Mods and bass version of Tonepad's speaker simulator?

Started by xorophone, March 12, 2017, 03:43:18 PM

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PRR

1uFd is full-bass for loads down to 10k.

1uFd is historically film/paper. 10uFd is usually electrolytic and cheaper. Especially by the handful. Especially bargain-bin stock. So it is common to  find 10uFd (or 5 or 22) electros all over.
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pee-j

so it is not "only 1uF" but "1uF" :) and it is not "instead of the 10 or 22uF" cap but in its own place :)

Well, the difference between engineers and simple people is that we, the latter, usually just imagine things, can't calculate...

How does this "1uF = full bass" conclusion come about, by the way?
For not knowing doesn't mean not wanting to know :)

Andon

What Paul is referring to is that the output cap and the shunt resistor afterward create a high pass filter which will allow frequencies above that threshold to pass and frequencies below that threshold to be attenuated.

Here's a handy tool for calculating that.

With regard to "1uFd is full-bass for loads down to 10K", if we plug in 1uF and 10K we get a cutoff frequency of roughly 16Hz, which is between B0/C0 on bass. This is about as low as I'll personally go when designing circuits, though if you look at many designs from BOSS, etc. you'll see cutoff frequencies as low as 7.2Hz (47nF and 470K).

The two schematics you're referencing will have a cutoff frequency of roughly 0.16Hz, which will let pretty much all bass frequencies through, including some potentially undesirable noise if not properly accounted for. It's also helpful to know that - on average - the normal low end of human hearing is 20Hz.
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pee-j

thank you, Andon,

I know about HP/LP filters,
what I was curious about was what elements form that HP filter...

my intuitions say that if we omit that 1M pulldown resistor, we'll still have such a HP filter somehow...
what comes to my mind is the Millenium bypass indicator circuit, in which the entire effect circuit is being used somehow -- as a resistor?? :)


PRR

Quote from: Andon on August 08, 2023, 08:23:13 AM.... the normal low end of human hearing is 20Hz.

That's very debatable. It trails off from hearing to feeling.

However it is almost impossibly hard to test because making deep bass needs BIG pistons/cones. It is very rare to find a speaker honestly putting out below 50Hz, maybe 40Hz. And even those are backbreakingly heavy.

Caps are cheaper than woofers so yes you do want the cap to pass nearly-all the bass and let the woofer do its thing. Though with phonographs and urban churches, a subsonic filter often cleans-up the ambiance.(*) But this should be accurate caps in a designed filter, not just a blocking-cap sized small.
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PRR

Quote from: pee-j on August 08, 2023, 02:14:30 PM
I know about HP/LP filters,
what I was curious about was what elements form that HP filter...
my intuitions say that if we omit that 1M pulldown resistor, we'll still have such a HP filter somehow...

What is connected to the OUTPUT jack?
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