@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...

Excursion has nothing to do with the properties of a diaphragm, its merely a function of the push/pull force applied on the membrane. One can lift a stone to the same height regardless of its weight, provided one has enough muscle power.Regardless of its thickness/weight, all diaphragms would...

Any info on this? I have a pair of C3M that I would like to make use of.

^Mylar

Quote: TBH, I haven't had much luck with transplants or rather my 'stock shell' mods have turned out so well that its hard to extract that level of performance from anything else.   Generally speaking, I 'd avoid using open backed headphones/large chambers with most vintage orthos. They...

Hi Nick!   Quote: That looks great Don and I bet that it sounds great too. Reminds me that I have a pair of yhe50 drivers lying around and I need to find some time for them...

My 6AS7 OTL handles the Yamaha orthos and LCD-2 with ease. The output stage is biased higher than the usual though.

Hi Nick, Yes, I am good and hope you are doing well too. I guess I haven't been very active here in the recent past but I do keep a tab of this thread.   About the PMB100 lacking the bass, its not just because of the lack of sealing pads. Also,the driver has 360 degree vents around the...

^ya, its only the foam back there which would mean that these are tuned much higher than most vintage orthos. They seems to be pretty close to being critically damped with just the foam, very fast and clean sounding. Its a bit rolled off at either ends but still very enjoyable in the stock form...

I got one myself couple of weeks back from the same seller. Quote: Nope.

Indeed. Mr. Gilmore has provided a great service to community by designing and providing constant updates and tweaks of these amplifiers for DIYers. If someone is smart enough to choose to build one of KG's design, he should certainly make sure that he has the ability to troubleshoot a faulty...