Darkglass - Microtubes B3K / B7K  [traced]

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Manfred
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Post by Manfred »

Sorry, Deltafred you are right and I must apologize you have written of non-buffered but not of non-inverting.
Thanks also to Jim to point this out.
I don't know why I misinterpreted that from the context.

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Post by Manfred »

I retraced my train of thought again and found out why I was wrong.
I considered the buffer to be inverting and made the conclusion, that by omitting it out, the inverting behaviour of the 4049 stage is lost.
This was wrong because the buffer is non-inverting.

Now I know what you meant, adding the buffer provides more gain and low output resistance of the 4049 inverter stage.
So this stage with the high input resistance, the high gain and the low output resistance behaves like an OP-amp as an inverting amplifier.
Therefore only the buffered version of the 4049 is usable for analog applications.

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deltafred
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Post by deltafred »

Manfred wrote: 01 Oct 2020, 07:09 Therefore only the buffered version of the 4049 is usable for analog applications.
I think you mean un-buffered.

I'm glad we've got that sorted out. The internet is not really the best platform for technical discussions.

Anyway my question still stands. Were those builders who were having problems with "crackling" using a 4049 or a 4049UBE? If any of them are reading this thread I'd be very interested.
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Manfred
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Post by Manfred »

deltafred wrote: 01 Oct 2020, 10:10
Manfred wrote: 01 Oct 2020, 07:09 Therefore only the buffered version of the 4049 is usable for analog applications.
I think you mean un-buffered.

I'm glad we've got that sorted out. The internet is not really the best platform for technical discussions.

Anyway my question still stands. Were those builders who were having problems with "crackling" using a 4049 or a 4049UBE? If any of them are reading this thread I'd be very interested.
Yes, you're right, I did twist it again.
I see in the buffered version there is an internal buffer at the input and the other one at the output.
Since both buffers are inverted, the signal remains non-inverting.
The transfer curve is very steep with a hard transition at the ends.
In the unbuffered version, the slope is noticeably flatter and the corners are rounded, making it suitable for analog applications.
I can imagine that the buffered version produces an unpleasant fuzz sound, because the input signal causes a fast flip of the output and so a steep square wave signal appears at the output.
I think now I have understood it.

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Manfred
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Post by Manfred »

I see in the buffered version there is an internal buffer at the input and the other one at the output.
Since both buffers are inverted, the signal remains non-inverting.
To avoid further misunderstandings I add that the function of the unbuffered version is maintained.

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Post by zyu »

deltafred wrote: 01 Oct 2020, 10:10
Manfred wrote: 01 Oct 2020, 07:09 Therefore only the buffered version of the 4049 is usable for analog applications.
I think you mean un-buffered.

I'm glad we've got that sorted out. The internet is not really the best platform for technical discussions.

Anyway my question still stands. Were those builders who were having problems with "crackling" using a 4049 or a 4049UBE? If any of them are reading this thread I'd be very interested.
I have both 4049 and 4049ube - will be at home soon (10-12 days) and check both in my pcb.

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Post by zyu »

sorry for the long delay. I checked both versions - I confirm, the buffered microcircuit sounds fuzzy and thin, I absolutely did not like this option. so yes - unbuffered IC sounds like it should.
797C3BB4-AF51-41F6-84B5-1A9A7193F9B9.jpeg

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