Saturday, June 25, 2011

B&O Beogram 4002 Turntable Output Adapter

I found a great B&O turntable on Craigslist as a replacement for my rather old and crappy deck that I have been using.

This is one of the older versions of the 4002 and it really is a wonderful piece of electronics. It was actually added to the Museum of Modern Art back in 1974. B&O makes such unique items and I am proud to own this.

It is a bit dirty and I can hear that there is some trouble with the gear mechanism that controls the tracking device. I am sure that once I get into it, it will just need to be greased or realigned. I am excited to get it cleaned up and up on the stereo rack.

The only issue with it is that the guy I bought it from forgot the output adapter. The B&O terminates with a 5 pin din cable that does not work with regular stereo gear. It comes with this 5pin socket to RCA adapter.

Before I dug into the unit, I wanted to make sure that it worked well enough to warrant it. The adapter cables on eBay tended to be in the $20 -$40 range and it seemed to be a bit too much for me.

I did some experimenting and found that the output fits a Midi jack. I had an old piece of Midi gear in my back closet that had a ton of sockets on it. So, I pulled one of the sockets out, cut up some RCA cables, found a pre used project box and went to town!

We basically set the output up into a pre/power amp then into some speakers and plugged the turntable into the midi jack. Then we just started matching wires to pins until we heard something in stereo.

Once we got the configuration right, we soldered all the points and closed it up.

When all is said and done, it works great!


A Quick Diversion to My Marantz 140 Power Amp

I picked this amp up about 5 or 6 weeks ago at a local Goodwill and was unable to test it. I had plugged it in and nothing lit up, but I could hear the "all clear" relay switch and nothing smoked, so I figured it was worth the risk.

When I got it home, Jeff and I fired it up and it was working rather well. The volume controls were clean and smooth and the output was even and sounded great.

We took it apart and cleaned it inside and out. We pulled the bulbs out of the meters and all 4 of them were blown. This was actually a relief because I was concerned that something else was wrong that they were all out.

I ordered a set of replacements online and we just popped them in and closed it back up!

One of the easier, catch-free jobs we have had in a while.

Friday, June 3, 2011

Finishing up the Wiring and Installing the Switch

So, we are basically finished. We ordered a switch/speed control for a ceiling fan to slow down the motor a bit. It works fairly well and slows it down, but we lose a lot of torque. We can get it to a point where the speed is ok and the torque is ok, but its not quite as slow as we wanted it to be.

Since we do not have many woodworking tools, we ended up drilling out a hole for the switch to be mounted in. It took some time, but with the cover plate on it, it will look fine!

Next week we will just need to button things up and put this project away.

Originally we planned for this to be a bit more involved but it kept getting more and more complex. The motor system really threw us off. Since the motor was too fast and the spindle too short, we spent a lot of time trying to adapt it to work. If we were to do this again, I would say we should spend a lot more time researching the proper motor. We scrapped the vacuum system as well because just the hose portion from VPI was $70+ and since we were compromising here and there anyways, we thought to scrap it.

We have to use a brush to wet the record and to distribute the fluid as is and we would just have to turn the same brush backwards to dry it. Next week we will post some photos of it working.