cademan
Lunatic Member
Okay, not mad, most people would point it out as just wondering why the old thread was resurected that's all.
7199 replacement?
- Thread starter MSamia
- Start date
Okay, not mad, most people would point it out as just wondering why the old thread was resurected that's all.
PakProtector
AK member
I don't quite see the issue with picking up an olde thread, save for the fact some of the original participants may be absent. The contents usually have enough info to be helpful, and we have a solid cadre of folk who have been around for a while and should be considered both skilled and helpful.
cheers,
Douglas
cheers,
Douglas
It deals with a product that has been out-of-production 50 years and will continue to be out-of-production for another 50 years. Still lots of people continue to use and replace these products. Thus information about the product ( 7199) will be relevant another 50 years.Okay, not mad, most people would point it out as just wondering why the old thread was resurected that's all.
Come back 2071 if thread is still active !
Pio1980
AK Member
The 6GH8 is supposed to be the closest to the 7199 as a direct replacement in the Dyna amps, tho most others appropriate seem to reportedly work well enough.
Nonetheless, having a $2-$5 drop-in plus $12pr adapter replacement for the 7199 is a long lived life saver for these amps as OEM Dyna.
Nonetheless, having a $2-$5 drop-in plus $12pr adapter replacement for the 7199 is a long lived life saver for these amps as OEM Dyna.
JohnT123
Super Member
Over the weekend I had an Ampeg guitar amp here. It had a very microphonic, but good, 7199 being used as the output driver. It took all of 2 minutes to rewire the socket for the 6GH8A and it worked very well indeed. I also modded my last ST70 to use the same tube as I have a bunch of NOS Westinghouse on hand. For me it's a no-brainer.
maxhifi
Addicted Member
The 6GH8A was stressed quite badly in RCA televisions of the 1960s, I believe it should last longer in audio service. I had two in an ST-70 work flawlessly for a decade until I sold it, but my RCA CTC38 television seems to need them changed every few years.
You're right. Most of the failures i had were in televisions because they were not used in audio back then.
I don't believe engineers would design a circuit that would deliberately over stress a tube, but you may have
a good point. Most 6gh8s were run at 3.58 MHZ. in chroma circuits. Maybe easier on them in audio circuits.
Also many TVs were run from dawn to bedtime back then. Great space heaters.
I was always a Zenith guy. My first new set was a 20cc50 chassis. Good to hear 480i is still alive.
I don't believe engineers would design a circuit that would deliberately over stress a tube, but you may have
a good point. Most 6gh8s were run at 3.58 MHZ. in chroma circuits. Maybe easier on them in audio circuits.
Also many TVs were run from dawn to bedtime back then. Great space heaters.
I was always a Zenith guy. My first new set was a 20cc50 chassis. Good to hear 480i is still alive.
kvflyer
Super Member
Let me expand if I may. One of my other hobbies is vintage vacuum tube television, which obviously include RCA. "Back in the day", RCA recognised the high failure rate of the RCA manufactured 6GH8 tube. They sourced the tubes from Sylvania and marked them with their own livery (RCA) even though they were manufactured by Sylvania. Why? Sylvania's tubes were surviving much better than those manufactured by RCA. One step further, RCA used Sylvania 6GH8 tubes in their televisions (marked RCA) when manufactured! New color receivers had Sylvania tubes in stalled, marked RCA. Yes, they were labeled "RCA". It was easy to tell who manufactured them by the font and ink marking that was used. 7199 tubes were worked very hard; therefore, few survive as "used".
trainbuftony
Electron Herder
I say keep bumpin the old threads.
We get to remember great AKers like Kegger, and so many others when people bump their threads. I say keep it up.
We can build and expand upon the knowledge base and keep all the relevant data on one thread.
We get to remember great AKers like Kegger, and so many others when people bump their threads. I say keep it up.
We can build and expand upon the knowledge base and keep all the relevant data on one thread.
Pio1980
AK Member
Due to stressful cdx of service in color TV sets, it was supposed to have been the sturdy choice for such.
maxhifi
Addicted Member
The one which seems to go bad in the CTC38 is the sync separator. When it goes bad, the horizontal hold adjustment starts to become really critical and eventually fails to work at all. The ones in the color circuit seem to keep soldiering on. Surprisingly, the one which has been working longest for me is a GE marked "Made in Great Britain".. maybe a Mullard?
I had a plasma TV in the living room for a while, but sold it and put the RCA back. I like having the tube TV still alive and well in 2021, it is such a relic but enjoyable to own.
2x’s
Ears for Beers
.
We can build and expand upon the knowledge base and keep all the relevant data on one thread.[/QUOTE]
No doubt! I revive threads with the best intel, in hopes to expand upon that, especially for vintage gear, or older technologies that are hard to find real world experience articles!
If a new question is posted it’ll just be “room treatment” or “speaker placement” or “cables”
Especially for the more advanced questions, I want to raise an old thread to “stand on the shoulders of giants” and continue an already intelligent conversation.
We can build and expand upon the knowledge base and keep all the relevant data on one thread.[/QUOTE]
No doubt! I revive threads with the best intel, in hopes to expand upon that, especially for vintage gear, or older technologies that are hard to find real world experience articles!
If a new question is posted it’ll just be “room treatment” or “speaker placement” or “cables”
Especially for the more advanced questions, I want to raise an old thread to “stand on the shoulders of giants” and continue an already intelligent conversation.
2x’s
Ears for Beers
Thanks!! 6U8 sounds like a dead ringer if I decide to upgrade! Should I be able to use an adapter so I can pull the 7199’s out to play when I grow bored of the 6U8?
KV -- By including your comment about how hard the 7199 tube was operated in a paragraph discussing your interest in vacuum tube TVs, I assume you mean then that the comment was relevant to the use of that tube in the vacuum tube TV set realm -- which surprises me. The 7199 was never intended for TV service, but for high quality audio circuits, possessing low hum and noise, low pentode partition noise, and low microphonics -- all qualities relating to high performance audio circuits. Therefore, I'm surprised they were even used in TV sets as your posts suggests, unless they were just trying to get the tube "out there". In audio circuits, I'm not aware of any designs running these tubes past their dissipation or voltage limits -- be it any of the Dynaco, Scott, or Fisher designs. I'm sure there were countless others that used the tube as well, so could you expound on what applications or manufacturers models ran this tube so hard?
Dave
Dave
Adapter unplugs just like a tube
2x’s
Ears for Beers
Awesome! I like a New York strip but sometimes I want brisket!!! That’s why I love tubes so much, a single component can be dressed for a refined hifi dinner or dressed casually for a rack of ribs and a cold drink!!!
All love!
Bobby2x’s Bobby2x’s
Pio1980
AK Member
Comments @ the big Stereo 70 base line thread seems to indicate little to no audible differences between good examples of the various optional variants and a properly functioning 7199 in the OEM circuit.
Destructor
Super Member
I have been using 6GH8 tubes in my Dynaco Series 2 and an Ultravalve of various brands and have never had a failure or bad sounding tube. The Chinese and Russian versions also work fine.
