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7199 recommendations

Sam Cogley said:
And the point is? Quite a few perfectly good tubes were repurposed from TV applications. The well-regarded 6BM8 output tube comes to mind.
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Not arguing, just sayin'.
I have been using 6gh8 in place of 7199 for about 10 years now. Mainly because they were easier and less costly to get. I have 5 different brands and of those I have two that are different structure.
However I still like to go back to my Dynaco MKIV's with original boards and 7199 driver/phase splitter now and then. BTW I'm set with 7199's for my needs.
 
I did the 6u8 swap deal on a Lafayette once and had oscillation troubles. Put it back to 7199s and problem went away.:dunno:
 
Bluelobster said:
Not arguing, just sayin'.
I have been using 6gh8 in place of 7199 for about 10 years now. Mainly because they were easier and less costly to get. I have 5 different brands and of those I have two that are different structure.
However I still like to go back to my Dynaco MKIV's with original boards and 7199 driver/phase splitter now and then. BTW I'm set with 7199's for my needs.
Click to expand...

I got the impression that the 6U8/6GH8 was being run down due to the TV origins, glad I was wrong.. :thmbsp:
 
Look at E80CF. I run them in my Scott 222s and Dynaco FM3s--an immediate improvement over the 6U8 types.

Only Mullard, Valvo and TFKN made the gold pin ones. The Buy It Now prices on ebay are silly!

Best from Tucson
Bob
 
The 7199 is a different pinout than the 6U8. The triode section is the same, but the pentode section, except for its screen grid, is all different. Oh, the heaters are the same. The 6U8 shares its pinout with many other tubes, but the 7199 looks to have no pinout mates.
 
Thanks for the input guys! I have read this about 4 times now and I think I've got the message on my options.
 
wa2ise said:
The 7199 is a different pinout than the 6U8. The triode section is the same, but the pentode section, except for its screen grid, is all different. Oh, the heaters are the same. The 6U8 shares its pinout with many other tubes, but the 7199 looks to have no pinout mates.
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I certainly would agree with that. I have seen a step by step rewire instruction but can't seem to find it now. I will keep looking...
 
Patrice B said:
I've been using 6U8's for a short while in my Scott where it calls for 6GH8's.
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I used 6GH8's in my Scott for a year until I recently switched them to 6U8's. I asked Craig and he said either/or is fine. The HH Scott site says 6U8 or 7199 for my 222c.....so I guess I have three options.
 
Just to be sure, are the tubes mentioned to replace the 7199's because of the cost or performance?


Regards,


Steve
 
For "rolling" purposes there are lot more choices/variety in the 6GH8 pinout verse the 7199.

Also the triode used in the 7199 for the splitter/driver is pretty week, it's alright for driving
smaller output tubes but most anything in the other pinout does a better job, I'm partial to
the 6BL8/ECF80 as my favorite "sounding" of the bunch.
 
I never met a 6U8 I liked, I have a stash of 7199's but so far, over 15 years, I've never needed to replace one. The amps I have that use 6U8 - 6U8A - 6GH8 - 6BL8's
have needed replacement and I've been through quite a few finding quiet tubes.
 
I've converted a few amps from 7199 to 6GH8 and the voltages (surprising to me!) came out dead on... not so when I plugged in 6BL8s. But tweaking a resistor value (cathode or screen) would take care of that. Keep in mind that this is generally a direct-coupled circuit - operating point of the pentode sets the operating point of the phase splitter. So it may be necessary to adjust a resistor value for lowest distortion... EVEN with different 7199s! As almost all of these pentodes have higher gain than the 7199, stability problems could occur, if there isn't much margin in the original circuit. I suppose lowering the plate load resistor (and the cathode resistor, to get back to the same plate voltage) would be one fix.
 
I'll certainly give that the 7199 is more "stable/reliable" from a tube to tube standpoint.

But for me the Amperex 6GH8 an 6BL8 have a lot more to offer in the sound department.
(in fact I don't think I've ever seen a "Good European" brand 7199, plenty in the others)
 
I needed to replace the power amp boards on my SCA-35, which originally take the 7199. The replacement boards from AudioRegenesis convert the boards to take 6U8A/6GH8As. Since I upgraded the whole boards and other parts, I can't say I've done a direct comparison of the two tube types, but my amp sounds fantastic now. I got some NOS Raytheon 6GH8As from Jim McShane. The amp is very quiet, that's for sure. Dead silent at full volume on all inputs except phono.

The AudioRegenesis boards add a 10K grid stopper to one EL84 on each channel. There are also a couple of extra components to make the tube conversion complete, and a couple of upgraded cap values. I'm happy with mine.
 
If you can't stand the 2 different labels ( I can easioly understand that... ) then just rewire those 3 pins. On the 222C those are not on a borad hey ? So just few soldering to do... And then you won't have anymore problems anymore. I have a 222D and it was built with 6U8 in the inverting section.
 
stoutblock said:
I'm going to start with 6GH8A with the plug in socket adapters...
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Well that did not work. unacceptable hum when using these tubes and adapter in both channels. Reset bias and balance with no change. let it run for 30 minutes, still hummed.

Back went in the 7199s, no hum.
 
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