T-Amp as power amp ?

[ciorbarece]

Hy guys,

I can hardly wait for my T-Amp, my Marantz PM7200 needs repairing and will be back in about 2 weeks, and I took the oportunity to try out an order the Sonic Impact at last. My curiosity grows every time I read some rave comments of this little thing, and I'm already planning to offer it a metal case, alps poti, rcas and so on. Reading the promising reviews I ask myself which part of the T-Amp is so great, the input or the output stage ? This is important to me because I think about using the T-Amp a a power amplifier and hook it up to maybe a Rotel preamp, in order to get tone controls, remote control etc.

But I don't know whether that would be a good idea, because so far I believe the T-Amps strength lies in its simplicity, and I wouldn't like to mess up the signal with an usual preamp. That would be the case if the t-amps strenght would be the preamp section. So what do you think about using a good quality rotel or so preamp with the t-amp ?

Greetings,

Chris

[ciorbarece]

Oh, by the way, speakers are T+A Stratos F1 2-way bookshelf speakers on arcus stands, rated at 90db and 4 ohms. I guess they will work pretty well with the t-amp...don't you ?

[cpu8088]

the stock t-amp is a bit bass shy

i have mine modded with stealth as suggested in http://www.michael.mardis.com/sonic/start.html

a good power supply is a must to achieve good sound

at this moment the t-amp is being used as an integrated amp for bedroom listening

i have tried using it as a power amp by maxing the volume and hook up with a pio elite 7.1 ht receiver driving the front L and R bookshelf 2 way speakers with 8" mid/bass. the result is very good.

[ciorbarece]

I'm also planning to apply the stealth mod to my t-amp, for that I just ordered 2x Mundorf-MCap 2,20 uF 400V, 3%. Those are made for crossover building, but I suppose them to work, or did I miss something ?

Does the stealth mod improve bass performance ?

@cpu 8088: I would love to see your t-amps interior !

So far I pretty much know what to do, but I still have one question about the power supply. I'm planning to use the t-amp with a regulated voltcraft 13,8V 4A psu, but don't know how to connect the psu to the t-amp. Should I use an adapter and connect it directly to the psu connector on the t-amp, or should I take those cables leading to the batteries an put some adapters on them and connect those with the 2 cables from the voltcraft ?

thx

[Pano]

Originally posted by ciorbarece
should I take those cables leading to the batteries an put some adapters on them and connect those with the 2 cables from the voltcraft ?

Yes. You should also put a better electrolytic onboard (C10). When you do, jump the positive leg of the new cap over like in the photo below. You'll see that i have slipped a bit of red insulation over the cap lead.
This jumper gives a more direct, lower resistance path from the PSU to the supply rail.

[ciorbarece]

Thanks a lot for the advice and the picture, if I got that right you would suggest to apply the stealth mode AND exchange the onboard input caps with better ones ? That would make 4 caps...right ?

And what about the power supply, are 2A sufficient or should I go for the 4A Voltcraft psu ?

I have a 12V 0,8A switching psu around here, that would fit with the t-amps psu connector, but I know that its underpowered with only 0,8 A and my question is if that would damage the t-amp ?

Sorry bout so many stupid questions, this is my first diy project, gotta learn...

Greetings

[cpu8088]

inside my modded t-amp is a mess and no exotic replacement caps either.

i am no good diyer just a newbie. i only followed pana's great advice and ideas

regarding power supply i am using a 12v 2a regulated one. i have modded the input to use a solid xlr type connection which you can see at the back of the case. if you can find a 12vdc 5a power supply that would be ideal.

beware of flimsy power supplies stated as 12vdc but actually higher. that would fry your t-amp

definitely the stealth mod improve bass. check measurements in michael mardis website

next stage for me is to have another mod t-amp as power amp for home theatre front LR speakers

[Pano]

You will need 3 caps. 2 for the inputs (left-right) and one electrolytic onboard.

A 2 amp power supply will probably be enough if your speakers are 8 ohms. During most music the amps draws about 0.3A But loud passages will draw much more. 3 amps seems to be plenty at 12V. Most regulated supplies will give you a brief burst of much more current than rated. How much and how well depends on the supply.

A lower current rating will not hurt anything - except the bass.
Be sure you get a regulated supply. Stay at 12 volts unless you add cooling to the chip.

The XLR used by cpu8088 makes a very nice power connector. A cheaper and easier connector is a 1/4" phone jack.

[ciorbarece]

Hy guys,

please take a look at this modded t-amp:

http://www.yurigagarin.ch/lazy-index.php?file=Baikonur/

The guy managed to include a source selector...

Great !

[Pano]

Nice box! Not crazy about the wiring though....

So that 's what Youri is doing now that he is retired from being 1st man in space. I wonder if Laika helped him....