"Better" is purely subjective, and system dependent. The RCA w/clips may very well sound strident/overly bright in a system that already has that tendency. It does provide the best sound staging of any 5751 type though. In general- many that like 5751s, prefer the RCAs over the Sylvanias. Usually the triple micas w/o the clips however, as they are somewhat warmer(I'm a TLK ECC803S lover myself). To tell anything with regard to tube life from test results, you have to know what that particular tester's tube chart lists as "nominal new", "minimum good", etc for comparison. I seems presumptuous of a seller to send someone tubes other than what was ordered, but- that's just my opinion.
Questions about RCA 5751tubes
I am needing some help..
I ordered a pair of Sylvania 3 mica Black Plate 5751s for $150
and was sent RCA JRC-5751s instead. Please bear with all my questions.
1. I was told these were better tubes and matched within 2.5%
One tube has a sticker with 1.5/1.5 and the other says 1.6/1.7
Can I tell if these are matched from these values?
2. What do these values mean? Are they an indication of life left
on the tube? If so what values are considered NOS and what
values are considered 50% and 75% life left?
3. Are RCA JRC-5751 Black Plate, 3 mica, (smooth edge top mica)
as good as Sylvania 3 mica Black Plate 5751s?
I was surprised to get a different tube than I ordered but wanted
to ask everyone if this really is a better tube? Anything you can
tell me about this tube would be very appreciated..
More info on these tubes:
The top of the tube (nipple of the tube)is painted half green/half red.
I assume these are military markings..??? What do they mean?
The silk screening is all white but 90% worn off so you can't
read anything but part of the RCA logo, 5751, and JRC
2 black plates
Each tube seems to have 2 paper clip looking supports (one at each
end) to tighten up and better secure all 3 mica disks.
square halos.
I ordered a pair of Sylvania 3 mica Black Plate 5751s for $150
and was sent RCA JRC-5751s instead. Please bear with all my questions.
1. I was told these were better tubes and matched within 2.5%
One tube has a sticker with 1.5/1.5 and the other says 1.6/1.7
Can I tell if these are matched from these values?
2. What do these values mean? Are they an indication of life left
on the tube? If so what values are considered NOS and what
values are considered 50% and 75% life left?
3. Are RCA JRC-5751 Black Plate, 3 mica, (smooth edge top mica)
as good as Sylvania 3 mica Black Plate 5751s?
I was surprised to get a different tube than I ordered but wanted
to ask everyone if this really is a better tube? Anything you can
tell me about this tube would be very appreciated..
More info on these tubes:
The top of the tube (nipple of the tube)is painted half green/half red.
I assume these are military markings..??? What do they mean?
The silk screening is all white but 90% worn off so you can't
read anything but part of the RCA logo, 5751, and JRC
2 black plates
Each tube seems to have 2 paper clip looking supports (one at each
end) to tighten up and better secure all 3 mica disks.
square halos.