A friend of mine wanted me to build him a 2x10 combo cab to house his Bandmaster, & while it's here I'm doing some basic repairs on it, too. I thought some of you would like to "geek out" (as the kids like to say) on the wiring. Who knows, you might see something interesting in there.
TOWARD THE FRONT:
TOWARD THE BACK:
Last edited by Cogs; 05-16-2023 at 10:39 AM.
Thanks!
Last year a guy brought me a Concert that "just quit", I was looking forward to seeing the interior, (it still had a 2 prong plug). After playing through it for a while, I noticed the pilot lamp wasn't working, replaced the bulb.
I never did open it up!
Were you going to do anything with that bias circuit, Rob? From the build date stamped on the chassis (41st week of '69) it appears to be the AC568 or possibly the AA1069 revision, with a bias-balance control in lieu of Leo's traditional layout.
"When injustice becomes law then rebellion becomes duty."
Man, that's WAY over my head. At this point I was just going to replace the standby switch (the bat is broken off) & the bright switch on the reverb channel. I also took some more photos that I will upload this evening. All the iron has been swapped out w/Mercury Magnetics stuff
Looks like some filter caps may be needed......at least those original Mallory's.
"When injustice becomes law then rebellion becomes duty."
I'm kind of puzzled over that. Wouldn't you normally change them all out together?
I'm pretty sure it's not the AC568 circuit, as I don't see the 150 Ohm 7 Watt ceramic resistors on the power tubes cathodes to ground.Originally Posted by phantomman
"When You're Riding Down the Highway at Night, And You're Feeling that Wild Turkey's Bite" ZZ Top
I finally put the finishing touches on this little bruiser & sent it back home.
I should have documented this project a little better. Here's the nearly-completed BMR combo conversion. All that was left was the upper bck panel at this stage.
Front:
& back:
A couple notes: After these photos were taken I swapped out the 160-5N two-prong chassis plug for the 160-2N.
I know the red & black speaker leads aren't "correct", but I thought it looked sporty.
The entire cabinet, while resembling a Fender cab outwardly, is actually constructed very differently from a Fender cab: 1/2" finger joints, removeable speaker baffle, no separate grill frame, etc
As mentioned earlier, surprised that all the filter caps weren't done at once.
Also, the carbon comp resistors on the power tubes and other power regulating circuits would be something I'd replace with modern metal oxide resistors.
Unfortunately, Mouser doesn't have their old model where you could just order a few resistors here and there and you have to get them in bulk now.
In the tone stack, if the carbon comps are good that's what makes each amp unique. When needing replacing I go with carbon film as their tolerances are tighter, but then, it's the larger variance of the carbon comps that make an amp it's own soul.
Thanks for sharing. I love me some SF Fender amps.
"...pray do not imagine that those who make the noise are the only inhabitants of the field;
that, of course, they are many in number; or that, after all, they are other than the little,
shriveled, meagre, hopping, though loud and troublesome, insects of the hour."
-Edmund Burke
This project was so gratifying that I went & bought a '69 BMR for my own. I've already replaced the 2 prong cord & the bright caps. This one I will try to document a little better
You will love the 1969 BMR. It's essentially a Super Reverb with a different output transformer. Would like to see some gut shots. I may have already mentioned it, but I run it through a 4 ohm 4 x 10 cabinet I built to the same dimensions as a Super Reverb.
Last edited by Michael Smith; 06-23-2023 at 04:43 PM.
"When You're Riding Down the Highway at Night, And You're Feeling that Wild Turkey's Bite" ZZ Top
Alrightie then, here are some gut shots:
https://www.thefenderforum.com/forum...b-On-The-Bench
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