sheltie dave Posted July 4, 2003 Share Posted July 4, 2003 Hey guys, I need some help with my 299c. One of the 7199 output tubes died - looks like it outgassed and released a milky smoke that colored the top of the tube. Is there an alternate or equivalent tube that I can tempoarily plug in to replace the 7199? I have a large supply of 12au7 and 12ax7s by Sovtek. Two sites say one of these is a sub for the 7199, but size is different and I know nothing regarding bias and filament voltages. Could I drop one of these(or another sub) directly in without checking these two settings prior to placing the amp back in service? I am not worried about blowing the substitute, but wasting a couple of the 7591s is what worries me. Any guidance would be appreciated. Thanks, Dave Quote Link to comment Share on other sites More sharing options...
NOSValves Posted July 4, 2003 Share Posted July 4, 2003 There is no plug in replacement that I know of for a 7199 so your going to have to order a few from somewhere. Craig Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted July 4, 2003 Author Share Posted July 4, 2003 Craig, is this the big reason you like the 299b over the c and d versions? with both the 7199 and the 7591 being stand alone tubes, it is pretty darn inconvenient scouring ebay and Vacuum Tube Valley for replacements. As long as the amp is down, what do you think of the $75 package deal VTV has for the caps and resistors for the 299 series? Is this a large gouge, and if you have a similar package that you recommend, how much would you want? I still have a comple system up at the new house, and I can switch over to a backup amp/preamp setup here while I work on the 299c. If you think this rebuild is beyond a knuckle-dragging machinist with a fluke and a good sodering kit, I'll send it up to you, even though I'm an Illini fan. In the meantime, any advice on decent prices I should expect to pay for a set of 7199s and a quad of 7591s? Thanks, Dave Quote Link to comment Share on other sites More sharing options...
sunnysal Posted July 4, 2003 Share Posted July 4, 2003 7199s are not hard to find or drying up...NOT TRUE! NOS 7199 tubes may be becoming scarce, though triodeel says they will have any many as you need for the forseeable future (though they ask over $30 each for them)...BUT 7199s are still being produced! sovtek makes them, they cost about $20 each, I have tried NOS and new and the differences are minor. so buy sovteks and enjoy! www.newsensor.com or dozens of other places...tony Quote Link to comment Share on other sites More sharing options...
Parrot Posted July 4, 2003 Share Posted July 4, 2003 This looks like a fun argument! Will a 7199 last less than 5 minutes or not? Quote Link to comment Share on other sites More sharing options...
Deang Posted July 5, 2003 Share Posted July 5, 2003 "Metalized polypropylene is the most popular, Mylar is the best." Actually, film and foil is "the best", and the Auricap metalized polypropylene is better than anything other than film and foil types. I can't believe you just recommended mylar for coupling caps - what have you been smoking? On the 7199, that's kind of interesting -- I did find a couple of things out there floating around about that Russian tube. "By the way, if the original Dynaco 7199 driver is worn out and you replace it with a Sovtek 7199, the amp will oscillate at 500 Hz. This is because the feedback set-up in the SCA-35 is a bit quirky and only just stable with the original 7199, but not with the Sovtek which provides more gain. Detach the 1 uF C18 from pin 6, the pentode section's cathode, and connect it to ground instead. This will vastly lower the loop-gain and stabilize the amp once and for all. Plus, it will sound a lot better because of the much lower feedback. Plus, the Sovtek 7199 sounds better than the original Dynaco." "The 7199, for instance, is being manufactured in Russia and is marketed by Sovtek, although it's been reported that the Sovtek 7199 is not a true 7199, but is merely pin compatible. (Supposedly their 5Y3 isn't a true 5Y3, either, and I've read the same of their 5881; it seems that many old Soviet tubes are similar to desired types, but not quite the same, but they number them as such anyway." Quote Link to comment Share on other sites More sharing options...
sunnysal Posted July 5, 2003 Share Posted July 5, 2003 well first the good news, these tubes worked fine for many, many months in my dynaco MkIVs and, as I said, are not rare or hard to get since they are still begin produced...now the bad news, seems some people say they don't work in your amp because they incompatible or "are crap". I am not an expert on your amp so the comments may be true, I say maybe because there is an element in town who hates anything made in russia or china tube-wise, I do not know if that is at work here or not. good thing I didn't listen to anyone before trying them, because I have had NO problems to date. BTW I am sure many would say the sovtek 2A3s and EH6SN7s suck as well (many people told me that), but you know they sound great in my current amplifier in fact the EH6SN7s sound better than all my big buck NOS tubes (though I like my 1940's tungsols, not better just different than the sovteks, at three times the price). so take it all with a grain of salt, make sure that someone refers to direct experience with a specific tube in your amp. not that a certain brand is crap. All I can tell you is that those tubes worked fine in my amps, nothing more can be said by me, nor was said. perhaps they suck in scott amps. just be wary of the "russian tubes suck" crowd, they will have you spending hundreds of dollars for NOS tubes with little or no improvement in sound. by the way newsensor has the JAN version of the 7199 (US made for russian haters) for about $35...I think triodeel does as well. I have that tube, have used it in my amp and it sounds fine too. best of luck with the amp. regards, tony Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted July 5, 2003 Author Share Posted July 5, 2003 Ryan, when you say "switch the pin out of the socket," I am assuming the ceramic socket is merely the frame into which a pin contact assembly is inserted on the underside? This would mean that the + and - wires would be soddered to the pin assembly, and that the socket is only a ceramic insulator and guide for the tube on the top side. All I would have to do is look through the triode site and find the Stock # for the 6U8 tube socket, order a couple, and afetr electrocuting myself three or four times, replace the driver and phase inverter sockets, replace the 7199s with 6U8s, check a couple voltages, and part one of the underhood restoration would be underway! Forgive my naivite, but the last time I played with tubes was on a submarine twenty one years ago. Looking under the hood of the 299 is initially very intimidating, and my wife prefers my bonding experiences with my newborn to be a whole lot closer to the diaper changing table than my basement workbench dave Quote Link to comment Share on other sites More sharing options...
NOSValves Posted July 5, 2003 Share Posted July 5, 2003 Boy some people never take a hint Dave do yourself a favor and just take this subject to email or a certain person will just keep butting in. I seem to remember the title saying Craig or Mark !! craigostby@comcast.net I would not bother with converting the 7199 and I also wouldn't bother with a VTV kit. If you need some 7199 let me know I have some and there the best pentode/triode made for that application bar none. Just buy up a few and have them as spares they last for years so why convert ? Oh and this sovtek being a repinned 6BL8 is some more anti foreign hogwash maybe there was a bad batch out there ? I have ran them many times and never seen one blow out in 5 minutes although I prefer to use USA made 7199 its probably impossible to tell the difference. Also let me know if you want some killer parts for the amp I have them or can point you in the right direction. I can not state if you have the ability to do the job right or not I have no Idea what your abilities are ! Craig Quote Link to comment Share on other sites More sharing options...
bkrop Posted July 5, 2003 Share Posted July 5, 2003 Sheltie: tell me you haven't been running a 40 year old amp, with $200+ worth of tubes in it with out having it rebuilt! You are lucky you didn't fry the 7591's or a transformer.Antique electronic supply 7199 NOS 27.99 They pick brand . website tumesandmore.com Thetubestore.com had some JAN sylvania 7199 for 29.99 back in march. prices are for each tube from then.EDIT: website should read tubesandmore.com DOH! Quote Link to comment Share on other sites More sharing options...
NOSValves Posted July 5, 2003 Share Posted July 5, 2003 Isn't it funny how the story never quits changing with certain people ! This is copied from the HH Scott forum april 8th 2002. Ken, The 7199 is certainly NOT a crummy tube. The 7199, when compared to the 6U8 is a better audio tube. The 7199 was designed specifically for use in audio as a phase inverter. The 7199 has reduced hum characteristics, and has a more rugged filament (heater) which is immune to hum. The old stock 7199's, especially RCA and Amperex, are excellent tubes. Too bad the new Sovtek 7199's are microphonic. The 6U8 tube is a general purpose pentode/triode that was commonly found in late 50's, and 60's television sets. They were used for vertical/horizontal deflection, and were very prone to failure, especially in RCA televisions. This is the main reason that 6U8's are so cheap, billions of them were made for use in televisions, and old stock is still plentiful, even to this day. These tubes were also used by the US military in communications equipment, and in 1986, the goverment sold out their remaining stock of JAN (joint army navy) Phillips ECG 6U8A's. The 6U8 is a fine tube for use in audio, but it is certainly not the best phase inverter tube ever made. 7199's were not mass produced like the 6U8 tube, as they were primarily used in HiFi audio applications. If you can find NOS 7199's at a resonable price, try these before converting your Scott amp to use 6U8's. If 6U8's are the best phase splitter, then why did HHS use 7199's in their LK-150 top of the line power amplifier kit? Regards, Ryan Quote Link to comment Share on other sites More sharing options...
Parrot Posted July 5, 2003 Share Posted July 5, 2003 LOL!!! I think there must be two Ryans. One of them should have the other arrested for identity theft. Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted July 5, 2003 Author Share Posted July 5, 2003 BKrop, of course I threw the Scott 299C into the fray without a rebuild! The tubes checked out fine, the transformers were good, and the amp looks a he** lot better than this creaking 40 something body does The seller told me the amp should be good for another fourty years...he just didn't say in what manner $200 in tubes can blow up a $2000 speaker which can catch a $200k house on fire. I worry about whole house ground isolation and gfci outlets; the equipment is relatively cheap and can take care of itself for the most part. Engineers used single fault isolation even in the fifties when possible(the 7199 went and nothing else.) The month with the 299 convinced me that tubes are a good way to go with Klipsch. They sound great with HKs, Crown, and Macs; they sing with the Scott Quote Link to comment Share on other sites More sharing options...
sunnysal Posted July 5, 2003 Share Posted July 5, 2003 again my main point was that 7199 are neither rare nor scarce, so I saw no reason to mod an amp away from them. that was all. btw all this motviated me this weekend to try some swapping of my NOS philips 7199s for some sovteks and realized I could not really detect any difference in sound, perhaps I heard slightly smotter treble in the philips but I cannot be sure. put the philips back in and went on listening. I had forgotten how good my Dynaco MkIVs sound! regards, tony Quote Link to comment Share on other sites More sharing options...
NOSValves Posted July 5, 2003 Share Posted July 5, 2003 Ryan, Please think before you type I don't need to grow up. I just like to put the facts on the table as they should be ! The 7199 is a better tube for audio than a 6U8 , 6BL8 or 6GH8 especially in the later HH Scott circuits ! This is the point I am trying to make and evidently you agree or do you ? So why have the guy with little electrical experience rewire his phase splitters for a inferior tube ? To save a couple bucks ? Cheap is not everything ! Rebuilding it on his own maybe complicated for him by itself neither you or I know his abilities. Craig Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted July 5, 2003 Author Share Posted July 5, 2003 Tony, thanks for stressing that the 7199s are still available. Ryan, your input was appreciated, and the place in Chicago looks like a motherload for tube supplies and valves. After bonding with my son for a while (and washing drool, spit and exploding diaper off twice), I came over to my wife's viewpoint. I'll be spending a lot of time helping with the son and chores around the house, Craig will be changing the diapers, er, caps, resistors, and tubes on the 299C. By the middle of next month, don't come knockin' if the the house be rockin'....40 wpc of Dr. Scott, I presume? Now I have to hit Vintage Vinyl to pick up Peter, Paul, and Mary's Greatest Hits for "Puff the Magic Dragon." More bonding with baby, you know! Quote Link to comment Share on other sites More sharing options...
The Fisher Posted July 5, 2003 Share Posted July 5, 2003 Craig, The 7199 isnt a better audio tube than a 6U8, 6AN8, 6BL8, or any other dual section tubes. The only extra feature of a 7199 is its spiral, hum canceling filament. But in reality, the hum canceling has little to no effect on actually reducing induced hum picked up by the filament. If you look at the operating characteristics of the 7199 and 6U8, youll see that theyre identical. The majority of Scott amplifiers utilizing a split-load phase inverter design used the 6U8 tube, but this was before the 7199 came out. Later on after Scott introduced the 299C, the 7199 tube was released by RCA, and claimed to be superior to any other dual element tube. RCA stated in their tube manual that the 7199 was designed strictly for AF (audio frequency) applications. However, the tube really wasnt that much better. Many 7199s had high failure rates, and were more expensive. Scott used the 7199 for a short time in the 299C and 222C, and then switched back to the 6U8 tube. During this short period, no circuit changes were needed to accommodate the 7199. There are more brands of the 6U8 tube available than the 7199. The 7199 was marketed by RCA, Sylvania, and Westinghouse. The 6U8 was made by dozens of manufacturers, some better than others. You have a greater variety to choose from if using 6U8 tubes. The circuit modification is simple, and only requires that a few pins be switched around. No sound improvement or difference will be experienced. The whole idea of the mod is to save money. The 6U8 and 7199 typically last around 2-3 years, depending on how many hours the amplifier was used. Ive searched around the internet and the cheapest price I found on the 7199 (all makes) was $25. Then I searched for the 6U8, and found them as low as $0.99. I used to get 6U8s at Radio Shack for $0.99, but they quit selling tubes last summer. Bottom line: There is no great difference between a 6U8 or 7199. Both are good tubes when performing up to spec. At $25 a pop, the 7199 really isnt a good investment when you could use an identical tube for much cheaper. Bill wjkubacki@aol.com Quote Link to comment Share on other sites More sharing options...
The Fisher Posted July 5, 2003 Share Posted July 5, 2003 Craig, The 7199 isnt a better audio tube than a 6U8, 6AN8, 6BL8, or any other dual section tubes. The only extra feature of a 7199 is its spiral, hum canceling filament. But in reality, the hum canceling has little to no effect on actually reducing induced hum picked up by the filament. If you look at the operating characteristics of the 7199 and 6U8, youll see that theyre identical. The majority of Scott amplifiers utilizing a split-load phase inverter design used the 6U8 tube, but this was before the 7199 came out. Later on after Scott introduced the 299C, the 7199 tube was released by RCA, and claimed to be superior to any other dual element tube. RCA stated in their tube manual that the 7199 was designed strictly for AF (audio frequency) applications. However, the tube really wasnt that much better. Many 7199s had high failure rates, and were more expensive. Scott used the 7199 for a short time in the 299C and 222C, and then switched back to the 6U8 tube. During this short period, no circuit changes were needed to accommodate the 7199. There are more brands of the 6U8 tube available than the 7199. The 7199 was marketed by RCA, Sylvania, and Westinghouse. The 6U8 was made by dozens of manufacturers, some better than others. You have a greater variety to choose from if using 6U8 tubes. The circuit modification is simple, and only requires that a few pins be switched around. No sound improvement or difference will be experienced. The whole idea of the mod is to save money. The 6U8 and 7199 typically last around 2-3 years, depending on how many hours the amplifier was used. Ive searched around the internet and the cheapest price I found on the 7199 (all makes) was $25. Then I searched for the 6U8, and found them as low as $0.99. I used to get 6U8s at Radio Shack for $0.99, but they quit selling tubes last summer. Bottom line: There is no great difference between a 6U8 or 7199. Both are good tubes when performing up to spec. At $25 a pop, the 7199 really isnt a good investment when you could use an identical tube for much cheaper. Bill wjkubacki@aol.com Quote Link to comment Share on other sites More sharing options...
Flux Posted July 6, 2003 Share Posted July 6, 2003 "In a Scott amplifier, they work for a short time (<5 minutes), and then develop severe oscillations, at a frequency of 3000 Hz. The tube basically falls apart in Scott application. Don't buy Sovtek 7199's, they suck." "Craig likes to copy my replies from years ago. My reply was directed to one individual, and the opinion of others was that the 7199 tube was no good. Of course, that isn't true. This person bought two new 7199's before he knew about the 6U8 conversion, I merely was trying to state that 7199's are good tubes." Whatever you say, if anyone can every figure out what you are saying. Looks like plenty of people have no trouble with them, looks like they are lasting longer than 5 minutes. Fisher guy has lots of Scott gear rebuilt by Mr. Contradiction. A contradiction in itself. Quote Link to comment Share on other sites More sharing options...
Deang Posted July 6, 2003 Share Posted July 6, 2003 Hey Flux, maybe you should learn how to read a little better. Ryan said the RUSSIAN 7199's suck, and in the post that Craig copied in, he's specifically talking about 7199 NOS -- not Russian 7199's. With all due respect Craig -- did you miss that too? At any rate, I say use the right tube for the job. If the Russian tube is repinned, I say just shell out the money for NOS 7199's or get rid of the amp and buy something more suitable to the pocketbook. Quote Link to comment Share on other sites More sharing options...
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