But not usable in the HorizonBlake highly reported it on the Horizon tube thread.
But not usable in the HorizonBlake highly reported it on the Horizon tube thread.
@rspyderThanks Gene. So the1939 RGN1064 has 4V filament rated at 1A. The 1944 AZ1 cathode is rated at 1.1A. If my theory holds, on which I would defer to Lukasz, those rectifier tubes would pair nicely with lower wattage pentodes.
Based on my Horizon trials, the KT170 (85W) sounded thinner and flatter with my Tele RGN2004 (4V/2A) and the 274B (5V/2A) than with my Ken Rad 5U4G (5V/3A). The Ken Rad paired far better with KT170 and Telsa EL51 (45W). Better bass (in slam and articulation), dynamics, tonality, air and overall realism. As noted above, my favourite pairing is the SFR P.17C (25W) with my most recently acquired black-mesh plate Tele RGN2004 Klangfilm rectifier tube (4V/2A). Like Goldilocks - not to hard and not too soft!
Given that Lukasz doesn't place a full load on the pentodes with his design (~25% of nomial output), big power tubes may be overkill. However, some Lampi owners prefer big wattage valves in the output seats of their DACs to capture a big dynamic sound. I have found that I'm getting as much from the 25W P17Cs as the 85W KT170s - with the right rectifier pairing.
I recognize that performance pairing will also be influenced by speaker impedance and its upstream impacts on source and linestage components. Accordingly, my general experience-based observations here are also system specific.
For what it's worth,
Ray
They look like 60-ies Christmas Tree DecorPT14 with adapters (for PX4 settings)
Looks like they were made especially for the Italian Ministry of Finance on the 24th of October 1959@mark-tube
Those are very cool and I’ve seen them on another Lampi as well. I had questions on what this tube was about but haven’t found anyone who can answer yet- unique and I’m assuming rare. Do you the history behind this tube and what applications it served? Any notes on output?
Yes those tubes are a special serie , not commercial , made for postal office station amplifiers the so called “serie telefonica” (telephone series) they are long life tubes made to last long for continuous working hours (their nickname here is “eternal tubes”@mark-tube
Those are very cool and I’ve seen them on another Lampi as well. I had questions on what this tube was about but haven’t found anyone who can answer yet- unique and I’m assuming rare. Do you the history behind this tube and what applications it served? Any notes on output?
The labels are the taxes payed October 1959 , those are postal tubes made especially for postal amplifiers (telecom serie) long life and not commercial tubes , made to last long , made for continuous working under severe conditions , not commercial tubes. During the 1950’s people couldn’t buy those tubes …Looks like they were made especially for the Italian Ministry of Finance on the 24th of October 1959
The picture has been taken by side and for this you can see “different” but tubes are the same with same size , picture below front wiew. The color is only silver and the coated is conductive , the treatment has been made to reduce noise and improve the performanceIt’s interesting to see the “non uniformity” of the bulb with two of them side by side. Had the glass not been treated with the star dust you’d probably not notice. I still want to find out more about it- did they do optional colors?
An high quality decor , long lifeThey look like 60-ies Christmas Tree Decor
Yes those tubes are a special serie , not commercial , made for postal office station amplifiers the so called “serie telefonica” (telephone series) they are long life tubes made to last long for continuous working hours (their nickname here is “eternal tubes”
It’s difficult to find advertisements or other infos because people at that time can’t buy these super tubes. Commercial tubes had much less lifetime…
Technical data will be shared in a separate post with all details from my old books
from the same type you will see two different suffix TS or PT (both stands for postal tubes / telephone series)
Regarding PT14: is a direct heater triode DHT equivalent to Ca Siemens (the German postal tubes) , the commercial equivalent is PX4 / RE604 .
Those tubes can be used with great results (with a proper adapter) in DAC Pacific , Golden Gate and others that use Power triode DHT
the silver coated glass helps to reduce noise and it’s an improvement for those tubes with excellent sound
they made the PT14 with different base: black Bakelite , black metal base, metal silver shining base
those tubes has been made in the 1950’s in Italy , Philips Monza plat (former Zenith Italy plant of production
You’re welcome ?? happy to share infos , not many people knows these tubes … hidden gems@mark-tube
Thank you for sharing the history on this tube- very cool!
'I love the look of those tubes- especially with the silver base! The big question is how do they sound and what would you compare them most to?