Cry for help with tube placement Ray Lumley M100

[vucubaquix]

So this is a pretty niche question. I am replacing all the tubes in my Lumley M100's . My question is , into what sockets does the 12AX7 and 12AU7 go? I thought it would be easy, just follow what was in my amps already. So, from a birds eye view looking down, the one on the left side was a 12AU7. So I replaced it with a 12AU7. But, the old small tube on the right was a 12AU7 as well. I thought the 12AX7 would go there. So, i don't know for sure which goes where . I wonder if anyone knows?? I just learned that one of the most gifted audio tube circuit designer technicians recently passed, Dan Santoni , who lived in Ontario Canada. He was my go to guy and will be sadly missed. Thanks in advance for anyone who can help.

 

[DasguteOhr]

trace the cable from the cinch socket to the circuit board and, if necessary, traces to the tube. the first tube is input stage ecc83 / 12ax7, the second tube 12au7 is the phase splitter. don't panic will also run with two 12au7 other input amplification.

 

[vucubaquix]

Wow, thanks so much for your super quick answer Stephan, I really appreciate it.

 

[DasguteOhr]

Wow, thanks so much for your super quick answer Stephan, I really appreciate it.

My pleasure,be careful with volume with ecc83 when you start the enginehave fun and listen

 

[vucubaquix]

will do !

 

[DasguteOhr]

Love lumley amps build allways as a tank , they also do good speakers

 

[vucubaquix]

Gotta luv those Lumley Mono's. So...... I uploaded my birds eye view. I don't think I can trace or see wires to sockets and the signal path . Any ideas?

 

[DasguteOhr]

I hope you have an ohm meter, lumley please disconnect the power supply, wait a little and then remove the two tubes. measure with the ohmmeter from the signal pin rca(middle) to tube socket pin 2 and 7 . both tube sockets. where you measure zero ohms is the input tube ecc83. If there is a coupling capacitor in the signal path in front of the tube, it becomes difficult because the capacitor does not let DC voltage through. good luck

 

[vucubaquix]

Thank's all, for your help and comments. So, the answer on tube placement , for anyone else that may need to know is, the tube closest to the input jack is the 12AX7 input tube. The tube to the right is the 12AU7 is the driver . That was confirmed by Chris Johnson, all around nice guy, parts guru, upgrade wizard, original founder of Sonic Frontiers and owner of Parts ConneXion in Burlington, Ontario .

 

[vucubaquix]

I wonder, might anyone have a copy of the schematics for the Ray Lumley M100 mono tube amps???

 

[zkidd]

While I cannot really help here, I do want to pipe up that it is so nice to read about others who own Lumley amps. I have a pair of Lumley Megavox 150 Signatures which use an octal (6SN7) for the drivers / splitters so no confusion on the part of which tube is which. Might I suggest that once you figure out where the 12AU7 goes and the 12AX7 as well, you get some dry number rub-on decals and mark the respective tube sockets for future use?
And yes to the gent who stated that Lumley amps can drive almost anything! Way back in the day I had some Apogee speakers, a notorious 2 ohm load and my Lumleys drove them without incident. I have owned mine for 28 years and have never heard their equal...