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Old 16th December 2012, 11:06 AM   #51
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Quote:
Originally Posted by Jan Dupont View Post
URLs are Death.
here my own schematics:
Attached Files
File Type: pdf C ...-A-Linn LK2-80 orig.sim.ckt.pdf (34.5 KB, 137 views)
File Type: pdf C ...-Linn LK2-80 Ampmod.ckt.pdf (58.8 KB, 110 views)
File Type: pdf C_Linn Kloud control_ckt.pdf (48.3 KB, 71 views)
File Type: pdf C_Linn Kloud_control_ckt.pdf (15.4 KB, 56 views)
File Type: pdf C_Linn_Kloud control_ckt.pdf (13.9 KB, 55 views)
File Type: pdf C_tmp_Linn LK2-80 II Kloud_ckt.pdf (71.9 KB, 80 views)
File Type: pdf C_tmp_Linn LK2, LK2-80 second stage_ckt.pdf (13.0 KB, 65 views)
File Type: pdf C_tmp_Linn LK2, LK2-80_ckt bias.pdf (9.7 KB, 63 views)
File Type: pdf C_tmp_Linn LK2, LK2-80_ckt buffer.pdf (10.6 KB, 71 views)
File Type: pdf C_tmp_Linn LK2, LK2-80_ckt complete.pdf (30.2 KB, 101 views)
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Old 16th December 2012, 11:08 AM   #52
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continuation
Attached Files
File Type: pdf C_tmp_Linn Kloud_ckt.pdf (55.4 KB, 92 views)
File Type: pdf C_tmp_Linn LK2, LK2-80_ckt input-st_.pdf (10.3 KB, 65 views)
File Type: pdf C_tmp_Linn LK2, LK2-80_ckt powersupply.pdf (8.2 KB, 81 views)
File Type: pdf C_tmp_Linn LK2, LK2-80_ckt shortprot.pdf (9.7 KB, 60 views)
File Type: pdf C_tmp_Linn LK2, LK2-80_ckt.pdf (34.1 KB, 84 views)
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Old 14th July 2013, 08:40 PM   #53
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THX !!
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Old 5th August 2013, 10:11 PM   #54
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Let's go on with tweaking classic LK1 and LK2.


Quote:
Originally Posted by fab View Post
I do not know about tweaks but the LK2-80 has an interesting schematics.

Here some items I can notice:

1) Fully regulated power supply (even the output stage)...but the 1st and 2nd stage are not filtered from the output stage..
Any ideas how do isolate 1st stage properly? I guess one resistor won't be sufficient.


Quote:
Originally Posted by fab View Post
2) CFP output stage but with current mirror instead of usual resistor as load of the 1st transistor of the CFP.
Could you please explain to help me getting an opinion?


Quote:
Originally Posted by fab View Post
3) "Split feedback" of some sort? FB1 goes back to 1st diff stage and FB2 (after complemetary VBE in CFP mode) goes to 2nd diff stage. Even the VBE multiplier seems to be connected to the output of the amp. Error correction? Is someone familiar with this topology what are the benefits?
dito


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Old 18th October 2013, 02:52 AM   #55
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The front end seems silimar and I guess these mods also apply to the older LK2 amps:

The unlikely star-candidate - Linn LK-100 - pink fish media

Another worthwhile read about tweaking an old LK2:

Linn LK2 | Owners Manual, Service Manual, Schematics, Free Download | HiFi Engine

Old vs New linn sound

Help needed with Linn LK2 schematic
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Old 19th October 2013, 04:52 PM   #56
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Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
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Last edited by ticktock; 19th October 2013 at 05:07 PM.
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Old 29th October 2013, 08:15 PM   #57
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Thumbs up modify Linn LK2/60 (LK2, LK260)

Sadly there are very few doing mods to scottish amps. Linniacs fear modding,
many DIYer don't like Linn gear. Several sites covering Naim mods show the
way though.

This has beeen one of the starting points to think about decreasing value of
C1 and increase C2/C20 - measurements of the der LK260 on the Vintage-
Radio-Forum:

Quote:
Left Channel:

Frequency response, -3 dB points: < 10 Hz and 37 kHz
Frequency response, -1 dB points: 18 Hz and 17.8 kHz
Frequency response, -0.5 dB points: 25.0 Hz and 12.0 kHz
Distortion: 0.012%
100 Hz spikes visible on output with no signal

Right Channel:

Frequency response, -3 dB points: < 10 Hz and 38 kHz
Frequency response, -1 dB points: 17.5 Hz and 19.0 kHz
Frequency response, -0.5 dB points: 24.0 Hz and 13.0 kHz
Distortion: 0.04%
100 Hz spikes visible on output with no signal
... and on Stereophile of the LK280, slightly better:

Quote:
At a 1V output level, the '280 was ostensibly flat throughout most of the audio band, though
there was a slight droop at the edges, the response being 0.75dB down at 21Hz and 20kHz.

Measurements will probably better after mod.


Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Linn LK2 Service Manual free download,schematics,datasheets,eeprom bins,pcb,repair info for test equipment and electronics

LK260:

Linn LK2 power amplifier - UK Vintage Radio Repair and Restoration Discussion Forum

LK100:

The unlikely star-candidate - Linn LK-100 - pink fish media

The later LK100 is a cheaper and simpler variant of the same of the almost
same circuit.

tweaking classic Linn LK1 & LK2 / LK280



I'd strongly recommend to do these mods to any owner of a LK2/60:

- do the Reliability Mods (R33 und R49 > 2 W, C6 & C19, see below)
- heatsinks for Q10, Q11 und Q14 (the still get hot)
- evtl. heatsinks for LM317/337
- add the two 100 µF, the LK2/75 comes with
- renew several lytics, e.g. Pana FC, Silmic or Nichicon Muse
- consider to renew the big lytics, go for 10.000 µF
- if you remove the transformers and put them in an external case, you'd gain spce for additional capacitance
- swap C5, C6 & C19 for Micas
- decrease C1 to 2.2 nF, C2/20 > 330 µF + MKP (e.g. 150 nF)

Hope I didn't miss anything.



Does it sound better?

It does.


The modded LK260 play more authoritively, quicker and more dynamicly. The
former "british Sounding" has gone. If you like the old british day, don't do it.
If you like music and realism - do it !!
Probably there are more modifcations you could do, but there's already more
air and a deeper basement. I can listen to Marcus Millers Bass lines better.

I have to say I already have put the transformers into an external case
(similar to "Spark").
Hard to understand why Linn chose C1 so big and C2/20 that small. I cannot
understand als why there are no heatsinks on Q10/11/14. Even with some
Copper HS they still are 55° - 60° C hot. No wonder the melt the styrenes.
R49 also still gets hot. This one is prone to burn as it's just two 1/4 W types
from factory.


ps:
The later Klout and LK100 etc. have similar circuits. The Klout is a LK280 in a
more beautiful chassis, the LK100 has a simple PSU and no dual mono design.
Likely LK240 monos are similar. The later LK85/140 are not though.
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Old 18th February 2014, 09:15 AM   #58
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Quote:
Originally Posted by tiefbassuebertr View Post
Please note, that it is necessary to mounting the regulator devices ( presently mounted on heatsink) on the bottom of the aluminium envelope (aluminium case) to use this case for the heatsink function. Now the life expectancy of the caps near by the old heatsinks is higher because now don't burn longer. Stuff for electric isolated mounting is additional necessary.
Various compensating caps you must solder directly on the leads of the regulators (LM317 and two BjT's in TO-126/SOT32 outline - as I know). now the length of the additional wiring (at whole 9 leads) are not longer a problem.
Use in all cases 63V versions. 1000uF/63V for the main caps behind the rectifier e. g. is a much more better choice than 4700uF/25V.
High Capacitance values are nonsense in general, if capacitor is connected in front of the voltage regulator instead behind.
Here jpg images of a tweaked version with DIRAK:
error-message:
Valid file extensions: asc bmp doc gif jpe jpeg jpg pdf png psd txt zip
why?

Last edited by tiefbassuebertr; 18th February 2014 at 09:32 AM.
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