|
Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
|
Thread Tools |
22nd Mar 2019, 4:47 pm | #1 |
Triode
Join Date: Nov 2018
Location: Pont Saint Vincent, France.
Posts: 37
|
Yamaha amp CA400 hissing
Hi all,
My YAMAHA CA400 amp has started hissing on the left chanel on all sources. It isn't lound and it doesn't change with the volume control. Even with the volume on zero, it hisses. The sound and volume is fine, no other problems, just this left chanel hiss. Any ideas ? Thanks Pete. |
22nd Mar 2019, 9:27 pm | #2 |
Nonode
Join Date: Jun 2007
Location: Coulsdon, London, UK.
Posts: 2,163
|
Re: Yamaha amp CA400 hissing
Faulty transistors or integrated circuits can introduce a hissing noise.
The faulty transistor / IC can sometimes be identified by spraying it with a 'freezer' spray. |
23rd Mar 2019, 8:50 am | #3 | |
Heptode
Join Date: Oct 2008
Location: Aalborg, Denmark
Posts: 903
|
Re: Yamaha amp CA400 hissing
Quote:
I would start out with transistors TR705/TR707 or TR706/TR708 (all 2SA763WL) according to channel, as they are the most likely to introduce this kind of noise. Keep a hand on the power-switch when spraying. I've seen violent reactions to freeze-spray on partially defective semiconductors. This amplifier has NO speaker protection-circuit. If any of the mentioned transistors should decide to go bang during the freeze-test, so will your speakers. Use a headphone during the test instead as at least it will be in series with a 270-Ohm resistor from the speaker-terminals. If inded you track the fault to any or more of the mentioned transistors I would replace all of them. - There's a so-so quality schematic diagram of this amplifier circulating the web. If you would like a higher quality specimen, send me a PM with your e-mail address. Be sure your mail-box will recieve an attachment around 13Mb in size. Rgds, /Torben |
|
23rd Mar 2019, 11:31 am | #4 |
Triode
Join Date: Nov 2018
Location: Pont Saint Vincent, France.
Posts: 37
|
Re: Yamaha amp CA400 hissing
Torben. You seem to know this amp. Pm sent with my email address. Thank you.
Pete. |