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Tube Rolling Temptation: your favorite 12AX7/EL84 combo?

Jon S said:
It really depends on your amp... I have two tube amps, a Willsenton R8 and a Muzishare X7... Using the British-made Gold Lion KT88s on the Willsenton sounds fabulous but the same tubes sound flat on t he Muzishare. OTOH, the Psvane KT-88-Z Treasures sounds great on the Muzishare but dead on the Willsenton.
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then whats your favorite 12ax7-el84 combination?

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Lavane said:
I bought two quads of Reflektor 6P14P-K's and really like them. They're the ruggedized 3000 hr rated version. If any wear out or fail, I'll get the EV's, I like the 6P14P's.
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I've done this too and found the same. I bought a set of 12 of them, and made two nice tightly matched quad's, two of the 12 were just so-so. I found they sound nice. I first had a quad of EV's which I paid too much for, they were also very good, but was having circuitry issues during that time, and caused red plating and buzzing; and bought the K's after repair. So far, they're holding up well after countless hours.

TBH, I have no idea anymore how a good a pair of orig. US made set of 7189's would sound in comparison; as It's been so long since I've last had a strong & well matched quad set of them in a good working amp, and in recent times been unable to justify the cost's of what an excellent matched quad set commands on the open market. I will say the 6P14P-'s have brought many pleasant listening nights; and not hard on the wallet.

I've been having very nice results with 6P14P-K's & Sylvania green JAN 5751's combo, which good sets can be had economically.
 
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mr_macgee said:
I've done this too and found the same. I bought a set of 12 of them, and made two nice tightly matched quad's, two of the 12 were just so-so. I found they sound nice. I first had a quad of EV's which I paid too much for, they were also very good, but was having circuitry issues during that time, and caused red plating and buzzing; and bought the K's after repair. So far, they're holding up well after countless hours.

TBH, I have no idea anymore how a good a pair of orig. US made set of 7189's would sound in comparison; as It's been so long since I've last had a strong & well matched quad set of them in a good working amp, and in recent times been unable to justify the cost's of what an excellent matched quad set commands on the open market. I will say the 6P14P-'s have brought many pleasant listening nights; and not hard on the wallet.

I've been having very nice results with 6P14P-K's & Sylvania green JAN 5751's combo, which good sets can be had economically.
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I had a couple 6P14P-K's red plate on me. I tried them in two different amps. I had bought them from a seller I don't normally use. When I tested them they tested like new. But ya, like you I've been happy with the 6P14P's.
 
Yep try out 6P14P-EV, the JAN equivalent to Russian tubes. Russian equivalents are a great way to start tube rolling without spending too much. They typically will be shipped from Ukraine, so you'll need to wait a week or two for delivery.
 
albusark said:
Yep try out 6P14P-EV, the JAN equivalent to Russian tubes.
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any russian tube can be military. youll see an "OTK"stamp somewhere. or not.
-EV/EB doesnt mean jan (6p14p-EB was originally designed for military) it means 5k hours life, high durability/tolerances.
6p14p = 6BQ5
6p14p-EB = 7189
 
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I am using Reflektor 6P14P-EVs, Fisher-branded Telefunken ribbed plate 12ax7s in the preamp and Telefunken smooth plates with the label worn off in the phono stage of my Sherwood. Sounds great. But it also sounded really good with just Sovtek 12ax7s and JJ EL84s in it. I'm not the biggest tube roller--I happened to find a console pull on Craigslist years ago that was stuffed full of Telefunken 12ax7s for $20. They all tested strong so that's what I'm using.
 
I like the 5751 tubes used in place of 12AX7 in some audio applications, JJ gold pin are nice ones to try. For low noise applications, the EH7025 are another great choice to swap in for a 12AX7, especially in something like a phono pre-amp. How much "rolling" changes things depends on the circuit, if it has a ton of global NFB you may not hear much if anything.
 
StepheK said:
I like the 5751 tubes used in place of 12AX7 in some audio applications, JJ gold pin are nice ones to try. For low noise applications, the EH7025 are another great choice to swap in for a 12AX7, especially in something like a phono pre-amp. How much "rolling" changes things depends on the circuit, if it has a ton of global NFB you may not hear much if anything.
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and subbing a 5751 for a 12AX7 is circuit - dependent.
 
I've enjoyed tube rolling a lot. It's a simple way to tailor the sound of your rig without changing out amps and speakers. Sometimes the differences are subtle, sometimes significant. Every tube sounds a bit different in every circuit, plus it's subjective ...you just never know until you try.

I'm currently running Mullard re-issue CV4004 for a smooth musical sound.
 
ceylon said:
and subbing a 5751 for a 12AX7 is circuit - dependent.
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Looking at the plate curves and the data sheet, I'm trying to understand why you post this every time the topic comes up. That main difference I see is the 5751 has lower gain.

I'm curious to see a scenario where a circuit designed for a 12AX7 would create a problem if a 5751 was tried to see what it sounds like.
 
StepheK said:
Looking at the plate curves and the data sheet, I'm trying to understand why you post this every time the topic comes up.
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i learned of it reading discussions here then studying the data sheets. as there is some nearly universal assumption/assertion that theyre interchangeable, its a good thing to note that aint necessarily the case. i wish to give accurate information a small service to those coming across this for the first time.
StepheK said:
That main difference I see is the 5751 has lower gain.
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they spec differently other ways too--heater, plate resistance (and current), transconductance...
StepheK said:
I'm curious to see a scenario where a circuit designed for a 12AX7 would create a problem if a 5751 was tried to see what it sounds like.
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id have to study this again to be certain, but i believe in a phono amp RIAA feedback loop, as such a substitution would screw up the RIAA correction.
 
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ceylon said:
i learned of it reading discussions here then studying the data sheets. as there is some nearly universal assumption/assertion that theyre interchangeable, its a good thing to note that aint necessarily the case. i wish to give accurate information a small service to those coming across this for the first time.

they spec differently other ways too--heater, plate resistance (and current), transconductance...

id have to study this again to be certain, but i believe in a phono amp RIAA feedback loop, as such a substitution would screw up the RIAA correction.
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The OP was asking about a 12AX7 EL84 amplifier...
 
I mostly enjoy 7025 or RCA 12ax7a, Mullard for the EL-84 old one's from Motorola suite case record players are MULLARD muddy top EL-84 the music is so creamy using them..they look like there is oil in them hence why my family of cousins Called them Muddy Tops. yeah may be old but tubes don`t fail do to age they fail from bad circuits. Ive got tubes from the 40's 6v6G Raytheon that sound great in a 6v6gT, 7408 circuit.
 
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fxer1982 said:
I mostly enjoy 7025 or RCA 12ax7a, Mullard for the EL-84 old one's from Motorola suite case record players are MULLARD muddy top EL-84 the music is so creamy using them..they look like there is oil in them hence why my family of cousins Called them Muddy Tops. yeah may be old but tubes don`t fail do to age they fail from bad circuits. Ive got tubes from the 40's 6v6G Raytheon that sound great in a 6v6gT, 7408 circuit.
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Black plate RCA 7025 tubes are excellent! :thumbsup:
 
kappclark said:
FWIW --- (and I can just imagine how good that equipment sounds stock) -- Find a composer/artist/genre and go all-in .. forget for a week/month about those hypnotic tubes, grab a cold beverage and be passive to your excellent equipment .. YES - keep walking (at least for awhile) ! :)
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This works so well. Looking at doing a few basic simple upgrades, but very happy with my whole system at the moment.
 
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