sure, but what`s the purpose to make it so complicated and to use an obviously more expensive part? the competition was very strong at that time. none of my business, but you have an interesring profile pic.
Any Experience w Ebayer 'hifiaudio-' Need volume pot for HK A300
- Thread starter liteagilis
- Start date
70s Soviet car grille emblem. Lada (Fiat)
I know, that`s why it seemed interesting to me. I`ve seen pretty many right-hand Ladas in England back in early 90s but never thought anybody in US would like them.
dear moderators, please forgive me for offtop, will never do that again.
Am I wrong that by definition a volume pot should be audio/logarithmic taper?
you are right and in most cases it is indeed audio/logarithmic. yet there`s an opinion that nobody either confirmed or denied, that in 50s and 60s log pots were more expensive to manufacture, so sometimes linear pots with 2 extra legs were used, 1 leg for loudness and 2nd as a law-faking to make it pseudo-logarithmic. HK Citation I that I posted earlier looks like it, 100K resistor attached to the second leg seems to be law-faking. but I`m not sure, that`s why I`m so persistent in hope to hear notions of those who have more experience. I made a linear potentiometer for HK and it works fine, volume adjusts progressively as if it was logarithmic, but I`m not so sure with the Scott-130, because it is clear that both legs in it`s original pot are engaged in loudness function.
A slight amount of thread drift / off topic is nothing to worry about, as long as it's brief, doesn't derail the thread, and is non contentious.
Kind of a pain to get it out of the system but would it be of use to take some measurements of mine in circuit?
analogadict
Active Member
I hope this is not the same fellow. Can someone confirm. Am planning to buy the kit in the link.
Regards,
Regards,
That's the guy to avoid.
it`s not a pain, it`s a disaster, I know it too well, please don`t do it. let`s wait till somebody with experience says something.
analogadict
Active Member
Thanks a ton,
Was going to buy two kits as a friend also purchased this Sanyo preamp based onmy recommendation. Would have been a huge disaster.
Regards,
Let me know if it would help.
I modeled the Scott volume control in LTSPICE to see how it behaves with the loudness switch in the normal position. That is to say, the caps are out of the circuit, and each of the two taps has a resistor to ground. Here are the basic numbers at a few points. The voltage numbers assume 1V is applied at the top of the pot and that rotation percent and resistance are linearily related. For example, at 10% rotation, the wiper is assumed to be 50K above ground:
It's clear from this that the circuit does indeed mimic a log taper pot if the actual taper is linear. In fact, it's very similar to the ALPS 15A taper shown in my post HERE. Based on this, it would be functionally impractical to use a log pot in this position with taps, but replacing it with one lacking taps would certainly require log taper.
Jack
It's clear from this that the circuit does indeed mimic a log taper pot if the actual taper is linear. In fact, it's very similar to the ALPS 15A taper shown in my post HERE. Based on this, it would be functionally impractical to use a log pot in this position with taps, but replacing it with one lacking taps would certainly require log taper.
Jack