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



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

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..

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!


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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.

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.

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

Getting Everything in place!

We spent some time measuring, sawing and drilling the motor into place. Its a bit crude right now, but we came up with a mounting scheme and will have to get a few more rubber washers and lock nuts, move around a couple of the pieces of all thread, but it looks like the method we have for mounting the motor will work!

We basically have 4 pieces of all thread mounted into the chassis that the motor is screwed to. We then just pulled the all thread through the top of the shelf and isolated it with a rubber washer on both sides and then mounted the other end to the chassis. This allows us to adjust the height of the motor and spindle as well having complete flexibility to make sure it is straight.

It needs work, but is really close!

Parts for final assembly!

Straightening the spindle and a crude assembly

After getting the all thread added to the spindle from the welder we were really concerned about getting it straight. There was a little bit of wobble and when we added the platter, it was all over the place!

Since it was welded, there was not too much we could do but try to flatten it with a vice and hammer. It took us a while, but I do think that we got it pretty straight.





This was our biggest stumbling block and it may be behind us and we may be able to move forward with assembling until into the cabinet. We marked out where it will all fit and have a new list of items to get together for the wiring and mounting etc.

Some Long Awaited Progress

We were able to get to the welder with the correct parts this time! We ended up with the original spindle that was sourced from the broken turntable and a piece of all thread. The hard part with this was getting them to be as centered as they could be.

Being that they are all different diameters, welding them was less than a perfect science. We got one piece at a time on and he tacked them, then we straightened them as much as we could and then secured everything.

It is mostly straight, but we cannot be sure until we get everything in place and spinning!

How do we connect this?

Jeff brought over the harvested bread machine motor and we got it working with the transformer and a simple on/off switch. The trouble we ran into is that the shaft coming out of the bread machine motor is too short to come through the cabinet.

We have the original spindle from the turntable and we need to figure out a way to get them connected. Jeff picked up a piece of all-thread that will give us the correct distance. Now, we just need to figure out how to attach all 3 pieces together.

Ideas we have are coupling clamps, threading the spindles and connecting them via coupling nuts, a quick little weld.... or maybe just some glue and masking tape :P

Another thing that we noticed is that the motor is a bit too quick for our purposes. We have found a ton of simple circuits to slow it down and will have to incorporate one into this unit.

What we need....

Tap and die set
DC Motor Speed Control Circuit
Reducing Coupler Nuts
On/Off Switches
Female Panel Mount BNC Connector (for lamp)

Vacuum Cleaner and Bread Machine Motor

We got pretty lucky this week and I scored the perfect vacuum from Goodwill for $7 and Jeff got a bread machine which he harvested the motor from.



The vacuum is rather small and quiet but should have enough force to clear the fluid and debris off the records.



This is the usable motor with transformer from the bread machine

Some Sourced Parts and Planning

So, I was able to score a sweet Sherwood turntable that a smashed stylus for $4.99 at goodwill! It has nice spring loaded feet, is direct drive, has the dust cover and slip mat etc.



Also, I scored a small Ikea style nightstand that will fit everything perfectly. (It's the one Jeff is sitting on in the picture below)

We took apart the turntable and isolated the motor, synchro lights, power transformer and platter. This is all working and usable but the torque on this motor is just too low. Even with some pressure from the cleaning brush, we can stop the motor from spinning all together.



After some research it looks like we can get into a very fitting motor out of a bread machine that will have the proper RPMs as well as much more torque to spin the platter.

Another piece to source from the thrift stores!! One of my favorite things to do ever

NEW PROJECT! Semi-Automated Record Cleaner!

We have been talking about buying a record cleaner that a few of us could share. Now, since we have "finished" the amp and have this time booked out each week we thought it would be best to just move straight onto a new project before we fill the time slot with anything else.

The basis of this project will based on Jimmy Neutrons design.

The plan is to source the parts (minus the VPI brush) from the local Thrift Stores and whatever parts that we have already.

List

Direct Drive Turntable with dust cover
Shop vac or small canister vac with hoses
Shelf or rolling cart with a door or drawer
Catch tank for fluid
Junction box for wiring
Switches and outlet for external control

The Finished Product!

We are still having some trouble with the excessive bass, but with the preamp it can be controlled a bit better.

The project took quite some time so, even though its not perfect, we decided to just put it into use.



Some of the final wiring.. It's not too clean, but its still something to be proud of.

I moved around some things and got this on top of the NAD pre and there is enough ventilation for it. I do like how it looks and I am sure over time we will tweak it a bit to get it to sound better, but as of now it is a great functioning amp.

So.. We Finished the Amp.. kinda : /

After all is said and done we tackled the rest of the components, checked and double checked everything and the moment of truth was upon us!!!

After shielding ourselves and putting in ear plugs, we went ahead and plugged it in!

To our shock, all of the tubes lit up as they should and the amp looked lovely... however, shortly after it began to make a strange noise and did not really function the way that we hoped.

So, off to AudioKarma.org for some advice! In the meanwhile.. look how pretty it is!

If you are curious... keep an eye on the thread at AudioKarma and DiyAudio