise, around 11nv/√Hz. TL072 is 18nv/√Hz. Perceptible? Doubt it.
TL072 has faster slew rate - 13V/uS, versus 1V/uS of NJM4558. Maybe for some "worse is better" applies here?
Quote from: diffeq on August 01, 2018, 02:48:57 AM
Datasheet for NJM4558 (made by JRC) shows a slightly lower noise, around 11nv/√Hz. TL072 is 18nv/√Hz. Perceptible? Doubt it.
TL072 has faster slew rate - 13V/uS, versus 1V/uS of NJM4558. Maybe for some "worse is better" applies here?
Not the whole story. 4558 has lower VOLTAGE noise than '07x, but higher current noise (though you have to really dig through the datasheets to find that parameter for the 4558). With high source impedance, current noise becomes dominant.
So, as I mentioned above, it depends on the circuit. You CANNOT make blanket statements like "a is lower noise than b", because it depends.
Here's a link to a datasheet with some info, you want figure 2. LINK (http://www.onsemi.com/pub/Collateral/KA4558-D.pdf)
Step 1) Go to any vendor's website.
Step 2) Hit the 'sort by most expensive first'.
Step 3) Congrats you've found the audiophile parts.
Of course real audiophiles will only accept single-ended triode monoblock tube gear, so there is no such thing as an audiophile transistor.
If you want to get into the Audiophile game then buy a few of these op amps at £42 each
to play with, or have a go at building some discrete op amps yourself to try.
https://orangeamps.com/product/op-amp/#specs
Ok, here's a question that has been bugging me. Why can't these fancy discrete op amps be simply shrunk down and turned into IC op amps instead? Is there something legitimate to their mojo that requires larger parts or wider part spacing? Is it just for showing off?
Here is something I've found, but it leaves me less impressed than I should be, perhaps:
"Class A biasing and high output current capability coupled with a proprietary compensation scheme requiring multiple NPO dielectric capacitors make these discrete op amps impossible to fabricate as a monolithic IC."
I'm waiting for someone to build a circuit that approximates a transistor's current amplification, using an arrangement of IC op amps.
IC op-amps are very sophisticated - look at the equivalent schematic of one. IC op amps are/were designed by electrical engineers and semiconductor process experts who are/were bigger wizards than any of us will ever be (Bob Widlar, but also many others), who exploited various features and limitations of semiconductor manufacturing to make differential amplifiers that are linear, stable, resistant to variations in operating temperature and other conditions, resistant to process variation, and so on. They used features such as having the transistors on the same substrate to control variations, that you can't do with discrete circuitry.
Discrete op amps are fun to talk about, like the kit that allows you to build a giant 741 out of individual transistors, but claims for their superiority are made by people who are not fit to carry the slide rules of IC op-amp designers.
Quote from: reddesert on August 01, 2018, 02:15:27 PM
Discrete op amps are fun to talk about, like the kit that allows you to build a giant 741 out of individual transistors, but claims for their superiority are made by people who are not fit to carry the slide rules of IC op-amp designers.
I´d say that´s wrong. There is no and will probably never be an off-the-shelf part that can do, what the Jensen 990 can do.
The complexity in integrated opamp design often solves problems, that audio processing doesn´t have in the first place, and is
therefore in that case overcomplexity. And then there is the "sound" factor which is totally subjective, API2520?).
IC´s are mostly classAB, discrete can be classA, which will sound...different.
Of course reddesert has a point there with a lot of BS and badmouthing of ICs going on. Everybody wants a special fetish,
that works better and is more special than everybody else´s.
There´s no such thing as a good or bad sounding transistor in itself, I have seen R.G. again and again explaining why, check the search.
Quote from: noisette on August 01, 2018, 03:19:14 PM
Quote from: reddesert on August 01, 2018, 02:15:27 PM
Discrete op amps are fun to talk about, like the kit that allows you to build a giant 741 out of individual transistors, but claims for their superiority are made by people who are not fit to carry the slide rules of IC op-amp designers.
I´d say that´s wrong. There is no and will probably never be an off-the-shelf part that can do, what the Jensen 990 can do.
The complexity in integrated opamp design often solves problems, that audio processing doesn´t have in the first place, and is
therefore in that case overcomplexity. And then there is the "sound" factor which is totally subjective, API2520?).
IC´s are mostly classAB, discrete can be classA, which will sound...different.
Of course reddesert has a point there with a lot of BS and badmouthing of ICs going on. Everybody wants a special fetish,
that works better and is more special than everybody else´s.
There´s no such thing as a good or bad sounding transistor in itself, I have seen R.G. again and again explaining why, check the search.
www.johnhardyco.com/pdf/990.pdf (http://www.johnhardyco.com/pdf/990.pdf)
Quote from: EBK on August 01, 2018, 08:35:49 AM
Ok, here's a question that has been bugging me. Why can't these fancy discrete op amps be simply shrunk down and turned into IC op amps instead? Is there something legitimate to their mojo that requires larger parts or wider part spacing? Is it just for showing off?
Here is something I've found, but it leaves me less impressed than I should be, perhaps:
"Class A biasing and high output current capability coupled with a proprietary compensation scheme requiring multiple NPO dielectric capacitors make these discrete op amps impossible to fabricate as a monolithic IC."
Discrete opamps have some advantages and some disadvantages compared to integrated circuit opamps. In fact, almost all modern solid state audio power amplifiers are in fact discrete opamps. Discretes can have a much higher power supply voltage, and have vastly larger current and power outputs. However, they do not have the temperature stability, low drift, DC accuracy, or other special features that can be implemented with identical transistors closely coupled on a single substrate. There are ways to get around the issues with discretes, but they all involve much more complicated circuitry and much higher costs. It may or may not be possible to equal the noise, dsitortion and/or some other characteristics of IC opamps in a discrete design, but it will be a LOT of work, and may sacrifice other characteristics of the opamp's performance. DC performance and offsets are one common area where discretes must be hand tweaked on every unit, and may not even then be able to compete with tweaking.
Hifi tweakos like discrete opamps and other such things because it adds a layer of complicating complexity to tweak.
Quote from: R.G. on August 01, 2018, 06:01:12 PM
Hifi tweakos like discrete opamps and other such things because it adds a layer of complicating complexity to tweak.
Hifi tweakos like discrete opamps and other such things because it adds a
coating of complicating complexity to contemplate.Sorry. Was feeling in an alliterative mood and heard some music there. "Complicating complexity" was my Muse. ;)
Apologies again. Carry on.
Hifi tweakos carefully choose components to compound the coatings of complicating complexity to contemplate?
Or feasibly philistines forget fine formulas for fitting fidelity?
;)
Quote from: ElectricDruid on August 01, 2018, 06:44:23 PM
Hifi tweakos carefully choose components to compound the coatings of complicating complexity to contemplate?
Or feasibly philistines forget fine formulas for fitting fidelity?
;)
Alliterations are awesomely adaptable and appropriate argument artifices. Approved!
"Hifi tweakos carefully choose components to compound the coatings of complicating complexity to contemplate?"
Dang! I bow to ED. :)
Well played.
Quote from: antiuser on August 01, 2018, 07:51:32 PM
Alliterations are awesomely adaptable and appropriate argument artifices. Approved!
adds antiuser.
Quote from: thermionix on August 01, 2018, 09:13:47 PM
Quote from: antiuser on August 01, 2018, 07:51:32 PM
Alliterations are awesomely adaptable and appropriate argument artifices. Approved!
adds antiuser.
Allegedly acting as an amicable acquaintance, although always ascribing asinine assumptions at audiophiles. Apt at avoiding angry altercations and advancing along an accordingly advantageous ambition.
Ok now this is getting as silly as audiophile snake oil...
> Why can't these fancy discrete op amps be simply shrunk down and turned into IC op amps instead? Is there something legitimate to their mojo that requires larger parts or wider part spacing?
* If you can buy it for 19 cents, it can't be AudioPhile.
* There's a mind-set in IC shops. The high cost of the first wafer means it "MUST" do many jobs with the LEAST amount of Silicon. This leads to devices too small for some audio tasks. The '5532 is an anomaly in that the input devices are "huge" by IC standards (it comes from a troubled history and unexpected uses). Even then it is not hiss-optimum below ~~1K.
However you can buy "large" devices individually. Just a matter of paying for area. Now the bean-counters switch from functions/wafer to selling wafers by the square inch.
* IC devices can be *strange*. If you know devices, you should read Hans' book.
http://www.designinganalogchips.com/
True, ICs have changed, maybe improved, since he worked and wrote. But the improvements have costs and the MBAs have hammers to keep costs down. You can break the "all NPN" rule, but good isolation eats-up die area, reduces chips per wafer.
Quote from: PRR on August 02, 2018, 12:32:25 AM
> Why can't these fancy discrete op amps be simply shrunk down and turned into IC op amps instead? Is there something legitimate to their mojo that requires larger parts or wider part spacing?
* If you can buy it for 19 cents, it can't be AudioPhile.
* There's a mind-set in IC shops. The high cost of the first wafer means it "MUST" do many jobs with the LEAST amount of Silicon. This leads to devices too small for some audio tasks. The '5532 is an anomaly in that the input devices are "huge" by IC standards (it comes from a troubled history and unexpected uses). Even then it is not hiss-optimum below ~~1K.
However you can buy "large" devices individually. Just a matter of paying for area. Now the bean-counters switch from functions/wafer to selling wafers by the square inch.
* IC devices can be *strange*. If you know devices, you should read Hans' book.
http://www.designinganalogchips.com/
True, ICs have changed, maybe improved, since he worked and wrote. But the improvements have costs and the MBAs have hammers to keep costs down. You can break the "all NPN" rule, but good isolation eats-up die area, reduces chips per wafer.
I will point out one upside to the selling of wafers by square inch, those of us doing R&D don't have to run a whole wafer to test a design, sometimes we can get as little as four MMIC chips from a run, several times a year folks do development runs of GaAs, InP, SiGe... I actually wrote a paper about the SiGe amp I designed for the Phased Array Feed on the Green Bank Telescope, I benefited from a development run of SiGe transistors Caltech/JPL had done. http://iopscience.iop.org/article/10.1088/1538-3873/aa7115 (http://iopscience.iop.org/article/10.1088/1538-3873/aa7115) Even so, there is very little being done to develop discrete devices anymore, bare die transistors require a level of assembly skill that isn't really that common of cheap when it comes to GHz and above technology so the industry is moving more and more to MMIC because the technology is now really competitive and sometimes better than discrete chip and wire units and MMIC technology allows us to build multi chip modules that combine things like amps, mixers, AD conversion, fiber transmission, and LO distribution into one module saving on space and power. Basically, MMIC is doing the same thing to our field that the packaged op amp did 40 years ago, but it wasn't until just recently the noise was good enough to compete with discrete transistors.
I posted it somewhere else, but hey...
Nice analysis of a TL084 die: http://www.righto.com/2018/06/silicon-die-analysis-op-amp-with.html (http://www.righto.com/2018/06/silicon-die-analysis-op-amp-with.html)
Can you spot the FET inputs?
(https://lh3.googleusercontent.com/-MEDIDbx4twg/Wy3HQsxZ6uI/AAAAAAABSEA/gw58z--7Gt4_SoibU3OzpDbgkzXVbPMWwCHMYBhgL/w700/die.jpg)
Quote from: marcelomd on August 02, 2018, 10:46:07 AM
I posted it somewhere else, but hey...
Nice analysis of a TL084 die: http://www.righto.com/2018/06/silicon-die-analysis-op-amp-with.html (http://www.righto.com/2018/06/silicon-die-analysis-op-amp-with.html)
Can you spot the FET inputs?
(https://lh3.googleusercontent.com/-MEDIDbx4twg/Wy3HQsxZ6uI/AAAAAAABSEA/gw58z--7Gt4_SoibU3OzpDbgkzXVbPMWwCHMYBhgL/w700/die.jpg)
Why would I want to do that? Is there a prize involved? :D
I used to work in a Remote Sensing department of a company that made rotating infrared scanners for shipboard use to detect incoming aircraft. One of the better detector formulations for a photoresistive detector for normal ambient temperatures was HgCdTe, mercury - cadmium - telluride which was sensitive to the 8 to 14 micrometre range of normal ambient temperaturres. The sensors were about 50 ohms output impedance and we found the best transistor for use at this impedance was the lowly 2N4405. The way you select a transistor is to use noise maps that are specified for some transistors in terms of current and voltage with noise in db but where these are not available, use a transistor where the current noise matches the voltage noise for the circuit impedance you are using.
Another detector formulation was designed for the 3 to 5 micrometre wavelength range which could detect the heated air from a jet engine even when the aircraft was at nose aspect. This was a photovoltaic detector meaning is was like a solar cell optimized for that waveband. Since it was photovoltaic, we used op amps configured as transresistance amplifiers where the detector was connected directly to the inverting input of the op amp and the feedback resistor was large, usually 25 megohm low-noise resistors. These were JFET op amps optimized for minimum current noise since the input impedance was so high. Having the detector forced to virtual ground gave the best linearity so although the detector was photovoltaic, forcing the voltage to remain at zero gave the most linear video.
> clearly above average silicon transistor sounds.
(https://s8.postimg.cc/4vkkadv4x/Better_Transistors.gif) (https://postimg.cc/image/4vkkadv4x/)