New Member, New Project, Here's my 400!

Northwinds said:
AWESOME Dan! I had no idea you were that skilled with a soldering iron
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SSSSHHHHH!! That's a secret. Lol.

But seriously, thanks man. I have a long way to go to match a lot of you guys here, but I am patient and anal retentive so I have good luck most of the time.

Anyway, I have this baby fired up and playing at a moderate volume now. No obvious issues, at least nothing serious.

My questions now, is there anything else I should be testing on this or am I done??

The one problem I noticed (which was there before) is that the right channel meter reads a little higher than the left. I switched inputs from the preamp left to right and had the same condition. I assume that if I adjust the meters per Joe's directions that will even out. I'll do that in a week or two when I feel like it. Until then I'll just listen.

Oh, and the input jacks are flakey. I have a pair of those coming from Don.

So thank you, thank you, thank you to all the guys that helped me through my first WOPL build! I know it's only a Quasi Comp build but I'm pretty happy and I hope this will give me years of service.

Dan
 
Awesome Dan, glad your finally going to be able to enjoy your amp!!!!!
 
Ok, so I've been enjoying playing with this thing for a bit now and I have one tech concern I can't really figure out. May or may not be the amp causing it. So here goes...

I have a NAD 1155 preamp I'm using to connect my turntable to this amp. When I turn the preamp on, once the relay engages on the amp, I get a loud hum through both speakers for like 3-5 seconds. Then it's quiet and acts normally. I have the amp plugged into the preamp rear panel. If I turn the pre (and the amp) off and back on, it will do it every time. Just lasts a few seconds then it's fine.

I installed my apt holman preamp instead and the problem went away. Hooked the nad to a lower watt carver amp, and no problems at all. Connect the NAD back to the pl400 and hum on startup. Does it even with no inputs to the pre and volume turned all the way down. Unplug the cables from the pre to the amp and it does go away.

Btw, the NAD has been recapped and other wise sounds fantastic. Any ideas???

Dan
 
Got a scope?? The fact that it goes away when you unplug the cables would point to the pre-amp. With a scope you could observe the pres outputs...
 
The Carver may have an input cap that is taking care of turn on noise of the Nad....
 
laatsch55 said:
Got a scope?? The fact that it goes away when you unplug the cables would point to the pre-amp. With a scope you could observe the pres outputs...
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Unfortunately I don't. Another interesting point is that if I turn the balance knob, it does not change the sound. Still comes from both speakers. But if I unplug only one cable, it goes away on that channel. So it does seem to be coming from the pre.

I'll try to stare at the schematic to see where the problem may lay. Clearly it's after the balance.
 
Dan , it may be that the Nad does not have an on muting feature. Or its not working. Do you have an owners manual or does the service manual have a circuit description section? Joe could tell by looking at the schematic, you should post the schemo...
 
Danimal1969 said:
Ok, so I've been enjoying playing with this thing for a bit now and I have one tech concern I can't really figure out. May or may not be the amp causing it. So here goes...

I have a NAD 1155 preamp I'm using to connect my turntable to this amp. When I turn the preamp on, once the relay engages on the amp, I get a loud hum through both speakers for like 3-5 seconds. Then it's quiet and acts normally. I have the amp plugged into the preamp rear panel. If I turn the pre (and the amp) off and back on, it will do it every time. Just lasts a few seconds then it's fine.

I installed my apt holman preamp instead and the problem went away. Hooked the nad to a lower watt carver amp, and no problems at all. Connect the NAD back to the pl400 and hum on startup. Does it even with no inputs to the pre and volume turned all the way down. Unplug the cables from the pre to the amp and it does go away.

Btw, the NAD has been recapped and other wise sounds fantastic. Any ideas???

Dan
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I hate gremlins!!!
 
As I said before, I don't run my power for the WOPL's off of anything but the wall, or a strip. NEVER another piece of gear. The initial charging of the caps can wreak havoc. Especially on a 700. (I won't say how I know this)....
 
TheWOPLwhiffer said:
As I said before, I don't run my power for the WOPL's off of anything but the wall, or a strip. NEVER another piece of gear. The initial charging of the caps can wreak havoc. Especially on a 700. (I won't say how I know this)....
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Ok, I will try plugging it into a different outlet tonight.

But in theory, if it was from the caps charging, why would that change when the RCA's are unplugged?
 
Danimal1969 said:
Ok, so I've been enjoying playing with this thing for a bit now and I have one tech concern I can't really figure out. May or may not be the amp causing it. So here goes...

I have a NAD 1155 preamp I'm using to connect my turntable to this amp. When I turn the preamp on, once the relay engages on the amp, I get a loud hum through both speakers for like 3-5 seconds. Then it's quiet and acts normally. I have the amp plugged into the preamp rear panel. If I turn the pre (and the amp) off and back on, it will do it every time. Just lasts a few seconds then it's fine.

I installed my apt holman preamp instead and the problem went away. Hooked the nad to a lower watt carver amp, and no problems at all. Connect the NAD back to the pl400 and hum on startup. Does it even with no inputs to the pre and volume turned all the way down. Unplug the cables from the pre to the amp and it does go away.

Btw, the NAD has been recapped and other wise sounds fantastic. Any ideas???

Dan
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Are you sure the power switch in the NAD is up to the task of turning on a high inrush amplifier? From the documentation, the switch looks pretty weak. What happens if you plug the amp into a separate switched power strip and also plug the NAD into that same switched power strip. Leave the NAD power switch in the on position.

When you toggle the power strip power switch, do you get the same result?

This may help you debug this.
 
So today I got back on this. Plugged both the NAD and the 400 into a power strip and then hit the strip power. Same sound. Then if I turned off the pre, it made a similar sound when powering down. Turning just the pre back on, same sound.

Back to basics...tried a different set of crappy rca cables and the noise went away. Lol. Guess I'm gonna have to rethink my cheap cable philosophy.

But it's good news I guess. :)
 
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