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What value pot?
What value pot?
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
---MIKE---
>>In the White Mountains of New Hampshire
>> (44° 15' N - Elevation 1580')
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
---MIKE---
>>In the White Mountains of New Hampshire
>> (44° 15' N - Elevation 1580')
Re: What value pot?
---MIKE--- wrote in message
<8186-481CAB79-425@storefull-3251.bay.webtv . net >...
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
---MIKE---
>>In the White Mountains of New Hampshire
>> (44° 15' N - Elevation 1580')
Probably anything from 1k to 10k would be typical. It's not rocket science.
The 50k should work fine too. You might find that a cheap pot won't track
very well between the left and right channels. You could always add a simple
resistive voltage divider and heat shrink it right into the cable.
bg
In the rocky mountains about 4500 feet
---MIKE--- wrote in message
<8186-481CAB79-425@storefull-3251.bay.webtv . net >...
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
---MIKE---
>>In the White Mountains of New Hampshire
>> (44° 15' N - Elevation 1580')
Probably anything from 1k to 10k would be typical. It's not rocket science.
The 50k should work fine too. You might find that a cheap pot won't track
very well between the left and right channels. You could always add a simple
resistive voltage divider and heat shrink it right into the cable.
bg
In the rocky mountains about 4500 feet
Re: What value pot?
"---MIKE---" wrote ...
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
Any of them would work. The lower impedance one(s) would
likely be less troublesome.
There are less expensive places to get pots online than Mouser,
etc. You don't need a brand-new one. Likely any of the ones
that RadioShack sells would have worked also, and no shipping
(assuming one in your town?)
"---MIKE---" wrote ...
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
Any of them would work. The lower impedance one(s) would
likely be less troublesome.
There are less expensive places to get pots online than Mouser,
etc. You don't need a brand-new one. Likely any of the ones
that RadioShack sells would have worked also, and no shipping
(assuming one in your town?)
Re: What value pot?
"---MIKE---" <twinmountain@webtv . net > wrote in message
news:8186-481CAB79-425@storefull-3251.bay.webtv . net
> My new digital FM tuner puts out too strong a signal
> compared to my other inputs (TV and CD). I want to
> install a dual pot between the tuner and preamp to reduce
> the volume. What is the best value pot to use for this.
> I have ordered 50K, 100K, 250K and 500K from Mouser (the
> pots are cheap - the shipping is not).
Well, we talked this one to death due to your post in rec.audio.pro.
I think that the 50 K pot is the best choice, and will work fine as long as
you keep your cable length under 4 meters.
"---MIKE---" <twinmountain@webtv . net > wrote in message
news:8186-481CAB79-425@storefull-3251.bay.webtv . net
> My new digital FM tuner puts out too strong a signal
> compared to my other inputs (TV and CD). I want to
> install a dual pot between the tuner and preamp to reduce
> the volume. What is the best value pot to use for this.
> I have ordered 50K, 100K, 250K and 500K from Mouser (the
> pots are cheap - the shipping is not).
Well, we talked this one to death due to your post in rec.audio.pro.
I think that the 50 K pot is the best choice, and will work fine as long as
you keep your cable length under 4 meters.
Re: What value pot?
On Sun, 4 May 2008 16:06:56 -0400, "Arny Krueger" <arnyk@hotpop . com >
wrote:
>"---MIKE---" <twinmountain@webtv . net > wrote in message
>news:8186-481CAB79-425@storefull-3251.bay.webtv . net
>> My new digital FM tuner puts out too strong a signal
>> compared to my other inputs (TV and CD). I want to
>> install a dual pot between the tuner and preamp to reduce
>> the volume. What is the best value pot to use for this.
>> I have ordered 50K, 100K, 250K and 500K from Mouser (the
>> pots are cheap - the shipping is not).
>
>Well, we talked this one to death due to your post in rec.audio.pro.
>
>I think that the 50 K pot is the best choice, and will work fine as long as
>you keep your cable length under 4 meters.
>
Much easier than that. Just put the pot at the input of the amp with
no cable, and make it big.
d
--
Pearce Consulting
* w w w .pearce.uk . com
On Sun, 4 May 2008 16:06:56 -0400, "Arny Krueger" <arnyk@hotpop . com >
wrote:
>"---MIKE---" <twinmountain@webtv . net > wrote in message
>news:8186-481CAB79-425@storefull-3251.bay.webtv . net
>> My new digital FM tuner puts out too strong a signal
>> compared to my other inputs (TV and CD). I want to
>> install a dual pot between the tuner and preamp to reduce
>> the volume. What is the best value pot to use for this.
>> I have ordered 50K, 100K, 250K and 500K from Mouser (the
>> pots are cheap - the shipping is not).
>
>Well, we talked this one to death due to your post in rec.audio.pro.
>
>I think that the 50 K pot is the best choice, and will work fine as long as
>you keep your cable length under 4 meters.
>
Much easier than that. Just put the pot at the input of the amp with
no cable, and make it big.
d
--
Pearce Consulting
* w w w .pearce.uk . com
Re: What value pot?
"Don Pearce" <nospam@nospam . com > wrote in message
news:482817f0.645244421@news.plus . net
> On Sun, 4 May 2008 16:06:56 -0400, "Arny Krueger"
> <arnyk@hotpop . com > wrote:
>
>> "---MIKE---" <twinmountain@webtv . net > wrote in message
>> news:8186-481CAB79-425@storefull-3251.bay.webtv . net
>>> My new digital FM tuner puts out too strong a signal
>>> compared to my other inputs (TV and CD). I want to
>>> install a dual pot between the tuner and preamp to
>>> reduce the volume. What is the best value pot to use
>>> for this. I have ordered 50K, 100K, 250K and 500K from
>>> Mouser (the pots are cheap - the shipping is not).
>>
>> Well, we talked this one to death due to your post in
>> rec.audio.pro.
>>
>> I think that the 50 K pot is the best choice, and will
>> work fine as long as you keep your cable length under 4
>> meters.
>>
>
> Much easier than that. Just put the pot at the input of
> the amp with no cable, and make it big.
Basically, a good idea. That's how some power amps get away with 100K pots
right at their input. There isn't much cabling loading them down.
Under the circumstances, I'd put the 50K pot as close to the input of the
power amp as is conveniently possible.
"Don Pearce" <nospam@nospam . com > wrote in message
news:482817f0.645244421@news.plus . net
> On Sun, 4 May 2008 16:06:56 -0400, "Arny Krueger"
> <arnyk@hotpop . com > wrote:
>
>> "---MIKE---" <twinmountain@webtv . net > wrote in message
>> news:8186-481CAB79-425@storefull-3251.bay.webtv . net
>>> My new digital FM tuner puts out too strong a signal
>>> compared to my other inputs (TV and CD). I want to
>>> install a dual pot between the tuner and preamp to
>>> reduce the volume. What is the best value pot to use
>>> for this. I have ordered 50K, 100K, 250K and 500K from
>>> Mouser (the pots are cheap - the shipping is not).
>>
>> Well, we talked this one to death due to your post in
>> rec.audio.pro.
>>
>> I think that the 50 K pot is the best choice, and will
>> work fine as long as you keep your cable length under 4
>> meters.
>>
>
> Much easier than that. Just put the pot at the input of
> the amp with no cable, and make it big.
Basically, a good idea. That's how some power amps get away with 100K pots
right at their input. There isn't much cabling loading them down.
Under the circumstances, I'd put the 50K pot as close to the input of the
power amp as is conveniently possible.
Re: What value pot?
Use the 50k. Once you figure out how much attenuation then measure the pot
with your meter. Get some resistors and solder them into cables near the
preamp. If you try you should be able to cover the resistors with the
existing cable shielding, just strip back a ways and plan accordingly.
Otherwise you have those pots sitting out in the open picking up stray
noise.
"---MIKE---" <twinmountain@webtv . net > wrote in message
news:8186-481CAB79-425@storefull-3251.bay.webtv . net ...
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
---MIKE---
>>In the White Mountains of New Hampshire
>> (44° 15' N - Elevation 1580')
Use the 50k. Once you figure out how much attenuation then measure the pot
with your meter. Get some resistors and solder them into cables near the
preamp. If you try you should be able to cover the resistors with the
existing cable shielding, just strip back a ways and plan accordingly.
Otherwise you have those pots sitting out in the open picking up stray
noise.
"---MIKE---" <twinmountain@webtv . net > wrote in message
news:8186-481CAB79-425@storefull-3251.bay.webtv . net ...
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
---MIKE---
>>In the White Mountains of New Hampshire
>> (44° 15' N - Elevation 1580')
Re: What value pot?
Mike,
A pot looking into a shielded cable will produce a high-frequency rolloff, the lowest
frequency being at the one-half resistance point of the pot. You'd want that rolloff no
lower than about 30 KHz. Of those you've ordered, use the 50K pot. Anything can drive an
impedance that high, but such a pot would have a high-frequency rolloff of 30 KHz if you
used 2.5 feet of that typical interconnect skinny shielded cable whose capacitance can run
around 90 pf per foot. With a more modest 30 pf/ft, you could get away with 6.8 feet of
cable, and with low-capacity cable, say 12 pf/ft, you could have up to 17 feet of cable.
If the pot were one half that value, the allowable cable lengths would double, etc.
--
Earl
"---MIKE---" <twinmountain@webtv . net > wrote in message
news:8186-481CAB79-425@storefull-3251.bay.webtv . net ...
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
---MIKE---
>>In the White Mountains of New Hampshire
>> (44° 15' N - Elevation 1580')
Mike,
A pot looking into a shielded cable will produce a high-frequency rolloff, the lowest
frequency being at the one-half resistance point of the pot. You'd want that rolloff no
lower than about 30 KHz. Of those you've ordered, use the 50K pot. Anything can drive an
impedance that high, but such a pot would have a high-frequency rolloff of 30 KHz if you
used 2.5 feet of that typical interconnect skinny shielded cable whose capacitance can run
around 90 pf per foot. With a more modest 30 pf/ft, you could get away with 6.8 feet of
cable, and with low-capacity cable, say 12 pf/ft, you could have up to 17 feet of cable.
If the pot were one half that value, the allowable cable lengths would double, etc.
--
Earl
"---MIKE---" <twinmountain@webtv . net > wrote in message
news:8186-481CAB79-425@storefull-3251.bay.webtv . net ...
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
---MIKE---
>>In the White Mountains of New Hampshire
>> (44° 15' N - Elevation 1580')
Re: What value pot?
"---MIKE---" <twinmountain@webtv . net > wrote in message
news:8186-481CAB79-425@storefull-3251.bay.webtv . net ...
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
**Depends on the output impedance of the source. Typically, 10k would be a
reasonable choice. Any higher and you risk losing HF response. Aim for a pot
impedance of around 10X the source impedance.
"---MIKE---" <twinmountain@webtv . net > wrote in message
news:8186-481CAB79-425@storefull-3251.bay.webtv . net ...
My new digital FM tuner puts out too strong a signal compared to my
other inputs (TV and CD). I want to install a dual pot between the
tuner and preamp to reduce the volume. What is the best value pot to
use for this. I have ordered 50K, 100K, 250K and 500K from Mouser (the
pots are cheap - the shipping is not).
**Depends on the output impedance of the source. Typically, 10k would be a
reasonable choice. Any higher and you risk losing HF response. Aim for a pot
impedance of around 10X the source impedance.
