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Mihkus 13th December 2012 04:24 PM

tda1514 Almost Hi-End or just another lie?
I have found amplifier IC similar to LM3... series
Dual rail, ~30w norminal out at 8 ohms even more..
Yet, some say its almost high-end, so i decided to build one by myself or
its not worth it?
I had old stereo amp from end 90s which sounded incredible it also had these chips pair per channel

I already made PCB and what about components?
May use ordinary old TV parts, for the looks only :)

johnr66 13th December 2012 04:31 PM

Build it and listen. If it sounds good it is good. Let your own ears be the judge.

t9crepair 25th December 2012 04:46 AM

I am working on a Marshall guitar amp that uses 1 tda1514. Bought 10 from Dalbani on ebay and going to breadboard the same circuit here, TDA1514 to test the lot. I may even try to build a stereo amp for my iPod with a couple. Normally I wouldn't calla guitar amp HiFi, though with a good preamp, it might be.Good luck with your project.

atupi 25th December 2012 09:46 PM

This chip can sound very good with a good implementation. Go for it and you will not be dissapointed. Make shure you use nos chips not fakes. Cheers !

JMFahey 25th December 2012 09:59 PM

The TDA1514 is *very* good, and was designed for Hi Fi .
Of course it can be used for guitar.
The problem is that it's currently out of production, so if you have a stash , use them of course (and save a couple for spares) but avoid using it for new designs.
I regularly repair 90's guitar amps who used them, and had to make a mini-board to mount LM3886 in the same heatsink or chassis space, wiring the corresponding pins together, because customers can't wait until "maybe, an original one becomes available".
I wouldn't depend on EBay suppliers.

t9crepair 26th December 2012 12:51 AM

Thanks, JM. I was thinking about doing the same to this Marshall 8040 after reading about the 3886 here in the forum. Did you ever plant one in this amp?

JMFahey 26th December 2012 04:36 AM

Yes, of course, it's the first one which forced me to do it ;)
Tons of Msh VS8040 in Argentina in the 90's.
It's relatively easy, you pull the TDA1514 out, pump desolder clean its holes in the PCB, you drill a new mounting hole in the middle of the 2 original ones (be careful with burrs or sharp edges) and mount the LM3886 "upside down" , so you have free access to its legs.
I cut them around 1/4" to 3/8" long and bend them altenatively parallel and perpendicular or in a staggered zig zag so it's easy to solder wires to the short stubs.
I made a miniboard but you don't *really* need it; you'll only solder 6 wires, plus the Mute RC (22K + 10uF)
The pin wiring is:
TDA1514 .................... LM3886
(1) +IN ...................... (10)
(2) Prot ..................... (NC)
(3) MUTE ................... (NC)
(4) -V ....................... (4)
(5) OUT ..................... (3)
(6) +V ....................... (1+5)
(7) BOOTSTRAP .......... (NC)
(8) GND ..................... (7)
(9) -IN ...................... (9)

You must also add a 10uFx50V cap from LM3886 legs 8 to 7 (+ end to 7) and a 22K 1/4W resistor from leg 4 to 8.

For neatness I'd remove the bootstrap resistors and capacitor connected to TDA1514 pin 7 or at least pull the bootstrap capacitor .

Works very well, of course there is no change in sound or power.

PS: don't trust me, check yourself the pin to pin compatibility with both datasheets side to side (at least the application schematic) and turn amp on with a bulb lamp limiter, without speaker.
Confirm that you have less than 100mV DC on LM3886 pin 3.
Good luck.

PS: in a similar way I could replace Fender's żuPC1188? .
The idea is to consider them non-pinout-compatible Op Amps and feed them what makes them happy.

t9crepair 26th December 2012 06:36 AM

Thank You. Your such a great help, Mr. Fahey! I have just ordered a sample from TI and will be looking forward to getting this amp back to the customer. You may remember me posting about this one over on the music-electronics forum, and after reading the great info here on DIY, I'm almost sure I have ordered a batch of "fake" or at least bad 1514 chips. I'll be certain once I get the test bed built and test them all.
Again, thanks for your excellent help and all you do for the amp repair community.

JMFahey 27th December 2012 02:21 PM

Ok,thanks, you'll make me blush !!:o
Remember to use a lamp bulb limiter at first, no speaker load, and check for all DC voltages OK.
Amd *maybe* there's some *other* problem, which killed the original TDA1514, just check around.
As of the Chip replacement, it works, they are basically two big bad Op Amps, in general lines functionally compatible, with a couple small differences which can be taken care of.
Good luck.

longzaijianghu 29th December 2012 02:10 AM

TDA1541 s1,wiht two maps is good!

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