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Chip Amps Amplifiers based on integrated circuits

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Old 14th October 2004, 09:58 PM   #1
Luke123 is offline Luke123  Canada
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Default About Linn power amps...

Hi

Anybody could tell me what brand and number of power chipamp was used in the Linn Klout? And the one in the Linn Klimax?

Thanks

Luke123
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Old 14th October 2004, 10:54 PM   #2
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Most Linn power amps use the TDA7293.
The LK140 uses them in parallel, as in the datasheet.
Don't know about these ones, though.
But I've heard them, with Linn Akurate speakers.
Nice.
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Old 14th October 2004, 11:43 PM   #3
matjans is offline matjans  Netherlands
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hi luKe,

indeed the klimax uses tda7293's (3 of them), just like the quekky pi7293 , a diy triple tda7293 based amp. Basically a Klimax Klone...

It's all in the K...
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Old 10th February 2005, 07:50 AM   #4
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If you look, to the picture on page 8 of the klimax twin manual, you will see several differences between the Klimax and quekky's amp.

First of all, the Klimax obviously does not use the slave configuration, mostly because of the reduced slew rate incurred by this mode (difficulty to drive the input capacitance of the MOSFET output stage): all people I know who have listened to a single TDA7293 and a configuration of Three ICs in the slave mode configuration say the single TDA sounds best.

In fact, it looks like a Klimax twin channel is made of three TDA7293, each one with its individual servo, with an op amp based input buffer (with its own servo). I can post my guess of a schematic, or maybe we open a new thread on the subject ("Linn Klimax backengineered"?)
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Old 10th February 2005, 10:37 AM   #5
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Seems relevant to the topic to me. Carry on.
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Old 10th February 2005, 01:02 PM   #6
steenoe is offline steenoe  Denmark
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Quote:
Carry on.
I second that Guess this thread could be exciting

Steen.
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Old 10th February 2005, 04:56 PM   #7
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I bought a Linn MAJIK about ten years ago -- with the SNEAKY modules for my Kelidh's -- here's a look at the insides:

Click the image to open in full size.
Click the image to open in full size.
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Old 10th February 2005, 07:33 PM   #8
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Some measurements of the Klimax:

http://www.soundstagemagazine.com/me...n_klimax_twin/

There's a recent Linn Klimax Chakra 500 twin.
And the top Klimax 500 Solo (with Sanken transistors), sounds very good indeed, I've heard it.
Switching PSUs to a good effect.
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Old 10th February 2005, 08:14 PM   #9
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OK, let's give it a try (I won't try the SMPS, because from experience, I know it is a mess to fix) . See the pictures attached

First of all, "1" looks like a balanced to single ended conversion chip, followed by a switch, and obviously this arrangement has been kept on the new Chakra design.

"6" is a bunch of low voltage regulators (for the logic + the buffer?…) + probably a small microcontroller used to monitor the thing.

For the rest, you can see two identical amplifier section, one for each channel.

For each section, there are three TDA7293s all used with the same components. The elco is the bootstrap capacitor, there are also two large SMD caps for IC decoupling, and two small chips close to pin 1 which could be mute transistors used to protect the TDA when switching on/off the input buffer power supply (I thought first that they were used to switch the mute/stdby pin, but then they would rather have been placed on the other side of the TDA). You can see the three 0,1 Ohm epoxy coated wirewound ballast resistors in section "4".

In "4" you also see two ICs, with identical accompanying resistors/caps. In section "5" is another IC, with a different configuration. I first thought that the three Ics, perfectly aligned with the TDAs, were servos (one for each TDA). I now believe that the 2 Ics of section "4" are double op amps used for 1 servo for each of the three TDA + one servo for the section "5" IC, which then would likely be an input buffer. The servos for the TDAs ensure a good current matching between the Ics, reduce the noise and avoid elcos in the signal path. The input buffer gives a decent high output impedance and drives the bipolar inputs of the TDA (relatively high input current + high voltage offset). I'd guess IC "5" is an OPA604, AD797 or alike (FET input, low noise, low offset, stable at unity gain- don't forget that the Linn has 28,6dB total gain, and that the TDA already needs at least 26dB of closed loop gain for stability, this gives little remaining gain for the buffer stage, except if there are some dividers somewhere in the circuit).

Questions I have:
-are the TDAs are used in inverting or non inverting configuration? (my guess: not inverted)

-same question for the input buffer (although I would guess it is inverting because the input impedance of the amp is low: 7,8 k!)

-is the TDA based gain stage included in the input op amp closed loop or not (if yes the combination creates a high performance high power op amp, but you have to be careful with stability)? Personnally, this is the one I would try!

-what is section 2? Another buffer (overkill!)? Or a signal detector used to switch automatically on/off the thing (but then why these nice, expensive, blue plastic caps? And why one section for each channel?)

Has anyone any clue? Has anybody opened the little Linn Klimax box and had a look at the IC references?
Attached in the other picture, some drawing thoughts (with a tube buffer IGC variation).
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File Type: jpg image2.jpg (36.0 KB, 1762 views)
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Old 11th February 2005, 07:15 AM   #10
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It seems that at least one picture did not come through. There it is ( extract from the manual).
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File Type: jpg klimax twin.jpg (63.2 KB, 2131 views)
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