Hey...found the Acoustat TNT-200 schematic! (and TNP preamp)

[KBK]

...on my work PC.

Anyone want a copy, email me. It's a high rez photo of the schematic from the manual. About 730k, 2217x1600 or so. Easy enough to read. If you want a copy, please leave your request here in the thread as well as emailing me....this way..if I don't answer an email 2-5 years down the road (people WILL ask me in 2010-2011, for sure!!!), then they can ask the NEXT guy in the list.

To give you and idea..I STILL get emails from people asking me about VGA video and video capture card modifications from the AVS forum. Those threads are 5-6 years old.

[Jan Dupont]

I would love to get the schematics

[Nordic]

These are amps for electrostatics ?
I am interested in the pre though, I love trying out preamps.

[Jan Dupont]

Thanks KBK

[KBK]

according to acoustat and fans of acoustat speakers, the TNT-200 is an excellent match. You would figure this to be true, the two being voiced together at the inception of the TNT design.

regardless, the TNT-200 is a classic all fet, pre-driver regulated PS, 200 WPC Hitachi MOS-FET amp, with no emitter resistors. The design uses output rail fusing only. It responds very very well to even minimal modification, as the circuit is dead simple.

Most specifically...look very, very closely and ponder the feedback loop section.

I have owned at least two of each of the preamp and power amp. The preamp is quite excellent for 80's preamp design. Some simple mods increase the fidelity dramatically. I believe that the balance pot is directly controlling the loop gain, so it has a very deleterious effect on the sound of the preamp. First thing I did, after I saw the schematic..is to remove the balance control and put in resistors.

[spind]

I'd like a copy of the amp schematics please.

thanks!
Steve.

[tvi]

I'd like a copy of the amp schematics too please.


Thanks
James

[bear]

Well it is an interesting amp.

It uses two feedback types simultaneously via a sort of bridge set up.

The kicker is that the speaker is connected between the CT of the xfmr and ground, iirc. The outputs are connected to ground. No, I'm not kidding.

It is not a high voltage direct drive ESL amplifier.

_-_-bear

[anatech]

Hi Bear,
That's okay, they sound very odd with normal speakers.

Ken, do I have those schematics already? I don't think I have the preamp yet (for sure).

-Chris

[KBK]

I'll get these requests out on Sunday, when I go into work for a bit.

Chris: I dunno if you have that schematic. You might..I can't find the original TNT-200 manual. You might still have it. I have the TNP (preamp) manual here.

at first blush (simply looking at the feedback loop in isolation) it almost appears as if it is method of phase (distortion) anticipation, ie a passive feed forward or similar. Pardon my lack of proper lingo, I only know what I see on the paper, with regards to passive devices in an active/passive circuit. It is elegant, as most simple and effective/working things are....

$20 says he did (Jim Strickland, the designer) it by feel first and then came up with the theory.