Alternatives for 7199 & 6973?

gogofast

gogofast

Addicted Member
hello,
i need to replace a few 7199's and 6973's and was surprised by how much they go for on ebay. i know that 6cz5 can be substituted for 6973's, but is there any alternative for 7199's?

also how are the 6cz5's compared to 6973's?
 
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NOS 7199's can usually be had for ~$10
You can rewire the sockets for 6u8/6GH8A, in fact Dynakit has an adaptor for $20 if you have the room in you amp.
 
drknstrmyknight said:
NOS 7199's can usually be had for ~$10
You can rewire the sockets for 6u8/6GH8A, in fact Dynakit has an adaptor for $20 if you have the room in you amp.
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hey-Hey!!!,
I'd put the usual price of a NOS 7199 at more like $30. Re-pin the socket for another triode/pentode, or abandon the circuit for a twin-triode diff amp, or pay for sourcing 7199's. The 7199 was both good and inexpensive enough that lots of designs got built with it. Neither show that better or more expensive weren't viable options outside of the cost-reduced commercial arena.
cheers,
Douglas
 
Aside from the common 6GH8 you can also explore the 6AN8--although they may suffer the same problem as the 7199--$-wise.
 
GOGOFAST I'm suffering the same fate as you , I have a amp from a AMPEX console that uses the same tubes, bought a three some of 7199 now i'm looking for 6973 ??
some where here on AK I belive someone said the the
6CZ5 tubes are good for 350v, 6973 voltage is 400 or more at least in my amp so their may be a problem there, Dont takle this as fact as I'm kinda new to tubes also Steve
 
The 7199 pinout is unique, but can be rewiers for others. I can't imagine that we'll ever run out of NOS 6BL8s, 6U8s, 6GH8s, etc. Although if we do, there are plenty of other triode-pentodes.

Look for RCA 6CZ5s in the taller bottle - I'd be leery of the later short ones and Japanese ones. I have found GE, DuMont, Sylvania, Tung-Sol labels on the RCAs - look for the octagon around the number.
 
The are new manufactured 6973s available by EH, I haven't personally gotten around to trying them out but it's nice to know they are there. This is one of those things I've been meaning to get around to but never do....:scratch2:
 
thanks for all the info.

nos 7199's are going for around $80/pair:eek:
i guess i'll have to figure out if rewiring is more cost effective and easy enough.
 
englissa said:
some where here on AK I belive someone said the the 6CZ5 tubes are good for 350v, 6973 voltage is 400 or more at least in my amp so their may be a problem there, Dont takle this as fact as I'm kinda new to tubes also Steve
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The Ampex stereo 6973 amp has 400v on the plates (if your wall voltage is 120v) but the cathode bias voltage is also about 33v, which puts the max voltage closer to 370v. The original schematic specified 385 volts on the plates with 115v wall voltage which would put a 6CZ5 just about at its max rating.

I've used 6CZ5's in my Ampex (at 400v plate) and thought they sounded fine although I didn't do any critical comparison. I have no idea how long they'd last because I only used them for a couple of weeks.
 
I checked some NOS 6CZ5s to pick out a few matched ones... they biased up nice and even at 370V, 40 mA. Didn't run 'em too long though - that's 15W! Back down on the current a little and they should be fine.
 
I guess I'm lucky - or patient, but I've got a half a dozen nos jan's, westinhouse and ge's - don't think I even paid more the ten bucks. Like most other tubes there seems to be a glut now and then. Seem to be more reliable than 6U8's...
 
I guess I'm lucky - or patient, but I've got a half a dozen nos jan's, westinhouse and ge's - don't think I even paid more the ten bucks.
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Huh!? Feel free to share. I nearly wore the letters off my keyboard and the lowest I came across that were $25. Yer sure they were NOS and not pulls?

Now I've done my shopping, I'm, ready to order soon. (My new PC-3 board came in.)
 
Hi All,

I'm pretty sure I've got some NOS 7199's in boxes too, mostly GE or RCA's, although I kinda remember Sylvania's for some reason too I think and probably some Dynaco or other stereo manufacturer used pulls. Does anyone remember if there were European branded ones like Mullard or Amperex? I'll have to dig them out of the stash to check now that my curiosity is piqued.

I probably picked them up a long time ago when I was hunting tubes more actively. I used to find them often at garage sales and occasionally at thrift stores (really long time ago). If you go to ham radio fests or known electronic swap meets, they sometimes show up.

Over the weekend, my brother called and said he stumbled on some tube stuff in a garage at an estate sale. He talked to the family selling all the father's stuff. Apparently, the garage was so full of stuff, they couldn't get into it to inventory it properly. They told him they hired a dumpster company and basically dumped one ENTIRE wall of the garage full of TUBES - most in boxes - and who knows what other audio/TV/electronics gear - to get at other "stuff" that they knew would be worth something. They said it all got hauled off 3 days prior to the sale!!! :tears::tears::tears: Course it could have been all old TV stuff but Jeeze, couldn't people just do a little homework to check value or just spread it out on the driveway in boxes and let potential buyers check it out before the dump? Sad!! :thumbsdn:

Unfortunately, I was out of town and my brother was unwilling to followup on it. Those type of leads, no matter how daunting, may still be worthwhile to check, if only to understand what was lost or to try to recover something and keep it out of the landfills. SIGH!!

Regards,

Bart
 
i heard that most US brands used to buy other company's over stocks and label them with their own. so RCA, GE, and Sylvania are all mixed but can tell the difference with certain marks - for example '7199' inside the rectangle, dots underneath, 'made in usa', and etc. i haven't yet seen european made ones.
 
My information is that the 7199 carried at least these names on the bottle: Sylvania, RCA, GE, Phillips, JAN Phillips, Raytheon, Westinghouse, Dyna and Dynaco. There may have been others. The Sovtek version was not really a 7199, but rather a re-pined, other triode-pentode tube. Of the tubes that carried both a triode and pentode circuit in the same bottle, the 7199 was the only one that was especially designed for audio application. Among its salient features was minimal noise. And, of all the tubes that the Dyna design team tested and evaluated, the Sylvania was selected for reasons of being marginally quieter than the runner-up — the RCA. Thus Sylvanias were supplied with the ST-70 production. Some of these were labeled as Dyna, and later as Dynaco. I believe that some of them were also branded as 'Sylvania'.

GE seems to have produced their own tubes, but some RCA versions carried the GE logo. Other combinations of actual production and applied brand names were extant.

All informed sources insist that there really is no substitute for the 7199. Any other tube is either subject to wiring alterations on the pins, or they constitute a compromise of what many observers claim was a tube that was already a sort of compromise in terms of how it was applied in the ST-70. This is the main reason why upgrade or updated boards employ a different tube complement, such as a cascoded triode for the driver tubes, and a separate triode for the inverter. The former emulates the pentode section. An overwhelming number hobbyists and professionals think that this is an effective update that is superior to the original configuration. Moreover, a number of tubes can be selected for the purpose — without altering the essential design very much.

In an effort to reduce the the parts count and keeps costs to a minimum, Dynaco settled on the 7199 pair. It produced the best cost/return ratio that could be constructed at the time. Some Dyna fans stick by the 7199 because they think that it provides the distinctive qualities of the stock ST-70 that they revere. Nevertheless, no one disputes that there is a difference between the updates and the original board, and the majority of users swear by later and numerous modifications.

Unless you change out the board for an updated version, or for one of the more radical redesigns of the driver section, you will be having to source NOS or used stocks of the 7199. I've been seeking info about substitutes for the 7199 for a long time — since I acquired my amp in 1988. There isn't one.

Recently, I have selected to rebuild my amp as close to stock. For that reason, I will continue to be in the way of the 7199. Later, I hope to build an ST-70 clone variant. Then I will have both a classic 70 and another that many people can perhaps quite rightly say is not an ST-70 at all. Classics in other fields have experienced similar developmental histories. For example, hardly anyone will argue that a Griffon engined Supermarine Spitfire F. 22 was the same aeroplane as the Merlin powered Mk II that flew in the Battle of Britain.

In IMHO, once you change the driver tubes, it is a slippery slope into the mod kitchen. And the recipes can easily and radically change the taste. I'm not advising purism — just observing.
 
Some good info about the 7199 here. It's definitely interesting, but now I'm a little worried about if I ever need to replace mine. :scratch2:
 
You may not be aware who a portion of your "competition" for 7199's (and 6973's) is...alternatively, you may not be aware of a possible source for them...jukeboxes! Seeburg tube stereo jukeboxes (there were four model-years of them before they went solid-state) used both a pair of 7199's and four 6973's. Most jukebox collectors and restorers are not interested in exploring substitutions, they want them to be rebuilt as original. Besides, I think the 6CZ5's are lower power and higher distortion. The 6973 was RCA's last gasp at hi-fi tube design before solid-state took over, and with all their accumulated experience, they crammed a lot of tube into that little 9-pin jug. Wurlitzer and AMI's also used 6973's, but I'm not so sure about 7199's since I'm a Seeburg collector (I have three of the tube stereo ones).

So, you are also bidding against stubborn juke collectors when you are trying to round up the NOS ones on eBay, but on the other hand, if you know of an old jukebox operator in your area who is cleaning out his shop, you might just be able to score some before the vintage-audio guys get hold of them!

--Bob
 
That explains a lot, Bob E., thanx for that info. Going by the chart of numerical IDs, my 7199s & 7408s were made by GE in '61, so with any luck at all, they won't NEED replaced any time soon. ;) But it's good to know one direction to look for spares. :yes:
 
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