Marantz 2385

[Duo]

Well, this is an interesting one. I have a marantz 2385 here that I'm working on.

What a receiver, I've not yet seen one quite this big.

It does unfortunately have some problems... First of all, one of the caps appears to have vented, which is saddening, but that's not the end of the world.

Next, the right channel has some serious problems. It works, however, it won't go up to proper bias no matter how far the pot is turned, and it craps out very easy when giving any sort of power, so I'll have to really troubleshoot that. I haven't gotten really inside it yet.

And lastly, I don't know if this is just a normal thing with these, but the peak system is nasty. As soon as the light for a peak comes on, the amplifier emits a very loud crack to the speaker. I'd imagine that this is not normal since it probably isn't too nice to the speakers.

Otherwise, there is absolutely no damage physically to the unit. The case is mint with all the screws, and all the innards are relatively clean. It's a very nice receiver. The tuner is pretty spectacular too.

So, can anyone help with this stuff??

[anatech]

Hi Duo,
I used to service Marantz (those) under warranty. You have a heavy hitter there. No, they don't normally "crack" when the peak leds light. They do sound very nice when working. I'll check if I still have a schematic. Check for open emitter resistors with an ohm meter. You will read approx. the correct voltage drop for bias when these open. If anyone does have a schematic, I'll look over it for you if you need.
-Chris

[Duo]

Ok, thanks.


Well, I opened it up an found a burnt trace on the board that takes a rail up to the driver transistor and flyback diode. I rebuilt the trace and now the channel biases and works properly. No other parts were fried in there, so that's nice.


But yeah, this thing makes a nice crack sound on either channel when you get to the peak light. It only happens on the channel being driven that hard.

I am using 4 ohm speakers on it, though I don't think this should be a problem for it either.

[anatech]

Hi Duo,
Sorry for the late reply, problems with my isp.
Well, if you are driving it that hard, you may be hearing the voice coil hitting the backplate in the speaker. This amp will dump lots of current. I have seen them take more abuse that a Bryston 4B. You are delivering more than the 185 W/CH (8R rating). BTW, Marantz had a bigger animal. The 2500. I'm trying to find insulators for the heatsink for one now. They all melted a bit.
-Chris

[Duo]

I was loading it with four ohms, but no, it is not the sound of the voice coil bottoming out. It had a long ways to go, as I have experienced with greater amounts of power.

[rickenbacker198]

I also have a Marantz 2385 with the same problem,,, it lets out a loud crack when the amp clips; and clips at low output,,, (with the volume knob at about 10:00
I am using 4 ohm speakers as well (PSB golds)

Did anyone find the solution to this problem?
Thanks

[anatech]

Hi rickenbacker198,
Odd problem indeed. I haven't seen this happen if it's the amp section. I'm also using PSB Golds with a little 300DC. It does not crack when the peak lights come on.

Is it possible the AC supply is collapsing? These have a soft start and I'm wondering if the contacts are burnt (shouldn't be). That's a total wild shot in the dark. I've seen 2385's out power Bryston 4B's without too much trouble.

BTW, your volume control position doesn't mean much. Depending on signal source levels you could easily be into clipping.

Hi Duo,
Remember that Marantz will happily dump huge current too. More than you would expect from it.

-Chris

[Original Burnedfingers]

BTW, your volume control position doesn't mean much. Depending on signal source levels you could easily be into clipping.

If I had a dollar for everytime someone brought me a blown amplifier and told me they only had it turned up to 10:00 on the volume control I could probably retire.

The volume control position is going to be relative to the signal being amplified. Lower signal input will mean a higher volume control setting to achieve the same level.

Do you happen to have a lot of EQ you are using? Bass and treble controls turned up? The more EQ being used the more the amplifier is being taxed.

[destroyer X]

My people loves to listen when the signal already gone to clipping...this happens almost daily in my place.

They said that the amplifier plays "loud"

I do not complain...really, i use to fix them....but if not ask too much money...as they will return very soon.

regards burnedfingers,

Carlos

[wsbinc]

Looking for a function switch for a Marantz 2385. Please email w.bermanassociates@verizon.net.