Transistor equivalent

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audioguru said:
My pc is running Windows 10 and takes a long time to stop or close a Falstad sim. I thought my pc was permanently frozen.
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I feel sorry for anyone using Windows 10 or running a slow PC due to slugware running. No one will ever convince me to switch to WIN10.

My win8 lappy can run several Falstad Java simulators easily, but only because I maintain it to be lean and very fast.
 
Some purists who can detect very small amounts of IMD will say that there isn't much high frequency gain left in Op Amps used for high gain, so the feedback gain is quite low and the IMD is much higher than the typical 1kHz THD test would suggest. YOu would need a number of frequencies above 10 kHz to cause this low frequency aliasing or Intermodulation Distortion. However my ears are already adjusted to the distortion in music and compress distortion on radio. But dearly miss my Bogan tube stereo amp and large single stage 12" Phillips speaker with tuned ducts in 4cm walls of compressed particle board for the acuity of imaging of all sources of sound in stereo or quad. It wasn't the best but it sounded like live music.

But then for low gain (x10), this Op Amp looks pretty impressive, which is pretty hard but not impossible to do with discrete BJT's, but very easy to do with low noise vacuum tube pre-amps and with much more gain.
 
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Hi Tony,

I know the feeling, but win 10 is fast from what I hear from the experts. I have a high end lappy with Win 7, and also found the sim ran very slow. I think there is more to it than hardware/OS.

I have been putting off moving from Win7 to Win10 because of the hastle factor and also because of the lovey touchy feely of some of the new stuff- Google are the worst. I'm hoping that you can strip it all out on Win10 like you could in Win7. Incidently, like Win XP before it, Win 7 is excellent- fast and just as importantly very robust.

Know what you mean about keeping your PC fast and lean- every time you load a new application these days it infiltrates all the other applications. Outlook was running slower and slower, so I had a look at the start ups- ther were something like 20- just stripped them all out and Outlook started instantly. Another approach, so I'm advised, is to instantiate a virtual machine and run any processing intensive stuff on that. Lock it down - no internet- so it just does raw processing. I always meant to do it, but so many other things to do too.
 
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Tony Stewart said:
...But then for low gain (x10), this Op Amp [LT1115] looks pretty impressive, which is pretty hard but not impossible to do with discrete BJT's, but very easy to do with low noise vacuum tube pre-amps and with much more gain. ...
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Hell, didn'know about that beauty.

Tony Stewart said:
... very easy to do with low noise vacuum tube pre-amps and with much more gain. ...
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'very easy' for you maybe!

Didn't know about low noise in tubes either. Thinking about it though, the front end video amps on the older RADAR systems used low noise tubes and they worked very well.

For years I had a ton of tubes, not just run-of-the-mill either. They were full Mil spec CV types, gold plated pins and all. They hung around for years and one day, durring a garage/ workshop clear-out, I gave the lot to a radio ham chap across the road. I wish I had them now. Not only would they be worth a fortune, but they would be good for experiments. Mind you, it's the same for other things, motorbikes and cars for example- you couldn't give away many of todays classics at one time. Even the lousy old transistors like the germanium OC71 fetch good money now.
 
I will toroidal transformer from salvaged toroidal core. It is the cheapest and safest way. High power transformer very expensive unless the makers cheated: wind aluminium wire or use low quality core instead of iron-silicon core ...etc.
uhm if choose impedance of speakers, I will choose 8ohm. 8ohm speakers need half or current but only quieter 3dB. My amplifier will hotter when drive 4ohm spkr.
But I can't understand why many people think 4ohm speaker is higher end than 8ohm while I have saw many tube amp use 8ohm spkr, many transistor amp use 8ohm spkr too.
 

Hi Tony,

Are you saying you found a problem with Win 10? What did you find out?

What we really need is another company that directly competes with MS for the Windows op sys. That's the only way progress is ever made. When one company dominates so much there's never any motivation to actually make it better.
What i have seen over the course of several win platform 'upgrades' is a tendency to go backwards to known issues and problems with a new release of the software. That is just nuts. They must have recognized a problem in the past, then forgot about it when the new system was designed. Either that or they like to purposely build in bugs before shipping.
 
Windows 10 has Bing for its browser. I like all the news articles and pictures on the first page of Bing. To do a few common things then I must switch the browser to Internet Explorer which is a nuisance. Some problems have quietly disappeared maybe due to updates.
 
MrAl said:
Hi Tony,

Are you saying you found a problem with Win 10? What did you find out?
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No. I am just saying No one could convince me to use it. ( Steve Gibson said the same)
It has many new different features that I dont want if it means loss of transparency or access to control. I haven't used it long but saw enough to make strong conclusions for me, not all others.

If I wanted I can make anything work well, but Win10 was designed to make it easier to do either swipe screens or touchpads or mouse clicks work well with big ugly drum pad icons. It's not a problem with compatibility, just flexible usability. I prefer a Win7 like environment and have hundreds of applications.

Win10 has more obfuscation. I like to know what my PC is doing in real time at the program level, not DLL level. All versions of windows have fault tolerant flexible interfaces but at a major loss in efficient programming and CPU usage.

I haven't used an antivirus-suite consistently in 10 years and use better security for me, that works just like having a Dog instead of a Secret Service, Homeland Security and Grocery Store security with guns. He then alerts me to take suggested action or not. It checks many thinks sniffing only the registry in critical locations where processes or services are triggered to start or stop for next boot or critical registry changes in other ways or file or class association hijacking. This is exceptionally faster than intercepting every file and scanning it for nasties when most are compressed and have stuff jumbled or encrypted anyway, hard for scanners to analyze. I can always check freeware ( by means it uses a signature with 56 AV suites online in seconds, which upload if necessary if unseen before and even do it from the special task mgr. (procexp)

Most people have way too much crap starting on boot that they aren't aware is running. I have dozen of tools to easily disable, better than msconfig.

If you want a performance boost or have a technical PC problem solved, I can solve just about anything. ( many past years volunteer admin for a PCtech forum)
 

It's the "car issue". Way back when, when tube radios existed in cars we had 40 ohm spekers because eof the high voltages. Because of bridging and 12 v systems, we had 4 ohm speakers because it was an EASY way to increase the power. Tube amps had 8 and 16 ohm taps for putting 8 ohm speakers in series.
Now we have easy to design switched mode power supplies (SMPS). My factory stereo is 100 W in 2000.
 
I had a car that came with 2 ohm speakers on the rear shelf and its 10" subwoofer had its amplifier with a voltage stepup power supply.
Look at these car subwoofers:
 

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A moment ago I got a Java update. Then it said Win 10 does not support Java, open Internet Explorer instead. Maybe that is why Falstad had trouble.
 
Hi,

Since we also talked about speakers...
I had a very old speaker so old it didnt even have a permanent magnet. Instead, it had a separate DC winding that had to be energized in order to make the magnet. It also had the normal AC audio winding of course. The DC had to be smooth too.
I never really used it though, only to test, because it was much harder to use needing that DC current as well as the normal audio signal.
Dont remember what the AC coil impedance was though.
 
In the late 50's an probably earlier the speaker magnet was done as you said, however the magnet was the L in the DC power supply filter. Have a console radio that has a >10" speaker that is of the construction you speak of.
 
audioguru said:
I had a car that came with 2 ohm speakers on the rear shelf and its 10" subwoofer had its amplifier with a voltage stepup power supply.
Look at these car subwoofers:
Click to expand...
I hope that wasn't the trigger for your hearing situation, but I can understand if it was.
 
My hearing follows the same high frequency loss (-45dB at 8kHz) as other men my age (70). I never listened to acid rock at full blast like some people who probably have more hearing loss than me. My hearing aids do not even play any low frequencies below 250Hz because my low frequency sensitivity is fine. I didn't know about normal high frequency hearing loss with age until recently when I ran out of excuses because it happens so gradually. Normal is -10dB at 8kHz at age 35, -20dB at age 45, -30dB at age 55, -40dB at age 65 and -45dB at age 70. I am glad the audiologist turned up the levels of high frequencies gradually over a period of about 6 weeks because it takes time to adjust to hearing normally again.

I like the tricks my hearing aids can do with a push button on either one (they communicate modes together with bluetooth):
1) Music which is wideband stereo without AGC
2) Very Sensitive with AGC
3) Muted which is good when a truck, motorcycle or siren drives past, or dogs are barking
4) Automatic which slowly reduces the level of background noise then quickly up to normal gain front or back when speech is heard. I think it is in mono, not stereo.

The tiny button battery cell lasts for one week then there is a voice announcement (LOW BADDREE) that I do not like so it is not activated, or BEEP BEEP then another beep beep half an hour later just before that one turns off.
 

As the other members say, the speaker impedance is designed to match the amplifier V/I characteristics. 15 Ohms was used in the valve days for hi-end amps because it was the best compromise between the output transformer design and speaker coil design. As far as the speaker coil is concerned, 3 Ohm is the best. That is why it was the standard for years- it uses a small number of turns with relatively thick wire which is more rugged, cheaper to manufacture, and better for heat dissipation. Why 15 Ohms then? It's because of the output transformer. The higher the turns ratio the harder it is to get a good performance. 15 Ohms is also better for distributed speaker systems as it has 0.2 the current of a 3 Ohm system for a given power, thus the resistive losses are lower- just like the mains power grid. For weedy amps, like in the early battery-powered transistor radios for example, speaker impedances as high as 300 Ohms were used.

Since the 1970s the trend has been towards 8 Ohms to match the V/I characteristics of solid state amps. In general 3 Ohms allows more power from a solid-state amp because, to a first order approximation, it is easier to provide more current than more voltage.

By the way, the stated impedance of a loudspeaker is only nominal. If you measure the resistance of an 8 Ohm speaker with a multimeter, it is likely to read around 7 Ohms, but this changes, sometimes radically, through the audio frequency spectrum, and some 8 Ohm speakers, with cross-overs, can drop to as low as 2 Ohms, particularly at bass resonance and the cross-over point of 300Hz to 3.5KHz.

4 Ohm, 8 Ohm, 15 Ohm make no difference to the audio quality of a speaker. In fact, it is not uncommon to see the same speaker chassis available in all three impedances.

 
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Interesting stuff. I have a friend who has lost all frequencies above 3.5Khz, and doesn't enjoy listening to music so much now- shame because he has good equipment. Me- still the same as far as I can tell: DC to 10Khz but can sense up to around 12Khz but notice the difference if 12Khz to 16K Hz is removed.
 

Yes, the good old days. I too had a few of those as a kid- great fun. The copper wire was handy for winding transformers!
 
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