How would a 3 stage electron tube or transistor hearing aid sound like as a studio microphone preamplifie?

Caution: At your own risk. Ears should be protected from high SPLs especially when using headphones.


On vintage hearing aids everything is analog and class A (electrons flowing all the time).


The anode potentials are low, typically 20V. This should give excellent low noise performance. See previous euroelectron posts on electron tube noise and low plate potentials.


The schematics look very similar to a Neumann U47 head amp.


It should be a marvel of quality and low noise.


If needed should be added a microphone input transformer, output transformer etc.


See also previous posts.

A 4 transistor heating aid class A amplifier schematic of the Philips KL 5500

See the Philips KL5500 paper including schematic:


A transistor hearing aid - P. Bloom, P. Bloxman - Philips Technical Review - Volume 19


http://www.extra.research.philips.com/hera/people/aarts/_Philips%20Bound%20Archive/PTechReview/PTechReview-19-1957_58-130.pdf

Hello to Netherlands, Germany, United States

Class D microphones?

https://www.edn.com/design/analog/4430264/Basic-principles-of-MEMS-microphones-

What is aging

At your own risk, this is not a medical advice.


Some people are doing so harm to their body and mind by inapropiate food, drugs, beverages etc for so many years that the body or mind can cope no more.

Τι ειναι γηρατειά

Με δικη σας ευθύνη. Δεν ειναι ιατρική συμβουλή.


Γηρατειά ιςως ειναι:


Κάποιοι κανουν κακό στο σώμα και στο μυαλό τους, με ακατάλληλη διατροφή, φάρμακα, αναψυκτικά  κτλ για τοςα πολλά έτη που πια ο οργανισμός δεν αντέχει.

Cartesian product in music, cooking etc

https://en.m.wikipedia.org/wiki/Cartesian_product


2 elements create something different.


For example 2 or 3 elements that create Pesto sauce


2 notes eg F (Fa) and E (Mi) together that create the color of major 7th in music. F bass, E somewhere high in frequency, the third added (A).


The brilliant and magical song without words Great Gig in the Sky - Pink Floyd is full of such combinations or chords called major sevenths, eg Fa La Do Mi, Do Mi Sol Si.