Vintage Impedence Selector Question

[JP2036]

I have no issue with modding amps. My favorite tones don't COME from STOCK Marshalls. But there are plenty out there that are already badly modded that you can pick up and re-mod BETTER, that I seen no reason to hack one up that's made it 50 years in its original state today. My '74 SL is modded and I'm not going to return it to stock condition, but the mods will be redone at some point for tonal improvements.

I can say with confidence that the virgin non-hacked/non modded JMP Marshalls are getting fewer & fewer which with JMP prices at an all time high already will just make them more valuble.

 

[Matthews Guitars]

I agree with that observation. I've come to realize that the prices I bought my amps for in the last two years will probably never come again.

Any all original early 70s JMP is 2500 dollars and up and that's going to be a rough looking example at that price. Better condition or older and the price goes up quickly.

One reason I seek out the most hacked up, badly modded amps I can find to purchase is because they at least sell for reasonable prices. And then I can make whatever level of effort I want to bring them back up to whatever level of originality I choose. I can leave it alone, or correct the worst sins, or do a frame-off restoration if I choose. I find that the deeper I dive into the work, the more I enjoy the work and also the more I enjoy playing the rebuilt amp after I'm done.

That 2203 I got for 1100 bucks about a year ago only needed to have its bad sounding Hammond OT replaced with a correct Dagnall, which I found. (Even period correct.) Now that that amp is back up to its original specs and has the right transformers and there's ALMOST no sign that anything was ever done to it, it's worth a lot more than my investment in it. But I don't feel the urge to sell it just yet.

 

[JP2036]

With all due respect, I disagree. That equipment was built right the first time, no " mods" needed.

No disrespect here but the Mercury/Gemini/Apollo/ programs were ever evolving/ever changing in nature. As an Engineer redesign or "modification" is common place. The explosive hatch bolts on Gus Grissom's "Liberty Bell 7" flight had to be redesigned. The entire Apollo Command Module was overhaul after the Apollo 1 fire the killed Chaffe, Grissom & White not only was it overhauled but the contract was given to a different company all together.
Apollo 13 Jim Lovell, Jack Swigert, & Fred Haise relied on NASA Engineers to get them home from Lunar orbit after the service module exploded.
The Challenger solid rocket booster O-rings and the crew cabin were completely modified/redesigned after that disaster.
Ask any Aerospace or Mechanical Engineer or for that matter the building trades where you work off Blueprints rarely does anything go according to plan.
Adapt/improvise/overcome is the name of the game.

 

[Emtbreid]

You can lead a horse to water ...

No mods....

 

[Matthews Guitars]

Even today, SPACEX uses data gathered from each StarShip test to guide the development of the next iteration.

The Russians used empirical engineering principles to develop the most efficient rocket engines ever developed, a design that is still used today, by the US space program with the RD180 engine that is derived from that legendary Russian design. They figured out how to make it by building it, testing it, watching it explode, picking up and analyzing the pieces, and figuring out what needed to be made stronger. Eventually they got a highly reliable and safe engine design that is more efficient than even the main engines made for the Space Shuttles.

Computer asimulations are not guaranteed perfect. There's no test that's quite as informative as real world testing.

 

[NOGE]

My Superbass had a busted impedance selector like yours. I enlarged the hole through the middle of the switch and fitted a NKK HS-13Y Heavy Duty 1 pole 3 way. No extra hole in the chassis. Great switch

 

[myersbw]

I'm not opposed to modded amps. Just to messing with amps that made it this far without being hacked on. It's nice to find clean original examples.

I'll add this for a case in point. I had a client bring in a 1965 Fender Champ. All original...including death cap and power cord (non-polarized). I could have left (and marked) the power cord as it would be "all original" or convince him to put a proper safety (earth) ground cord in. Thank God he did.

It's one thing to donate a piece to a museum where it forever sits and presents no danger. It's quite another to see a dangerous risk left at the possibility of a player dying. Sorry...the amp in question was only "right" for the time period. That particular impedance selector did not stand the long haul and has been the culprit of many a transformer replacement. I've replaced two with the newer coin-twist style after presenting the client with options. Both chose the newer Marshall style to keep the amp in the spirit of Marshall functionality vs. a plate with a rotary. (I don't object to the newer rotary...but, regardless of enlarging a whole...a different style switch is still a mod.)

My take is...these amps have survived and are meant to be played, thus enjoyed. They do no one good as museum pieces. I'm good with one donated to preservation, and let all the rest of us rock on with much safer amps than earlier days. Side note: Another example of not the best design...?...Marshall Major with that outrageous B+ level. No one of that year anticipated a fuzz box being slammed into that circuit. Can you say...up in smoke?

 

[JP2036]

I'll add this for a case in point. I had a client bring in a 1965 Fender Champ. All original...including death cap and power cord (non-polarized). I could have left (and marked) the power cord as it would be "all original" or convince him to put a proper safety (earth) ground cord in. Thank God he did.

It's one thing to donate a piece to a museum where it forever sits and presents no danger. It's quite another to see a dangerous risk left at the possibility of a player dying. Sorry...the amp in question was only "right" for the time period. That particular impedance selector did not stand the long haul and has been the culprit of many a transformer replacement. I've replaced two with the newer coin-twist style after presenting the client with options. Both chose the newer Marshall style to keep the amp in the spirit of Marshall functionality vs. a plate with a rotary. (I don't object to the newer rotary...but, regardless of enlarging a whole...a different style switch is still a mod.)

My take is...these amps have survived and are meant to be played, thus enjoyed. They do no one good as museum pieces. I'm good with one donated to preservation, and let all the rest of us rock on with much safer amps than earlier days. Side note: Another example of not the best design...?...Marshall Major with that outrageous B+ level. No one of that year anticipated a fuzz box being slammed into that circuit. Can you say...up in smoke?

 

[Emtbreid]

I'll add this for a case in point. I had a client bring in a 1965 Fender Champ. All original...including death cap and power cord (non-polarized). I could have left (and marked) the power cord as it would be "all original" or convince him to put a proper safety (earth) ground cord in. Thank God he did.

It's one thing to donate a piece to a museum where it forever sits and presents no danger. It's quite another to see a dangerous risk left at the possibility of a player dying. Sorry...the amp in question was only "right" for the time period. That particular impedance selector did not stand the long haul and has been the culprit of many a transformer replacement. I've replaced two with the newer coin-twist style after presenting the client with options. Both chose the newer Marshall style to keep the amp in the spirit of Marshall functionality vs. a plate with a rotary. (I don't object to the newer rotary...but, regardless of enlarging a whole...a different style switch is still a mod.)

My take is...these amps have survived and are meant to be played, thus enjoyed. They do no one good as museum pieces. I'm good with one donated to preservation, and let all the rest of us rock on with much safer amps than earlier days. Side note: Another example of not the best design...?...Marshall Major with that outrageous B+ level. No one of that year anticipated a fuzz box being slammed into that circuit. Can you say...up in smoke?

Safety concerns like a non polarized plug and death cap I wouldn’t see as “modifications” per se. I have a ‘73 twin that I got cheap but was modified internally (blackface spec) as well as having a proper ground/death cap removed. My 78 JMP on the other hand hasn’t been modified in any way. Electrolytics and tubes aren’t original, and that’s it apart from 3 resistors that had to be changed (which I bought nos pihers to put back in). Impedance switch is modern but fixed to a mounting plate with no chassis changes.