hello from France, I recently got an ml 27.5 and need advice for its overhaul, there is a slight hiss in the speakers and a bit more to the left. I replaced the 9 Rifa, the 6 chemical condos on the 2 rear panel cards. and the 2 small Spragues accessible on the power cards. The breath is always present. there are still the 2 other small Spragues which are very difficult to access to replace. what do you think of what I can do?
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agree with Hugo and Mark. stressed (from static or other electrical surges) or old-generation bjts (some older parts have a history of getting hissy as they aged) in the input diff stages are likely candidates. power supply caps would impact hum and buzzing more than hissing.
but are you sure it's not behaving as it should and it is just a noisy design ?
but are you sure it's not behaving as it should and it is just a noisy design ?
Hiss is normal, especially for output amps with high-ish gain and no volume pots.
Does it hiss when you connect the pre-amp/source to its input?? It shouldn't.
Does it hiss when you connect the pre-amp/source to its input?? It shouldn't.
This amp should be dead quiet.
I agree with netlist that chances are that it’s a transistor problem, but you will need a scope to get more information.
Hans
I agree with netlist that chances are that it’s a transistor problem, but you will need a scope to get more information.
Hans
Philipp Krauspenhaar
SUN AUDIO Vertriebs GmbH
Neherstr. 1
81675 München
Tel. +49-89-479443
Otherwise you can try "L'atelier de l'audiophile" in Montpellier, but I have no opinion on it, I don't know or have heard any positive or negative reviews.
In any case, take as many photos as possible of the inside of your amp before taking it to a "repairer" because today there are more "capacitor changers" than real professionals.
Otherwise, Sun audio, you can contact them and send them with your eyes closed.
SUN AUDIO Vertriebs GmbH
Neherstr. 1
81675 München
Tel. +49-89-479443
Otherwise you can try "L'atelier de l'audiophile" in Montpellier, but I have no opinion on it, I don't know or have heard any positive or negative reviews.
In any case, take as many photos as possible of the inside of your amp before taking it to a "repairer" because today there are more "capacitor changers" than real professionals.
Otherwise, Sun audio, you can contact them and send them with your eyes closed.
Hello, great example that people believe that if they replace all the capacitors in older devices then it will be like new again. This device belongs in the hands of ML experts who also have the necessary specialist knowledge. I am over 70 years old, an electronics engineer. specializes in audio technology and am an official service point for ML devices with type numbers less than 400 in Switzerland. I grew up with devices like this. I only repair ML devices and obtain spare parts that are still available from ML's Swiss general agency. However, if parts are no longer available and cannot be replaced with current parts of the best quality, it will be very difficult to carry out a repair successfully. So SUN Audio Germany is OK - good address.
If the route to me is shorter, please feel free to contact me.
Walter Krein
Audio engineering
Salensteinerstrasse 10F
CH - 8272 Ermatingen
If the route to me is shorter, please feel free to contact me.
Walter Krein
Audio engineering
Salensteinerstrasse 10F
CH - 8272 Ermatingen
I completely agree that just replacing caps with no indication that they are faulty, is almost a cult with most of the time very questionable results.
Hans
Hans