F5 power amplifier

[Tea-Bag]

B4

Thanks danny_66.

"The B4 Crossover / Equalizer has been designed around the needs of full range speakers (Lowther, Fostex, and all the newer entries). It has circuitry for equalizing to the needs of full range drivers and for adding a woofer."
perfect for my Fe206.

Perfect for my Lowther DX4 as well. I would not mind seeing this one soon. Replace my DCX2496 and get rid of Dick O's notch filter in one box. I am sure it will have better bandwidth.

If NP wants me to tell him how a prototype compares, I am more than willing to help test pre-production units....

 

[jackinnj]

Of course, but I just wanted to make sure you don't need that much dissapation for some reason not obvious to my tiny brain. Since it is just feedback I doubt it. Likely the 100r 3w are just what Nelson had a lot of so there are two ;-)

NP recommended the rez in parallel as the 3W flavor are less expensive.

The 10R resistors are probably 1W.

As I said before, I have a bunch of Caddock 35W TO-220 resistors from another project -- they have to be heat-sinked. There's no point in letting them collect dust.

I believe that Caddock also make a TO-126 version with 15W dissipation.

 

[jackinnj]

Anyone who wants a ZIP file of the copper top, copper bottom, silk, bom and drill files for the input compensated PM me. I changed the hole-sizes to 150mils to accomodate a threaded 6-32 standoff. (FWIW, I use nylon standoffs so I don't have to worry about the metal coming into contact with a trace.

You can easily take the gerber files, load them into a viewer like Pentalogix and print at 100% to make your own photo-masks.

 

[Nelson Pass]

Re: B4

If NP wants me to tell him how a prototype compares, I am more than willing to help test pre-production units....

Several units are being prepped to go out to the "trade" in 1 to 2
weeks. After those are evaluated, design revs.

 

[Tea-Bag]

Re: Re: B4

Several units are being prepped to go out to the "trade" in 1 to 2
weeks. After those are evaluated, design revs.

All I have to trade right now is some japanese maples and heatsinks.

I must be happy with what I got. Stop wanting stuff. Be more like the Dharma.

 

[fredlock]

Jack, I just e-mailed you about the zip files. Thanks.

 

[steve jones]

Will the F5 work as well driving 16 ohm speakers as it does 8 ohm ones?

Are there ways to optimize it to drive the higher load?

 

[juma]

Will the F5 work as well driving 16 ohm speakers as it does 8 ohm ones?

Are there ways to optimize it to drive the higher load?

Higher Z load wants more voltage and needs less current - keep power dissipation the same and don't forget to cascode the JFETs

 

[MEH]

Or just bridge a pair of F5 channels.

 

[Nelson Pass]

Either of those will work.

 

[Peppe]

Any PCB group buy for F5 yet?

Please, please....

 

[Nelson Pass]

If you're not in a hurry, www.passdiy.com will be offering boards
in a month or so.

 

[chrismercurio]

WOW.

That is awesome.

 

[hc167]

General question, where can we get 2sk370 and 2sj108?

 

[Variac]

Maybe they could come with the boards..

 

[hc167]

that would be great idea.

 

[neutrino_th]

http://www.audioprojekte.de/html/semiconductors.html
Deutsch shop, "We match all transistors to your needs"

You can use 2SK170 and 2SJ74.

 

[hc167]

that is good site. thanks a lot. I didn't know this site. I will save it in my bookmark. now, I can think about building a F5 too

 

[steve jones]

I got my matched JFETs (2SK170BL and 2SJ74BL) and MOSFETs at:

http://www.tech-diy.com/hexfets.htm

Super service from Jack. Highly recommended.

 

[Tea-Bag]

JACK

I got my matched JFETs (2SK170BL and 2SJ74BL) and MOSFETs at:

http://www.tech-diy.com/hexfets.htm

Super service from Jack. Highly recommended.

Agreed. I buy my NP science project stuff from him.
He is helpful and has got your stuff available matched. A good dealer and first choice.