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

D

Danimal1969

Journeyman
#121
Joined
Feb 4, 2016
Messages
94
Tagline
---
#121
Northwinds said:
AWESOME Dan! I had no idea you were that skilled with a soldering iron
Click to expand...

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
 
D

Danimal1969

Journeyman
#125
Joined
Feb 4, 2016
Messages
94
Tagline
---
#125
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
 
laatsch55

laatsch55

Administrator,
Staff member
#126
Joined
Jan 14, 2011
Messages
75,005
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#126
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...
 
D

Danimal1969

Journeyman
#128
Joined
Feb 4, 2016
Messages
94
Tagline
---
#128
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...
Click to expand...
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.
 
laatsch55

laatsch55

Administrator,
Staff member
#129
Joined
Jan 14, 2011
Messages
75,005
Location
Gillette, Wyo.
Tagline
Halfbiass...Electron Herder and Backass Woof
#129
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...
 
Northwinds

Northwinds

Veteran and General Yakker
#132
Joined
Mar 18, 2013
Messages
7,566
Location
Coventry, CT
Tagline
Fondler errrr... fan of all Nav's avatars
#132
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
Click to expand...
I hate gremlins!!!
 
WOPL Sniffer

WOPL Sniffer

Veteran and General Yakker
#133
Joined
Aug 10, 2015
Messages
11,540
Location
Minnie-Soda
Tagline
Screw it
#133
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)....
 
D

Danimal1969

Journeyman
#134
Joined
Feb 4, 2016
Messages
94
Tagline
---
#134
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)....
Click to expand...

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?
 
Gepetto

Gepetto

Administrator
Staff member
#135
Joined
May 15, 2011
Messages
14,098
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
#135
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
Click to expand...
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.
 
D

Danimal1969

Journeyman
#136
Joined
Feb 4, 2016
Messages
94
Tagline
---
#136
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. :)
 
You must log in or register to reply here.
Top