Plastic knob shafts? WTF?

E

emperor_black

New member
I took off all the knobs on my Uberschall. Since I bought it used, the knobs were showing signs of wear. To my surprise, I see that the knobs were originally black and painted over with creme color...probably to match the Bogner logo? Except for the master volume, I see that all the knob shafts are made of plastic. A $2500 (new price) amp with plastic knob shafts? A guitar headstock striking a knob is all it would take to shear the shaft right off. Somehow I'm not impressed with Bogner quality especially comparing it with a early 90's Mark iv.
 
I guess they have their own reasons for having installed a plastic shaft... As i have heard ENGL too have used plastic shaft after reading an article about their pros and cons using it and if i could still remember was to protect the PCB board.. but anyway i have come to know that my VHT CL also comes in with plastic shaft but painted thou but in white high quality plastic shaft... IMO i guess i prefer plastic shafts over metals because it wont create unnecessary noise (hum) when touching knobs i guess when you have a grounding issue... ??
 
Well, if you get them high-quality CTS pots, they are self-cleaning and they usually dont give any grounding issues. It costs like $14 per shaft or something. In bulk, they would be less than $10 per shaft. Even the new Marshall JVM's have plastic knob shafts. But the shafts are not the only problems with those JVM's I heard. :LOL: :LOL:
 
I guess if the pots are going to be PCB mounted, either way, then plastic IS the way to go.

It's easier to replace one bad pot, then a cracked PCB, right?

NOT that I'm condoning the use of plastic pots at all... that kinda freaks me out, dropping $2500+ on a new amp that has plastic pots... but I guess we'll see what happens.
 
jlbaxe":r7l60b48 said:
you guys buy cars with plastic bumpers and you worried about a knob on an amp. :LOL: :LOL:
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I guess there's a perspective we oughta all consider... :confused:

V.
 
I think it's the automatic assumption that plastic = garbage cheap junk.

For all we know, the plastic shaft pots they're using are better than some other metal shaft pots available. Who knows...
 
RockStarNick":2e2qqtqh said:
I think it's the automatic assumption that plastic = garbage cheap junk.

For all we know, the plastic shaft pots they're using are better than some other metal shaft pots available. Who knows...
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very true...

but its still unsettling, truthfully IMO for $2500 the pots shouldn't be attached to the board at all. Even my Krank has chassis mounted pots ...
 
RockStarNick":e5x7v1ud said:
I think it's the automatic assumption that plastic = garbage cheap junk.

For all we know, the plastic shaft pots they're using are better than some other metal shaft pots available. Who knows...
Click to expand...

The one thing 6 yrs of mechanical/materials engineering has taught me, plastics are indeed weaker than metal shafts. :LOL: :LOL: A metal shaft pot is not just sitting there. Its screwed to the faceplate with a washer and nut. The washer and nut will "fail" under an impact load, i.e some drunk throwing a beer bottle flying at the amp thus preventing damage to the pot. Even if they dont fail, the metal shaft is good enough to take loads that the amp knob might break first before the shaft failing. An easy fix.

In case of plastic shaft, the weakest link in the equation is of course the shaft. Once that breaks, you have to take everything out, replace the entire knob, etc. What a pain! I cant think of any other reason to use plastic other than cost saving. =cheap! :thumbsdown:
 
I thought the same thing when I noticed they were plastic. I had to get a road case so I won't get one broken off in the band van.......... :no:
 
Well perhaps is just on individuals who are viewing it differently... but yet i agree a boutique amp should have used higher quality accessories and parts... so did my boutique amp was as the plastic shaft didnt really bother me at all but recently have taken the shell off and did a small inspect in to circuit board non other than me trying to figure out on how to bias this baby as i am a novince here ... and i have just found out that they were using a Made in china omron's 12V DC contactor !! is not that i dislike MIC products but is just that their quality are still not on par.. as omron's 12VDC have higher grade of thoese Made in japan.. not that i am a japanese but a chinese here certainly am not condemning any of chinese products here but facts are it.... and why is it having such quality with such high price? hope thoese contactors would be long lasting and not fail anytime after 10 years lol
 
hopkinWFG":2pm150yf said:
I guess they have their own reasons for having installed a plastic shaft... As i have heard ENGL too have used plastic shaft after reading an article about their pros and cons using it and if i could still remember was to protect the PCB board.. but anyway i have come to know that my VHT CL also comes in with plastic shaft but painted thou but in white high quality plastic shaft... IMO i guess i prefer plastic shafts over metals because it wont create unnecessary noise (hum) when touching knobs i guess when you have a grounding issue... ??
Click to expand...

The combos have plastic knob shafts but ive tried the invader/steve morse and i own the special edition with all have metal shafts no hums here i have snapped a plastic shaft on a randall before though. Although to be honest i dont think my marshall has plastic shafts o_O
 
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