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Old 25th February 2015, 09:21 PM   #11
Zen Mod is offline Zen Mod  Serbia
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just to be sure - that motor sound is same on both channels ?

one thing more - put some signal ( even mp3 player or phone ) direct to pot/power amp, to confirm that culprit is really in preamp
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Old 25th February 2015, 09:38 PM   #12
RS232 is offline RS232  United Kingdom
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I Zen Mod
Yes the sound is the same on both channels.
The funny thing is that it takes a couple of seconds for it to start.
I going to try and make another recording just with sound unless I send it to you (17mb)
Will try CD player direct on the volume has you say but only tomorrow is getting late.

Ric

Last edited by RS232; 25th February 2015 at 09:41 PM.
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Old 25th February 2015, 09:48 PM   #13
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no need for fiddle with recording ; it'll say no more than set of tests we can figure to make
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Old 25th February 2015, 09:54 PM   #14
AMV8 is offline AMV8  United Kingdom
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RS232
The pcb you show in post 10 picture 2 and 3 is the mm and mc pnono pre. I have a pcb just like that as a KL stand alone mm and mc phono preamp.

The ic's on the mm and mc board are just transistor arrays. You do not have a fet input on the mc. If you want to improve the quality of your mm and mc stages you can isolate the pins on the ic which provide the input pairs for each stage of the phono pre. On more expensive models KL used lm394 dual transistors as the input LTP's.

The line amp is all on the main amplifier pcb. The amplifier is designed as an intergrated amplifier with an added mm/mc section at the rear of the amplifier.

Many of the KL amplifiers have slight differences from amplifier to amplifier. On your amplifier the later versions used mosfets as output devices and some had a dac included. These were marked "digital" on the front panel.

Looking at the pictures you have provided seems to show that the rectifier diodes are brown. Have you checked those?

I do not have an overall schematic of your amp. However KL use similar circuits on all amplifiers and if it is of help to you e mail me and I will send you schematics drawings of your mm and mc pre and the two most common pre amp line amps. All of these have been back engineered for my KL amplifiers. ( My hand drawings are too large to add onto diyaudio.)

Don
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Old 25th February 2015, 10:00 PM   #15
Zen Mod is offline Zen Mod  Serbia
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if that suits you , you can send these files to me and I'll resize them and post here
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Old 26th February 2015, 10:09 PM   #16
RS232 is offline RS232  United Kingdom
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Sorry guys didn't make it today...
Here is the audio file (.amr estension)
Promise to answer all the question tomorrow.
Thanks for all the help and sugestions

Ric
Attached Files
File Type: zip KL2.zip (50.7 KB, 30 views)
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Old 27th February 2015, 04:19 PM   #17
RS232 is offline RS232  United Kingdom
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Ok, here we go
Zen Mod,
Connected CD player directly on the volume pot and sound is clear no background noise (listening to Freddy Mercury Best off right now).

AMV8
Yes they are tested, the board under the diodes is discolored do to the heat from them they sit strait on the board without clearance.

So now I'm sure the faulty is on the phono/input stage going to check the 15/0/15 power supply and go from there.

Zen Mod
What are the tests you want me to do ?

Ric

PS; Freddy really sound great (listening with KL (without input stage) and my old philips CD104 (original no mods))
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Old 27th February 2015, 07:28 PM   #18
RS232 is offline RS232  United Kingdom
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SUCCESSS
Found the offending part...
And the winner is the LM79L15 regulator for the phono/input stage.
Now one question:
I have 2 tantalums left in the board just after the signal input and the million dollar question is... do I use same capacity polar cap or bipolar ?
Going to have dinner and think about it...

AMV8
Thanks for the offer on the diagrams/schematics but problem is sorted so have no need for them but thanks anyway

Ric

Last edited by RS232; 27th February 2015 at 07:52 PM.
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Old 27th February 2015, 09:37 PM   #19
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are those tantalums in signal route ?

and what is their value ?
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Old 27th February 2015, 10:00 PM   #20
RS232 is offline RS232  United Kingdom
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Hi Zmod
They are the input caps on the amp and they are 2.2uf.
I replaced them with Nichicons with same capacity and polarized.
Is sounding great just a very low level noise that was always there since I got this amp about 6 years ago but I have to be very close to the speakers to ear it.
The other thing is the bass, there is not much of it but it depends on the speakers I tested it with my old Whaferdale Diamonds and was not impressed with it but with my Aurum Cantus speakers the bass is much better.

Ric

Last edited by RS232; 27th February 2015 at 10:05 PM.
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