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unknown tubes! Probably Mullards
Posted: Thu 09/01/11 8:48 am
by ian86
Posted: Fri 09/02/11 1:44 pm
by menger
you can tell mullards by the base in center of pins there is a pyramid, teles have diamonds, the mullards are small markings there not alway dead centered mark
Posted: Fri 09/02/11 3:09 pm
by ian86
There is no mark in the base
Posted: Fri 09/02/11 6:50 pm
by kleuck
Inclined getters ? Should be ****.
Posted: Sat 09/03/11 1:52 am
by ian86
kleuck wrote:Inclined getters ? Should be ****.
Posted: Sat 09/03/11 12:15 pm
by kleuck
Matsus
Posted: Sat 09/03/11 9:59 pm
by zaphod_phil
Merd!
How about Matsush.ita
Posted: Sun 09/04/11 1:40 am
by ian86
A valve has the getter slightly inclined, the other has the normal getter.
So it should not be a Matsushi.ta
Posted: Sun 09/04/11 8:20 pm
by kleuck
Right, and i must be blind cause your tubes have longer plates, but it's not easy to say, some Mullard had these LP, some old Matsus too, not alway the same getter.
Posted: Tue 09/06/11 10:22 am
by dotfret
@kleuk - what makes you say these are long plate? I scaled the dimensions from one of the photos, and the plate length comes out around 13-14mm, using a ruler and my famously defective eyesight.
Whatever, I think all are agreed these are Philips style. There were a few people that made to Philips pattern but did not apply Philips code. If that 48L4 mark is a partial code, then Venolanda of Venezuela is a possibility, but I think it is more likely that these are BRIMAR - the print on BRIMARs rubs off easier than any other maker!
Edit: I just looked at the pics again, and I think it is likely that these are actually Mazda Ediswan. At the time they were made, they were part of the same company as Brimar, but I have reminded myself that Brimar used to put the innards into the gass envelope quite neatly, whereas Ediswan always seemed to push the works in a bit skew-wiffy - and these look a "bit that way".
Brimar and Ediswan used to label each other's products indiscriminately, but Ediswan production codes rub off a lot less easily than Brimar - another reason to suspect these are Ediswan, IF the code reads along the long axis of the valve, as opposed to across the long axis of the valve like most valve print.
I might also mention that to get around the Matsushi.ta problem, it is easier to call them Toshiba - which was the label on most of those valves.
Posted: Tue 09/06/11 3:13 pm
by ian86
These valves come from an Italian amp of the early seventies.
the manufacturer told me that in the early seventies they used european tubes made by Mullard, Telefunken and Tungsram.
Posted: Tue 09/06/11 3:58 pm
by dotfret
They are not Mullard - no Philips code.
They are not Tungsram - Tungsram have the US plate orientation (look at the valve with the gap in the pins in front of you, and you are looking between the two triodes' plates).
They don't look like ribbed plate Telefunken, either - the plate anchor tags that push through the mica are triangular/clipped corner on Telefunken that I've seen, not Philips style half hexagonal. In the early 70s Telefunken would be made in E Germany, which would explain the lack of a diamond - but the getter post is not typical E German.
They might be from Fivre (Milan), if the amp is from Italy. I've only seen a couple of those. They didn't get out much. Or even CIFTÉ - but Kleuk would know better than me about those.
Have you tried chilling them in the fridge? Sometimes you can read print remains on the envelope when condensation forms on the envelope of a chilled valve. Just cool and breathe on it ...
Posted: Wed 09/07/11 9:29 am
by kleuck
dotfret wrote:@kleuk - what makes you say these are long plate?
First image got me wrong
Posted: Fri 09/09/11 9:51 am
by p_christov
It seems to me that the first symbol is "delta" - if so this is the date code and they are Philips, made in Heerlen.
It's strange that the first part of the Philips code that indicates the type of the tube is missing.
Have you tested them to see if they are ECC83?
Posted: Fri 09/09/11 12:36 pm
by ian86
p_christov wrote:It seems to me that the first symbol is "delta" - if so this is the date code and they are Philips, made in Heerlen.
It's strange that the first part of the Philips code that indicates the type of the tube is missing.
Have you tested them to see if they are ECC83?
Yes, they are ecc83.
Looking closely, the first symbol is "delta", not 4.
Posted: Sun 09/11/11 4:46 pm
by dotfret
Thanks to P_christov for seeing that, I couldn't see a code at all on my clunky old computer. Now I'm in a different location on a new laptop, it is as plain as day.
Yes, that's a delta mark for Philips Heerlen. Try the fridge test and see if the line above is revealed (should be I63, might appear to be 163). Plenty of those sold marked "Mullard Made in Holland".
While we are talking about this, I looked at a lot of Japanese 12AX7 in passing today, Toshibas (Philips tech) and Nationals (RCA tech). They all have nicely rounded plate lugs - so there is another distinguishing factor for the next ID challenge ...