NOS 6L6, 5881's

Chappy · Post by **Chappy** » Thu 09/21/06 7:21 pm

I have an opportunity to buy some NOS tubes probably pretty cheap. Is an RCA 6L6 metal can tube a suitable choice for a single ended amp, or should I just stick with the glass tube versions?

I've also seen some vendors on Ebay bashing JAN Philips tubes saying that their sound quality sucks. Is there any merit to this? I was under the impression that military tubes were the best. I'm asking since I might also have the opportunity to pick up some NOS 5881's and other assorted JAN types which were made for the military by Tung Sol & Philips respectively.

Any enlightenment/first hand experience before I buy would be greatly appreciated.

Chappy

dartanion · Post by **dartanion** » Thu 09/21/06 11:12 pm

Tone is in the ears of the beholder

Metal envelope tubes are fine, all be that those 6L6s are not the same as a 6L6GC. The old metal 6L6s won't dissipate as much wattage as the GCs.

Yeah, some folks aren't fond of the JAN Philips, but again, if you get a good deal on them, they are good quality tubes. Tung Sols ARE THE GOLD STANDARD 5881!!!

Chappy · Post by **Chappy** » Fri 09/22/06 4:53 am

Thanks for the response Dartanion

I have already acquired quite a few used old military tubes from a flight simulator. I just got my hands on a high quality calibrated tube tester and I've done some testing over the last few nights. I was amazed to find that 10 out of 11 of my old 5881's (mostly Tung Sol, few CBS?) tested strong on the life test, with all showing good transconductance. Same also for some 6V6's, 6SJ7's, 6AQ5's and 12AT7's.

If the 5881's are the "Gold Standard" then I guess I'll be making my next amp out of them!

Chappy

bamboo · Post by **bamboo** » Fri 09/22/06 5:54 am

No question that the Tung-sols are worthy.
As for the JAN Philips 6L6GB tubes, I like them. Been running them in a Super Reverb for several years. They seem to break up a little earlier than most, which is a good thing in a Super Rev. The tone is strong and fendery with a good bass response. I can see where they wouldn't be some folks cup of tea, but they are not a "bad" tube by any means.

If you can get them cheap, and test/match them...I say go for it. You can always Ebay them if you don't like them. (and probably sell to the same vendors bashing them!)

7enderman · Post by **7enderman** » Tue 10/03/06 5:58 pm

Hi Chappy,
from my personal oint of view NOS Tubes are great in the Preamp Section but not needed for the Poweramp.
I tried several NOS and new Tubes in my Amps and for me JJ 6L6 are fine.
Warm, loud and reliable and last but not least: cheap.

cheers
MIKE

dartanion · Post by **dartanion** » Tue 10/03/06 6:33 pm

Oh, but a good set of NOS 6L6s can make a HUGE difference in tone.

To my ears, NOTHING compares to RCA Blackplate 6L6GCs!!!!

Some new production tubes will sound good, but I haven't seen many last all that long. My SFTR has it's original RCAs that sound flippin' awesome. Not bad for 37+ years of use/abuse

lastwinj · Post by **lastwinj** » Tue 10/03/06 7:06 pm

all metal encased tubes are black plates by the way...at least the ones we are talking about here.

jeremy

Trout · Post by **Trout** » Tue 10/03/06 8:20 pm

Be Careful with those metal can 6L6's, That outter shell on many of those old 6L6 Metal bodies are interally connect to pin 1? I forget, which is often concidered an unused or non-existant pin.
Either way, I would check the Shell /Pin Continuity

In some amps that can represent a hazard.
Trout

Trout · Post by **Trout** » Tue 10/03/06 8:22 pm

Trout wrote:Be Careful with those metal can 6L6's, That outter shell on many of those old 6L6 Metal bodies are interally connect to pin 1? I forget, which is often concidered an unused or non-existant pin.
Either way, I would check the Shell /Pin Continuity

In some amps that can represent a hazard.
Trout

OOOPS wrong button

Chappy · Post by **Chappy** » Tue 10/03/06 11:50 pm

Trout

Thanks for the tip. I'll keep that in mind as I just bought a NOS RCA metal 6L6. I also got an assortment of NOS 6V6, 6K6, 6W6, & 6F6's.
I should be able to audition them soon as I am almost done wiring up my testbed amp.

Chappy

7enderman · Post by **7enderman** » Wed 10/04/06 3:02 am

Dartanion,
might be a problem with my ears

or my now 40years old Super Reverb is so much forgiving.
anyway - i have RCA Blackplates in the Preampsection, probably i should give some Blackplate 6L6 GC a try once again.

MIKE

praga · Post by **praga** » Mon 10/09/06 10:11 pm

I've just come across a couple pairs of the metal 6L6 tubes (RCA and NOS Sylvania). Can these can safely be used in place of 6V6s in amps like a tweed deluxe?

Spankenstrat · Post by **Spankenstrat** » Mon 10/09/06 11:39 pm

Phillips 7581A's

Post by **zaphod_phil** » Tue 10/10/06 4:16 am

Why would you want to build an amp with 6L6s or 5881s anyway? Those tubes don't break up much and are mainly for uber-clean Fendery amps.

IMO KT66s, KT77s, EL34s and 6V6s are going to be much more rewarding to build with.

dartanion · Post by **dartanion** » Tue 10/10/06 12:52 pm

zaphod_phil wrote:Why would you want to build an amp with 6L6s or 5881s anyway? Those tubes don't break up much and are mainly for uber-clean Fendery amps. IMO KT66s, KT77s, EL34s and 6V6s are going to be much more rewarding to build with.

Well, if you are like me, I have a couple of those Uber-Clean Fenders in my collection. They have "that" clean tone everyone wants. I've got my Marshall's and original designs for distorted tones.

bamboo · Post by **bamboo** » Tue 10/10/06 1:24 pm

Not only do Fenders like the Bassman (5881) and Super Reverb (6L6) have a great clean tone, but the OD tones are pretty sweet, too!

Post by **zaphod_phil** » Tue 10/10/06 2:43 pm

They tend to go farty at those volume levels. And besides, clean is for sissies!

dartanion · Post by **dartanion** » Tue 10/10/06 2:48 pm

zaphod_phil wrote:They tend to go farty at those volume levels. And besides, clean is for sissies!

I guess I need to get a Hello Kitty Strat for playing clean

sgtoverdrive · Post by **sgtoverdrive** » Thu 10/12/06 10:35 am

with all due respect dont give the 5881 a bad rap this is a tube with a purpose! i didnt have anything with low enough plate voltage to run em safe,or so i was led to believe. when tungsol put out the data sheets on 5881 they were quite conservative.two reasons for this both prudent ones .they had a huge military contract .and when you sell something to the govt,it better work! the engineers underated their capacity on every curve of the graph.when i purchased and old gretsch fury twin ,that came with blackplate rcas .the amp had seen twenty hours of use since its purchase in 1966. from the otis kansas high school bandroom.so they were virtually new.in no way shape or form did these have anything on the tungsols.this amp puts about 375 on the plates at idle and has more sustain and clear bell tones with later breakup as you would expect from str 387 envelope.so i disagree with a few things regarding there characteristics.it is quite possibly the finest tube ever made.and i hoard them like no other.the us gov did not choose kt66 or 77 or rca blackplates to open the bombbay doors on there pre solid state aircraft.they chose the tube in question.i have original 1st issue raytheon 5881s that must have 15 thousand hours on them pins are broke flashing almost non exsistant,yet the mutual conductance is still in the 600 range.not to shabby for a pygmee version of the 6l6.they have more harmonic capability then there larger cousins at lower voltages .i took an old whacked out set and put them in the meat grinder ,.....gibson atlas 510 at idle .cathode bias tube killer.couldnt kill em .i got the idea from bits and volts for safe operation by way of sgt ods retard zener diode lol two surface mount 200 ohm 50 watt resisitors right to the secondarys ...trimmed a hefty 90 volts off so i could run this type in my mercury!.sustain breakup and elegance is what i hear! course im an old man and my ears aint what they used to be 100 years ago! Sgt overdrawn...

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NOS 6L6, 5881's

NOS 6L6, 5881's