Hello ! Unfortunately my brand new used Mark levinson no.26 preamp is making this weird noise from the one channel that you will hear in the video. When i open the preamp for the first 10 minutes there is no noise at all. After these 10 minutes the noise start to get louder but after some hours the noise become lower but still noticeable. The preamp had been recaped from the previous owner - also the psu . Unfortunately he replaced also the square spargue capacitors inside. Also the toroidal power supplies don't have their covers also (but they are the original) . The noise is there even nothing is plugged on the preamp and its in both outputs (xlr and camac). Any help???ml no26 noise - YouTube
When you have a scope, it could reveal a bit more than just this scratching.
But in fact, it can be almost anything, a leaking cap, a transistor that is giving up, a broken trace, etc.
That’s why a scope trace could tell a little bit more.
Are you using a balanced output or not.
Would be interesting to know whether both balanced outputs from this same channel are producing this noise.
Hans
But in fact, it can be almost anything, a leaking cap, a transistor that is giving up, a broken trace, etc.
That’s why a scope trace could tell a little bit more.
Are you using a balanced output or not.
Would be interesting to know whether both balanced outputs from this same channel are producing this noise.
Hans
First isolate the problem to a particular section of the circuit.
Determine which channel, whether in phono or line stage, before or after the volume control, etc.
Then focus on the section that you have isolated.
You are fortunate that someone has reverse engineered the schematic for you.
Mark Levinson 26 pre-amp schematics
Determine which channel, whether in phono or line stage, before or after the volume control, etc.
Then focus on the section that you have isolated.
You are fortunate that someone has reverse engineered the schematic for you.
Mark Levinson 26 pre-amp schematics
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After you isolate the problem to a specific circuit section, use freeze spray on one component
at a time in that section, to see if the noise is affected. Solder joints could also be a problem.
at a time in that section, to see if the noise is affected. Solder joints could also be a problem.
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Good suggestion to use freeze spray, but you better connect a cheap LS to your main amp, because reactions can be violent.
Hans
Hans
Do you think that the problem could come from the psu or inside the preamp? The psu has been recaped (including the replacement of the original square spargue capacitors with good quality but classic type ones) .
I have same problem with my Mark Levinson 26. I recapped all capacitors both channel and recapped PSU, i recapped many capacitors, replaced transistors, trimmer..v..v.. but NO WORKING. When connected cable camac or balance from ML26 to power amplifier Krell KSA 300S. it makes power amp turn off, no light power.
Attachments
So now we have two broken 26 amps, a shame for such a nice preamp.
Where do you both live ?
Hans
Where do you both live ?
Hans
I live in Greece! I hope its something easy to fix. The no26 sound so nice. Because there is no distortion in sound of mine i believe could be a ground issue or maybe a transistor that its close to end of its life...
Unfortunately my repair guy couldn’t even hear the noise in his system. But here is pretty noticeable so I have to found someone else for the repair…
Assuming the repair guy isn’t a complete no no, how certain are you that the 26 is the cause.
You could disconnect all interlinks, input and output, and connect a simple iPhone or similar set of earphones to you 26 as the only connection.
This way you could find out if it is indeed the 26 producing the hiss.
Hans