IMO it’s important to match original rubber as it has it’s own resonance and in tonearm everything is important.
Have a Victor UA-7045 tonearm coming
I've been searching for either a Victor UA-7082 or a UA-7045 tonearm ever since I purchased my Victor CL-P2 plinth with two arm boards.
The rear arm is almost ready to go, it's a Audio Technica ATP-12T mounted in a custom aluminum armboard. I also had to machine a bracket to add a Jelco JL-45 tonearm cueing device and a tonearm rest. This should be perfect for my low compliance DL-103.I have been looking at both models of the Victor arms and have posted WTB on several forums, watching Ebay but nothing nice has come up. So for the past month I have been keeping an eye out on the Japanese website Yahoo Buyee and finally saw something I liked. It's a clean looking UA-7045 that should work out nicely.
https://buyee.jp/item/yahoo/auction/v741873067?_=cnZxVG5GZVlFQTA3VEZVTDBjQnRCS1RGYWtnTW1ZOTZORUVmb2R...=I won the auction this morning for $202.81, way cheaper than I've ever seen one of these go for. estimated shipping is around $50.00 via DHL. It takes up to two weeks for the seller to get the arm shipped to Buyee and they will inspect and repackage it for shipment via DHL. So in several weeks I'll have this in my hands.
Since I know the spindle to pivot distance I will machine an armboard for it in advance.
Anybody familiar with this series of arms knows all about the rubber damper in the counterweight stub that degrades and causes the dreaded tonearm droop where the weight starts hanging down.
There are two types of this series of arms, those that have the droop (most) and those that will develop it soon. Aging rubber and gravity never let up. Every arm will eventually have this problem.
I've talked to my friend Elliott about this as he had one of these arms for a short time. He sent me a sketch of a rubber piece that he made from hardware parts that he used to fix his. Between Elliott and the internet I found enough info to figure out how this comes apart but I'm not entirely happy with the fix. Since Victor can't supply the rubber dampers I've been thinking about possibly making a mold and casting them out of urethane. I have samples of urethane coming to me from a supplier so I can compare the hardness of the rubber bushing to the urethane samples to find a close matching durometer value.
The mold will be a simple affair, machined out of aluminum. I need to dig out a vacuum pump buried in my garage to see if it works and I found a vacuum chamber on Ebay for 50 bucks.
Once I get the arm I'll pull the stub off and get some critical measurements and work from there. I can even do a temporary fix on the stub until I have a decent result as I have never cast urethane before.Anyway, I'm very excited to be getting this tonearm and at least one member here (chakster) talks very highly of it.
BillWojo
The rear arm is almost ready to go, it's a Audio Technica ATP-12T mounted in a custom aluminum armboard. I also had to machine a bracket to add a Jelco JL-45 tonearm cueing device and a tonearm rest. This should be perfect for my low compliance DL-103.I have been looking at both models of the Victor arms and have posted WTB on several forums, watching Ebay but nothing nice has come up. So for the past month I have been keeping an eye out on the Japanese website Yahoo Buyee and finally saw something I liked. It's a clean looking UA-7045 that should work out nicely.
https://buyee.jp/item/yahoo/auction/v741873067?_=cnZxVG5GZVlFQTA3VEZVTDBjQnRCS1RGYWtnTW1ZOTZORUVmb2R...=I won the auction this morning for $202.81, way cheaper than I've ever seen one of these go for. estimated shipping is around $50.00 via DHL. It takes up to two weeks for the seller to get the arm shipped to Buyee and they will inspect and repackage it for shipment via DHL. So in several weeks I'll have this in my hands.
Since I know the spindle to pivot distance I will machine an armboard for it in advance.
Anybody familiar with this series of arms knows all about the rubber damper in the counterweight stub that degrades and causes the dreaded tonearm droop where the weight starts hanging down.
There are two types of this series of arms, those that have the droop (most) and those that will develop it soon. Aging rubber and gravity never let up. Every arm will eventually have this problem.
I've talked to my friend Elliott about this as he had one of these arms for a short time. He sent me a sketch of a rubber piece that he made from hardware parts that he used to fix his. Between Elliott and the internet I found enough info to figure out how this comes apart but I'm not entirely happy with the fix. Since Victor can't supply the rubber dampers I've been thinking about possibly making a mold and casting them out of urethane. I have samples of urethane coming to me from a supplier so I can compare the hardness of the rubber bushing to the urethane samples to find a close matching durometer value.
The mold will be a simple affair, machined out of aluminum. I need to dig out a vacuum pump buried in my garage to see if it works and I found a vacuum chamber on Ebay for 50 bucks.
Once I get the arm I'll pull the stub off and get some critical measurements and work from there. I can even do a temporary fix on the stub until I have a decent result as I have never cast urethane before.Anyway, I'm very excited to be getting this tonearm and at least one member here (chakster) talks very highly of it.
BillWojo
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I own a UA 7045. I ended up using a piece of delrin rod, turned down to fit and cut to stub length, center drilled and fitted with a small bolt onto which the counterweight stub could thread onto, plus some neoprene washers, so the counterweight is effectively decouple from the arm assembly. Total cost out was about $15 for the rod, hardware and washers. |
@billwojo I also bought a Victor 7045 in Japan some time ago and luckily the rubber damper holds the weight very well, so I only sent it for a complete overhaul in a technical laboratory, but I also own a QL7 with the same arm but built in simpler way, where the damper had yielded and the counterweight had dropped dramatically. I repaired it myself with the rubber gaskets for sealing the taps and it started working excellently. https://i.postimg.cc/kgGh2X8y/DSCN5962.jpg https://i.postimg.cc/MGDcgxPh/DSCN5956.jpg If you can make the mold to build your own rubber damper that’s a great idea ... you could do business with manufacturing many rubber dampers for the many UA 7045/7082 arms around the world. A tip: the vintage tonearms bought used must always be revised if you want to keep them in perfect efficiency as new; bearings with hardened and out of tolerance grease, and a lot of dirt stuck to it... hardened and dried out connecting cables, lifter not work or without siliconic grease and other problems that are not noticed take functionality away from the initial design and the cartridge will never track to the best of its ability. Around $ 150 should always be budgeted for an overhaul when buying a used vintage arm as they are delicate mechanics like watches; Have you never had your famous brand mechanical watch serviced? I really hope not otherwise it would be very bad. |
https://www.diyaudio.com/forums/attachments/analogue-source/619994d1496782254-jvc-ql-7-counterweight...If you look at the picture you will see that the brass bolt does not touch the aluminum ring, the rubber gets pushed into the notches and is trapped by the square head of the bolt. This gives total isolation of the tonearm stub when assembled. That small bit of rubber doesn't need to deteriorate much before the stub and counterweight droops. I think this point is often overlooked when folks repair these arms. They let the brass bolt come in direct contact with the ring, this will render the damper as ineffective. BillWojo |
I'll have to take mine apart to see what you are talking about. It's only apparent from the outside that there is the one black rubbery donut that creates the decoupling of the joint to the shaft that holds the CW. Do you mean to say there is another non-metallic part inside? Have you got a schematic or diagram? My 7045 is not in use, so I haven't had to worry about it. I replaced it in the context of my QL10 with a Fidelity Research FR64S. (QL10 = TT101 + plinth + tonearm, originally either a 7045 or 7082.) |
lewm, you don't seem to understand that there is rubber inside and on the other side of that short aluminum piece that is attached to the pivoting collar. That must be replaced as well. The brass bolt must never touch any other metal except the stub that it screws into. The original rubber piece was a molded part and it's the best way to replicate it. It's actually a very simple shouldered bushing with a hole in the middle. Very easy to make a mold up. As far as o-rings I have o-ring kits in both inch and metric as I am a service tech. I also have an account at McMaster Carr, the main warehouse is only 35 minutes from me. BillWojo |
Here you go, urethane O-rings up the yin-yang:https://www.theoringstore.com/store/index.php?main_page=index&cPath=367_454 |
Bill, Now I am not sure what it is you want to replace. I had assumed you are talking about the rubber (I used the word "rubber" as a catch-all; I did not mean to insist on rubber in the formal sense) donut that provides decoupling of the CW assembly. So what are you referring to when you say, " if the square head of the bolt touches the small collar that holds the assembly in place than you have lost the damper effect"? Obviously you would choose a replacement part that does the job right. Incidentally, these days you can buy O-rings made from just about any variant on rubber that makes sense. Just go on-line to McMaster-Carr or there is another site that specializes in O-rings per se. Neoprene and urethane and etc are probably available. In fact, it would probably be more difficult to buy an O-ring made of conventional "rubber", if you wanted to. By the way, I have written this elsewhere many times in the face of Chakster’s insistence that the CW has to stick out the back like a full-blown erection, there is some mechanical advantage to having a slight droop such that the center of mass of the CW lies in the plane of the LP. If you notice the design of modern tonearms, like the Triplanar and the Reed and etc, that’s how they do it intentionally. |
lewm, o-rings won't fix the problem if the rubber is deteriorated to the point that it is falling apart. You can add all the rubber you want to the exposed section of the tonearm and make the stub stick straight out but if the square head of the bolt touches the small collar that holds the assembly in place than you have lost the damper effect. Might as well epoxy it in place as a rigid unit at that point. I would like to develop a permanent solution that fixes it forever. Urethane doesn't degrade like rubber. When new the square head of the bolt when tightened deforms the end of the rubber bushing and pushes it into the notches of the collar, there is no metal to metal contact. BillWojo |
Bill, in my opinion, you are way overthinking this. I would just go to a good hardware store and find a tiny O-ring of the proper size that does the job. Although I have never yet replaced the rubber donut in my own 7045, I have seen that most good hardware stores have O-rings that would work. I see no need to be anal about casting a perfect replica. |
Bill, Congrats, I was very impressed with the workings when I took the one I had apart before sending it back. Not to send bad vibes, however, don’t be drilling any holes yet, the thing could get destroyed, and even if perfect, you might find a great 7082 an hour from now. Patience, until you have the bird in hand. |
Well it came with a nice TT 61, a rare unit only found in Japan it seems. Not quartz locked though. I started looking around and came across a recapped and serviced TT 71 for an awesome price so it sits in my plinth now. The specs on the TT 71 and TT 81 are the same for speed and wow and flutter so I figured it's good enough. I do love the digital speed readout on the TT 101 though. The more I learn about Victor and the engineering that went into this series the more I like them. They really were on top of their game and were a big supplier to Micro Seiki and others as well. BillWojo |
My current rig is a Victor CL-P2/TT-81/UA-7082 and I've been very pleased. It replaced a Technics SH15B1/SP-15/modded Rega RB250 and gives me both better sonics and much more flexibility. My counterweight droops a bit but I don't believe it degrades the sound; just lowers the counterweight towards the stylus, right? Regardless, it's a great setup and I think you'll like your UA-7045. What motor will you you be using? David |