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Old 22nd December 2012, 07:35 AM   #71
Philfr is offline Philfr  France
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Hi Mooly,
Thank's, so it's a Zobel !
All is clear now with schematic..
Heatsink : I have one recovered from an old vintage amp, black and "honeycomb".
Do you think it's a problem to attach the two TDA on the same heatsink ?
Maybe I can isolate them..
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Old 22nd December 2012, 09:54 AM   #72
Mooly is offline Mooly  United Kingdom
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The metal tab is connected to pin 3 and so is the ground connection in a single rail amp.

I'm going to say its very dependent on wiring and wiring practice how well both IC's would be with the common connection. There could be the possibility for interaction due to the small but finite resistances of the wiring.

Isolating kits are widely available. If they are mica you need thermal grease. If hey are synthetic material then often you don't. The package of the IC is a T0220 type.

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MK3306/S - UNBRANDED - TRANSISTOR INSULATING KITS TO | CPC
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Old 22nd December 2012, 09:54 AM   #73
JMFahey is offline JMFahey  Argentina
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So in a nutshell: are we choosing the single supply option?
Are we still going biamplified?
OK, then run the TDA2050 from the +24V rail, the TA2020 plus the digital stuff from the +12V rail.
Agree on that?
Yes, in theory the lower 12V battery will last a little less than the upper one, no big deal.
You monitor voltage on the lower one, as soon as it falls to, say, 11.5V , you stop and recharge.
Maybe the upper one had an extra hour life. So what?
Anyway, since you will charge both in parallel (I like that ), they will automatically self equalize, the flatter one will take more current from the charger .
*If* you happened to charge them in series, yes, the upper one *might* be overcharged, the lower one undercharged, but that's not a problem now.
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Old 22nd December 2012, 11:26 AM   #74
Philfr is offline Philfr  France
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Mooly,
I will use synthetic mica (no need thermal grease) and screw isolate :

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Old 22nd December 2012, 11:34 AM   #75
Philfr is offline Philfr  France
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Hi JM,
Yes for all you said.
And a few days ago I wrote :
"Left (on schematic A) at 18 Amp/h and right at 24 Amp/h for example. That compensate the differences in uptake."
Recharge is not a problem (for me), for 8/10 hours of listening per week, maybe I will recharge one time per month..
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Old 7th January 2013, 11:16 AM   #76
Philfr is offline Philfr  France
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Hi All,
First, happy new year !
I received all componants, so works will be strarting..
I did not use pcb but a little piece of Altuglas and make connections on "air" with gold plated connectors.

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Old 7th January 2013, 11:41 AM   #77
Mooly is offline Mooly  United Kingdom
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That should keep you busy

Take it slowly checking along the way.
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Old 7th January 2013, 03:29 PM   #78
Philfr is offline Philfr  France
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Hi Mooly,
I think select cap and resistor by mesurements to have about same values "pair to pair"..
But fot TDA's ?
Maybe that's need some equipement, and I did not.
I have four, two with "mar 825" and two "mar 941".
What means this serial nomber ?
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Old 7th January 2013, 03:49 PM   #79
JMFahey is offline JMFahey  Argentina
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825 and 941 are date codes, as in
Year: 2009
Week : 41 (October 5 to 11)

Mar is probably a Country or Factory code.
Never seen that one , but "Mal" is very common: Malaysia
Tons of ST and TI chips made there.
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Old 7th January 2013, 03:56 PM   #80
Mooly is offline Mooly  United Kingdom
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You won't need to match any parts, just take care with the wiring (the grounds) so as not to run into any stabilty issues.
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