Greetings and my 1959-60 M11

[(ggwatt)]

I just got a M11 from a friend who has had it since 1966. I dated the volume pots and the speaker to 1959 so I'm assuming the amp is a 59 or 60 model. I'm excited to restore this amp to the most original state as possible.
I have three issues/questions to resolve:

The schematic that is available shows 6SC7 preamp tubes. My amp has a 12ax7 and one tube I cannot read. I suspect it is a 12au7, but I may be totally off. It also takes a 2 amp fuse and the schematic shows 1 amp. Is there a different circuit for the M11?

The tone pot with the on/off switch is gone. The switch went out years ago and the previous owner hardwired it so the amp comes on when it is plugged in. I would like to find an original type switch/pot for it and would appreciate any insight on how to wire it.

There are four inputs. All the pictures I have seen show three. The fourth one, closest to the MIC Volume knob is spaced slightly different than the first three. My first assumption was it is a mod, but the wiring looks factory. I also noticed someone posted this observation before with no responses.

Any help and input are much appreciated, thanks
Ken

[(libratune)]

Welcome to the forum, Ken!

It would be easier to help if you provided photos of your amp.

Is your M-11 a "big box" or a small box?

Big box: http://www.rickresource.com/register/vi ... lebrity%3D

Small box: http://www.rickresource.com/register/vi ... lebrity%3D

[(ggwatt)]

Too Cool! Mine is the Big Box, which I had never seen a picture of before. The serial number is FOL165 L. I will post pics tomorrow, Thanks!

[(doctorwho)]

Cool! Can't wait to see the pics!

[(ggwatt)]

Here are the pictures. Nothing is marked, does anyone know what the preamp tubes should be? Thanks!

[(doctorwho)]

Does this schematic at the RIC corporate site help?

http://www.rickenbacker.com/pdfs/m11.pdf

[(ggwatt)]

Thanks for the reference,
The schematic shows 6SC7 preamp tubes. My amp has a 12ax7 and one tube I cannot read. I suspect it is a 12au7, but I may be totally off. It also takes a 2 amp fuse and the schematic shows 1 amp. Perhaps there are two M11 circuits?

[(libratune)]

I have a 1959 big box M-11 (see above) that has a serial number that's 4 numbers away from yours (F0161). Unlike yours, the electronics in my amp don't appear to have been altered from stock. I'll pull the preamp tube covers off mine and let you know what the tubes are.

[(libratune)]

My '59-'60 big box M-11 has two 12AX7 preamp tubes. The schematic that Gary found must be for an earlier, small box model M-11. Here's an example of a small box 1957 M-11 that has two metal 6SC7 preamp tubes:

Bottom line: I think you are safe to go with the 12AX7 or 12AU7 preamp tubes for your big box M-11. The latter has a higher output and should give a slightly cleaner sound.

[(ggwatt)]

Sorry for the delay in my response. I am in the process of changing jobs and moving my family.

Thank you all for the help. This is a great forum! I'm going to find a sutable pot for the tone control/switch and try to figure out how it was wired.

Thanks again!

[(lmark)]

I realize that this thread is a little old, but my M11 small chassis calls for a 12ax7 and a 12au7. I found that if I put the 12au7 in V1, which is where I would think that tube ought to go--and how the chassis is marked, I get tons of nasty distortion. If, however, I put the 12au7 in V2 and the 12ax7 in V1, the amp sounds superb. Two 12ax7s side by side sounds good, too. Mine was my dad's, purchased around 1955 along with a black solidbody guitar made by a some company called Gilson or Gibzon or something . . . . LMark

[(jps)]

I hope you not running that baboon Gibbon into the amp!

[(ggwatt)]

Thanks for the post!

[(electrofaro)]

I found this review of an M-11 online (eBay) and thought I'd share it here. I printed it as PDF as the forum didn't like the picture size

[(lmark)]

Re-Awakening this thread, for an update. I recently recalled that my father had said that the volume controls on the M-11 were interactive. Got to experimenting. Want glassy clean? Put the 12au7 in V1; 12ax7 in V2. Turn on and leave the tone in the full treble position. Plug in to the INST jack. ZERO the INST Volume. MAX the MIC volume (Hopefully your 12au7 is not too microphonic--ALL 12au7's will exhibit some microphony in this situation). Now turn the INST vol to NOON or so; maybe 2 o'clock. How do you like that? LMark