I am looking to replace all the trimpots, but have difficulties finding a multi-turn replacement which will fit and would still be accessible (especially on the amp boards). Does anyone know the best solution for this? I have included some photos of the amp and a Bourns trimpot which might fit, but the legs need to be left long. All help is welcome! 😱
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I can see the problem in the first picture not much access ,have a look at -
Trimpots for Prototyping and Breadboards - Robot Room
The third one is multi-turn with the adjustment vertically.
Trimpots for Prototyping and Breadboards - Robot Room
The third one is multi-turn with the adjustment vertically.
Hi,
Really like the information here. May need to consider most small trim pots are extremely limited in wattage. As long as that isn't an issue, they make adjustments so much easier.
Really like the information here. May need to consider most small trim pots are extremely limited in wattage. As long as that isn't an issue, they make adjustments so much easier.
I had a look at your link Duncan2, but it's not clear to me which pot you mean. Maybe with a short plastic screwdriver its still possible to access a regular multi-turn pot? Any idea how to determine the pin out? 123, 321
Downside to small pots is that the legs might not be long enough (happened to me when I bought expensive Vishay pots for my Quad 303 🙁 )
Its the words-
Third from the left . I don't see what your criticism is all small pots have a limited life but your not continually adjusting them -----are you? and using a small screwdriver its simple to adjust from above.
And yes I once owned a Quad 303 ,somewhere I have the original Quad circuit diagram its pretty bombproof and smooth.
Just install them in the same physical relationship as the old ones .
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I'm sorry if I wasn't clear. I am not criticising the limited life span of the small pots. I just meant that they might not physically fit.
Quad 303 had a horizontal pot, so the pins were further apart. (I should have measured the distance at the time)
Here it's more about accessibility. I have only found one vertical multi-turn pot where the adjustment is done from the side, but unfortunate it's too expensive.
Quad 303 had a horizontal pot, so the pins were further apart. (I should have measured the distance at the time)
Here it's more about accessibility. I have only found one vertical multi-turn pot where the adjustment is done from the side, but unfortunate it's too expensive.
But the adjustment in the link I gave shows a vertical multi turn pot with the adjustment ----at the TOP--Mouser sells it.
You know that "multi turn" pot is just a regular pot with a screw drive. I've found those to be more trouble than
they are worth. Use a single turn and develop the "touch". It's not difficult.
G²
Hi Stratus46, Why are they more trouble then they're worth? Could you elaborate on your experience please? What kind of pots would you go with?
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In the picture you provided of the internals of your amplifier you have vertical access therefore no problem adjusting from the top.
Bourns is a good make there are worse makes than them.
Yes, but the boards are fitted vertically and the screw of the pot would therefor be horizontally.
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Your right Freebee my mistake--sorry .
In that case on Bourns website the first two when mounted vertically will have the adjustment facing the top of the amplifier.
Multiturn Trimpot Trimming Potentiometers - Bourns
In that case on Bourns website the first two when mounted vertically will have the adjustment facing the top of the amplifier.
Multiturn Trimpot Trimming Potentiometers - Bourns
There is inevitable slop in the screw drive and the center of the main pot can move laterally a bit. What this means
is as you turn the screw and go a little past the place you want, when you reverse the turn there will be a dead zone
and probably another jump in the setting. The long rectangular pots like the Bourns 3006 series is a lot better but
I don't think those will work for you. I've been 'tweaking' units for lots of years and those little square pots with the
screw drives are less good. It's faster with a single turn because if there is dirt in the pot, running it back and forth
a few times often clears it up. That is real hard to do with the little worm drives.
G²
Bourns 3296P series, similiar to one shown in original post. Often the circuit ties 2 of the legs together, in this case you can connect corresponding legs together and pass through one hole, if this makes it easier. Would not use single turn trimmers for bias. No problems with the mult-turns in over 20 amps...