Reminds me of some of the BMWs, which have the little sticker about high octane gas requirement. The car's been obviously engineered to run better on high octane gas. Perhaps all you were missing John, is the little sticker that mentions cable requirements. One can hardly make the argument that said BMWs are subject to bad engineering because they require good gasoline.
Ikoflexer, we OFFERED to build in a low Z buffer, IF it was requested. This was in our specifications. Every BLOWTORCH was made to custom specifications. You could have: phono, balanced input, different impedance TKD pots, and an OUTPUT BUFFER. These usually cost extra, but they were offered to discerning clients, to meet their specific needs. Balanced output was usually offered without charge, but I have an example here that does not have balanced output, as the client thought it unnecessary at the time.
Yes. HP 8001 anyone? It made a difference in fractional uS risetimes and high frequency transients. About 4 orders of magnitude above audio frequencies? 😉
Anyway, 1k was never a standard. 1k, and sometimes even up to 5k, Zout came from the technical limitations of vintage (tube) preamps and/or its designers. Nowadays, it is really trivial to get a few orders of magnitude lower Zout and that way, orders of magnitude less influence from load pecularities. Tradeoff? What tradeoff?
jd
John, I wasn't criticizing your choices, in fact I find them perfectly sensible. You achieved the results you wanted.
These people are shouting from the hill top that your preamp is obsolete, meaning there are much better choices lately. Hey, the Honda S2000 is an engineering masterpiece, but I'll go out on a Sunday anyday in this obsolete one
These people are shouting from the hill top that your preamp is obsolete, meaning there are much better choices lately. Hey, the Honda S2000 is an engineering masterpiece, but I'll go out on a Sunday anyday in this obsolete one
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Really? The only thing I noted was a discussion on preamp Zout.
Also, John stated that the reason for the high Zout on the BT was that it was requested by the customer. So, why not give him what he pays for? John is perfectly able to make a Zout as low as he wants, within reason.
But in engineering terms, high Zout is not a good thing because you surrender the performance of your preamp to whatever is hung off of it.
Don't read what isn't there 😉
jd
'Obviously' this is extremely naive.
In fact one can. It's more difficult to engineer a car to run well on low octane than high octane fuel.
jd
It's not like they haven't done it, as in the R1200GS bike, which features automatic knock control. But as an engineer you know yourself the difference between not having the problem in the first place, and having the problem AND adding extra design and manufacturing to provide a solution.
Sometimes you can have a simpler design (and manufacture) IF you allow for less options, as in "stick to cables with X and Y parameters" or "stick to high octane gas." I do see it as a trade off. Plus, he says the offer for the extra circuitry was available. I find that reasonable.
Sorry, but ignoring the problem and leaving it up to the customer to fix it (i.e. find cable xyz) is bad engineering in my book. But I agree, if that is what the customer wants, hey, it's his money.
But anyway, I prefer to stick to engineering. Anything else like you mentioned above comes dangerously close to marketing strategy 😉
BTW Nice car. Shelby?
jd
If I may be so bold...
Since this thread is frequented by some of the smartest engineering minds this side of Aldebaran, can I pose an off-topic question (only one John, I promise to leave it at that. Please):
Is there an easy way to determine the zero's in this transfer function:
Please contact me at jan AT linearaudio DOT nl
Since this thread is frequented by some of the smartest engineering minds this side of Aldebaran, can I pose an off-topic question (only one John, I promise to leave it at that. Please):
Is there an easy way to determine the zero's in this transfer function:
Please contact me at jan AT linearaudio DOT nl
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Challenger Trans Am, he forgot to post a picture of a 1970 Mopar Hemi
My nextdoor neighbor has the SRT8 version of the latest model Challenger, much nicer imo.
This is unfair. I chose 1K as a REASONABLE output impedance, that served most needs, without adding added stages. What is wrong with you?
Jan
Is it a quiz or is it something you need?
It’s a Bode equation of a closed loop (with two filters and the open loop) right?
Cheers
With a 1k output resistance you'd need ~8nF of cable capacitance to be down 3dB at 20kHz. I don't see a typical line-level signal cable making a huge difference here.
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