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Bringing A Braun Ps 600 Back To Life
Posted: 06 May 2011 19:20
I'm a noob. To the site, I mean.
I recently acquired a Braun PS 600 turntable, it was purchased new by my uncle in 1973, two years before I was born. It was given to my dad when the tone arm return mechanism stopped working, and it sat in his basement for about a decade. Now its mine, all mine.
I've been fabricating a replacement tone arm lift lever (though I use the term "fabricating" loosely as I am limited to working in soft metals with hand tools like files and a hacksaw.) For those unfamiliar, there is a pushrod actuated lever under the tone arm that lifts the arm when its being returned to the cradle when a disc is done playing. The original one has more or less disintegrated, so the tone arm does really unpleasant things to LPs when they're done playing.
I've been documenting the process, but since I'm new to the community I thought I would gauge interest before posting a lot of photos. Is it appropriate for me to post some pics of the work I've been doing?
Also, my uncle (the original owner) was a service rep for a Boston-area audio company in the 70s and he had access to a lot more info than the rest of us. I have the owners manual (in english), the service guide with both an exploded parts view and complete schematics, and the original bill of sale. I understand these turntables are rare and manuals even rarer, so I will try to find access to a scanner and contribute those to the archive.
Posted: 07 May 2011 06:53
Do post photos. See the FAQ at top.
Posted: 07 May 2011 11:13
I second the motion. Take your time, tomorrow will be fine.
Posted: 07 May 2011 19:40
Thanks for your interest. :) I'm not going to embed every image I took because that might be overwhelming, so I'll link to the whole album at the end.
So here is where I started, the turntable with the dust cover and headshell removed.
http://farm6.static.flickr.com/5186/569 ... ec2ba4.jpg
I took apart the tone arm "tower", not sure what else to call it, which was a bit of a trick because of the tamper-resistant screws. They look like Spanner "snake eyes" pattern but they're not, or perhaps they're metric. Anyway, I got them off with some minor scratching using the tips of snap ring pliers.
The internal lever that lifts the tone arm was made of some sort of alloy, and either corrosion or moisture caused it to expand, crack, and wedge itself in the pivot mechanism so it stopped working. It also made it so the lever crumbled apart when I removed it. Here's what's left:
http://farm6.static.flickr.com/5109/569 ... 83b778.jpg
Not much useable here - except perhaps in figuring out the shape of what I need to recreate.
Here's a view down into the inside of the tone arm tower:
http://farm6.static.flickr.com/5301/569 ... c3ce55.jpg
On the right are the uprights that support the axle that the broken lever pivots on. On the left is the tone arm, set aside.
I need to make a new lever but the old one is a puzzle of crumbled pieces. So I can use the points of reference in the tone arm tower to estimate the dimensions I need. I make a "story pole" out of a toothpick and mark the pushrod hole, the axle/pivot position, and the edge of the opening where the lever ends flush with the outside of the tower:
http://farm6.static.flickr.com/5262/569 ... fa1400.jpg
It sounds like I know what I'm doing but I'm really just making this up as I go along. ;)
I take the story pole and the leftover pieces of the old lever and sketch out what I think the new lever needs to look like. I cut out a rough blank from a piece of 1" x 1/4" aluminum bar stock I got from the hardware store. Crude work, since I'm limited to hand tools like a hacksaw.
http://farm6.static.flickr.com/5227/569 ... 3a3ca4.jpg
I use a grinding wheel, a dremel with a flexible attachment, and some needle files and spend about an hour shaping the new part:
http://farm6.static.flickr.com/5027/569 ... ed95df.jpg
I reinstalled the pushrod so I can test the fit and the action:
http://farm6.static.flickr.com/5261/569 ... 466af1.jpg
I install the new lever with the axle:
http://farm3.static.flickr.com/2730/569 ... 282c44.jpg
At this point I have to put the tone arm and the tone arm bearings back in, test the action, and then pull it all back apart and file down parts of the lever that aren't fitting or moving right. This was really tedious. It was also tough at times to figure out where the lever was hitting the tone arm or the tower shell because when you have the arm in place, you can barely see the arm at all. I probably put it back in and pulled it back out to tweak the shape a dozen times or so.
Here is the final shape:
http://farm6.static.flickr.com/5223/569 ... 268d31.jpg
It's not perfect. I removed too much material from the lower "nose", which is the part to the right in the picture above, so there is a gap between the lever and the base of the openening in the arm tower. There is also a gap to the left and right because the metal stock I used was only 1/4" wide and the opening is about 1cm. But considering the turntable was unusable on a shelf before I got it, I think my goal of functionality over cosmetics is acceptable.
http://farm3.static.flickr.com/2694/569 ... 525894.jpg
There is a washer on the right side to reduce some "play" in the action because I filed down the part of the lever that sits between the pivot uprights a little too much. It doesn't look too bad, I don't think.
Here is the turntable reassembled and with the lift action adjusted. It works properly now, and that makes me really happy.
https://farm4.static.flickr.com/3130/56 ... 749376.jpg
Next will be adjusting the arm balance, replacing the cartridge with something that hasn't been sitting for 20 years, etc. Right now it makes noise, but it doesn't sound very good.
Here's the rest of the photo album for those who are interested:
http://www.flickr.com/photos/14714378@N ... 696757808/
Thanks for reading!
Posted: 08 May 2011 07:14
Very good work. =D>
Posted: 08 May 2011 13:01
Excellent work you did with the facilities available.
Ask any further questions you wish anbd you'll soon have good sound.
Posted: 09 May 2011 01:46
Thanks guys. :)
The main issue I'm having now is distortion during loud passages, more pronounced as the player gets to the inner tracks on a disc. I think there are some other sub-optimal aspects of my setup, for example the interconnects are permanently attached to the turntable and can't be swapped and I think one has an intermittent connection, and also my amp sucks. But because I hear distortion most on the inner tracks, I believe it's more a physical issue, hopefully setup/adjustment.
I have a tracking force gauge and I set up the tone arm with the recommended downforce per the cartridge specs (a Shure m97xe 'til I'm sure I have a good working player) and the sound was thin, so I temporarily increased the downforce a bit and it helped, and that got me to the place I am not, with distortion at some times.
I'm not confident in my cartridge alignment. The cartridge came with a basic protractor and I tried to use it, and maybe I'm just being dumb, but with my headshell being bulky like it is, and the cartridge not having a single straight surface on it, I'm having trouble determining if the cartridge is aligned or not. In addition, the stylus mount screws are not top-accessible so adjusting the cartridge is a pain. Any advice there would be appreciated.
One last thing, the headshell mount on the end of the tone arm was slightly rotated, which obviously would cause problems with the stylus not seating in the groove properly. I would expect it wasn't supposed to move, so I'll look into that further, but I rotated it slightly so the top of the headshell (and therefore presumably the cartridge) are now parallel to the platter. Is that how they should be?
All in all I feel I'm making good progress. Considering the forces at work here - a 4mv signal from a stylus in a tiny groove amplified hundreds of times to be audible, I'm impressed it sounds as good as it does with a few things out of whack. The system is very quiet on the lead-ins and sound quality overall is respectable and I'm mostly using leftover equipment I have sitting around. Eventually I'd like to get some old tube gear I've collected over the years into serviceable shape and then I'll really have a nice vintage setup. :D
Anyway, suggestions/advice on the issues above with what might be causing the distortion on inner tracks, cartridge alignment, headshell leveling, and anything else you think might be relevant would be very much appreciated.
Posted: 09 May 2011 03:51
At the top of the page is a link to Alignment Protractors, that you can print out.
At the top of the Cartridges and Pre-amps section is a link to Conrad Hoffmann's custom protractor program.
And you are right. From the front, as well as from the side, the top of the cartridge should be parallel to the record.
Take care to get the protractors printed to the correct scale.
Posted: 09 May 2011 10:53
I agree, a little work and you have made great progress. Inner track distortion is set up, and better sound will come from more tweaking. The internal wires really sound like they need replacing. You want perfect connectivity everywhere for such a small fragile voltage, not a broken wire. Replace with something good and you will be rewarded.
Really like the look of the table and the arm, worth the effort you are putting in. The amp in the series is so similar in look. Dieter Ram knew his stuff in industrial design. Formed the basis of what Jonathan is doing for Apple.
Posted: 10 May 2011 02:14
I've aligned the cartridge using one of the downloadable protractors. Things are definitely sounding better. I think I need to listen to a variety of stuff (and also let my VERY new stylus break in a bit) before I fuss much more with it.
On a brand new LP with a perfect surface and no visible dust, I'm hearing occasional pops or clicks. Could this be from static? If so, is there any reasonable way to retrofit a grounding wire? Or should I just use a cleaner to dissipate static before playing something, and hope for the best?
The turntable plug to mains is 2-prong, which I assume is typical.
Posted: 10 May 2011 06:13
I use a carbon fiber brush before every play, laying it across the turning surface, and drawing it off the edge. This gets almost everything off a "clean" record, and leaves a small pile of dust beside the platter.
A 2-prong power cord is standard for turntables. Another ground there would make a ground loop, resulting in 60 cycle hum (50 in some places).
Posted: 10 May 2011 20:27
Any recommendations on a good brush? I was browsing around Amazon and there are a lot of varied reviews...
I also read that the carbon fiber brush is good, as you said, for use before each play but not really appropriate for cleaning. Seems the good quality Discwasher of old is not what it used to be... what do you use for cleaning, fingerprint removal, etc?
Thanks as always,
Posted: 11 May 2011 06:25
A Diskwasher, sprayed with 20% isopropyl alcohol, 80% distilled water + 1 drop detergent, will do a decent job. Remember to roll the Diskwasher as you lift it.
If you get serious, a PHK machine from Brazil is an excellent vacuum cleaner at a reasonable price.
http://www.needledoctor.com/Audioquest- ... egory=1177
Is sold under different names, at various prices. I think they are all the same, and you should be able to get one for $20 or less.
Posted: 07 Jul 2011 04:53
Greetings Jeff...How's the project coming along? As the original owner of one of the same, I may be able to help with specific questions about servicing and maintenance. Mine has been in regular use, and so has not suffered from sitting idle, but still needs routine CLA. It is still my favorite tt. A word of caution: do not tighten the center screws for the three hydraulic dampers (located on plinth underside). They are factory set adjustment screws and overtightening can cause a damper body to crack. One problem in fitting the M97xE is that like the V15 V, the top of the cartridge is not made to be parallel with the record surface making visual VTA setting difficult due to the depth of the headshell. The original set up on mine (Bill Carnell at Opus One in PGH) was done using a V15 II (or III, now still in use) with spacers enough to allow seeing the top of the cart., which makes VTA adjustment a snap using the built in VTA adjustment in the headshell. Overhang can be set using the alignment gauge supplied with the M97xE, or any other similar tool. Hope this helps. The PS 600 is a high water mark of design, function and utility.
Posted: 09 Jul 2011 23:30
Hi,, great post, I have one of these as well in great shape, have not done any type of repairs as you mentioned, mine when push play just doesn't go to the record, it drops down just before record. Other than that its fine.