Need some advice on my first Pass build

[more10]

My objective is to build a low power (~10 W) amplifier to drive my Radian 465PB with a small LeCleach horn. It will be crossed at 2,5 kHz. The driver is nominal 16 ohms. I will use balanced input.

I need advice on which Pass design to build. First choice, should I go for voltage or current source?

 

[wdecho]

My choice would be the F4, it is one of, if not my favorite. You will need a good preamplifier to drive it with and not a buffer or just pots. The BA-2 build is pretty much the same thing but with a front end built in. For SE go with the Aleph J. All should sound great with the horn except maybe the F5 but then some like it with horns.

 

[more10]

Oh, I am going to use an active filter with balanced output.

 

[fabrice63]

I have read somewhere a guy saying so . "To my knowledge the only speakers for a current source amp are open baffle dynamic driver loudspeakers. Nelson Pass has experimented with this technique and you can find information about that on his websites"

is that mean you should better ask the man ( Nelson Pass ) himself ??

I guess so ;-)

.

 

[fabrice63]

I found this , interesting to be read :

Atma-Sphere music systems, inc.

.

 

[JeffYoung]

Nelson has a couple of articles on current source crossovers and using current source amps with full-range drivers:

http://www.firstwatt.com/pdf/art_cs_xvrs.pdf

http://www.firstwatt.com/pdf/art_cs_amps.pdf

 

[Russellc]

M2 or wait for the new Amp Camp...

Russellc

 

[2 picoDumbs]

If you don't need a balanced Amp then ACA.

If you want a balanced amp and have some patience ACA 2 will be released soon.

Both of these amps are very nice and available in kit form.

A balanced F4 would also be extremely nice.

 

[plasnu]

For 10W output and pro level balanced input, OP would not need a lot of gain. How about MR L'amp with input transformer? This minimal VFET SE amp sounds really good with horn speakers. It is not an official FW amp, but similar to SIT-1 or 2.

 

[more10]

If you want a balanced amp and have some patience ACA 2 will be released soon.

Where do I get information about the ACA 2?

 

[more10]

Thanks all for your replies.

I will not dare to balance two SE amplifiers.

But is it possible to lower the voltage of for example an F4? I don't need that much power. Lower rail voltage should mean less heat.

 

[Nelson Pass]

On this page #21:

My M2 story

 

[more10]

On this page #21:

My M2 story

Preliminary specs:

Three versions in a single chassis with two sinks and one supply
Class A, No feedback
7 watts stereo output into 8, 10 watts into 4 at about 1% thd
20 watts @ 8 ohms mono bridged, 20 watts @ 2 ohms mono paralleled
Nominal distortion at lower levels 0.1%
Gain = 11.3 dB
Input impedance = 50K
Damping factor = 20 @ 8 ohms
Bandwidth 10 Hz to 45 KHz
Noise = 50 uV @ 20-20KHz unweighted

I like this. I should get 10 watts into 16 ohm bridged. Seems to be the perfect first class A project.

 

[2 picoDumbs]

Yep