NOS 12ax7's in Rectos??

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Nick Lehman

Nick Lehman

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Have been really happy with my JJ ECC83s, in all positions in my 2 channel triple.

I got the " want to try something different " phase going on and have tried EHX, Tung-Sol, and Sovtek, none of which I liked better than the JJ's.

Been thinking about scoring some old RCA 12ax7's off eBay.

Wondering if anyone has tried them in a recto, and if they will be good for down-tuned heavy metal.

I like my amp on the dark/warm side, I'm currently running the treble and presence around 12:00.

I always run in the Bold setting and use the tube rectifiers, which I replaced with some old RCA 5U4GB awhile ago ( big difference but thats another story )



Black plates? Grey Plates? Long Plates? Short Plates?
 
Careful buying NOS tubes on E-bay. You can get royally screwed.

RCA was not known as anything special in the preamp positions, RFT, Mullard, Mazda, and the all powerful Telefunkin, are the holy grail of NOS preamp tubes.

RCA made some great power tubes though, Sylvania as well. Old RCA black plates are amazing, and so is the price to aquire them.
 
afu said:
Hey, tell me the other story (rectifiers).

My amp had GT big bottle 5u4 in it when I bought it. Had an issue that needed a tech to look at and he told me they were super weak. They had alot of nice sag to them but didn't work very well for metal. I thought about switching to the GZ34, but i got scared off from reports there was basically not much difference from the diodes.

I scored a quad of rca 5u4gb, tightened up the amp considerably but I can still get a little sag when cranked up. I was very pleased to say the least. The amp is a monster through my 1960A cab w/ v30s. Sounds way better than my buddies 3 channel triple. But his is totally stock except for Ruby EL34s ( which came in my amp )
Click to expand...
 
vick1000 said:
Careful buying NOS tubes on E-bay. You can get royally screwed.

RCA was not known as anything special in the preamp positions, RFT, Mullard, Mazda, and the all powerful Telefunkin, are the holy grail of NOS preamp tubes.

RCA made some great power tubes though, Sylvania as well. Old RCA black plates are amazing, and so is the price to aquire them.
Click to expand...

Yeah I wasnt planning on spending alot on them. I was just hoping someone had first hand experience with them in a recto.

Im planning to do the bias mod soon so I can try lots of different power tubes. KT77 now, thinking about KT66 or 88 next
 
In order to run KT88s, you either need tubes hand picked that have low current draw, and run them in tube rectifier mode. Or have the amp modded to supply reliable current to the heaters on a KT88.
 
I run NOS Mullards in my Rectoverb. My treble is actually full blast now and I run my gain about 2 o'clock (play rock from the 60's to present in a gigging band). Mids are about 1 o'clock and same for bass. The sound is less brittle with these tubes from my personal stand point. I run JJ KT77's in the power section.
 
Nick Lehman said:
afu said:
Hey, tell me the other story (rectifiers).

My amp had GT big bottle 5u4 in it when I bought it. Had an issue that needed a tech to look at and he told me they were super weak. They had alot of nice sag to them but didn't work very well for metal. I thought about switching to the GZ34, but i got scared off from reports there was basically not much difference from the diodes.

I scored a quad of rca 5u4gb, tightened up the amp considerably but I can still get a little sag when cranked up. I was very pleased to say the least. The amp is a monster through my 1960A cab w/ v30s. Sounds way better than my buddies 3 channel triple. But his is totally stock except for Ruby EL34s ( which came in my amp )
Click to expand...
Click to expand...

That's cool. I like the sag, but being able to reduce it would be nice for some applications. Have you tried one of the NOS with a Mesa or other modern 5U4GB to check results?

BTW, I really, really like Ruby 6L6 tubes. Best bang for my buck and sweet sounding. I'm trying to work EL34s into my budget and I'm going with Ruby again. I know they aren't NOS, but I'm in love. I'm also trying to work in new rectifiers to see what differences in feel/distortion character I can find.
 
That's cool. I like the sag, but being able to reduce it would be nice for some applications. Have you tried one of I the NOS with a Mesa or other modern 5U4GB to check results?

@ afu... I've only tried them against the mesa 5u4 and cant really tell a difference.

I did some tube rolling in my buddies 3 channel and found a decent combo. He had 4 mesa "chinese" 12ax7 and one JJ. I put the jj in v1, ehx in v2 & 3, tung sol in v4, & sovtek lps in PI. Sounds loads better than before. Also noticed one of his mesa rectifier tubes wasnt lighting up, which can attest to build quality these days. Went ahead a bought a quad of old sylvania 5u4gb, guess he'll have a spare.
 
I am working on getting my two Tremoverbs to have a tighter attack or something similar to what the plexi attack is or check out Henric Hermansson and his work and you will see what I mean.

I thought the silicon diode was the ticket for that and not rectifier tubes...am I on the right track.

And, am I foolish to think that when I use my clean channel that I like the rectifier tubes better than the silicon diodes?

Maybe my understanding of this isn't correct.

Oh, by the way, I do use a clean boost in front and use a Parametric EQ in the loop to reduce 200Hz.

So it does not have the flub anymore...lol.

Thanks.
 
TremoJem said:
And, am I foolish to think that when I use my clean channel that I like the rectifier tubes better than the silicon diodes?
Click to expand...

Nope.

This is one of the reasons I use a Roadster while my 2 channel sits unused.
 

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