I have been visiting Stringer A for a few times to get my strings done till one day I heard my friend broke his racquet when Stringer A was stringing. Few days later, I broke my YY ZSlashTH without clashing as well. I tot it could be stringer A problem. However, since day 1, I have always liked stringer A's job as he is able to deliver the tension that I want and it feels good. Besides, it is able to maintain d tension for sometime. He is using yonex Es5 pro I think. (4knots)
I tried stringer B and he uses fleet electronic machine. This is my first time to B. the racquet strings were far beyond my expectations and it does not feel it is at that particular tension. And after one game, I really feel a great drop in d tension. (2knots)
Strings involved are BG80P. I saw both setting the tension on their electronic machine. Both are 28lbs main, 30lbs cross. Why is this happening? However, there are two different racquet. At stringer A it is d VTZF, while at stringer B it is VTZF limited.
Why is this happening? Same string but the quality is different. Is it the stringer problem? I would like to go to A, but there's two cases of racquets broken. I slightly suspect it could b d stringing job.
There are several variables that could lead to a different feeling even though you're using the same string and the same tension:
1. Different racquets (as you said)
2. 2 knots vs 4 knots (as you said)
3. Different string machine
4. The stringer's style and skill
1. Even if you brought in 2 of the same racquets, there will always be subtle differences. Manufacturers don't make identical racquets, but rather racquets that are within spec. One could weigh more or even flex more, but the two should feel similar as they did manage to fulfill the range required in the factory.
2. This has been debated to death so I won't say much, but they might feel different, retain tension better or worse, or it could be all in your head.
3. The two machines could've been calibrated differently or not even calibrated at all. For all you know, the Fleet machine might've been pulling closer to the actual tension you requested versus the ES5.
4. I think this is honestly the most important thing in the list: the stringer's skill as this is where most of the variability arises. It's all up to the stringer to mount the racquet (how firmly), knotting, straightening of the strings during and after stringing.
There are probably some things I forgot to mention, but that's the gist of it.
when you string a racket at 28/30lbs, it is hard to put blame on the stringer when the racket broke. it is sitting at the threshold of where most rackets are designed to be strung and above the threshold in which Yonex will warranty it.
and also given that stringer A use one of the best machine in the world, it would be safe to assume that he strung it at proper 28/30 while B's machine didn't.
both cases makes it difficult to blame stringer A.
if you do need such high tension, then you are taking the risk and thus need to bear the responsibility of racket breaking.