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-   -   JVC A-K100 Schematic (http://www.diyaudio.com/forums/solid-state/214589-jvc-k100-schematic.html)

Carlosraj 16th June 2012 12:47 PM

JVC A-K100 Schematic
 
Dear Friends,

I am badly searching for a schematic of the above amplifier to fix it. Please if anyone has this schematic, can you kindly forward me a copy of it.

Thank you

Carlos Rajoo

east electronics 16th June 2012 02:02 PM

since schematic is unavailable you may as well state the nature of your problem and may be some pictures that can be also very helpful

Most of these models are alike so you may get some help
Kind regards
sakis

Carlosraj 21st June 2012 10:36 AM

JVC A-K100 Schematic
 
Quote:

Originally Posted by sakis (Post 3061681)
since schematic is unavailable you may as well state the nature of your problem and may be some pictures that can be also very helpful

Most of these models are alike so you may get some help
Kind regards
sakis

This amp uses a 250K stereo volume pot with 4 pins on each channel. One channel of the pot is open. I can only get a normal 250K stereo pot here.( 3 pins on each channel). The only 4 pin stereo pot available is 100K. Can I use this pot safely for this amp. Are there any ways of modifying this pot. Please assist.

Thank you

Carlos

east electronics 21st June 2012 10:57 AM

using a 250K 2X4 pin potentiometer will exactly mean that
A) input Z of your amp is quiet high
B) there is a loudness circuit involved

There are three things that will go wrong if you use a 6 pin 100k potentiometer

A) there is going to be some loss of dynamics in low or very listening levels but this will be even hard to notice ( due to input mismatching )

B) the loudness function will not work at all any more

C) the original pot probably made by ALPHA or ALPS is almost custom made so it starts very gently for low listening levels then in the middle provides an average listening level while removing automatically the loudness function and then the maximum level of power will start to appear above the 75% of the range of the pot ...This particular handling of volume cannot be found in any of the pots ( eventhough logarithmic ) existing in the market

solution A
You may try ebay and you will probably find some blue alps that is exactly what you want 250K /2X4pins / especially made for amplifier volume ...though size is almost 4 times than the original pins do not fit and knob will not fit ...skills there required for the adaptation

Solution B ( mostly working very well )

Check with your local YAMAHA shop many ( more than 20 ) Yamaha amps working with the exact same pot only problem is that people have to find the pot by looking at it rather checking to match it through a code ( Yamaha don't write in the books 250K /4 pins the have their own code system for parts )
This is working very well in Greece i don't see any reason why not in UK Yamaha shops are obliged to keep these in stock .... only thing they have to do is look ....

Kind regards
sakis

EDDELARUE 21st June 2012 02:12 PM

From similar - JVC A-K200
 
1 Attachment(s)
Quote:

Originally Posted by Carlosraj (Post 3061615)
Dear Friends,

I am badly searching for a schematic of the above amplifier to fix it. Please if anyone has this schematic, can you kindly forward me a copy of it.

Thank you

Carlos Rajoo

I haven´t found the a-k100 but the attached partial schematic is from JVC A-K200. Maybe it helps you. I wish.

eD


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