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Old 16th April 2004, 12:35 PM   #21
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Thanks Wayne for your effort!

George
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Old 10th May 2004, 12:36 PM   #22
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After many days searching the net and sending numerous emails I have not found someone selling such a pot. Michael Percy has a Nable pot which , including the shipping expenses, is very expensive when you consider the amp it will go into. This amp is an old one, early 80's.

My final hope is someone to draw me an equivalent network using a universal 100K dual pot to acheive the same results as a pot with a 40% loudness tap. I know that I have asked a question like this before but this time I am hopeless!

Thanks for all your help
George
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Old 10th May 2004, 06:47 PM   #23
amb is offline amb  United States
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Quote:
Originally posted by gchrist
My final hope is someone to draw me an equivalent network using a universal 100K dual pot to acheive the same results as a pot with a 40% loudness tap. I know that I have asked a question like this before but this time I am hopeless!
There is no way to wire up an equivalent to the loudness tap with external resistors. If the Noble pot is too expensive, why not use the one from Radio Shack/Tandy? The Radio Shack part number is 271-1732 and the price is $2.99USD.

http://www.radioshack.com/product.as...Fid=271%2D1732

They do not sell online for shipment to non-US destinations from this site, but if there are Radio Shack or Tandy stores in your area you can just get it there. If all fails, send me email directly and I'll see if I could help you out.

-Ti
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Old 12th May 2004, 09:29 AM   #24
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Smile 4 legged ideas

Hi gchrist,

Here's some schems of whats used in most Kenwood Amps and a good compromise using the Radio Shack part or an audio taper pot. As you can see there is a BIG difference between the two.
Using the RS pot there will be a difference in level with respect to the volume control posistion and the amount of loudness "boost". Experiment with the value of C2 in regards to the amount of boost and frequency where the action begins (turnover freq.).
I never did like Kenwoods or most other brands choice of turnover frequency (272Hz), I usually changed C1 to 68nf and R3 to 12k (195 Hz). Usining the values in the schem for the RS pot will give you a turnover of 194Hz and is a good compromise in level with respect to control position, you'll find using the RS pot you'll have to turn the control up higher to get the same volume. Also the bass boost will be somewhat less.
I hope this gives you some ideas. Do you have anything like yard sells or surplus stores in Greece? Maybe you can find a junker where you could salvage the volume control.

Good luck
Wayne
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Old 12th May 2004, 12:03 PM   #25
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Thank you Wayne,

I have searched here in Greece but I have not found anything.
Thank you for your schematics, I will surerly use them.

George
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Old 13th May 2004, 10:46 AM   #26
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Wayne correct me if I am wrong:

The Radio shack pot has a loudness pot. The only problem is that it is not linear. To fix this problem I will have to install R6 and C2 from the right schematic you posted above without changing anything else?

If I use a linear pot, other than the RD pot, without a loudness tap then what do I do? Do I get a loudness feed from the central wiper installing R6 and C2 also?

On the above schematics the resistors R1,R2,R4,R5 are included in the pot. They are not resistors connected externaly on the pot. Correct? The only thing missing from the pots are R3-C1 and R6-C2.

I am really a bit mixed. Thank you for your help anyway!

Regards,
George
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Old 14th May 2004, 11:44 AM   #27
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Quote:
Originally posted by gchrist

The Radio shack pot has a loudness pot. The only problem is that it is not linear. To fix this problem I will have to install R6 and C2 from the right schematic you posted above without changing anything else?
You don't *install* R6 and C2. They are already there in your receiver. Wayne was simply suggesting that you change the values of these parts so they might work a bit better with an audio taper pot, and to get a lower turnover frequency.

Quote:
If I use a linear pot, other than the RD pot, without a loudness tap then what do I do? Do I get a loudness feed from the central wiper installing R6 and C2 also?
If you don't use a pot with a loudness tap you lose the loudness function, period.

Quote:
On the above schematics the resistors R1,R2,R4,R5 are included in the pot. They are not resistors connected externaly on the pot. Correct? The only thing missing from the pots are R3-C1 and R6-C2.[
R1,R2,R4,R5 depicts the resistive element inside the pot. The reason why there are two resistors is to show at which point the pot's "tap" is attached. R3 and C1 is what's already in your receiver, probably with the shown values. R6 and C2 is what Wayne is suggesting you change those to. Also, remember there are a set of these per channel.

Hope that clears this up.

-Ti
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Old 14th May 2004, 12:40 PM   #28
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Yes it clears everything ,

Thanks
George
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Old 16th May 2004, 12:28 PM   #29
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I also should probably mention that the "43%" referrers to the percent of rotation from fully counter-clockwise rather than the percentage of value. amb is correct in his analysis, I should have explained it more clearly.
There is a way of doing it with a "regular pot" as seen at Steve Bench's site, the link I gave you in an earlier post. But it is very involved and would require building an entirely new circuit with many additional parts and the volume/level would never go to fully "zero" except when the loudness is switched out. In his first example he uses a 500k audio taper pot with a inductor and a more complicated switching arrangement. Plus you need to take into account the balance control's location and it's value and the input impedance and gain of the input circuitry, which in SS circuitry usually has a fairly low input impedance.
Here's a couple stabs in the dark:
Have you tried contacting Kenwood directly for replacement parts? They used to be pretty good about that, don't know about now though. I don't hold much hope for that since we're talking about something from the 80's which has long been out of production.
Replace the input capacitors for the input circuitry, they sometimes become "leaky" and pots don't like D.C. on their wipers.
I'm sorry I couldn't be of more help! Try the Rat Shack pot and change the parts I suggested. A higher value of C will give a lower turnover, whereas a lower value of C will give a higher turnover freq. and a more apparent bass boost but a muddier sound.

Wayne
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