Changing from Split to Shared cathode what do I need to do?

harddriver · Post by **harddriver** » Fri Dec 01, 2006 10:12 am

Hey guys,
I have a 72 super lead that is spit cathode right now, I would like to try shared. So what do I need to do?

Is there a layout diagram somewhere that I missed?

Thanks!
Mark

mightymike · Post by **mightymike** » Fri Dec 01, 2006 10:36 am

To switch from split to shared on v1:

disconnest the yellow wire going to V1 pin 8 from the .68/2.7k.

Then run a jumper from pin 3 to pin 8 on v1

rgalpin · Post by **rgalpin** » Fri Dec 01, 2006 10:50 am

yeah that's it!

when i did it, i disconnected the wire running from the 68/2.7k to pin 8 and just put a little shrink tubing around the end so i could easily put it back to split.

and instead of running a jumper from pin 3 to 8, i connected a wire to the the turret where the 330/820 is connected to the board - ran that wire to pin 8. same result as what mike said - i just thought it was easier than messing with the connection at pin 3. i'm not the greatest soldererer in the world - so i didn't want to cause myself possible heartache at pin 3 - bla bla bla...

i think i have a picture - lemme look.

rgalpin · Post by **rgalpin** » Fri Dec 01, 2006 11:06 am

pic

awangotango · Post by **awangotango** » Fri Dec 01, 2006 1:52 pm

instead of heatshrinking that yellow wire's end, you can also just solder it back to the .68 cap turret, just to keep it from floating around and touching something.

harddriver · Post by **harddriver** » Fri Dec 01, 2006 3:15 pm

Thanks guys I really appreciate it.

I just got done putting my 100 watt load box together and was test driving it. It sounds pretty good. The line out is definitely not as hot as line out on the weber mass I had to crank my power amp some more to compensate this would problably drive into another tube head inout pretty well for slaving as Mark Cameron said. I does sound less harsh than the weber line out. I have a little 8 watt plexi I am slaving into it to test. If it blows I won't be upset. I am still exeprimenting but turned pretty good.

I took me about an hour drilling the box and soldering everything. I am not sure if it sound better than a good master volume at very lower levels yet. It does give the type of dynamic response found it ED's tone.

I am also installing the Type 2 master soon so I will compare and report back.

texwest · Post by **texwest** » Sat Dec 02, 2006 12:17 pm

I had the same question about switching to shared. After reading this it seems to me that you could just take the remove the wire from .68/2.7 and move it to 330/820. Is this correct?

mightymike · Post by **mightymike** » Sat Dec 02, 2006 4:17 pm

yep..

Janglin_Jack · Post by **Janglin_Jack** » Mon Dec 04, 2006 11:13 pm

Couldn't you get the same tone by doubling the cathode value? So instead of 820 split, go to 1.64, (or the next nearest standard value of 1.5K). Wouldn't that give you the same "tone" as the shared cathode of 820 but giving you the flexibility of a split cathode??

Jack

rockstah · Post by **rockstah** » Wed Dec 06, 2006 11:08 pm

Janglin_Jack wrote:Couldn't you get the same tone by doubling the cathode value? So instead of 820 split, go to 1.64, (or the next nearest standard value of 1.5K). Wouldn't that give you the same "tone" as the shared cathode of 820 but giving you the flexibility of a split cathode??

Jack

this is a very good question and youve done the math correcty. A 1.5k would be close enough.
but the idea of using two cathodes within the dual triod ( preamp tube) seems to me there is a gain factor involved in this alone. the actual parralelling of cathodes - perhaps someone can explain it better if this is, infact, true.

Brentsp · Post by **Brentsp** » Thu Dec 07, 2006 12:36 pm

You know, I've always gone along when someone talks about the 820 resistor when wired as a shared cathode being 1.64k becuase I've read this many times............but after thinking about this, that doesn't make sense. Yeah 820 + 820 = 1064 but wheres the 2nd 820 ohm resistence coming from for it to equal 1.64k. When you have the cathodes shared, theres nothing on the other cathode (V1b) for it to equal 1.64k

Someone smarter explain this to me..........I guess I should wire mine as shared and get a reading on V1b cathode and see if its 1.64k

rockstah · Post by **rockstah** » Thu Dec 07, 2006 12:39 pm

Brentsp wrote:You know, I've always gone along when someone talks about the 820 resistor when wired as a shared cathode being 1.64k becuase I've read this many times............but after thinking about this, that doesn't make sense. Yeah 820 + 820 = 1064 but wheres the 2nd 820 ohm resistence coming from for it to equal 1.64k. When you have the cathodes shared, theres nothing on the other cathode (V1b) for it to equal 1.64k

Someone smarter explain this to me..........I guess I should wire mine as shared and get a reading on V1b cathode and see if its 1.64k

two cathodes using the one 820 = 1.6k since both are getting 820 resistence.

Brentsp · Post by **Brentsp** » Thu Dec 07, 2006 12:42 pm

rockstah wrote:
Brentsp wrote:You know, I've always gone along when someone talks about the 820 resistor when wired as a shared cathode being 1.64k becuase I've read this many times............but after thinking about this, that doesn't make sense. Yeah 820 + 820 = 1064 but wheres the 2nd 820 ohm resistence coming from for it to equal 1.64k. When you have the cathodes shared, theres nothing on the other cathode (V1b) for it to equal 1.64k

Someone smarter explain this to me..........I guess I should wire mine as shared and get a reading on V1b cathode and see if its 1.64k
two cathodes using the one 820 = 1.6k since both are getting 820 resistence.

Hmmm I know its 1.6k as you guys say but it just doesn't make sense to me. If both are seeing 820.....how can you take a 820 resistor and double it without using another 820 resistor? See what I'm saying?

rockstah · Post by **rockstah** » Thu Dec 07, 2006 12:46 pm

Brentsp wrote:
rockstah wrote:
Brentsp wrote:You know, I've always gone along when someone talks about the 820 resistor when wired as a shared cathode being 1.64k becuase I've read this many times............but after thinking about this, that doesn't make sense. Yeah 820 + 820 = 1064 but wheres the 2nd 820 ohm resistence coming from for it to equal 1.64k. When you have the cathodes shared, theres nothing on the other cathode (V1b) for it to equal 1.64k

Someone smarter explain this to me..........I guess I should wire mine as shared and get a reading on V1b cathode and see if its 1.64k
two cathodes using the one 820 = 1.6k since both are getting 820 resistence.
Hmmm I know its 1.6k as you guys say but it just doesn't make sense to me. If both are seeing 820.....how can you take a 820 resistor and double it without using another 820 resistor? See what I'm saying?

two cathodes = 820 x 2 - u are sharing and thus using two cathodes each cathode has 820 on it - shared is combined = 820 x 2 = 1.64

mightymike · Post by **mightymike** » Thu Dec 07, 2006 8:54 pm

I thought he was saying use a 1.64 K Ohm RK`on v1a and another 1.64k OHM RK on V1b, wired up in split/parralell so that the toatal =820ohm on both when channels are jumped. sounds worth a try

So I gues you would use .33uf CK v1a , and another.33uf CK for v1b to equal .68uf. Unless you're going for the 250uf, or 330uf sound, in which case you would use 125ufs, or 165ufs respectively. You could voice both combined to eaqual v1a or v1b spec.

I have 2.7k/.68uf on my v1b split setup

So with the same logic I would have to have V1 wired up with 5.2k/.33uf on each side, and jump the channells.

So you would e using both side of the tube, but would equal the 2.7k/.68uf like the the split cathode V1b sound.

Is that what you guys are talking about?