[buldogge]

  This looks very interesting... A way to improve our LDs that is a bit less drastic than replacing capacitors....   Could this "DACT Type 21 Stepped Attenuator Potentiometer 100K" referenced above by Buldogge be used in an LD 1+?
 
 

As long as there is 21mm D clearance to the PCB, I wouldn't see why not...might use solid pins/wire to connect it to the PCB.
 
-Mark

 

[gibosi]

  Received several 6f8g waiting for adapters  Glenn made for my tubes. was asking guys in WooAudio thread about branding and its a real mess looks like you really have to see the tube regarding the structure .So far what i found was that Westinghouse ,Philco, Tung Sol, can be similar or not ,RCA ,SYLVANIA ,G.E,RAYTHEON , also G.E. and Kenrad can be similar or not theres seems to be more than one structure type for the same brand like i said a mess .Like my Westinghouse plates looks similar to your Philco                                                                                                                                                                                                                                                                                    

 
This is especially true regarding the Tung Sol. I have seen some with round plates and some Sylvania-style shiny black T-plates. From what I have read, both of them are wonderful, but if you are looking for a pair, they just might sound a bit different. I have also noticed that Sylvania and RCA tubes manufactured in the 1940s have grey-smoked glass, but in the 1950s, the smoked glass was discontinued. As a consequence, good pictures are especially important. If I can't see the details in the pictures, I ask for better pictures. And if they don't comply, I pass.
 
Regarding National Union, I spent quite a bit time studying lots of pictures on eBay, and when I found the Philco rebrand, I was able to compare it to these pictures. Apparently, unlike their 6SN7s, National Union never used smoked gray or black glass in their 6F8G. Judging from the shape of the plates, the clear glass bottle, the two copper support rods, the shape of the micas and the way the copper wire connected to the top grid cap is twisted and terminated, I feel very certain that the Philco is a National Union.
 
Mikelap: Yours sure looks like a National Union except the shape of the micas. On all the National Unions I have seen, the micas are somewhat rectangular with smooth long sides and spikes on the shorter rounded sides that contact the glass. That said, NU used rounded spiked micas on the first version of their black-glass 6SN7, so it may be that yours was manufactured after mine, perhaps in the late 1940s or early 1950s. In the end, if yours is not a NU, then I have no idea what else it could be.

 

[MIKELAP]

 

  Received several 6f8g waiting for adapters  Glenn made for my tubes. was asking guys in WooAudio thread about branding and its a real mess looks like you really have to see the tube regarding the structure .So far what i found was that Westinghouse ,Philco, Tung Sol, can be similar or not ,RCA ,SYLVANIA ,G.E,RAYTHEON , also G.E. and Kenrad can be similar or not theres seems to be more than one structure type for the same brand like i said a mess .Like my Westinghouse plates looks similar to your Philco                                                                                                                                                                                                                                                                                    

 
This is especially true regarding the Tung Sol. I have seen some with round plates and some Sylvania-style shiny black T-plates. From what I have read, both of them are wonderful, but if you are looking for a pair, they just might sound a bit different. I have also noticed that Sylvania and RCA tubes manufactured in the 1940s have grey-smoked glass, but in the 1950s, the smoked glass was discontinued. As a consequence, good pictures are especially important. If I can't see the details in the pictures, I ask for better pictures. And if they don't comply, I pass.
 
Regarding National Union, I spent quite a bit time studying lots of pictures on eBay, and when I found the Philco rebrand, I was able to compare it to these pictures. Apparently, unlike their 6SN7s, National Union never used smoked gray or black glass in their 6F8G. Judging from the shape of the plates, the clear glass bottle, the two copper support rods, the shape of the micas and the way the copper wire connected to the top grid cap is twisted and terminated, I feel very certain that the Philco is a National Union.
 
Mikelap: Yours sure looks like a National Union except the shape of the micas. On all the National Unions I have seen, the micas are somewhat rectangular with smooth long sides and spikes on the shorter rounded sides that contact the glass. That said, NU used rounded spiked micas on the first version of their black-glass 6SN7, so it may be that yours was manufactured after mine, perhaps in the late 1940s or early 1950s. In the end, if yours is not a NU, then I have no idea what else it could be.

Expecting a NU tube next week did not see a picture but for the price i took a chance .

 

[gibosi]

  Are the grey glass NUs made by NU...any other brands they were sold as to look for?  The black and grey glass tubes seem to go for silly (to me) money...
 

 
The grey-glass NUs are fairly rare and often go for silly money. I have yet to see a rebranded grey-glass National Union 6SN7GT. However, National Union and Philco were pretty tight, so I wouldn't be surprised to see one of these carrying the Philco brand someday. I currently have three, two with war-time VT-231 and Army Signal Core markings and one with a clean black base with no visible markings. At first glance, these look very similar to the RCA grey-glass. However, the mica spacers attached to the top mica are square whereas they are rectangular on the RCA (and round on the TS mouse-ears). And if the vendor provides a good picture of the top mica, you will see these two very distinctive U-shaped structures on the NU.
 
On the other hand, the later black-glass NUs can often be found fairly inexpensively, and were often rebranded by Philco, Motorola and others.
 

 

[gibosi]

 
As long as there is 21mm D clearance to the PCB, I wouldn't see why not...might use solid pins/wire to connect it to the PCB.
 

 
The next time I open it up, will take a better look and check that clearance. Thanks!

 

[Oskari]

  However, National Union and Philco were pretty tight, …

 
So tight that Philco bought NU in 1947. 

 

[i luvmusic 2]

Since the Attenuator posted above is not designed to mount directly onto the PCB it might be a(bottom space between the PCB and the Attenuator) problem for the LD 1+ but is best suited for the MK III.
 
 I will be replacing the MK III's POT with the ALPS BLUE soon when i got a chance to do it,I just replaced my +1 pot last week.

 

[gibosi]

  Since the Attenuator posted above is not designed to mount directly onto the PCB it might be a(bottom space between the PCB and the Attenuator) problem for the LD 1+ but is best suited for the MK III.
 
 I will be replacing the MK III's POT with the ALPS BLUE soon when i got a chance to do it,I just replaced my +1 pot last week.

 
So.... which replacement pot do you recommend for the LD 1+?

 

[i luvmusic 2]

 

  Since the Attenuator posted above is not designed to mount directly onto the PCB it might be a(bottom space between the PCB and the Attenuator) problem for the LD 1+ but is best suited for the MK III.
 
 I will be replacing the MK III's POT with the ALPS BLUE soon when i got a chance to do it,I just replaced my +1 pot last week.

 
So.... which replacement pot do you recommend for the LD 1+?

 Anything that is PCB mounted that have similar size with the stock pot,the one posted above it may work by soldering a wire to the attenuator then to the PCB.My question is is there enough GAP between the Attenuator solder PODS and the PCB? Since my LD 1+ is butchered i will be redoing the pot that i just installed temporarily it will be replace with the ALPS BLUE i will let you know if the ALPS will fit into the LD 1+.

 

[adtrance]

   Anything that is PCB mounted that have similar size with the stock pot,the one posted above it may work by soldering a wire to the attenuator then to the PCB.My question is is there enough GAP between the Attenuator solder PODS and the PCB? Since my LD 1+ is butchered i will be redoing the pot that i just installed temporarily it will be replace with the ALPS BLUE i will let you know if the ALPS will fit into the LD 1+.

 
Looking forward to this!

 

[i luvmusic 2]

Hopefully sometime next week........
 
For the MK III the ALPS BLUE may not fit so i probably need to make a new FACE PLATE or butcher it like what i did to my 1+.

 

[MIKELAP]

  Hopefully sometime next week........
 
For the MK III the ALPS BLUE may not fit so i probably need to make a new FACE PLATE or butcher it like what i did to my 1+.

Its seems the pot cant me more than 21mm in dia. for it to fit in the MK3 

 

[MIKELAP]

 

[i luvmusic 2]

I've used two of these one for the CRACK and one for the S.E.X.,I Ordered 2 more for the LD 1 and MK III.

 

[i luvmusic 2]

 

  Hopefully sometime next week........
 
For the MK III the ALPS BLUE may not fit so i probably need to make a new FACE PLATE or butcher it like what i did to my 1+.

Its seems the pot cant me more than 21mm in dia. for it to fit in the MK3 

 I opened mine this morning and it looks like the stock pot is very closed to the PCB but i did not measure it.I may need to make a new Faceplate.
No matter how difficult it is to fit it into the MK III i will do my best to replace that stock pot,If it wasn't one day i had a channel Imbalanced with the 1+ i would never thought replacing the pot.Definitely those stock pot should be replaced unless you already have the ALPS BLUE VELVET installed like some models.