 Romy the Cat wrote: | That sucks. I use to have a box of perhaps a dozen of YO186 but I did not see it for a while, pretty much from the time I moved to new house. I was listening today some of my “critical” reference stuff and concluded with very high certainty that my MF is gone, it just does not have the tonal yield that it use to have.
Well, the way how Milq is built is very simple to put in there any 45/2A3 or any 4V European tube, so I did today for a couple hours. To my disappointment I did not get the Sound that I was getting before. Other tubes give me very clean and very effective sound but none of them can do brass that my old YO186 was able to do. I am looking for very specific portraying of brass micro- bubbling, of that super-granular, abrasive, coarse tonal texture, when overtones clash like waves during Nor'easter storm and harmonics have legs growing right from neck down. My other best tubes, including my best Nazi tubes, just do not got for that brass complexity and their brass sound more like string’s rosin bite. With YO186, when it was alive, brass was felid with zillion explosive micro-bubbles that make it immensely pleasurable and super fascinating to listen. When NDR Symphony unleash own brass in Bruckner it is no tomorrow in my playback without my YO186. I want my brass back, I want my YO186 back. I only hope that Amy did not learn how all those tubes cost and did not pound them in order to raise money to by her new cosmetics….
The caT |
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This nigh I made a very interesting discovery. It turned out that my YO186 tube did not dive. The sound from the midrange was too soft and not distinctive. I was experimenting with different tubes to substitute YO186 and while I did it I was following my Macondo calibration sheet. Thanks god I did it long time back and locked all outputs:
http://www.goodsoundclub.com/Site_Images/MacondoCalibration.jpg
So, paling with all of it I realized that the acoustic output of my YO186 was dropped from reference 81dB to 78dB and 79dB. I have the “smart” attenuator in the secondary and I added volume to MF and hallelujah- the playback once again sounds just wonderfully!
However, this made me to think: how the hell my MF was able to lose around 3dB? The first blame would be for the demagnetization of drivers. I very much doubt that it might be the case. Drivers demagnetize with temperature, excessive power or DC. Neither is in presence. The drivers see high pass of 3kHz and around 400mV there is absolutely no power to demagnetize them. Then I begin to blame the amp.
Well, the amp is not truly blamable. If the tube did get worn then the tube gain shall not change. The tube gain is the geometry of electrodes; the tube with lost cathode emission shall not loose gain. Something might get overheated in the amp with time and the amp might lose gain. I was looking and looking and thinking and thinking about the amp circuitry and I do not see anything that might be responsible for it.
http://www.goodsoundclub.com/Site_Images/Melquiades_YO-186_Attenuation_revision.jpg
I was even thinking that the cleaning lady accidently did it but she prohibited to clean amps and thank God she does obey it. I still would like to know the answer how I lost my 3dB in both channels. I think it did happen during the last 2-3 months and that was when I begin to notice that my playback is slightly tonally softer and less articulate then what it used to be.
Rgs, the Cat
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