• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

EL34 vs. 6L6GC vs. 7591 ? Truth - Who's Best !

Old thread.
IMHO-if your amps can run either run Tung Sol 7581A, or Gold Lion KT66-these are most likely going to sound better than other tubes in this lineage, new production or NOS.
Just be forewarned the 7581A is a very dynamic tube-it's not bright, or harsh, but dynamic, top to bottom.
The GL KT66 is very dynamic as well, but more 'composed'.
Both have lot's of tone/texture and harmonics.
I could live with either-but lean towards the GL KT66.
Both great sounding tubes.
Upscale recommends these quite frequently now for power tube upgrades on the PL's.
They seem to mate well IMHO.
Kicked every larger power tube to the curb except the Shuguang 90's GEC KT88 copies built for ARC.
Nice sales going on now-get 'em before you have to pay a 50% tariff!
 
Last edited:
automojo said:
Old thread.
IMHO-if your amps can run either run Tung Sol 7581A, or Gold Lion KT66-these are most likely going to sound better than other tubes in this lineage, new production or NOS.
Just be forewarned the 7581A is a very dynamic tube-it's not bright, or harsh, but dynamic, top to bottom.
Click to expand...
I tried the TS (Russian) reissued matched-pair 7581As in my 1967 Fender Super Reverb. I did not like them. They lacked the sparkle and clean shape to notes of the GE 7851A which I'm accustomed to. This was 5 years ago — maybe the new TungSols are better? :idea:

I've been using EH 6L6GC. Sound is consistent, and they seem to last.
 
Last edited:
Mr Boochie said:
I tried the TS (Russian) reissued matched=pair of 7581A in my 1967 Fender Super Reverb. I did not like them. They lacked the sparkle and clean shape to notes of the GE 7851A which I'm accustomed to. This was 5 years ago — maybe the new TungSols are better? :idea:

I've been using EH 6L6GC. Sound is consistent, and they seem to last.
Click to expand...
Well, just because it sounds good in a guitar amp doesn’t mean it’s a good hi-fi tube, or vice versa.
I don’t think they’ve changed the tube much that I know have pretty much the same as it was introduced.
In my Prima Luna plenty of high in detail.
Good sounding tube for Hifi.
Quite frankly, I’ve seen great reviews for guitar amps as well so whatever your mileage may vary.
With that particular and you’re probably better off sticking with the ancient Egyptian tubes and the lore they seem to have.
Good luck with that!
 
The end of era stuff like 7788, 7591 and 8417 were pushing the construction methods about as far as they could go, and sometimes a wee bit further than that. They were not around long enough to get wide usage, or proper methods for making them reliably, so amp designers went elsewhere.

Douglas
 
automojo said:
Well, just because it sounds good in a guitar amp doesn’t mean it’s a good hi-fi tube, or vice versa.
Click to expand...
This is not universally true. In my experience, the best audio tubes are the best for guitar amps.

My "standards" for comparing other brands are about the same as those of Hi-Fi folks.
 
ab79e7ba-8269-464b-ba65-a810d1ff4ffe.jpg

I like it when Hi-Fi folks say, "Why are you wasting all those great Hi-Fi tubes in a guitar amp?"

If you play guitar, you'd know.
 
Mr Boochie said:
This is not universally true. In my experience, the best audio tubes are the best for guitar amps.

My "standards" for comparing other brands are about the same as those of Hi-Fi folks.
Click to expand...
OK, I’m certainly not an expert on guitar ants
Case in point
New production TS 7581A
It’s not a perfect tube, but I certainly haven’t heard anyone said it like high end sparkle or energy..
Tubes are obviously are circuit dependent, but in my opinion, I’d be looking at something else in my amplifier… if the NP TS 7581A sounded dull.
Same for the NP Gold Lion KT66.
 
Mr Boochie said:
ab79e7ba-8269-464b-ba65-a810d1ff4ffe.jpg

I like it when Hi-Fi folks say, "Why are you wasting all those great Hi-Fi tubes in a guitar amp?"

If you play guitar, you'd know.
Click to expand...
Well, I certainly wouldn’t say that
Put the tubes in there that give you the sound you want, I don’t see how that’s any different than hi-fi.
Point being tubes are circuit dependent so you might not always get the same results.
But I do agree with the generality good sounding tubes usually sound good and all amps
Perfect?
Nope
But you can hear the good qualities for sure
And that’s why my comment on the new production tTung Sol 7581A sounding dull in my experience doesn’t make any sense.
It’s a first
 
But to add
I bought a slightly used set if the Tung sol 7581 A
In reality, they had a lot of hours of it and not much of a blue glow anymore
They sounded dull.
Sent them back to the seller
They don’t sound anything like a new one/ low hour tube.
I would imagine these tubes are probably good for 1000 hours max, I’m not sure
Haven’t run them that long yet
 
Agreed.
It’ll be interesting on how long these last.
Prima Luna are easy on power tubes.
Technically, I don’t care. I’ve got four quads of each now I bought a good price is brand new from the three major reputable sellers so I should be good for the next decade!
Each one of these particular tubes of what I enjoy in tube audio so I don’t need to roll anymore.
If I had to choose one to live with it would be the Gold Lion KT66.
But luckily, I don’t have to make that choice!
 
Mr Boochie said:
In my modest experience, the MOV/GEC KT-66 (UK) tubes were some of the finest audio output tubes ever made. I haven't heard any unit loaded with these tubes in 25 years.

e7c4483c-ee7c-4f76-9eca-5d65bb9f6e6f.jpg
Click to expand...
Great!
So, dollar for dollar-what you paid for them today-they sound that much better than NP KT66's?
Worth double/triple $$?
1k quad?
IMHO-kinda doubt that, if it parallels GEC KT88-vs, say the Shuguang KT88 copies made for AR.
I agree, with more than a few many, these copies sound better.
Clearer than the GEC NOS-yet still not harsh.
And they have same durability as the old Brit gas tubes.
Lucky for me-the lore is still strong-people pay crazy $$ for not even the best sounding (IMHO) KT88's out there.
1k for a quad of old Brit's gas?
WOW
Tubes can be very subjective-and people, old like myself, have a tendency to think things were better "back in the day", regardless of reality.
Frankly-this tendency has gone on since the dawn of men.
Just open a history book....etc...
Funny how many people still buy into this-and then wonder why history repats itself....
Frankly-when I listen to the GL KT66's-I can't really imagine anything sounding really any "better".
Different?
For sure....try a Chinese KT66 and plug your ears!!
The GL's are pretty much as good as it gets-with these PL amps.
Upscale 'under the table" recommends the GL KT66 for the bigger Evo amps now.
For good reason...
Regardless-when people talk old tubes, at the price they are now commanding-unless you parallel that with todays purchasing power vs NP, it's purely a pining thread.
Not to mention-buying NP tubes helps improve the products.
Just look at the garbage in the 80's/90's vs today...
 
Last edited:
I can't answer your question. I never paid for any KT-66. I heard them on another person's system.

Regarding audio quality, the original GEC/MOV KT-88 is not up to the level of their KT-66. Only their KT-77 is on the same level.
 
Last edited:
All of those tubes are fairly different from one another still, so drivers, transformers, etc make it pretty impossible to do a direct comparison.


I find a lot of this stuff is also amp dependent. I've listened to a couple EL34 amps and different ones sound different even with the same output tubes. Different transformers, driver circuitry, feedback levels, etc play into what any specific tube is going to sound like. Even people who own a Dyna ST-70 and have changed the driver board to a different design will tell you it sounds different, despite retaining the same output tubes and transformers.
 
You must log in or register to reply here.
Back
Top Bottom