I recently bought a 2ndhand marantz PM4000 for use as a tweeter amp in my active 4-way.
After hooking it up and measuring the tweeter I noticed it sounded quite noisy and there was some weird signal in the impulse response. I measured again with an old pioneer all in one and my NAD c356bee.
I then opened up the amp and found some corrosion inside, since it's not near anything I assume something on top of the amp broke down and dripped this stuff in the amp.
Except for the corrosion under the heat sink I can't see anything out of the ordinary.
My knowledge of electronics is very limited. I do have a multimeter, soldering iron and I can measure driver impedance with my soundcard.
Is this a "sure we can talk you through some things to figure out what's wrong" or more of a "sell it again or take it to a repair man" problem?
After hooking it up and measuring the tweeter I noticed it sounded quite noisy and there was some weird signal in the impulse response. I measured again with an old pioneer all in one and my NAD c356bee.
I then opened up the amp and found some corrosion inside, since it's not near anything I assume something on top of the amp broke down and dripped this stuff in the amp.
Except for the corrosion under the heat sink I can't see anything out of the ordinary.
My knowledge of electronics is very limited. I do have a multimeter, soldering iron and I can measure driver impedance with my soundcard.
Is this a "sure we can talk you through some things to figure out what's wrong" or more of a "sell it again or take it to a repair man" problem?
Well, I never owned a marantz before so was interested in hearing one. This one isn't impressing me. But I'm open to suggestions, bear in mind all my audio gear is 2ndhand so it's more about what are people selling now for cheap then what's best. I got this one for 60€ and can probably sell it for a bit of profit as is.
Using an amplifier that features an electronic input selector like this one ( outdated TC series ) especially for 4th way tweeter use is absolutely pointless ...Any of the quality of the sound will be consumed on the selector switch and the preamp section.
If the amplifier has separated input for the main amplifier then there is point and it might sound well If not the all idea is totally pointless ...
Kind regards
Sakis
If the amplifier has separated input for the main amplifier then there is point and it might sound well If not the all idea is totally pointless ...
Kind regards
Sakis
The PM4000 is not bad at all. Some people have no idea about upper range Philips amplifiers.
They usually have top grade components and the input switching is not noisy. If it was, they would have got a bad review, which they didn't.
The amplifier has a good frequency response; 10HZ to 50kHZ with a damping factor of 80 making it more than good enough for your requirements.
Does the noise increase with volume? If it does, take a look around the pre amp/tone section, it won't be an output stage issue. That will give you an idea of where to look.
They usually have top grade components and the input switching is not noisy. If it was, they would have got a bad review, which they didn't.
The amplifier has a good frequency response; 10HZ to 50kHZ with a damping factor of 80 making it more than good enough for your requirements.
Does the noise increase with volume? If it does, take a look around the pre amp/tone section, it won't be an output stage issue. That will give you an idea of where to look.
Beats me why people like to crap on other people's purchases... Pretty rude if you ask me. I think Marantz amps are rather good myself
JohnSnell .... you need to learn now at old age (i expect ) to properly read spec sheets
The bandwidth 10HZ to 50kHZ with a damping factor of 80 is written in the spec sheet and refers to the MAIN AMPLIFIER ONLY !!!! Like one is ever going to use the amplifier on its own
Now if you try to measure the complete device which actually happens to be an integrated amplifier you will see that numbers are by far worst ...
Do you expect the input of the amplifier and the selector switch to be able to perform at this bandwidth where discrete circuits and relay operated input configuration hardly manage ? I dont ...
Many of the manufacturers do that, some Pioneer service manuals have been honest enough and bother to type the F** words so it says for example:
Distortion figures and next to it in a parenthesis is the magic word
( amplifier only )
If TC selector IC could perform that well that it will be still used till today ....
The bandwidth 10HZ to 50kHZ with a damping factor of 80 is written in the spec sheet and refers to the MAIN AMPLIFIER ONLY !!!! Like one is ever going to use the amplifier on its own
Now if you try to measure the complete device which actually happens to be an integrated amplifier you will see that numbers are by far worst ...
Do you expect the input of the amplifier and the selector switch to be able to perform at this bandwidth where discrete circuits and relay operated input configuration hardly manage ? I dont ...
Many of the manufacturers do that, some Pioneer service manuals have been honest enough and bother to type the F** words so it says for example:
Distortion figures and next to it in a parenthesis is the magic word
( amplifier only )
If TC selector IC could perform that well that it will be still used till today ....
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Beats me why people like to crap on other people's purchases... Pretty rude if you ask me. I think Marantz amps are rather good myself
rude next to reality choose on your own ...
Marantz Pm series amplifiers with relay operated inputs or simple switch operated inputs have by far better performance next to the TC input selector ( TC is used only to provide button or RC operation )
Remember also that manufacturers beyond "amplifier only" phrase forget to include crosswalk figures in their amplifiers spec sheet to avoid comparison and trouble with the customers ..( and TC crosstalk figures are worst than classic switches and so is bandwidth )
So there is nothing rude here ...Just technical facts ...
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Hi Zonneschimmel,
Have you tested the speaker relay? Run a low level tone, around 1 KHz. Lightly tap the relay to see if it cuts in & out. Tap more strongly if it doesn't respond, but not too hard.
Marantz was a brand that I did warranty service for, for many years. I had to drop the line after Philips ruined the quality. The Gold series was early "not great" stuff. With Philips selling the Marantz line back to people who care, the quality has shot up much higher again. The top end Marantz is about equal in quality to things like the 300DC and the rest in that years lineup.
I recommend Marantz to people once more these days.
HAve a look at the rear panel for a pre-out, main-in set of jacks. Otherwise you may have to do surgery. The inputs are probably capacitor coupled to the volume control wiper, but there might still be other controls and switches in the way after that. You have the manual, I don't. Look at the main volume control and see where the signal goes from there.
-Chris
Have you tested the speaker relay? Run a low level tone, around 1 KHz. Lightly tap the relay to see if it cuts in & out. Tap more strongly if it doesn't respond, but not too hard.
Marantz was a brand that I did warranty service for, for many years. I had to drop the line after Philips ruined the quality. The Gold series was early "not great" stuff. With Philips selling the Marantz line back to people who care, the quality has shot up much higher again. The top end Marantz is about equal in quality to things like the 300DC and the rest in that years lineup.
I recommend Marantz to people once more these days.
HAve a look at the rear panel for a pre-out, main-in set of jacks. Otherwise you may have to do surgery. The inputs are probably capacitor coupled to the volume control wiper, but there might still be other controls and switches in the way after that. You have the manual, I don't. Look at the main volume control and see where the signal goes from there.
-Chris
The "preamp" part is really the voltage stage for the "current part" (drivers ,
outputs , Vbe , and heatsink).
They use the AN7062 for the input /voltage stage , run traces from preamp --->
amp part (and feedback back to the AN7062). Similar to our modern
LME49811.
OS
The manual for the amp can be found here: http://diagramasde.com/diagramas/audio/marantz_PM4400.pdf
I'm starting to see the forest through the trees. On the pre-amp part are 3 sockets, 2 of them come from the front panel with balance and tone controls. 1 of them comes straight from the volume control.
If that is the case the following traces should feed the amp part:
I'm starting to see the forest through the trees. On the pre-amp part are 3 sockets, 2 of them come from the front panel with balance and tone controls. 1 of them comes straight from the volume control.
If that is the case the following traces should feed the amp part:
Tapping the speaker relay while playing a 1KHz test tone did not cut out the speakers.
Dunno if it helps but have you seen this ?
http://www.hifidatabase.com/marantz_pm4000.pdf
Fixed one a few years back suffering from the mute problem , maybe the problem can manifest in different ways and create the results u got initially?
http://www.hifidatabase.com/marantz_pm4000.pdf
Fixed one a few years back suffering from the mute problem , maybe the problem can manifest in different ways and create the results u got initially?
Thanks John ... I like that you use nice arguments to what i often write down for you to read ....
best regards
Sakis
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