BAT VK5i power tubes.. 6l6? 5881? kt66? by who?


Need help yet again... looking to replace/add to my currrent stock of Tung sol 5881 (NOS, NOT RE-ISSUES), i RECENTLY OPTED FOR the 'reissueed Tung sol 5881... fair price I guess compared to the NOS version... but two things come to mind...
1. Just how long do these tubes take to open up? ...under low to moderate power they produce little above the mid range... add power and they open up more, though not what i'm used to with the NOS versions... they've got about 100 hrs. or less right now...

2 Is it true that RCA & GE 5881's were made by Tung Sol? how can you tell?

I run a complete set of PQ USA AMPEREX WHITES W/SHEILD in the sig set... a pair of Amperex 7308 whites in the shunts... and I just bought another pair of the PQ USA 7308'S about a week or so ago... they opened up pretty quick... I don't think the 're-issued tung sol's 5881" have as yet... or they are bad. also one of the re tugns has a dent in the top of the tube... is that OK?

OTHER'S HAVE MENTIONED that 6L6, KT66, and some other tubes work the same as 5881's.... but I do not know myself... especially in the BAT vk5....

Any help is more than appreciated.... what's the best choice in the output tube slots for a bAT vk5i?
blindjim
I liked the Sylvania 6L6WGB in place of the Sovtek 5881...
Larry
thanks, Larryken...

I gues I should take this time to post what I've found out just recently... via two tube selling resources.... and my recent experience.

Either I got a bum pair of Tung sol 5881's, ("re-issued" currently available) on E bay and the web and maybe here too... or, the 're-issues should only be bought via 'try B 4 U Buy' condition. (that's how I got the pair I bought), After approximately 100 hours no top end was apparent unless the volume was above the moderate listening level... where it's difficult to talk to someone else. I put them into a BAT vk5i. I put back in the other working pair of original Tung Sol 5881's I was replacing....

Although the 6L6, 5881, family are interchangeable, the physical dimensions of the 6L6 prohibit running the vk5i with the top up. It must be run with the top down. . . or a hole saw is needed... I guess either way wouldn't be too bad actually. I've noticed that with some signal tubes, especially the 6922's, and Telefunken 6dj8's, riding the 'convertible' is pretty good. Much more air & soundstaging.

The 5881's according to two sellers have little breaking in to deal with... two or three days and right off the bat they should do well enough to tell if you have a good pair or not. Even the Amperex PQ USA White label w/emblem take only a day or so and sound fair right off... though they do open up and gain body shortly thereafter.

According to BAT the 6L6 & 5881 are electrically the same... plate voltages change going to the KT66, or L34, the latter tubes aren't recommended by BAT for use in their preamps.

Lastly, also according to BAT the main area to change for most increase in performance are the six signal tubes... the shunts, the two well off to the side of the tow rows of sig tubes, need only to be the same type... so save some duckets there friends.. Phillips, Sovteks, etc. so long as they are compatible with the sig tubes you might normally use ... 6DJ8, 6922, 7308, AS long as they match each other.

Personally I've put in a couple different brands, and models, keeping them matched by type, of course, and the folks at BAT are absolutely right! No noticeable increase or decrease in sonic quality....

Thought i'd pass that along as I'd not seen it posted that particular way to current or prospective, vk5/vk5I/vk5iSE owners.
Hi Blindjim, I have a Bat vk5i with 4 sets of 7308 Amperex USA white label pq's circa 1963-65. They're very dynamic with a good soundstage, good detail and good highs. I also run late 1950's Tungsol 5881's. I got my pair (for around $100) from Andy at Vintage Tube Services. You can get his phone number off his web site. He's easier to reach by phone. He still had a few good sets as of a couple months ago. A pair of good Tunsol 5881's will take you to a new level. Way better dynamics, bass, soundstage and detail. As said previously, it should only be a matter of days for them to open up. All his tubes are tested at his shop. He has alot of the old testing equipment from the tube manufacturer's assembly lines dating from the 1920's to the mid 1960's. He's very knowledgable and also tests tubes. He has tested all my 7308's for 5 or 6 bucks each. (I bought those particular tubes elsewhere, actually.) All the tubes that I've bought from him have been first rate. I'd give him a ring. Best wishes. Stan
Stan, yeah, I bought some new/old Tungs just the other day from him... should be here hopefully today... then I should be set. One other unrelated item... he also mentioned some Matsushita tubes from the early 70's, or late sixties... as a warmer & richer sounding tube than the PQ's. Ever try them? ...or know someone that has? the price seems reasonable if the description bears out to be true...

As I have a number of lightly used signal tubes still in my little 'tube inventory' I'm not too sure about buying more... I doubt they'll be any richer than the Telefunkens I have. though they seem a mite light on the bottom end... I'd certainly love to have a set of tubes that provide the warmth, and richness the Tele's do though better on the bottom end...and with more 'body'.
Hi Blindjim, No I've never tried the Matsushita. The Matsushita are from Japan's electronics boom in the early 70's. They were used in televisions mostly, as I understand it. Andy told me that they are excellent tubes, but still aren't Telefunkens or Amperex. They are better than anything made new now, however. I think that dynamics, clarity, top end and bottom end would be quite a bit better with Tele's or PQ's. For a nos tube, I'd put them just above the middle of the nos tube pack. Best wishes. Stan
I own both a quad of Amperex Orange Globe Logo Made In USA 7308s as well as a quad of Matsushita Made in Holland 6DJ8 (the Mats were from Andy of VTS) and yes the Mats are a tad warmer and richer than my 7308s. However, I like the sound of 7308s better since they seem to sound more natural. Nonetheless the Mats are nice tubes, a lot better than the Sovteks and Brimars I tried.
I also like the original Tung-Sols in the power supply.My 5se now has the 6H30s for the signal, but still uses the 6DJ8s in the outboard regulators. So I can't match the reg tubes with the signal tubes. There I use the Siemens 6DJ8s.

I would like to know if anyone has been using the 6L6GCs or any of the newer brands of 5881s, such as TAD or Electro-Harmonix ?