timjimbaker
Member
- Joined
- Feb 10, 2010
- Messages
- 12
Hey guys, I've been working on my stereo EMT 140 lately. I started by removing the plate, I cleaned some duct tape residue that was on it from what i assume was from shipping it at some point. I got the bit of rust that was on it cleaned off and I buffed the whole thing to a shine. Then, I hung and tensioned the plate which is a harrowing task. I had gotten a few extra clips from dan alexander but I broke a few in the process of tensioning it. Jim Cunningham's operation seems to be defunct now. If anyone knows where to get more clips these days, I'd really appreciate a heads up.
So I hung the cleaned plate, tensioned it (not perfect but pretty good, scared to break another clip) and got the driver and pickups remounted. At that point the plate was working but it was noisy and had quite a (60 cycle) hum to it as well. I decided a recap was in order. I recapped the all of the electrolytics except the large metal can cap because I couldn't easily find a source for one. The recap got the amp sounding better, it removed the hum in one channel entirely and brought the noise floor down a bit. After that I swapped the 709c opamps out for some 5534's. That made a big difference in the quality of the sound and brought the noise floor down even more.
The unit is sounding pretty damn good now. The only issue is the ground hum on one of the channels. I opened the box up last night and checked all the connections. I figured maybe a shield got disconnected somewhere inside. Everything looks good. I also isolated the inputs to make sure the hum wasn't being introduced from somewhere else. I'm pretty sure the hum is coming from within the amp. I've had the unit connected to my console a bunch of different ways and the hum always stays the same.
Does anyone have any suggestions on what my next move should be... Any advice would be greatly appreciated. Also, I was wondering if someone might be able to take a high res shot of the component side of the 162's pcb. Mine seems to have had some work done on it. It would be nice to compare it with another 162. The last thing is that the schematics I have for my 140 are difficult to read. I got them from AnalogRules.com. While I really shouldn't complain about free shematics, does anyone have a 162 schematic that is easier to read.
Thanks for your time... Regards, Tim.
So I hung the cleaned plate, tensioned it (not perfect but pretty good, scared to break another clip) and got the driver and pickups remounted. At that point the plate was working but it was noisy and had quite a (60 cycle) hum to it as well. I decided a recap was in order. I recapped the all of the electrolytics except the large metal can cap because I couldn't easily find a source for one. The recap got the amp sounding better, it removed the hum in one channel entirely and brought the noise floor down a bit. After that I swapped the 709c opamps out for some 5534's. That made a big difference in the quality of the sound and brought the noise floor down even more.
The unit is sounding pretty damn good now. The only issue is the ground hum on one of the channels. I opened the box up last night and checked all the connections. I figured maybe a shield got disconnected somewhere inside. Everything looks good. I also isolated the inputs to make sure the hum wasn't being introduced from somewhere else. I'm pretty sure the hum is coming from within the amp. I've had the unit connected to my console a bunch of different ways and the hum always stays the same.
Does anyone have any suggestions on what my next move should be... Any advice would be greatly appreciated. Also, I was wondering if someone might be able to take a high res shot of the component side of the 162's pcb. Mine seems to have had some work done on it. It would be nice to compare it with another 162. The last thing is that the schematics I have for my 140 are difficult to read. I got them from AnalogRules.com. While I really shouldn't complain about free shematics, does anyone have a 162 schematic that is easier to read.
Thanks for your time... Regards, Tim.