robt62 Posted March 22 Posted March 22 (edited) I recently purchased a pair of used ja-0513 tweeters on eBay from Japan: https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.ebay.com.au/itm/125044536090%3Fsrsltid%3DAfmBOoqkOgE8ioN7YosjUw_dEW4JUbxK58KOmYjPg-7F8ZXnK_IOVKmE&ved=2ahUKEwiggNm0jp6MAxUPhlYBHQ4YCmAQFnoECCwQAQ&usg=AOvVaw1KxCLOs18kcJHj1GCF1g0O I purchased a set of these as they do look in decent condition and arrived in decent condition, very well packed. They do look original and the snipped wires do look original. I did a basic wiim ultra room correction to one stock-standard ns-1000m speaker with the original tweeter and then the 2 purchased tweeters installed. The speaker did not move position during these tests with UMIK-1 microphone on axis with the tweeter and 80 cm in front of it. I'm very familiar with the expected frequency response curve of these ja-0513 tweeters installed in the ns-1000m. I noticed the 2 purchased tweeters did not have anywhere near as flat a response as my original tweeter displays above 6 khz on the following graphs (focus on 'Measured'). My original: https://photos.app.goo.gl/6epq2gmYKijXBHeo7 2 purchased on eBay: https://photos.app.goo.gl/2cY8b6vAjpS4C3s38 https://photos.app.goo.gl/cdGzpo9WRRgkx5fZ8 Comparing the resistance of each tweeter when disconnected from the speaker, the original measures 4 ohms and the other 2 purchased on eBay both measure 5.5 ohms. Having had these speakers for over 40 years, only the tweeters have been susceptible to getting blown in my experience. Could the inability to have a flattish frequency response where the original does, be due to a repair of some sort to tweeters that had been blown? Or could it be something else that causes this difference? Thanks in advance, Robin Edited March 22 by robt62 Add missing close bracket ')'
robt62 Posted March 24 Author Posted March 24 I decided to install and use the purchased tweeters in my set of ns-1000m speakers, even if only temporarily. This proved to have been a good idea. Having played them quite a bit over the weekend, I noticed they were sounding better this morning, so I retested them the same way as last time and now find their frequency response curve is more like they should be: https://photos.app.goo.gl/yt8Ka4REVyvshw3eA https://photos.app.goo.gl/hJb74r5xT3GL2XEG8 I can only surmise that taking them out of the box they arrived in and testing them immediately was the cause of their previous disappointing frequency curve. Running them in seems to have got them to performing as would be expected. I had been planning on purchasing a second set of tweeters, as these ns-1000m speakers were the only speakers I've ever owned and the only ones I ever intend to own. I decided I was now confident enough to purchase another set from the same eBay seller
robt62 Posted March 27 Author Posted March 27 Since I have now purchased 2 sets of ja-0513 tweeters from eBay, I must be considered a big fan now. I got this seller offer from eBay to purchase these Vintage Yamaha JA-0513 Tweeters Pair Beryllium Dome NS-1000M working Japan VG: https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.ebay.com.au/itm/134448502539%3Fsrsltid%3DAfmBOore4UEZKWGLxL3txdQlN_WsiDACxeqSDyMqLJ8q-W9APo3HxL99&ved=2ahUKEwj3roXdnauMAxWNsFYBHXPBGWgQFnoECCMQAQ&usg=AOvVaw0WEAaTHxEj9Vf6JzIXoaBv Only thing is the pictured tweeters in that deal aren't Yamaha ja-0513 tweeters. I saw there was an option on the eBay page to report such things, so I thought I'd do the right thing and point out this issue. A day later I got an email response from eBay: A decision was made on the listing you reported Hello, Thanks again for reporting the listing(s) you found. What happened: We looked into your report and didn’t find the listing to be in violation of our policy. This determination was made by a customer service agent. If you reported content that isn’t listed below, we’ll send a separate email once we’ve made a decision. Your reference ID: 2-192191879580 Here are the listings you reported that are included in this decision: Item: 134448502539 Vintage Yamaha JA-0513 Tweeters Pair Beryllium Dome NS-1000M working Japan VG Thank you for being part of the eBay community.. Regards, eBay Well, at least I tried. Not sure how Ebay came to that conclusion. 1
Spinspin69 Posted March 27 Posted March 27 1 hour ago, robt62 said: Since I have now purchased 2 sets of ja-0513 tweeters from eBay, I must be considered a big fan now. I got this seller offer from eBay to purchase these Vintage Yamaha JA-0513 Tweeters Pair Beryllium Dome NS-1000M working Japan VG: https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://www.ebay.com.au/itm/134448502539%3Fsrsltid%3DAfmBOore4UEZKWGLxL3txdQlN_WsiDACxeqSDyMqLJ8q-W9APo3HxL99&ved=2ahUKEwj3roXdnauMAxWNsFYBHXPBGWgQFnoECCMQAQ&usg=AOvVaw0WEAaTHxEj9Vf6JzIXoaBv Only thing is the pictured tweeters in that deal aren't Yamaha ja-0513 tweeters. I saw there was an option on the eBay page to report such things, so I thought I'd do the right thing and point out this issue. A day later I got an email response from eBay: A decision was made on the listing you reported Hello, Thanks again for reporting the listing(s) you found. What happened: We looked into your report and didn’t find the listing to be in violation of our policy. This determination was made by a customer service agent. If you reported content that isn’t listed below, we’ll send a separate email once we’ve made a decision. Your reference ID: 2-192191879580 Here are the listings you reported that are included in this decision: Item: 134448502539 Vintage Yamaha JA-0513 Tweeters Pair Beryllium Dome NS-1000M working Japan VG Thank you for being part of the eBay community.. Regards, eBay Well, at least I tried. Not sure how Ebay came to that conclusion. Unfortunately we live in a buyer beware world. 1
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