Marantz 2265B pulse on power down???

[eddgie]

I have a related thead on the Vintage Audio forum, but thought I would post here as well.

I have a black faced Marants 2265B. I use the tuner section and AUX input to drive a Bose 1801 400 WPC (4 ohms) power amp.

I have the gain on the 1801 set up to limit the 1901 to 256 WPC. This allows me to turn up the 2265B Full Throttle and not melt anything in my speaker enclosures.

Now the problem is that when I turn off the 1801, it "keeps running". In other words, sound continues to come from the speakers if the source is on.

When I turn off the 2265B, after shutting down the amp, there is a huge pulse to the speakers, which I THINK is being amplified by the 1801.

Now if I simply turn on the 1801, then turn it off, the cones don't budge.

Is anyone else using a Marantz receiver of this vintage with a big power amp? Do you experience any similar problem when switching off the receiver if the amp is still on?

Thanks....

 

[EchoWars]

Sounds to me like you're going to have to wait longer after you turn off the Bose amp before you turn off the Marantz.

 

[eddgie]

Well, YES.. Why didn't i THINK of that!

LOL.. But I would need a lot of time on my hands.

 

[tarior]

Hey EchoWars, do you think it would help if he put some 2.7Kohm bleeders across the filter caps in the Bose amp? Maybe he wouldn't have to wait quite so long to power down the Marantz.

 

[Tronhead]

The Marantz has no muting for turn off in the pre section as the out put section is taken care of in normal operation. Echowars is on the money, turn off tha amps, count a little then turn off the Marantz. Or turn the input gains down on Bose first. Actually, there is no reason to ever turn off the Marantz. 1: draws no real idle current 2: looks pretty 3: light bulbs will last longer 4: cool nite lite.

 

[tarior]

Turning down the input gains is probably the most simple solution, and I can't argue with just leaving the amp on.

 

[Tronhead]

thanks tarior, like your attitude.

Tronhead

 

[whsh93a]

Yes - turn down the volume on the amp, first. Wasn't that considered standard practice when turning equipment on and off in the old days? At least I always do it out of habit learned years ago.

DH

 

[tarior]

thanks tarior, like your attitude.

Tronhead

Sometimes it's just too easy to overlook the simple ideas in favor of a "tech" solution.

 

[cincy]

eddgie have you tried turning the 1801 speaker selector switch to off? That way the speakers would no longer be connected to the 1801 amp and there would be no running on and no thump.

 

[EchoWars]

Hey EchoWars, do you think it would help if he put some 2.7Kohm bleeders across the filter caps in the Bose amp? Maybe he wouldn't have to wait quite so long to power down the Marantz.

Depends on what the cap voltage is...otherwise it might have to be a pretty large (powerwise) resistor.

 

[Fred Longworth]

One solution is to install a muting circuit in the 1801 at the front end. Some audiophiles will argue that such a circuit introduces a coloration in the sound, but, that aside, there are two easy ways to do it. One is to install a pair of FET's at the front end, wired up as analog switches, with drive capacitors hooked in so that the instant the power switch goes off on the 1801, the two FET's go to "hard off" and stay that way for up to, say, a minute. This would take very little current, and could be run straight off the 1801's power supply without significant additional loading. Another solution would be to install a tiny signal relay at the front end, with a hard turn-off circuit similar to how protection-relays are wired up on Marantz's, Sansui's, Pioneers, etc. Again, this would take very little current, and could run off the 1801's power supply.

Fred Longworth