View Full Version : 807 vs 6L6 as an output tube


gadget73
11-05-2010, 10:26 PM
Does anyone have input on the sound of an 807 vs the 6L6GC ? I'm possibly looking at buying a mate to my Stancor Williamson amp, and its been modded to take a 6L6. I have one thats still fitted with the original 807 tubes. If I did get this, I'd probably be buying 4 tubes of either type but I'm looking for thoughts on which type to buy. I'm sort of leaning towards the 807 for price and the fact it has that cool plate cap, but should I really consider a 6L6GC or a KT66 or something ?


http://www.pmillett.com/file_downloads/stancor_ul_schematics.pdf

the second set of schematics for the amp in ultralinear mode is what I'm working with.

jaymanaa
11-05-2010, 10:34 PM
Just my ears but I'll take a 6L6 over an 807 / 1625 every time. They sound better to me, and seem to be much more durable.

battradio
11-05-2010, 10:41 PM
Hi ,

I would consider the 6BG6 , wire both chassis for these they are reasonabled .

http://www.vacuumtubes.com/6BG6.html .

Your would have the advanages of the 6L6GC with the price of the 807 .

gadget73
11-05-2010, 10:44 PM
moot point, had a login issue and ended up missing out on it. There are days where I truly despise technology. Stupid login timeouts.

Sam Cogley
11-06-2010, 03:22 AM
Just my ears but I'll take a 6L6 over an 807 / 1625 every time. They sound better to me, and seem to be much more durable.

I wonder how, since the 807/1625 is just a higher-voltage 6L6.

seta1
11-06-2010, 06:52 AM
[QUOTE=gadget73;4120030]Does anyone have input on the sound of an 807 vs the 6L6GC ? I'm possibly looking at buying a mate to my Stancor Williamson amp, and its been modded to take a 6L6. I have one thats still fitted with the original 807 tubes. If I did get this, I'd probably be buying 4 tubes of either type but I'm looking for thoughts on which type to buy. I'm sort of leaning towards the 807 for price and the fact it has that cool plate cap, but should I really consider a 6L6GC or a KT66 or something ?
/QUOTE]

The problem with the 807 is that it is no longer made while the 6L6 is still in production. Although vintage 807's are not priced in the stratosphere yet, it will only be a matter of time before their prices go crazy. The 6L6 sounds great and is as good or better sounding then the 807. The 807, though, looks cooler.
As for the KT66, it is NOT a drop in replacement. It's filament current is half again the filament current of a 6L6. This can be fatal to certain amplifier's power transformers. This is especially true with vintage amps which normally have power transformers that are just adequate with no reserve capacity. Can't tell you how many Fender guitar amps I have had to replace power transformers in because someone decided to cram a set of KT66's in place of the correct 6L6GC's. Also, the 6L6GC is a 30 watt plate dissipation tube while the KT66 is rated at 25 watts. The KT66 is what is called a "Kinkless Tetrode" while the 6L6 is a beam pentode. Just remember that for every pair of KT66's used in an amp, you need 1 amp more filament current then what you would for a pair of 6L6's.

sebrof
11-06-2010, 08:20 AM
I have an amp that was designed for the 6L6, and I got adapters so I can drop in 807s. RCA NOS 807s are dirt cheap and to me sound much better than the new production EH 6L6s that came with the amp. Also better than an old pair of 6L6s (Sylvaina??), but I'm not sure of the history of that pair, they may be spent.
As far as durability - My understanding is that the 807 is one of the most durable tubes on the planet (as far as audio output applications), having been designed as an RF transmitter tube and made mostly for the military. I've read stories of people in the Ham Radio world pushing them way way beyond their rating and running them that way for years.
I believe that any amp that takes 6L6s will take the 807 with the adapters. $50 for the adapters, and NOS in the box 807s will run you about what a pair of new production EH 6L6s will.

jon_s
11-06-2010, 08:31 AM
. The KT66 is what is called a "Kinkless Tetrode" while the 6L6 is a beam pentode.

Fortunately they both mean the same thing, just different marketing :thmbsp:

ducati_EL34
11-06-2010, 08:42 AM
As far as durability - My understanding is that the 807 is one of the most durable tubes on the planet (as far as audio output applications), having been designed as an RF transmitter tube and made mostly for the military. I've read stories of people in the Ham Radio world pushing them way way beyond their rating and running them that way for years.


Well Amateur radio operators are not worried about high fidelity, just a clean 800Hz CW tone... :D

Along those lines, there is a guy who builds old CW transmitters, 1929 vintage, and use 45 tubes for the finals. He says he buys "weak" ones from the hi-fi guys, who no longer find them fit for hi-fi grade audio...