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Best 7199 Substitution

207.6.238.50

Posted on July 3, 2011 at 17:01:59
Bubbasweet


 
Is the 6U8 the best sounding 7199 Substitution or are there others that are better?

THX

Bubba

 

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RE: Best 7199 Substitution, posted on July 3, 2011 at 19:27:29
Listens2tubes
Audiophile

Posts: 140
Location: New Jersey
Joined: January 14, 2006
Just get an RCA Black Plate 7199. http://www.nj7p.org/Tube4.php?tube=7199 or http://www.duncanamps.com/tdsl/show.php?des=7199 show no subs. This tube is a combo of triode and sharp cutoff pentode. Not jsut anything close will work. With adapter or rewire a 6gh8 is a close cousin.
Have you tweaked today?

 

RE: Best 7199 Substitution, posted on July 4, 2011 at 16:45:06
Bubba


 
I don't understand you reply. Just get RCA Black Plate 7199s? I cannot find any that is why I asked about the best tube to sub out?

What are you talking about?

 

6GH8, posted on July 4, 2011 at 17:16:02
Paully
Audiophile

Posts: 5907
Location: West Virginia
Joined: February 15, 2004
First, there are 7199 black plates for sale on ebay.

But might I suggest you try some 6GH8(A)? I have tried 7199's of various vintage such as black plates, Sylvania, and Philips. I find that the 6GH8A sound so good that I don't worry whether they are truly better or not. And they are cheap! I haven't seen any around lately but you can acutally find 6GH8A black plates. But regarldless, this is a pretty standard sub with a socket adapter and for good reason. I don't know who the actual manufacturers really are, but there are Amperex, RCA, etc... And you can get them for $4-5 each instead of $50 each. Worth a try.

 

RE: 6GH8, posted on July 4, 2011 at 19:53:57
Bubba


 
Firstly thanx for your comment,

Are 6U8 or 6EA8 the same thing?

I may try the adapters.

 

RE: 6GH8, posted on July 4, 2011 at 20:21:52
Paully
Audiophile

Posts: 5907
Location: West Virginia
Joined: February 15, 2004
I don't know, I can only tell you what people say in the archives of the tube asylum, which you can search yourself as well.

The guy in the link below says you can do a direct sub with a 6U8 for a 6GH8 so if you have the adapter according to him you can.


Also:
http://db.audioasylum.com/mhtml/m.html?forum=tubes&n=212697&highlight=6u8+6GH8&r=&search_url=%2Fcgi%2Fsearch.mpl%3FForumSelect%3DSelected%26forum%3Dmug%26SelectForummug%3Dmug

 

7199 Subs, posted on July 5, 2011 at 16:04:32
Joe Curcio
Manufacturer

Posts: 1261
Location: Northern CA
Joined: October 10, 2001
I don't want to pour cold water on this but they're all terrible. I recently did comparison of st-70 driver stages mostly looking a THD+N, IMD, noise and linearity over the output voltage range. By a wide margin the 7199 and the 6AN8 were superior to 6GH8 and 6U8 when used in the stock st-70 driver circuit. The 6GH8 samples I tried (5 samples) all showed very high THD+N and IMD (by a factor of 4 to 10 times worse) compared to the 7199's or 6AN8's.

Listening tests also confirmed the poor measured test scores with muted mids and rough (un-musical) high frequencies. Bass was pretty much the same.

When I get some time I will publish the test results.

Bottom line - opt for 7199's or use an all triode replacement module (which measures best BTW).

 

RE: 7199 Subs, posted on July 5, 2011 at 18:07:07
Paully
Audiophile

Posts: 5907
Location: West Virginia
Joined: February 15, 2004
I really hate it when people with measurements disagree with me. Blah!

 

RE: 7199 Subs, posted on July 6, 2011 at 15:27:26
GP49
Audiophile

Posts: 382
Location: No Cal
Joined: April 21, 2009
The 6AN8 (and 6AN8A) are common, too; and cheap. Use them in the Stereo 70 with the circuit values in the Mark II (I don't even know if they are different) and you'll be fine. Repinning required, but it is for the 6GH8 also.


GP49

 

Amperex Bugle Boy 6BL8/EFC80............, posted on July 6, 2011 at 19:15:28
viridian
Audiophile

Posts: 3836
Location: Portland, Oregon
Joined: May 26, 2005
Contributor
  Since:
February 1, 2012
...not well known and cheap. Same pinout as 6U8/6GH8 etc. They probably measure like crap, but I don't listen to a scope; I'm still using an amp to power my speakers for the moment.

And to stir the pot a bit more, sonically I prefer the triode/sharp cutoff pentode tubes to an all triode front end. Maybe I prefer the greater distortion, or the spectra of that distortion, or the demons have completely taken over my brain.

And to answer your earlier question, while 6U8, 6BL8 and 6GH8 can be subbed for one another without issue, the tubes are actually a bit different in their electrical characteristics which will result in different subjective sounds.

 

RE: Amperex Bugle Boy 6BL8/EFC80............, posted on July 9, 2011 at 20:54:57
GP49
Audiophile

Posts: 382
Location: No Cal
Joined: April 21, 2009
Minor nitpick: the alternate designation for the 6BL8 is *ECF80*

It was used by Dynaco, not in an amplifier, but in the FMX-3 multiplex adapter and the FM-3 tuner.

GP49

 

Thanks for the correction. A common tube in Scott and Stromberg-Carlson integrateds as well. nt, posted on July 12, 2011 at 12:35:14
viridian
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Location: Portland, Oregon
Joined: May 26, 2005
Contributor
  Since:
February 1, 2012
nt

 

RE: Thanks for the correction. A common tube in Scott and Stromberg-Carlson integrateds as well. nt, posted on July 13, 2011 at 20:58:25
Bubba


 
I broke down and bought 2 Jan Philips USA 7199s. 5 Modern Mullard 12ax7s and I also bought a 6 pack of NOS GE 6ea8..

I was looking close at the 6ea8 compared to the Jan 7199. The are very close. Almost identical in construction. So what does the big supposed tonal difference come from?

 

RE: Thanks for the correction. A common tube in Scott and Stromberg-Carlson integrateds as well. nt, posted on July 14, 2011 at 07:18:22
GP49
Audiophile

Posts: 382
Location: No Cal
Joined: April 21, 2009
I don't have direct knowledge of exactly what is different, but much of what determines how a tube functions is invisible without destroying the tube and taking the guts apart: how the grid is wound and spaced, both between its own windings and from the cathode and plate. The way audiophiles identify tubes by ribs and ridges and stuff on their plates is only that...a means of identification. The plates actually have far less to do with how a tube functions than the grid.

Can you tell by a non-destructive look that a cross-section of an EL34's grid windings are a different shape from those in a 6550 or KT88? Didn't think so. And that's a much bigger tube than a nine-pin miniature like a 7199 or 6EA8.

GP49

 

RE: Thanks for the correction. A common tube in Scott and Stromberg-Carlson integrateds as well. nt, posted on August 21, 2011 at 21:10:57
Bubba


 
I tried the subs and they sound fine to me..

 

RE: 7199 Subs, posted on November 22, 2016 at 21:34:38
Posts: 1
Location: Tucson, AZ
Joined: November 22, 2016
Did you ever publish the test results of your comparison of the 7199 to the 6GH8 when used in the stock Dynaco st-70 driver circuit? I am particularly interested in the IMD.

 

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