Robert was indeed kind enough to send me some specimens to try out, needless to say I am excited because these have a different topology than what I normally use.
Since the whole system is a symbiotic relationship I was thinking of setting up a test in a different manor than discussed in this thread. I want to make a circuit with 10x gain for different opamps, say 4558 and the LT1358. I will have a partner swap out the black boxes and see if I can hear a difference once levels are matched. What I want to do different is use a microphone and REW to make total system synergy measurements. I can also do some regular distortion measurements too but most likely the distortion will be below what I can measure
Same address as the company.🙄 Let's see, what is the minimum investment for an new IC op-amp? And the plan is to sell them one at a time on eBay? Am I curious enough to buy one and have it de-capped?
Ultra Analog used to be a maker of DACs in the late 80's/early 90's. It was a USA company. So now I see a UK operation selling a surface mount chip mounted on an 8 pin dip socket adapter board. Nice, I guess, to commandeer a respected name and sell part soldering services at a hefty markup.
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Or we could just compare the specifications with existing or recently obsolete products. Probably less than 20 we would need to search. But then they might be selecting chips and dumping the rest.
But the humor is that the magic opamp is a monolithic unit!
wasn't somebody doing this earlier? MA systems or something like that?
i have vague memories of a part MA-332 that was a selection of some existing part ...
mlloyd1
i have vague memories of a part MA-332 that was a selection of some existing part ...
mlloyd1
i found it.
this is the part: Analog Systems MA332
i've read (maybe even here somewhere?) that it was a selected 5534A.
mlloyd1
this is the part: Analog Systems MA332
i've read (maybe even here somewhere?) that it was a selected 5534A.
mlloyd1
I was thinking selected LME49990. It didn't come in a DIP. Of course no longer available. They did restart production on many of the previously discontinued parts. But not those.
Those tubular resistors are/were common in tuner modules, ditto tubular capacitors.....what's special about them ?.
Dan.
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MELFs? higher power handling and sometimes better matching. Other than that a PITA as they roll off the board before they hit the IR oven if you get your pasting wrong.
Nothing. The point is the UK company using "Ultra Analog" It's like if I started using HH Scott.
Makes sense, but as I explained to a QC guy years ago noise does not have a normal distribution. If typ really is .9nV there are 0% well before .7nV. They also take a hit for no reason on specing 20% or so more slew rate (unless the spec is sandbagged OR they are making it up).
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Since the whole system is a symbiotic relationship I was thinking of setting up a test in a different manor than discussed in this thread. I want to make a circuit with 10x gain for different opamps, say 4558 and the LT1358. I will have a partner swap out the black boxes and see if I can hear a difference once levels are matched. What I want to do different is use a microphone and REW to make total system synergy measurements. I can also do some regular distortion measurements too but most likely the distortion will be below what I can measure
4558 with biased outputs using 7K5 resistors to + rail are different beasts compared to unbiased opamps. Try and compare. If it did not work I would replace all opamps in my console to something modern.
So, Anotoliy, you are in effect saying that the "sound" of opamps, (when not good) is due to the output stage?
_-_-bear
_-_-bear
Using just a resistor to sink current from an op amp output forces it to drive not only DC current to do the biasing but also AC current has to drive the load. An active device mostly just sinks DC and is a very easy, high impedance AC load on it. Compound that bias resistor with the not so robust output drive ability of the 4558, well its no wonder the high frequency envelope of the vocals of Wave's outdoor setup were strained.
I'm still going to try it (4558 +7.5k pull up) once I can get a little setup made to buffer the 4558 from driving the 600 ohm RIAA network I use. I'll see, but I don't think it's going to be pretty.
I'm still going to try it (4558 +7.5k pull up) once I can get a little setup made to buffer the 4558 from driving the 600 ohm RIAA network I use. I'll see, but I don't think it's going to be pretty.
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