Tuesday, September 6, 2011

The Whole Switcharoo!

This whole blog started a while back when Jeff and I were starting work on a Chinese tube amp kit. I figured the only way to track what we are doing is to take photos and document our steps. We were meeting up once a week at best and some weeks we would be confused where we left off. Since we were taking pictures and tracking what we were doing anyway, I thought to just post it in a blog that both of us could access.

That amp has been long since finished and put into action for a while, taken out of action when the Marantz 140 and came back into action for a short time recently. I decided that no matter what, that amp will stay around. We put a lot of hours and energy into it and it would be a shame to ever sell it.

The Marantz 140 was a nice, quick project and had a simple and powerful sound that was really gratifying compared to the flawed circuitry of our first attempt at building anything from scratch, nonetheless a Chinese tube amp with no instructions. Maybe in the future when we know much more than we do now, we can revisit the wiring of that amp and make it a bit more than it is now....

The switcharoo... Well, I decided to part with the Marantz and get some cash towards a new amp. I was looking at some assorted, lower end tube mono blocks and couldnt really find anything under $600 or so that would sound decent. I was on the fence about a pair of Dareds that were rather new to the market, but at the last minute decided not as all the tubes were very, very generic and low quality.. it made me question everything about the amp.

I was tracking a no name pair of amps and at the last minute ended up being the high bidder, but did not meet the reserve. I asked the seller if he would sell it to me at my high price and he agreed. However, he ended up listing them anyways with a lower reserve and not getting back to me. So, I waited it out and just decided to keep looking while following his auction. After the auction ended again, unsuccessfully, he sent me a second chance offer, but it was for my first bid and not for the final bid that I placed. In the end, I scored a questionable set of amps for a great price.

I knew that had 1 Mullard, 1 Ruby and 1 Sovtek each, came with original boxes and had under 40hrs each.

When I got them... I was surprised to say the least. They were about 2x the size I expected! There is much more amp than I expected.

I got them setup and as it turns out, the front tube is a magic eye signal detector tube! I am such a fool for gimmicks like this.

I have a bit of tweaking to do still, but am very, very happy with what turned out to be an even trade across the board for the Marantz 140!



In the new Ikea entertainment center... which Jeff calls "The Best Deal in Audio"



With some sweet new speaker cables!



In all its sweet tube glow

video

The Magic Eye is one of my favorite features of this amp.... check it out!



Saturday, August 13, 2011

Technics SL-1200 MKII

For someone who collects and listens to a ton of records.. i really have a shitty turntable.

I finally decided on the Technics 1200 as its a great deck for the price, is completely customizable and repairable and are rather easy to find parts for still (though discontinued).

I found one on CL from a guy who lives close to me. We ended up working out $200 on the deck with a headshell, Staton 500II cart and no needle.

The dustcover was there, but scratched up pretty bad, covered in stickers (awesome ones) and had no hinges. Also, the On/Off switch mechanism was broken from the inside and needed to be repaired.

Jeff and I tore into it and realized, right off the bat, that the bottom casing had no screws in it. The guy who repaired it last and upgraded the cables probably just forgot to put them back in!

We got it all apart and made a list of all the parts that are needed to get this guy up to snuff.

I caught an amazing break that next week.. the dustcover is usually around $50 -$60 and the hinges are another $40..and.. the hinge receivers are another $20! Thats a lot of cash just for the cover. At a Value Village in Lake City I found a technics sl-q2 that was pretty beat up but had a headshell that I could use for the 1200. Also, it had a good slip mat and decent tone arm. I figured it was worth having around for parts. When I picked it up, I realized that the dustcover didnt fit it.. it was a bit too large and the hinges didnt mount into the deck. It actually looked like the one I needed for the 1200 and it was in great shape! Sure enough, I took it home and it fits like a glove!

I placed and order with Panasonic for most of the parts and got 2 random pieces from eBay and 1200parts.com.

Next week comes cleaning fixing and reassembling... possibly even painting!

Asst Projects in between

Been collecting assorted items from Craigslist and the local thrift stores and working on them.

In the last couple of months, there has been an Alesis DM5 drum module, Tascan 414 4track recorder, B&O RX2, Technics SL-Q2 and a handful of other things..

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!


i




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.


Friday, May 27, 2011

Setting the Motor and Platter Into Place

After dry fitting it last week, we actually tried to get this thing in straight and at the right height. We basically mounted it with 4 pieces of all-thread with a nut, washer, lock washer and rubber washer on top and bottom of the shelf and the mounting brackets for the motor. We put one set of washers and nuts on both sides so that we could get them nice and tight and to minimize vibration of the motor. With this method we could rise and lower any of the pieces of the all-thread, before tightening everything down to get the spindle as straight as possible.



We have the spindle gear coming up about 1.5" from the table top and it is sitting rather flat.



With the platter on, its starting to look like something useable!



Next, we wanted to fabricate something to add a bit more pressure to the platter. We did a test run with a Discwasher brush and if you hold down on the platter hard enough, you can stop the platter from spinning... but, the spindle will keep moving.

Jeff had picked up an old hockey puck from work and drilled it out to cover the spindle. First, he had to find the center of it by using some old school mathematic procedures!



Go Science!

Then, just drilled out a center hole...



And when added to the spindle, it increases the torque a lot