Pot Substitution

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kd
Posts: 102
Joined: Fri Mar 17, 2006 2:10 pm
Location: South Texas

Pot Substitution

Post by kd »

I've placed two orders now and both times forgotten to put a 250k audio pot on the order for my mid control. I'm building the ODS 101 non hrm and this is the only thing keeping me from completing the build. I have a few other pots in stock. Will one of these be a suitable substitute: 250k linear, 100k audio or 100k linear.

Thanks,
Ken
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ChrisM
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Re: Pot Substitution

Post by ChrisM »

A 250K linear will work for the time being. In the end you do want an audio (log) pot though in the end.
dimitris
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Re: Pot Substitution

Post by dimitris »

I would use the 100k linear.A 250k log pot used as a variable resistor in the middle of it's rotation range would give you about 37k to ground.A 100k linear in the same position would give 50k to ground.I think it's good enough even to use it permanently.
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Structo
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Re: Pot Substitution

Post by Structo »

The stock D'Lite amps have a 100K linear in that spot.
Might not be ideal but it worked fine.
Tom

Don't let that smoke out!
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hairyandy
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Re: Pot Substitution

Post by hairyandy »

ChrisM wrote:you do want an audio (log) pot though in the end.
...he said, half in Ernest!

Andy
marcos
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Re: Pot Substitution

Post by marcos »

I have tried all the variations and would definetely go for a log pot.
The linear pots do much past twelve o´clock.I think HAD used them mostly because they were readily available (Fender reverb pot).
Funny, I have seen five Dumbles (including my personal amp),
and all of them had a log pot for the mids, either 100K or 250K.
When I first saw a linear pot in a schematic I thought it was a mistake.
kd
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Location: South Texas

Re: Pot Substitution

Post by kd »

Thanks guys, I'll pick one a see how it goes.

Ken
JD0x0
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Re: Pot Substitution

Post by JD0x0 »

kd wrote:Thanks guys, I'll pick one a see how it goes.

Ken
the 100K log will work pretty good for a mid pot, i like to save the 250K linear for treble pots. JMO

i really like the 250K log for mid pots so i'd swap it out ASAP after you fire up your amp for the first time.
It's true i've lost my marbles and i cant remember where i put them
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Structo
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Re: Pot Substitution

Post by Structo »

I don't mean to derail this thread but since we are talking about tone pots I was wondering something about the bass pot.

What does the .001uF cap across the bass pot do?

I assume it is there to bleed off some highs but is there a scientific reason beyond that?
Tom

Don't let that smoke out!
JD0x0
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Re: Pot Substitution

Post by JD0x0 »

Structo wrote:I don't mean to derail this thread but since we are talking about tone pots I was wondering something about the bass pot.

What does the .001uF cap across the bass pot do?

I assume it is there to bleed off some highs but is there a scientific reason beyond that?
I've wondered this too, my layout says to use a .01uF cap while most dumbles say to use a .001uf

I just threw a .0022uF cap on there for now but im not sure what it does
It's true i've lost my marbles and i cant remember where i put them
JimiB
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Re: Pot Substitution

Post by JimiB »

you do want an audio (log) pot though in the end.


...he said, half in Ernest!

Andy
ROFLMAO!
Sicko :lol:
I love my rail tone amp!
Jana
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Re: Pot Substitution

Post by Jana »

Dang, I saw the post title and thought it was about something else. :D
Chad
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Re: Pot Substitution

Post by Chad »

Jana wrote:Dang, I saw the post title and thought it was about something else. :D
:lol: :lol:
llemtt
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Joined: Sat Feb 04, 2006 3:13 pm

Re: Pot Substitution

Post by llemtt »

Structo wrote: What does the .001uF cap across the bass pot do?
it improves the functionality of the mid control when using the .01 mid cap and reduces also very high freqs a little

it let's you scoop mids by 1-2 dB more than without it, to me it's definitely a must in a skyliner stack

you can try values up to 2-3n here, no more or you start to loose to much highs (think Jazz setting)

cheers
teo
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Structo
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Re: Pot Substitution

Post by Structo »

So if you use a .05uF mid cap, should this .001uF cap on the bass pot be eliminated?
Tom

Don't let that smoke out!
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