Like the TXO, the Sympatico uses a Texas Instruments THS4131 fully symmetric op-amp for voltage gain, and a National Semiconductor amplifier chip in a nested feedback loop for additional voltage gain and current drive. Rather than three separate modules and two LM3886 amplifiers of the TXO, the Sympatico is a single small module per channel with one LM4780 dual amplifier chip in a balanced, bridged configuration. Some other design elements of the Sympatico include:

-> Fully symmetric, balanced operation
-> Ultra-low noise floor (perfect for high efficiency loudspeakers)
-> 100+ Watts/Channel into 8-ohm loads (conservative)
-> Precision SMD passive components for ultra-short feedback loops (0.5% thin film resistors)
-> Instrumentation front-end (LM4562) for high input impedance and easy interfacing with single-ended gear (balanced inputs recommended for best performance)
-> Single user-selectable gain control resistor (through hole)
-> Through-hole supply capacitors for easy tweaking
-> On-board discrete shunt voltage regulators for lower voltage stages
-> Multi-option power and signal connectors (faston, terminal block, direct wire)
-> Small form-factor (3" x 4")
-> On board power supply for easy installation

We will be ordering the first prototypes soon, and will be posting progress reports as we have them.

Edited by user Friday, May 30, 2008 6:25:10 PM(UTC)  | Reason: Not specified

Hi Akione,

We have always been very pleased with the TXO-2. Being fully symmetric it seems completely immune to hum and common mode noise in general. On my listening room amp you can hear no hiss with your ear to the tweeter, none. Try that with an ordinary chip amp. :) Also because of the fully symmetric nature, power supply ripple rejection is incredibly allowing for the use of simple inexpensive unregulated power supply.

While the Sympatico will need a decent sized heat sink if you push it hard, for normal use I have found a simple 4" x 5.5" x 1.25" heat sink was just fine, just as it is for the TXO-2.

Cheers!
Russ

Edited by user Friday, May 23, 2008 6:55:06 AM(UTC)  | Reason: Not specified

Sweet,
I don't need any new amps, but I want to build one anyway. My nephew needs a rig, I may build him an integrated, what is in works for a preamp for this baby.

Bill

Hi Bill,

Just about any preamp will work.

The input impedance is 100K

And you can do SE or balanced inputs.

Joshua Tree would be a solid choice.

Cheers!
Russ

Some nice improvements, there, Russ, but ........


....... I was planning a case with the top as heatsink, a la A1 (actually from my old A1 ),

but it's only 3 inches high .......

Ah well, I'll think of something else ........

[ Perhaps you could perforate the board, so the p/s section could be separated. ]

by the way i love the new multi-option connectors !

so the sympatico will be scalable to 200W or 400W right?

Thanks.

I can't say yet. It will have to be tested first.

I am quite confident it will do 100-150W with any problem. It not so much designed for high power as ultra clean low distortion power.

Cheers!
Russ

Excellent. I have been waiting to see what this would be. How about some pics? What would you recommend for transformer for 4 ohm load?

Oh I forgot to state voltage. I would recommand 48V center tapped or dual 24V secondaries (which will be connected to the amp as it were center tapped).

You could go a volt or two higher, and it would probably actually work fine down to say 36VCT.

Cheers!
Russ

Hi Evan,

I have been going back and forth between discrete diodes(with or without caps) and the bridge.

If there is enough demand I will go ahead and do the discrete diodes. What I don't want to do is a layout that supports both(either actually) as it makes for a icky looking routing situation.

Cheers!
Russ