Goldmund Studio PL5 or PL6

Hello Everyone,

This is my first post here so for starters I would just like to introduce myself.
My name is Bryan and I am an electronics technician by means of an ancient degree and have had the great fortune of allowing my career to follow my passion for music, my intrigue by audio and recording equipment and an early interest in electronics to all come together. I think everyone should be so lucky as to be able to follow a hobby into their career.
Along the way I have gained a bit of valuable knowledge and experience in these areas so hopefully I can become not only a friend to many of you, but also a helpful resource and an interesting member of this forum as well. I prefer to not be judgmental or jaded in my opinions as experience has shown me that anything is possible in this world, no two paths are the same, and what you think you know today may be proven wrong tomorrow. With that being said I prefer to keep an open mind and always try to think outside the box and to show respect to everyone's opinions.
As you can see, I have sold some very nice gear here on Audiogon in the past and my excellent feedback shows my dedication to my selling reputation. But my reason for this post is not to sell anything but rather to reach out for help with a challenging project I have started.
So here is my challenge and project at hand. In a recent road trip and audio-goodies treasure hunt I was the lucky finder of an early Goldmund Studio turntable with a T3 tangential arm in pretty ratty shape. However, the cables, platter motor power supply and most importantly, the PL5 Servo unit had all been lost in transit some time ago when the unit was shipped from California to South Carolina. Well to make a long story short, Goldmund has been fantastic with regard to support but I am now faced with the challenge of building, from scratch, the PL5 servo unit as they of course are long ago gone. I have already successfully repaired the Papst platter motor and built a nice fully regulated 24VDC power supply for it so if any members on here need assistance with your non-functioning Papst motors I may be able to help you out with that. So with the platter motor all being in place its now time to move on to the challenge of the arm servo unit. Goldmund provided me a copy of a basic hand-drawn schematic of a PL-6 servo unit that could be adapted to drive the T3 arm but unfortunately there are major differences between the PL5 and PL6 and there are some details in the PL6 schematic that are a mystery. The schematic shows IC4 and IC6 as "boxes" in the schematic that do not conform to standard schematic symbols so an educated guess is the best I can do to identify these devices. IC6 is obviously a voltage regulator as evidenced by its three connections, one being power in, one ground and the other I assume VCC for all the other ICs, but to guess that its a 15VDC regulator could only be my best assumption. IC4 is a real mystery though. The schematic shows two logic inputs to the drawn box, three leads that are directly strapped to VCC, one lead tied to VCC through a resistor and that lead coupled to another lead of the device through a capacitor. The output of the box feeds two paralleled inverters.
If anyone has the PL5 schematic, that would be very helpful because the PL5 servo is obviously a very different design than the PL6 and other than the two drive motors, an opto sensor and a few LEDs mounted in the T3 arm, everything else is a completely different layout. Also, if anyone would be willing to open the top cover of their PL6 and snap a shot of the board, that would be very helpful too as I could simply read the IC numbers right off the top of the chips.

Thanks Everyone
why go to all that trouble for the T3 arm ...the arm was the main draw back to the Goldmund studio TT. I would unless, your hobbie is to frantically pull your hair out trying to build the servo unit. Why not refurbish the Table and mount an arm of your choice. That will most likely beat the pants off the T3.And save you allot of wear and tear. I wish you the best with the table. I know it is worth saving. But the T3 arm just forgetabout it. And go with a less cantankerous arm.
Hello Schipo,

Thanks for responding to my thread! Wow, there are actually other vinyl geeks like me out there. LOL
Well, anyhow, I am really interested in hearing the synergy I keep reading about between the Goldmund Studio and the original T3 arm and since this is all just a very fun hobby to me, I am going to pursue the challenge. Fortunately, I have plenty of time to fart around with stuff like this and actually enjoy the challenge of circumstances like these. From everything I have read on the web the T3 is a very finicky (to say the least) arm, but there are many out there on the web that say if you have the patience to fidget with it, and get it set up right, that there is some true magic in the sound of the Studio with the T3 arm. So that is what I would like to find out. Don't get me wrong, I have heard many a claims about "the magic" in the sound of many a component just to try it and wonder what they were hearing because I never heard it. LOL
Right now I am using a Thorens TD124 with a Grado Laboratory (wooden) arm fitted with a Denon DL103 cartridge and the sound is good. Its a very warm, involving analog combination but the Thorens has a bit of background noise that is bothersome at the ear-splitting levels I sometimes listen at. You can actually place your ear on the table and hear the mechanics of the motor, idler, and intermediate pulley. I have been through the unit head to toe and it is just the nature of the beast, to most it would probably be of no concern, but to me its another baby step towards the music. The Goldmund on the other hand is DEAD SILENT with regards to the platter, plus the table has a suspension, another thing the TD124 lacks. I know I might very well be headed down a road that ends up being one not worth traveling, but I'm willing to trek that road to find out.
To me, this all is half the fun of listening, the chance to get one baby step closer to the music and that has always been my goal. And of course, try to make that step without spending a lions share of the budget.

Thanks again Schipo and happy listening!
Nice hearing from you concerning the Goldmund studio and t3 arm. My first high end purchase in 1985 was the Goldmund Table with T3B arm. The Table was purchased from a very snutty high end store in manhattan {guess LOL}. The table itself was a joy considering some of the offerings for the time. The arm is another story. Try as I did I could never get this arm to cooporate. The arm would on it's own terms lift off during play without my help. I only solved this problem trading in the arm and going with a Sumiko arm that worked very well indeed and wish I never sold this wonderful unit. The best to you and hope it works well.
This is not the first time I have heard this complaint. The T3 arm servo drive circuit had a safety feature that would sense a lack of travel in the arm (meaning the sled action was either hung up, jammed or somehow at fault) and in order to avoid catastrophic damage (to the record or stylus) the servo would trigger the cueing motor to engage instead. The fix for this was an adjustment of that circuit making it less sensitive to error cueing. I'm surprised Goldmund never alerted you to this issue and filled you in on the fix. The circuit is effective and I would never bypass its operation but just like everything, there are tweaks that can be made. So you liked the platter even though it is direct drive? Seems like everyone out there is so jaded towards direct drive that nobody is even willing to consider it as an option any more. I prefer to never rule out any options in the physical world.