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Topping D90LE - "Valve" and "Transistor" effects measurements

restorer-john

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To add a basically but not utterly irrelevant aside, if I may: ;)

Long, long ago, there was a flurry of "sub-bass synthesizer" products (all analog, AFAIK) that did the same thing, but in the other direction (i.e., added some signal at half the fundamental frequency).

View attachment 214612source: https://worldradiohistory.com/Archive-All-Audio/Archive-High-Fidelity/70s/High-Fidelity-1978-09.pdf

This one may have just been a tone control, though, for all I know.

View attachment 214613
source: https://www.radioshackcatalogs.com/flipbook/1983_radioshack_catalog.html?fb3d-page=92

N.B. Note that I didn't say these products worked well. ;)

The Realistic Bass enhancer is a great little product. The only real issue with it is residual noise. It's basically a parametric EQ with a very good subsonic filter, so good for both vinyl and small speakers.

It was an add-on sold with Minimus 7 and other small speakers for years.

I've got one here and ran some FR plots on it a while back if anyone is interested in seeing what it does.
 
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mhardy6647

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I've got one here and ran some FR plots on it a while back if anyone is interested in seeing what it does.
Well... I mean... I would be :)
Not sure anyone else'd care, though... but if you feel like starting a little thread sometime, I'll read it!
 

restorer-john

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Well... I mean... I would be :)
Not sure anyone else'd care, though... but if you feel like starting a little thread sometime, I'll read it!

Here you go. A few combinations with equal 'db' and 'freq' increments to show the parametric effect.

realistic bass enhancer right ch.png


Bypass (purple) vs in circuit (yellow), no boost. Vertical scale in Volts. Notice the inbuilt low filter- brilliant for small speakers and possible vinyl sources.
realistic bass enhancer straight vs bypass.png
 

fpitas

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fpitas

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... or at least fairly high output impedance.
If it's tweakable, people will spend happy hours introducing more or less boominess. Who am I to criticize?
 
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