No personal experiences, but I've found those quartz tube descriptions to be very informative:
"By looking at the type code first, GA of the GA0 (is G-A-’zero’, not G-A-O) clearly presented in indicative of the tube variant, in this case ECC88, a European designation for the 6DJ8 tube types. 0 is the batch number, an indication only important to the factory that produced these tubes. The next code in line is supposedly indicative of the Mullard manufacturer in this case. While ‘B’ is still quite clearly seen followed by ’6′, which says it was made in Mullard plant in Blackburn, England, in the 1966, the subsequent codes are harder in distinguishing. Those will only be indicative of the month and week of production.
Tube variant #1 has an additional print of Holland, although that is only an indicative sign that Mullard plant in Blackburn made that tube for one of Amperex OEM, HP, which Amperex made some of the other labels like Philips, Dario Miniwatt, DuMont etc under the same Bugel Boy factory in Heerlen factory, Holland.
So, seemingly Holland labels, but British made! Mullards are known for their warm velvety sounds that some cherished and loved so much, for that they feel bring out the analogue sound that translate to natural and living. Yes, these tubes showed such characteristics in our tests.
For those who have been listening to solid-state (SS) amps or using tubes that exhibit all the cleaniness and crispiness of sounds might find these HP 6DJ8 A-frame tubes slightly less sharp. It could be a bit uneasy at first, but hold on, and you might begin to just feel so comfortable with the smooth rendition of the highs and mids. Vocals are especially feeling very warmth and intimate. Bass is ever so laidback but never uncompromising. Resolution is fantastic, to leave one not congested from the warmth which some SS tries to sell the ‘tube sound’."
In this case, however, I'm not sure if the factory code descriptions are accurate. All the info I've been reading suggest that A-frame support was more of a 70's invention. There is definitely B6 to be seen, but I think that #1 is actually a 1976 Mullard 6DJ8 A-Frame (similar to this: http://www.ebay.com/itm/1-Matched-Pair-H-P-Mullard-A-Frame-ECC88-6DJ8-E88CC-6922-CV2492-Cca-TUBES-/271175276100?pt=Vintage_Electronics_R2&hash=item3f234e5644). # 1 is in better condition but the price is too high for 70's A-frame IMO.