@Philimon : AFAIK, all Yamaha orthos except YHD series are non-tensioned.

Got a couple of these, mine are labeled Raytheon though.

NEC 6080 and 6520 weren't that great but not bad either. Haven't tried TEN yet.

Toshiba 6080 is a great tube and my personal favorite among 6080/6AS7 tubes. Sounds much better than the RCA 6080 so I am sure they aren't a rebrand. Didn't really care for the Toshiba 6AS7 though.

^Ya, I have one. Nice tubes, structurally they are identical to early 50's sylvania tubes and sound like them too.

Yup, looks like this is CV31 aka U18/20, a 4V version of U52 with 4 pin European B4 base. Doubt that any any pin was ever broken, more like someone trying to drill in another hole for some incomprehensible reason.

^Are you sure that it is a U52, because that looks like a B4 base to me?

Its a 4V rectifier and can't be used in place of a 5 V rectifier without making allowance for that.

Actually, I am the one who won that auction today. I haven't seen a yh100 for less than 150 for a few years now, at least in auctions which are available to us international buyers.So, I don't find that price to be unreasonable. But if any of you wants to sell your yh100 for $100-120, I am all...

^Thanks. I did a bit of digging and found this auction http://www.ebay.com/itm/-/190917447473? where the seller seems to think that these tubes are B65 indeed.   Not a bad haul then!

      Hi guys, Can any of you confirm if these tubes are actually an ECC33, never seen pics of a version with metal base.

Ahh, didn't notice that you were enquiring only about the servo, I doubt that changing that would have any effect on sound.I had used only the BC devices in that particular amp, since I didn't have the Toshiba transistors at hand at that point of time.

I used them in my original EHHA -1 and it worked fine. Its been a while so I can't remember the details but at that time I felt that the one with Toshiba devices sounded slightly cleaner(not much of a difference though). P.S. - Don't forget to twist the legs of BC devices to match the pin...

  Actually I sold my pair to kabeer and I think that he is the one who sold it to you. So, basically yours is the only reported silver fork T30 in existence. ;)

No, not just planars. You have to realize that how a headphone ends up sounding is a function not only of its driver but also its surrounding environment. While a thinner diaphragm may be more 'agile' than a thicker one, its still bulky enough that its movements cannot be controlled without some...