Noise & crackle in the speakers of my brAun A1 Atelier amplifier, bought for ƒ595 in 1981. Initial thought: electrolytic capacitors are old, dried out, and may be leaking.
Removed the pre out/main in connectors (back side of A1): symptom persists. Analysis: problem located in main amplifier (Endverstärker).
Opened the A1: everything looks good, except the large 10,000 µF caps (C808 and C809). Both have their top somewhat bulged. One even dangerously bulges out in the side near the top. Also, after removal, both seem to have leaked in the past.
Wiggling the speaker relais produces similar noise & crackle. Slightly worrying.
Decided to first replace all electrolytic capacitors on the main amp board.
| C602 | 10µ | 50V | ø05 | h11 | – | radial |
| C609 | 33µ | 35V | ø06 | h16 | – | radial |
| C604 | 47µ | 10V | ø05 | h11 | – | radial |
| C603 | 100µ | 50V | ø10 | h16 | w05 | radial |
| C619 | 100µ | 50V | ø10 | h16 | w05 | radial |
| C809 | 10000µ | 50V | ø30 | h50 | w10 | radial |
Replacing these caps was relatively straightforward. Required some fiddling in narrow spaces. Double-, even triple-checked correct polarity to avoid exploding electrolytic capacitors.
Reconnected amplifier to mains, speakers, and my old little Mac mini music server. Turned Volume all the way down. Carefully switched the amp on, ready to quickly turn it off if needed. Heard the reassuring and comforting click of the relais. Gently pressed the the Speakers 2 button and turned up the volume. Oh, what a wonderful sound.
Let it play for the rest of the afternoon. Sounds good. Problem fixed.
Omit needless features
In my old – 42 years in 2023 – and loyal A1 friend, almost all switches malfunction (speaker 1/2, tone controls, input selectors, etc. Crackle, noise, and hum. Would like to fix that, too. Yet, I’m using the amp only for amp. Source selection is just between computer and TV receiver. Tone control is done by computer. Only use speaker 2 outputs (since speaker 1 switch is broken). So it is of no use.
If I had to redesign this beautiful device, I’d just build a main amplifier and omit all source, and speaker selection control. All in the spirit of the original minimalistic design, where brAun hides rarely used controls behind a lid.
Thank you Dieter Rams, for your elegant design and “Good Design Principles”.