[pataburd]

Quote:

Originally Posted by Skylab /img/forum/go_quote.gif OK what you need is an RCA grey-glass 6SN7GT. Use that with a grey-plate RCA 6AS7G, and that is as syrupy as you can get with the 336SE, IMO/E.

What he said! Double up on the RCA, and make sure the rear tube is the 6AS7G grey-plate, NOT black-plate. You do pay, though, with a bit of a softer presentation, very midrange rich, but a little hazy in the bass, too.

 

[BIG POPPA]

It won't have a softer presentation. I forgot to mention that the wall receptacle is an Oyaide R1 and with the SR it fixes the decadent sound of that. The sound I have with my 336se is pretty awesome. Just have to tweek the last 1% with some tubes. Tube roll, fuse roll, powercable roll. What next?

 

[Oskari]

Quote:

Originally Posted by shiaokun /img/forum/go_quote.gif Oskari, your Sylvanias do look younger. mine have that 50's feel.

Yep. Your youngest one, I think, is later than 50s, though.

Quote:

Originally Posted by shiaokun /img/forum/go_quote.gif this week, starting the GE run. the first one is a 6SN7GTA (the first one from the left.) i suppose the "188-5" is a factory code? three of them have it. the other one says 188-4.

188 = GE
5 = Owensboro, Kentucky (Ken-Rad) plant
4 = maybe Owensboro as well

Quote:

Originally Posted by shiaokun /img/forum/go_quote.gif that leaves "4-09" as the date code? the 9th week of 54?

Yes. The 6SN7GTB was introduced in 54, and probably soon replaced the GTA introduced in 50.

Quote:

Originally Posted by shiaokun /img/forum/go_quote.gif oh, this one hums in the beginning. after about 45 minutes it went away.

By the way, I Fitz-modded my 336SE with 220uF/25V Elna Silmic II caps but I haven't properly listenned to it yet.

 

[pataburd]

Quote:

Originally Posted by BIG POPPA /img/forum/go_quote.gif It won't have a softer presentation. I forgot to mention that the wall receptacle is an Oyaide R1 and with the SR it fixes the decadent sound of that. The sound I have with my 336se is pretty awesome. Just have to tweek the last 1% with some tubes. Tube roll, fuse roll, powercable roll. What next?

Maybe "softer" wasn't the best adjective to use. The RCA 6AS7G grey plate will bring expansiveness and a nice, open midrange, but bass will not be as prominent or punchy.

Try taking the power strip out and see if the bass comes back. Some (active) power conditioners can rob your system of dynamics.

What next?

(1) Try some tube dampers. Herbies damping rings work well; the Duende titanium/teflon rings work even better, I think. You can get heat resistant "o-ring"-type dampers cheaply on e-Bay, and they work fine, too, for the price. Some damping, I think, can be beneficial; but you can overdamp tubes and deaden the sound, too.

(2) Try isolation/vibration control under the amp. I used the Herbies gabon ebony Domes to good effect, or DH Labs cones.

(3) You can make a platform with five Vibrapods, five racquet balls and a piece of 3/4 inch MDF board on which to place the amp. I call it the "Cloud Nine-to-Five" DIY platform.

(4) I've also made small wooden boxes, about 2 inches deep, open at the top, and filled and levelled them to about 1.25 inches with fine sand. Cut a piece of 3/4 inch MDF to fit inside the inside dimensions of the box (offset about 1/8 inch in from all sides) and place over the sand. Put the amp on top of the MDF. This is one of the most effective and least expensive isolation platforms I've ever used.

If you have a CD/DVD player as a source, then isolate it first, since it should benefit most from isolation/vibration damping.

PAB

 

[shiaokun]

no kidding! just received a package of 4 6AS7G tubes:

1. GE JAN-CG-6ASTG 5-39 188-5 (Oskari, thanks for decoding the factory code.) (P1440570)
2. RCA JAN CRC-6AS7-G 3-04 then a mark S-C 177 (see the zoom-in pic.)
3. RCA 6AS7 G 8-26 (P1440569)
4. RCA JAN 6AS7G 69-39 (red text) (P1440571)

i see there are grey-plate and blcak-plate RCA. can someone tell me which plate exactly am i looking at? the plates all look grey/black-ish to me.

am thinking to have a GE combo next week.

 

[Skylab]

Little hard to tell but those all look like black-plate to me. The black plates sometimes look very dark grey; the grey plates are light grey and are unmistakeable.

 

[Oskari]

Quote:

Originally Posted by Skylab /img/forum/go_quote.gif Little hard to tell but those all look like black-plate to me. The black plates sometimes look very dark grey; the grey plates are light grey and are unmistakeable.

I agree that the gray is really quite light but it can look darker in photos. The attached photo gives one example. The plates look lighter than this in real life.

Quote:

Originally Posted by shiaokun /img/forum/go_quote.gif 4. RCA JAN 6AS7G 69-39 (red text) (P1440571)

Based on the photo (and date) this could be a gray-plate tube but it is indeed difficult to tell.

Quote:

Originally Posted by shiaokun /img/forum/go_quote.gif 2. RCA JAN CRC-6AS7-G 3-04 then a mark S-C 177 (see the zoom-in pic.)

I've seen this mark before but I don't know the significance of it. The letters could be SAC.

 

[shiaokun]

my curiosity got the better of me and i replaced the Svetlana 6H13C yesterday, which had been running since May 11.

now using a GE combo.
6SN7GTA 4-09
6AS7G 5-39
both have the same factory code: 188-5

that mark does look like SAC. i overlooked the A.

SAC = Strategic Air Command?!

 

[glitch39]

Quote:

Originally Posted by shiaokun /img/forum/go_quote.gif no kidding! just received a package of 4 6AS7G tubes: 1. GE JAN-CG-6ASTG 5-39 188-5 (Oskari, thanks for decoding the factory code.) (P1440570) 2. RCA JAN CRC-6AS7-G 3-04 then a mark S-C 177 (see the zoom-in pic.) 3. RCA 6AS7 G 8-26 (P1440569) 4. RCA JAN 6AS7G 69-39 (red text) (P1440571) i see there are grey-plate and blcak-plate RCA. can someone tell me which plate exactly am i looking at? the plates all look grey/black-ish to me. am thinking to have a GE combo next week.

#4 with red text is gray plate. the first three are all black plates

 

[pataburd]

Is that GE a rebranded RCA? I've never seen/owned one like that.

 

[Skylab]

It is an RCA - later production. I have a few like that. Mine are all gray-plate - they look MUCH lighter than that picture, but it must just be the light.

It does seem that the black-plates were all earlier production except for the shiny black plates like the ones in the GE tube above (the first in the picture) which I have somewhat recent (late 60's at least) Tung-Sol production.

 

[Oskari]

Quote:

Originally Posted by Skylab /img/forum/go_quote.gif It is an RCA - later production. I have a few like that. Mine are all gray-plate - they look MUCH lighter than that picture, but it must just be the light.

Sorry, Skylab, what was this in reference to?

 

[pataburd]

Quote:

Originally Posted by Oskari /img/forum/go_quote.gif Sorry, Skylab, what was this in reference to?

I think he's answering my question about tube #1 on shiaokun's tube/picture list (the GE-branded RCA 6AS7). He mentions that he has a few 6AS7 like that (i.e., GE-branded RCA), but that his are all gray-plate types, then how easily distinguishable a gray-plate should be from a black-plate 6AS7.

 

[Skylab]

LOL - sorry - my first comment was in reference to the tube on the far RIGHT of the four original pictures, in response to the post by Glitch.


The second part of my post about the shiny black plates (with no shielding below the plates) is the GE tube in the "#1" left position.

Sorry for the confusion.

I have about 40-50 6AS7G tubes currently, and they do come in a variety of subtly different flavors:

> Black vs. Gray Plates

> Top vs. Bottom Getter

> metal "shield" below the plates, vs. not

There can be any combination of these things.

And the 5998 and the GEC 6AS7G have completely different structures.

 

[shiaokun]

so i do have a gray-plate: the number 4 RCA JAN 6AS7G 69-39 (red text) (P1440571)! yeah!

will try that in the next round.