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2359glenn | studio
Apr 17, 2015 at 2:57 PM Post #11,446 of 39,986
Behave! I'm having breakfast in a sports bar in Waikiki. Isn't that right, Steven?
 
Apr 17, 2015 at 4:07 PM Post #11,447 of 39,986
Enjoy Clayton!!!!!!
 
Apr 17, 2015 at 4:24 PM Post #11,448 of 39,986
It appears that my earlier post got buried under all this talk of food and stealing (borrowing?) amps... lol :)
 
So I will try again:
 
The Brimar 5Z4G is said to be a very good rectifier. However, with an output of only 125ma, it cannot provide enough current for use in Glenn's OTL. But I have been wondering...  Would it be possible to build an adapter to allow the use of two of these in order to bring the output current up to 250ma?
 
Is this feasible? Or just nuts?
 
Apr 17, 2015 at 7:27 PM Post #11,450 of 39,986
gibosi said:
  It appears that my earlier post got buried under all this talk of food and stealing (borrowing?) amps... lol :)
 
So I will try again:
 
The Brimar 5Z4G is said to be a very good rectifier. However, with an output of only 125ma, it cannot provide enough current for use in Glenn's OTL. But I have been wondering...  Would it be possible to build an adapter to allow the use of two of these in order to bring the output current up to 250ma?
 
Is this feasible? Or just nuts?
Click to expand...

 
Yeah tube talk is usually secondary to food talk.  It's the reason I didn't talk here for a long time, I'm not a foodie and I felt like I was talking to myself when I would talk tubes.
 
I think the big question here is, is the 5Z4G enough of an improvement over other options to justify going to the trouble even if it is possible?  I would wager a no personally, but that's only my own opinion.  Plus, even two of them together are still basically maxed out in an OTL.  For example if you took Soviet tubes and ran them at the 5998 setting you have a 260mA B+ draw. 
 
Heater current would likely not be an issue, but getting the same voltage to each rectifier would be the trick.  Maybe split it and use a doubler inside the adapter?  Plus the rectifiers might not heat up and both start conducting at exactly the same time, this could cause issues during startup of the amp.
 
Apr 17, 2015 at 9:26 PM Post #11,452 of 39,986
xcalibur255 said:
  Heater current would likely not be an issue, but getting the same voltage to each rectifier would be the trick.  Maybe split it and use a doubler inside the adapter?  Plus the rectifiers might not heat up and both start conducting at exactly the same time, this could cause issues during startup of the amp.
Click to expand...

 
Thanks for the thoughtful reply. So while it might be possible, a custom adapter could be rather expensive. And as I too doubt that the 5Z4G is enough of an improvement to justify an expensive adapter, I think I can easily live without it. :)
 
~~~~~~~~~~~~~~~
 
On another topic, has anyone removed an octal bakelite tube-base in order to check for loose connections and/or repair such?
 
I was able to find the following article:
 
http://www.nostalgiaair.org/References/Articles/TheFlash/Flash08.htm
 
I've got a 6F8G that works fine if I apply pressure from the top. But as soon as I remove my hand from the top grid-cap connector, the heaters quit working. Perhaps a loose connection in the base? As this is an inexpensive Sylvania, it occurs to me it might a good tube to learn how to do this procedure.
 
If anyone is aware of any other tips and tricks I would be grateful.
 
Apr 17, 2015 at 10:24 PM Post #11,454 of 39,986
parbaked said:
 
rosgr63 said:
  I've been banned for eating too many Easter sweets and cakes.
Click to expand...

I am on a low carb diet too Stavros.
I'm not consuming any carbs except for pizza and booze....ok, and rice...and pasta...
Click to expand...

I keep the pizza box on the floor for my low carb diet....
 
Apr 18, 2015 at 12:06 AM Post #11,455 of 39,986
longbowbbs said:
  I keep the pizza box on the floor for my low carb diet....
Click to expand...

That's brilliant...from now on I'm eating my pizza in the basement!
beerchug.gif

 
Apr 18, 2015 at 3:41 AM Post #11,456 of 39,986
gibosi said:
   
Thanks for the thoughtful reply. So while it might be possible, a custom adapter could be rather expensive. And as I too doubt that the 5Z4G is enough of an improvement to justify an expensive adapter, I think I can easily live without it. :)
 
~~~~~~~~~~~~~~~
 
On another topic, has anyone removed an octal bakelite tube-base in order to check for loose connections and/or repair such?
 
I was able to find the following article:
 
http://www.nostalgiaair.org/References/Articles/TheFlash/Flash08.htm
 
I've got a 6F8G that works fine if I apply pressure from the top. But as soon as I remove my hand from the top grid-cap connector, the heaters quit working. Perhaps a loose connection in the base? As this is an inexpensive Sylvania, it occurs to me it might a good tube to learn how to do this procedure.
 
If anyone is aware of any other tips and tricks I would be grateful.
Click to expand...


Yes, it was discussed in the 6SN7 tube addicts thread.
Just be careful you don't damage the connectors which could be partially oxidised and fall apart.
 
The safest is ti remove/suck out the solder from the pins and run fresh solder again without removing the base.
 
An easier solution is to run a hot solder iron tip along the pins to remelt the solder.
 
A fourth solution is to send the tube to tube repairer to rebase it for you.
 
Back to pizza again..............
 
Apr 18, 2015 at 12:52 PM Post #11,457 of 39,986
rosgr63 said:
  Back to pizza again..............
Click to expand...


Pizzahacker's "Shortbridge Pizza" - named for their friendly competitor Longbridge Pizzeria
Sopressata, house-made sausage, mushrooms, Bianco/DiNapoli tomato sauce, fresh house-stretched mozzarella, oregano & Grana Padano
 
Apr 18, 2015 at 4:46 PM Post #11,459 of 39,986
gibosi said:
 
xcalibur255 said:
  Heater current would likely not be an issue, but getting the same voltage to each rectifier would be the trick.  Maybe split it and use a doubler inside the adapter?  Plus the rectifiers might not heat up and both start conducting at exactly the same time, this could cause issues during startup of the amp.
Click to expand...

 
Thanks for the thoughtful reply. So while it might be possible, a custom adapter could be rather expensive. And as I too doubt that the 5Z4G is enough of an improvement to justify an expensive adapter, I think I can easily live without it. :)
 
~~~~~~~~~~~~~~~
 
On another topic, has anyone removed an octal bakelite tube-base in order to check for loose connections and/or repair such?
 
I was able to find the following article:
 
http://www.nostalgiaair.org/References/Articles/TheFlash/Flash08.htm
 
I've got a 6F8G that works fine if I apply pressure from the top. But as soon as I remove my hand from the top grid-cap connector, the heaters quit working. Perhaps a loose connection in the base? As this is an inexpensive Sylvania, it occurs to me it might a good tube to learn how to do this procedure.
 
If anyone is aware of any other tips and tricks I would be grateful.
Click to expand...


Don't take the base off just get a very hot soldering iron and re solder the pins if the filament is the problem
Just try re soldering pins 2&7
 
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