[palchiu]

Dear all,

I've some questions with my new PPX3-6SN7

1. three tubes on the PPX3, which one is for gain? and right, left channel?
2. what for gain? how it works?
3. What tubes for my baby, will getting better sound?

RCA VT231 for Gain, RCA 6SN7GTB(Top Clear Type & Side Getter) for left & right channel, is that a good combination?

I'm a newbie with tubeamps, sorry for these stupid questions!

Thanks all!

 

[sacd lover]

Quote:

Originally Posted by palchiu Dear all, I've some questions with my new PPX3-6SN7 1. three tubes on the PPX3, which one is for gain? and right, left channel? 2. what for gain? how it works? 3. What tubes for my baby, will getting better sound? RCA VT231 for Gain, RCA 6SN7GTB(Top Clear Type & Side Getter) for left & right channel, is that a good combination? I'm a newbie with tubeamps, sorry for these stupid questions! Thanks all!

Going left to right the gain tube is first, followed by the left and then right channel outputs. The gain tubes works like any of the others. You dont need to do anything special. The output tubes dont need to be closely matched but should be the same tube type.

The RCA vt-231 is a good tube for gain but using more RCA's on the outputs will give you one of the darker tube combinations I have heard. If you like a dark and rich sound this combination would be fine. The RCA vt-231 sounds very good with sylvania 6sn7gta or 6sn7gtb tubes for the outputs, IMO.

The standard clear glass RCA is another good tube to use for gain and its usually easier to find and cheaper.

Here are some of my favorite combos:

Gain tube/ Output tube

Ken Rad black or clear glass 6sn7gt/ Sylvania 6sn7gt/ gta or gtb
RCA gray glass vt-231/ Sylvania 6sn7gt/ gta or gtb
RCA gray glass vt-231/ Hytron 6sn7gt
National Union black glass 6sn7gt/ Sylvania 6sn7gt/
RCA clear glass 6sn7gt/ Sylvania 6s7gta
RCA clear glass 6sn7gt/ Hytron 6sn7gt

As you can see I prefer the Sylvania or Hytrons for output tubes. Both these tubes are basically neutral and let you fine tune the sound to your liking with the gain tube. There are many good gain tubes and even more good combinations. The Tung Sol black glass round plate is the one tube nearly everyone raves about. But the round plate Tung Sol is very expensive and hard to find. The Tung Sol clear glass is another excellent gain tube along with the above mentioned Ken Rad's, RCA's and National Union.

 

[3lusiv3]

Congrats on your new PPX3.

 

[palchiu]

SACD Lover, Thank you very much!!!

I'll try the tubes that I can get(or $$$).


To 3lusiv3,

Team Singlepower!

 

[Rob N]

Earl If you ask me (Or fellow Headfier Len) the National Union grey glass is the most elusive of all the 1940's - 1950's tubes.

BTW earl how do you rate the Syl 6SN7GT 'bad boy' from late 1951 to early 1953.the ones with copper grid posts and 'mirror' type micas?

 

[sacd lover]

Quote:

Originally Posted by Rob N Earl If you ask me (Or fellow Headfier Len) the National Union grey glass is the most elusive of all the 1940's - 1950's tubes. BTW earl how do you rate the Syl 6SN7GT 'bad boy' from late 1951 to early 1953.the ones with copper grid posts and 'mirror' type micas?

I like the 'bad boy' better than the sylvania vt-231's. The sound is similar but the 'bad boy' has excellent bass. I think the 'bad boy' is probably my favorite output tube in the singlepower amps period. Interestingly, I like the sylvania 6sn7gta too, specifically for this same reason. The sylvania gta's(green label tall bottle) have great bass and a richer overall tonal balance. Of course, the gta's dont have that wonderful airy treble of the vt-231's. But for my tastes I prefer gta's most of the time to the vt-231's.

I have found four gray glass, round plate National Union 7N7's. Thats right round plates.

I have some adapters coming soon and one of these is going to be doing duty in the gain position of my old chassis mpx3. The other 7N7's (early versions) all appear to be exactly like sylvania vt-231's.

 

[Len]

Earl, nice find with the round plate 7N7. NU seems to be the key manufacturer of round plate 7N7 (looks to be 6SL7 tooling). FWIW: Plate shape really doesn't have all that much to do with sound quality (comparatively speaking versus all the other differences within tube designs). Tung Sol round plates really gave this particular plate shape notoreity, but keep in mind most 6SL7 tubes are round plates .... and they sound nothing alike

 

[sacd lover]

Quote:

Originally Posted by Len Earl, nice find with the round plate 7N7. NU seems to be the key manufacturer of round plate 7N7 (looks to be 6SL7 tooling). FWIW: Plate shape really doesn't have all that much to do with sound quality (comparatively speaking versus all the other differences within tube designs). Tung Sol round plates really gave this particular plate shape notoreity, but keep in mind most 6SL7 tubes are round plates .... and they sound nothing alike

From what I can find out the NU was the ONLY round plate 7N7. All the other early 7N7's, doesnt matter what brand, look like sylvania VT-231's. The later 7N7's I have from 1956 and newer all seem to look like sylvania 6SN7GTB's. This coincides with my research on the 7N7, crediting sylvania with producing the tube for everyone but NU. NU obviously did buy from sylvania as I have one NU branded 7N7 thats clearly a sylvania. Sylvania could have bought from NU. But, I have yet to come across any round plates that are not from NU.

I use the 6SU7GTY variant of the 6SL7. The early 6SU7GTY is a tung sol black glass round plate, with a brown base, that was almost perfectly matched between sections before leaving the tung sol factory. This tube is exceedingly good in my preamp. There is also a later tung sol clear glass 6SU7GTY that has parallel flat plates. I have a couple, but I have never listened to them yet.