I have just bought an RT 12AX7S valve, and underneath the 12AX7S and the letters HF.
Any idea what these mean?
I have just bought an RT 12AX7S valve, and underneath the 12AX7S and the letters HF.
Any idea what these mean?
Kevin
Too busy enjoying the music....
European loan coordinator for Graham Slee HiFi system components..
Guessing the "F" means it was made in Suresnes, France, and the "H" denotes August. As to the year (> 1955), you will need to find a number.
https://tubemaze.info/deciphering-eu...be-date-codes/
Barry
Not sure what the 'HF' is, Kevin, but they're FAB tubes! Much did they set you back?
Marco.
Main System
Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.
Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.
Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.
CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.
Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.
Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.
Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.
Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.
Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.
Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!
Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!
3BCD0C7D-C6EE-4A9A-A7BE-B5D665E7DF7D.jpg
I bought this one for €55 posted.
Thanks for the info. I thought the code on RT was FRS for Suresnes? There is a 4 digit code, which I assume is the date, something like 6332 from memory.
I also have a nice silver plate Mazda 12AX7S on the way, a 5* version, which again is an -H.
Kevin
Too busy enjoying the music....
European loan coordinator for Graham Slee HiFi system components..
If the date code is 6332, then the valve was manufactured in the 32nd week of 1963. So anytime between 9 - 15 August 1963.
Under the CV (Common Valve) system of notation, a group of letters were used to denote where the valve was pumped out. For La Radiotechnique the following two letter codes applied:
DN - Caen
JK -Suresne
https://www.valvecollector.uk/cv-valves.htm
Barry
Nice one, Kevin. These are the ones I got, which are slightly older: https://theartofsound.net/forum/show...160#post841160
Superb sounding tubes. It took a NOS Mullard (early 60s issue) M8137 box-plate to oust it, and that one cost me £150, but can often go for nearly £300 a piece!
Marco.
Main System
Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.
Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.
Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.
CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.
Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.
Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.
Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.
Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.
Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.
Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!
Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!
I received one of the valves today.
It has the three magic letters on it - FRS, so it looks like HF is a batch code, or similar.
Kevin
Too busy enjoying the music....
European loan coordinator for Graham Slee HiFi system components..
Now you're asking, mate. It was a while ago. Don't think it was ebay, or a private individual, probably a specialist tube seller. They're pretty rare,
I only ever buy genuine NOS (or NIB) valves, which are balanced (or balanced as closely as possible), and thus have been measured by someone with the necessary testing equipment, as you'll see evidence of with the stickers
I don't buy random untested valves, as they tend to be unreliable.
Marco.
P.S I should clarify that the NIB valves I buy are always 'sold as seen', therefore untested, and NOS ones are only such, as far as only having been 'used' once for testing/measurement purposes, not in audio equipment.
Main System
Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.
Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.
Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.
CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.
Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.
Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.
Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.
Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.
Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.
Protect your HUMAN RIGHTS and REFUSE ANY *MANDATORY* VACCINE FOR COVID-19!
Also **SAY NO** to unjust 'vaccine passports' or certificates, which are totally incompatible with a FREE society!!!
I guess it depends where you look.
I am sure this guy http://www.electrotubes.com/index-en.html would have something? He seems to have a good reputation on the French forums. He does not list balanced/matched pairs of the RTs, but I am sure he could find something.
If I didn’t have a nice Tungsram Foil getter ECC83, a Mazda silver plate 12AX7s and another RT on the way, I would be speaking to him.
Not sure what the Brexit implications are though, as I am not sure if he is a registered business, as I have never used him.
He certainly has some interesting valves available though.
Kevin
Too busy enjoying the music....
European loan coordinator for Graham Slee HiFi system components..