What is wrong with op-amps?

Status
Not open for further replies.
Jump to Latest
#1,405
benb said:
I just found this Discrete Opamp, I don't know how I missed it when it first came out:
The XL741 Discrete Op-Amp Kit

It doesn't have the greatest specs, and it's really expensive, especially for only a single unit, but I thought it might be of interest.
Click to expand...

i took a look its the real thing.

-
 

Attachments

  • image.png
    image.png
    101.1 KB · Views: 359
#1,406
billshurv said:
Cherry keys are still made, and used in for example Das Keyboard - The Ultimate Mechanical Keyboard Experience for Badasses . My daughter has the ultimate. Still not quite as noisy as the classic IBM terminals though.
Click to expand...

I'm picky about laptops (old school IBM Thinkpads were the best, RIP my T43) and use an old Compaq keyboard on my home computer. Why? Cherry browns. The IBM keyboards that mimicked the weight of a typewriter are a bit excessive for me, but I can see the appeal. That and if you should ever get so frustrated with other members on DiyA, it will take the physical abuse with aplomb. 😉

I'd just love this thread to be retitled, "What is wrong with some peoples' perception of opamps?". Buuuuut my opinion on demanding nature of line-level audio, which has been the thrust of most of the ostensible comparisons, was already made clear. 😀 (Pick one from the mid-80's and onwards, make sure it's implemented correctly, and it's probably good enough that you'd never confidently, e.g. using proper procedure and stats, tell the difference. So the decision is largely arbitrary, have fun)
 
#1,410
I've kept an old Logitech keyboard just for the reason that the key feel is so much like the typewriters that I grew up learning on in the dark ages. The only problem is that I can only use it on my very old desktop computer as it has the old round keyboard connector and not the newer usb type of connector. I tried one of those adapters that adapts it to a usb connector end but the newer laptop I use most often will not recognize the device, a real bummer as I really like the keyboard and wish it was able to work on a newer computer. Anyone know of a way to make the computer recognize an older device like this through an usb connection to an external device? If you look at the device manager in Win7 it just doesn't see the external device.
 
#1,412
Kindhornman said:
Anyone know of a way to make the computer recognize an older device like this through an usb connection to an external device? If you look at the device manager in Win7 it just doesn't see the external device.
Click to expand...

IIRC, most adapters are passive pass-through types that ultimately require the (now too old) keyboard to make the handshake, whereas there are some (more expensive, of course) adapters which act as the ps2 to usb converter, and thus tend to work with any old keyboard you may have.

Hope that helps.
 
#1,413
DPH said:
IIRC, most adapters are passive pass-through types that ultimately require the (now too old) keyboard to make the handshake, whereas there are some (more expensive, of course) adapters which act as the ps2 to usb converter, and thus tend to work with any old keyboard you may have.

Hope that helps.
Click to expand...
Yes, absolutely. This one (and the other models, I use a similar one with USB connector is a little bit bigger and holds the converter chip and an LED, and it has the two PS2 cables coming out) works:
FRYS.com | SHAXON

Supposedly, for a short time when when USB was introduced, keyboards were made with both the PS/2 and USB interfaces, and (with the cheap $2 or $3 passive adapter) could detect and operate when plugged into a USB port. I wouldn't recognize such a keyboard if I saw it, but I'm sure 98 percent of PS/2-interface keyboards made do NOT also have USB built in. I'm sure 100 percent of the IBM keyboards don't.

I use one of these on my laptop, along with an IBM Model M Space Saver and Logitech Trackman trackball (T-CH11).

Just to be on topic, this allows me to operate LTspice simulating opamps with ease on my computer.
 
#1,414
Thanks for the answers guys, it would be great to keep this keyboard working for as long as it functions. I also use a Logitech Trackman trackball and hate to use a mouse. I have one of the first trackman trackballs with the pool ball sized ball that also needs an adapter to work with usb connections. These were the best trackballs Logitech ever made, the newer usb trackballs from Logitech are really cheaply made and never last more than about one year at best, the switches just die on them. I think I've gone through about 5 or 6 of the newer Logitech trackballs but my original one is at least 15 years old and just keeps on working.
 
#1,418
bear said:
monkeybear, can you characterize in words the difference in sound that you hear??
especially in sibilence and things like cymbals - and maybe any other tonal changes?
Click to expand...

Hiya Bear. Here's a quick sample. It's a bit of bass guitar - pretty raw and unedited, with a 90Hz single order highpass filter applied. In one case its just like an ordinary resistor / capacitor real world filter. In the other example its the impulse response of that filter but reversed. So its kind of working backwards in time. The effect on the relative energy at different frequencies is just the same so they're alike 'spectrally'. The two waveforms look clearly different cos the effect in the time domain is different. It's subtle, but to me the top end of the bass is a little clearer or more forward in the reverse example, compared to the slightly more mute top end in the 'standard' version. The phase shifts of the two are different so maybe a psycho-acoustic thing from different masking effects? Or perhaps I'm imagining it! 🙂
https://www.dropbox.com/sh/dr3ndqux1b6k3m9/AACsbyvO6YYdeEg4G13hS9Xwa?dl=0
 
Status
Not open for further replies.
Top Bottom