yan_b

in another forum...
« on: May 14, 2005, 04:41:24 PM »
i saw this at psw http://recforums.prosoundweb.com/index.php/t/5178/8872/?SQ=5e109b1d4530f48ff13d74983b2463f6

am i the only one who feels that the orginal post is far from been thecnicaly accurate?
I love the smell of burned electrolyte in the morrning.


in another forum...
« Reply #1 on: May 14, 2005, 04:53:19 PM »
Ha Ha!  That thread is hilarious!  

Although I must admit that I am somewhat embarassed for a few of those guys...

bcarso

in another forum...
« Reply #2 on: May 14, 2005, 05:18:37 PM »
Oi.  I just read that whole thread.  I guess I can write it off as "continuing education."

One opinion that does bother me is the notion that more active devices means more corruption of the sound.  Even the proponents of this view will most likely agree that is is indefensible when N gets small enough, for example a one-transistor amplifier.

James Boyk, who had T shirts made saying "digital finishes what the transistor began", had his students make one-transistor and one-tube amplifiers in the course lab, and then listen to them, in an attempt to "prove" that transistors basically sucked.

I have some ideas and opinions on this subject, but in the spirit of keeping this thread going I'll withhold further details for the moment.

Gus

in another forum...
« Reply #3 on: May 14, 2005, 07:10:21 PM »
bcarso posted


James Boyk, who had T shirts made saying "digital finishes what the transistor began", had his students make one-transistor and one-tube amplifiers in the course lab, and then listen to them, in an attempt to "prove" that transistors basically sucked.

Wow that is just wrong!  One needs to think a little different when building with transistors or tubes.  Same laws of physics, design "rules" are a little different what are the input and output Z, power supply voltage(s) etc..................................

  Restricting the circuit to one gain part is bad thinking and setting a circuit up for failure.  That IMO is a reason not to read anything he does.

  Funny thing the more I build, the more I am moving to solid state and away from tubes.

  I chuckle when I read post about how bad TL07x and 553x are.

  Again one can post anything they want on the web,  real, made up etc.

  One of the best is how a certain pro audio seller stated how good a GT44 is.    I fell for that one I bought two gt33s and a gt44 the electronics are OK/good the capsule sucks IMO.

in another forum...
« Reply #4 on: May 14, 2005, 07:35:46 PM »
Quote
I guess I can write it off as "continuing education."


Right, that's what kind of makes me embarrassed for them...it reminds me of myself when I first started studying electronics.  Although I don't think I ever posted anything like that in a forum, I did have some silly misconceptions.

It just goes to show that a little knowledge is indeed a dangerous thing.

*edit--spelling*

fum

in another forum...
« Reply #5 on: May 14, 2005, 08:46:58 PM »
I had read this,  :roll: , and walked away.

gotta love the net, where everything is the truth! :wink:

ju

in another forum...
« Reply #6 on: May 14, 2005, 09:47:46 PM »
Threads like that can take the fun out of DIY and recording if you take them seriously (which I don't).

Sammas

in another forum...
« Reply #7 on: May 14, 2005, 10:25:51 PM »
I'm sick of threads like those... they are everywhere.

If he really wants to know whats killing the music (& industry), its people *****ing and whinging and trying to pinpoint what is wrong with the industry or the music and blaming in on petty crap like digital sound or ic's or home studios or CD's or the lack of talent...

trying to avoid being any more hypocritical than i've already been (pinpointing the pinpointers  :oops: ) i say f%&k where music has been, its where its going that counts. Technology and all.

"The "Golden Age" of this industry has pasted. Its not coming back. To want the current state of the industry to be like it was 30 years ago is like asking every household to forfeit its computer and reserve them for technologically elite institutions or uber rich technoheads."

soundguy

in another forum...
« Reply #8 on: May 15, 2005, 12:16:09 AM »
that site in my view has always been and will always be one big giant pissing match over nothing.  nobody helps each other, its just one idiot making a statement, two or three friends defending it and then the rest of the board ganging up and high fiving each other, its pretty retarded, I hate that website.  IC's killed music, please.  All music?  Thats just a flat out moronic thing to say.  If it wasnt for the IC, there wouldnt be any electronica, period.  Im pretty sure techno qualifies as music...

dave

chips are good with dip...

dayvel

in another forum...
« Reply #9 on: May 15, 2005, 12:32:46 AM »
Quote
As far as I know the OP-AMP was conceived as a predictable and stable DC amplifier for Analog computing circuits.


That's one of the few things in that thread that's correct.


pstamler

in another forum...
« Reply #10 on: May 15, 2005, 02:35:09 AM »
Quote from: "dayvel"
Quote
As far as I know the OP-AMP was conceived as a predictable and stable DC amplifier for Analog computing circuits.


That's one of the few things in that thread that's correct.


Indeed. And if folks doubt that the "lowly" 5532 can sound good, they ought to check out various products from Benchmark Audio some time. That's just about all they use for the active circuits, and -- with much attention to the details -- their stuff sounds excellent.

"The 5532, properly applied, is better than what 95% of audiophiles have in their systems." - I'm pretty sure it was John Curl who said that; if it wasn't, then it was Nelson Pass. But I'm betting on Curl.

It's the "properly applied" part that jumps out and bites you every time.

Peace,
Paul

Gus

in another forum...
« Reply #11 on: May 15, 2005, 09:57:00 AM »
Paul you posted

"The 5532, properly applied, is better than what 95% of audiophiles have in their systems." - I'm pretty sure it was John Curl who said that; if it wasn't, then it was Nelson Pass. But I'm betting on Curl.

Didn't Curl design the first Mark Levinson 25 watt class A amp and preamp?

I think the 5534,2 were designed correctly by real designers.

  What year was the 553x chip designed and built , mid 70's?  

  I agree grounding, power supply and layout etc can make a big difference.

dmlandrum

in another forum...
« Reply #12 on: May 15, 2005, 10:15:16 AM »
Yeah, they're at it again.

That board is either unsubstantiated claims, or a bunch of old industry guys pining for the good old days to come back. There are very few worthwhile threads. Recently, one was started about why use of the forums is slowing down so much. Look in the mirror, folks. That's why.

There is only one place I find myself sometimes agreeing with them, and that is in the seemingly widespread use of software such as Autotune and Beat Detective as general fix-it tools.

I would, however, like to give a shout-out to Harvey and his forum over there. He's a cool guy, and seems genuinely interested in helping people.
Darren Landrum

Be comforted that in the face of all aridity and disillusionment
And despite the changing fortunes of time,
There is always a big future in computer maintenance.

TomWaterman

in another forum...
« Reply #13 on: May 15, 2005, 11:21:30 AM »
Quote from: "soundguy"
that site in my view has always been and will always be one big giant pissing match over nothing........IC's killed music, please. All music?........If it wasnt for the IC, there wouldnt be any electronica, period.  Im pretty sure techno qualifies as music...


Dave, without sounding like an ass-kisser, I think your points are pretty much on the head of nail ALL[/b] of the time.

The thread about ICs is so moronic its funny.

Gus, I would love to see a few more discussions around here about the correct implementation of ICs, in particular things like grounding, compensation etc....

I'd love to learn what the 'small details' are and should be...how to do it right like the guys at Benchmark etc

-Tom

cannikin

in another forum...
« Reply #14 on: May 15, 2005, 11:54:26 AM »
I couldn't finish reading that thread,  I was getting rather tired of the debate/banter/BS.   I used to read John Klett's forum regularly but he rarely posts and I just don't find value in the discussions at that forum especially in comparison to depth and generosity here at prodigy.`

hey Tom, Dave, and buzz time to bump that calrec 1061 thread! :razz:
Tube limiters..yum!

pstamler

in another forum...
« Reply #15 on: May 15, 2005, 01:36:28 PM »
Quote from: "TomWaterman"
Gus, I would love to see a few more discussions around here about the correct implementation of ICs, in particular things like grounding, compensation etc....

I'd love to learn what the 'small details' are and should be...how to do it right like the guys at Benchmark etc


There was an interview with the head honcho of Benchmark in, I believe, the 1996:2 issue of Audio Amateur. He emphasized the need to always use a cap in parallel with the feedback resistor so the amplifier isn't running flat out to the point where it intersects the open-loop gain curve. I've found really good supply regulation, and film decoupling on each IC package, crucial. Also keeping the output in Class-A wherever possible; it's normally biased at only about 0.2mA, so either you have to operate into highish impedances or bias the output up into single-ended Class-A using a resistor or, preferably, a current source.

I also like to include a resistor between the output pin and the place where you take the output and feedback (see the circuit I drew for the -10>+4 converter thread) for maximum stability (Walt Jung trick) and another in series with the output if it's going to look at the outside world. Oh, and lots of RFI-proofing on the inputs.

Peace,
Paul

[email protected]

in another forum...
« Reply #16 on: May 15, 2005, 01:41:57 PM »
Arguing about what sounds better is akin to arguing that blue is superior to green. Also, there is the red camp that knows better than all...

TomWaterman

in another forum...
« Reply #17 on: May 15, 2005, 02:28:18 PM »
Quote from: "pstamler"

There was an interview with the head honcho of Benchmark in, I believe, the 1996:2 issue of Audio Amateur. He emphasized the need to always use a cap in parallel with the feedback resistor so the amplifier isn't running flat out to the point where it intersects the open-loop gain curve. I've found really good supply regulation, and film decoupling on each IC package, crucial. Also keeping the output in Class-A wherever possible; it's normally biased at only about 0.2mA, so either you have to operate into highish impedances or bias the output up into single-ended Class-A using a resistor or, preferably, a current source.


Good stuff Paul, is there any amount of current that should be drawn to ensure class-a operation....i.e how much greater than 0.2mA?

Quote from: "pstamler"
I also like to include a resistor between the output pin and the place where you take the output and feedback (see the circuit I drew for the -10>+4 converter thread) for maximum stability (Walt Jung trick) and another in series with the output if it's going to look at the outside world. Oh, and lots of RFI-proofing on the inputs.


That resistor on the op inside the feedback loop seems like a solid addition, its funny I just put that in the schematic for the headphone amp im in the middle of and then saw your excellent post for the balanced stage....great!!

Oh and back to the initial topic, if any of the guys on Prosoundweb think ICs are to blame for the state of todays music, then they are in my opinion looking for an excuse to cover up their lack of creativity.....(not targetting anyone in particular).

There is some good stuff over there though.

Cheers Tom

in another forum...
« Reply #18 on: May 15, 2005, 03:10:03 PM »
Quote
is there any amount of current that should be drawn to ensure class-a operation....i.e how much greater than 0.2mA?


As a rule of thumb, always bias from the negative supply.  The reason for connecting the current source to negative is that it forces the NPN transistors in the op-amp to remain active instead of the PNP ones. Biasing the output to V+ would also work, but in general PNP transistors don't behave as well as NPN ones, so we'd rather make the NPN's do the work.

The current level that must be passed by the current source depends on what load the op-amp is driving. The rule for this is that to keep the op-amp in class A, it has to be passing more current all the time than the load would take on its own.

As for the 5534...honestly I could never understand why you guys like them.   It just seems like a strange fascination to me (same goes for the MC3307x's and the LF386).

If you've got a good supply that sources current adequately, and you've decoupled properly etc, obviously it will sound good, but there are other opamp IC's that sound better under the same conditions.  I've used two ISA110's with 5534's in one and AD797's in the other side by side, and the 797 was the clear winner to me.

It's a personal opinion, I know...

bcarso

in another forum...
« Reply #19 on: May 15, 2005, 03:13:02 PM »
"Good stuff Paul, is there any amount of current that should be drawn to ensure class-a operation....i.e how much greater than 0.2mA? "

Depends on how much current the circuit is going to pull at the magnitude of the peak voltage that is the polarity subtracting from the bias resistor's current.  For example, if it is a resistor to the negative rail then as the amplifier swings negative you are asking that the current be supplied by that resistor.  The voltage at which the load current equals the current through the resistor plus (about) the quiescent bias is the point at which the upper output transistor of the op amp output stage is turning off, i.e., no longer operating class A.

A current sink load extends the range of operation, but at some point the current source runs out of voltage compliance.  This can be as low as say 0.8V above the negative rail though, for a two-series-diode-biased transistor.

(as you can see featherpillow beat me to the punch here ;-)


 

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