Roadster chewing RFT.

[2CDR]

anyone else have issues with roadster killing RFT 12ax7 in V1 ? mine has eaten 2 of them now.....

 

[domct203]

I ran an RFT 12AX7 in V2 for about a year in mine with no issues.

Dom

 

[2CDR]

I ran an RFT 12AX7 in V2 for about a year in mine with no issues.

Dom

interesting.. i have had an RFT in V1 in my rev G for a few years now with no issues at all.. roadster has killed 2 now in the space of a few months in V1.....

 

[mark1406]

Who sells RFT valves?

Thanks for your assistance.

 

[kmanick]

Hmmm Interesting, I have an RFT in the V3 of my Mark IV, no issues so far (I have a Mullard blackburn in V1)
I have RFTs in the V2,V3 slots of My Splawn as well, I've never tried one in V1

 

[bandit2013]

Hard to say if it is plate voltage related or if it is due to heaters being DC voltage on V1 and V2.
Do you have a means to test the tubes after they have failed? It is possible it is not the tube and something else. Have you tried other tubes in V1? At least that way you can confirm if this is an amp related issue or if the RFT tubes where rejects from the start. Hard to tell what you are getting these days when it comes to NOS tubes.

 

[tbonesullivan]

That's definitely odd. I know that the RFT EL34s don't like high plate voltages. Are there any specific limitations on the preamp tubes? I would assume if an old production tube can get toasted by V1, then the new production tubes would be dying all over the place.

 

[2CDR]

all other 12AX7 that i put in V1 have been/are fine.. just seems like this roadster does not like RFT in V1.. i put a china B back in V1.

 

[rarebitusa]

Who sells RFT valves?

Thanks for your assistance.

https://www.thetubestore.com/rft-ecc83-12ax7

 

[bandit2013]

The RFT will be a hard find. Most that list the tube are out of stock.

Tubes unlimited was one resource.
https://www.nosvacuumtubes.net/product-category/pre-amp-tubes/pre-amp-tubes-12ax7/

Ness Tone is another.
https://nesstone.com/product-category/vintage-nos-tubes/nos-preamp-tubes/12ax7-ecc83/

KCA was another.
https://www.kcanostubes.com/content/nos-rft-12ax7

I have bought the RFT and Ei tubes from Tubes Unlimited. There are probably more resources out there. Reverb often sells NOS tubes, not sure who the vendor is but they come up once in a while.

 

[2CDR]

i have 6 RFT left in my stash... wont be going back in the roadster tho lol..

 

[bandit2013]

What I meant was try a different tube than the RFT. Mesa, Tung Sol, whatever is not a NOS tube that costs more money and hard to get. No point in wasting the expensive tube if there is an issue with the amp.

 

[mark1406]

https://www.thetubestore.com/rft-ecc83-12ax7

Thanks for the link.

Regards

Mark

 

[2CDR]

What I meant was try a different tube than the RFT. Mesa, Tung Sol, whatever is not a NOS tube that costs more money and hard to get. No point in wasting the expensive tube if there is an issue with the amp.

look back up. its fine/been fine with other tubes..just hates RFT..