Aikido Line-Stage jumper question

nanchangbob · 18th June 2011, 01:52 PM

I recently built an Aikido Line-Stage and everything is working fine. I'm using 6cg7 currently but I wanted to try some 12bh7's that I have sitting around. I just have one question about the jumpers. In the book it says the following.

HTML Code:

When using a 5687-based tubes with a 9H basing as the output tube, use jumpers J3, J5, J7 only. When
using a 6DJ8-, or 12AU7-based tubes as the output tube, use jumpers J4, J6, J8 only.

The 6DJ8 is a 9AJ and the 12au7 is a 9A base socket. Does this quote mean only these two tube and their variants need the jumpers or would all 9A or 9AJ family tubes need the jumpers including the 6cg7 which I'm currently using they are also 9AJ.

I looked over this the first time and didn't pay attention but since I started looking up the tubes and which base they were it confused me. If someone could straighten me out I would be grateful. I wrote to JB but no reply.

Thanks

DF96 · 18th June 2011, 04:03 PM

All valves with the specified base (i.e. pin layout) need the jumpers setting. This is mainly for the heater, but also the screen on those which have a screen. In addition, you might need to change resistor values as appropriate.

nanchangbob · 18th June 2011, 04:20 PM

Thanks for the reply. I do understand the resistor changes for different tubes and setting up the bias and how to determine R15 and R16 values. I was just a bit confused on jumpers J3-J8. I'm pretty sure they are in there because so many different tubes can be used. If it read all 9H based tubes use J3, J5, and J7. All other tubes use J4, J6 and J8. But it only says using a 6DJ8 or 12au7 based tube. They are all dual triodes as far as I can tell. I can pull them back out and measure where they go too. I was just hoping someone might know which tubes needed them.

nanchangbob · 18th June 2011, 06:21 PM

Okay now I got it. I found the Revision C pdf and it has the picture of the jumpers I mentioned. http://www.tubecad.com/Product_PDFs/...Mono_Rev_C.pdf On page 11.

The revision E book does not have the picture of the schematics with the jumpers in it. He added the Mokido and deleted the page with the schematic that included the jumpers and the pin numbers on the tubes. I used my dmm to check and the new one is the same. I hooked up J4, J6, J8 and all is now well. I won't need to roll the 12bh7's now. Big difference in sound. I just can't believed it worked without them in?

18th June 2011, 01:52 PM	#1
nanchangbob diyAudio Member Join Date: May 2009 Location: Southern China	Aikido Line-Stage jumper question I recently built an Aikido Line-Stage and everything is working fine. I'm using 6cg7 currently but I wanted to try some 12bh7's that I have sitting around. I just have one question about the jumpers. In the book it says the following. HTML Code: When using a 5687-based tubes with a 9H basing as the output tube, use jumpers J3, J5, J7 only. When using a 6DJ8-, or 12AU7-based tubes as the output tube, use jumpers J4, J6, J8 only. The 6DJ8 is a 9AJ and the 12au7 is a 9A base socket. Does this quote mean only these two tube and their variants need the jumpers or would all 9A or 9AJ family tubes need the jumpers including the 6cg7 which I'm currently using they are also 9AJ. I looked over this the first time and didn't pay attention but since I started looking up the tubes and which base they were it confused me. If someone could straighten me out I would be grateful. I wrote to JB but no reply. Thanks

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18th June 2011, 04:03 PM	#2
DF96 diyAudio Member Join Date: May 2007	All valves with the specified base (i.e. pin layout) need the jumpers setting. This is mainly for the heater, but also the screen on those which have a screen. In addition, you might need to change resistor values as appropriate.

18th June 2011, 04:20 PM	#3
nanchangbob diyAudio Member Join Date: May 2009 Location: Southern China	Thanks for the reply. I do understand the resistor changes for different tubes and setting up the bias and how to determine R15 and R16 values. I was just a bit confused on jumpers J3-J8. I'm pretty sure they are in there because so many different tubes can be used. If it read all 9H based tubes use J3, J5, and J7. All other tubes use J4, J6 and J8. But it only says using a 6DJ8 or 12au7 based tube. They are all dual triodes as far as I can tell. I can pull them back out and measure where they go too. I was just hoping someone might know which tubes needed them.

18th June 2011, 06:21 PM	#4
nanchangbob diyAudio Member Join Date: May 2009 Location: Southern China	Okay now I got it. I found the Revision C pdf and it has the picture of the jumpers I mentioned. http://www.tubecad.com/Product_PDFs/...Mono_Rev_C.pdf On page 11. The revision E book does not have the picture of the schematics with the jumpers in it. He added the Mokido and deleted the page with the schematic that included the jumpers and the pin numbers on the tubes. I used my dmm to check and the new one is the same. I hooked up J4, J6, J8 and all is now well. I won't need to roll the 12bh7's now. Big difference in sound. I just can't believed it worked without them in?

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