EB-TA0103A integrated amp.

[Fin]

I recently came across an EB-TA0103A Evaluation Board and am planning ot build an amplifier based on it.

For the power supply - I was thinking of using two of these SMPS:

Specifications from retailer:-

New 200W Lambda Switching power supply, open frame.

Input 100V - 240V AC. Output:

+ 45 Volt @ 2 Amp, continuous
- 45 Volt @ 2 Amp, continuous, both rail voltages trimpot adjustable by 10%

Delivers 3A peak for load transients.

also 5V and 3V outputs @ 5 A, good as housekeeping voltages for lamps, relays etc.

Only 1.75" high, (43mm), runs cool, low ripple, thermally and short-circuit protected, and because it's Lambda, it's overengineered and underspecified. Schematic included.

Size: 4 x 7 x 1.75 inches.

Can be used to power chip amps (LM3875, LM3886, LM4780) since these parts' absolute maximum ratings allow supply voltages of up to 94V (+/- 47V).

Instructions are also be provided for dual linear post-regulators, to lower the supply rails to as low as +/- 30Volts (free of charge).


Total continuous output power: 200W.

Can connect multiple units in series/parallel for greater current or voltage.
Lambda part nr: SCS200-P48480503W.

For a volume control I thought one of these might be nice:
Stereo Stepped Attenuator

Would the 50K value be appropriate?

I would also like to replace the input capacitors (C13 and C16) with some better quality film caps. The value of the existing caps is 1uF. Should I implement any other changes to the input circuit?


And this seems like good value for a chassis to put it all into:
Black Metal Chassis

Any thought's, ideas, warnings or other advice would be appreciated.

ED-TA0103A Datasheet

 

[Pano]

Hi Fin - I got your email.

That eval board looks like fun, good find! The power supply will certainly give you the +/- 45V you want, but the current will be a bit limited. Especially if you want to drive a 4 ohm load. You won't get all the power the amp is capable of with that supply. But if you keep it down under about 130 WPC, no worries.

Don't forget that you also need a 5V supply.

The stepped attenuator is nice, I've used the 50K. Buy it assembled, I did. I think it's worth the extra $$ to have it tested and ready to go. 50K is fine, 20K should be OK for almost any use, too.

The input caps are smaller than on the other T-Amps we know because the input resistors on this board are twice the value of what we normaly use. So 1uF is the same as ~2uF on the other T-Amps. You can still use a 1.5 or 2.2 if you want to.

Keep us informed as to your progress.

EDIT: Oh, I see the supply also has 5V and 3V - cool! Be sure to filter them well.

 

[Fin]

Thanks for having a look Michael.

I've actually got two of those supplies.....which seems like they will give me about 4A per 45V rail. Probably going to use some 8 ohm speakers that are 93db/w............so I think that the available power will be adequate. They are plenty loud with the little SI T-amp, so this big boy should have no trouble.

Thanks for the advice on having the stepped attenuator asembled. That will save a lot of trouble.

Should I just connect it to the inputs on the board and leave everything else in place - or should the 50K input resistors be removed when using a 50K pot/attenuator....and the input configured like your stealth mod? That way I could fit my big 1uF Obbligattos in there...

Yes - there is a 5V output from these supplies - very handy. I wonder if it is worthwhile connecting them is series to give 10V and then regulating it back down to 5V to get a very stable 5V....or would lots of filtering be enough? Appearently the 5V supply is critical on these boards.

It will probably be a while before I get around to doing this project but I would like to get the planning and parts ordered in advance.

Thanks again