Krill - The little amp that might...

[Steve Dunlap]

Solid state would make some sense, however anyone with a project that is not a speaker will still need a metal case.

I checked with an on line metals source since my last post. I used the dimensions of my current preamp (17" x 9" x 3" with a 3.5" x 19" faceplate) because I would like to replace it. The price for pre cut to size Al with shipping was $85. This was using .09" plate for top, bottom, front and back with .25" side panels and faceplate. You can save money by using thinner metal, but I would not recommend thinner than .0625 for larger flat pieces. This is thick enough to mount heavy objects like transformers. Does this seem to be a reasonable price for a nice case? Some assembly required.

I am not selling these. I only plan to give some sources for on line metals and directions (with pictures) of how to build your own. Think of it as a DIY thing.

http://www.onlinemetals.com/

Check for sources near you or that will ship to you.

[c2cthomas]

Hi Steve - I looked around and couldn't find anything that would be nearly as nice as the chassis you are describing!

OH MAN - now I will need to decide on the titanium or the carbon fiber! Ohh - and brass and copper too!!

Add a touch of wood and maybe an LED or two and - WOW!

I've been considering something to slap about 4 of your monoblock amps into (one per chassis - for bi-amp project) along with some type of built in active crossover that could be user adjusted (freq. and slope). Still considering the use of (dirty word) opamps or xsistors for that little guy tho -.

As long as I don't need to come over and use your mill to machine something out of solid stock - I'm game!

[troystg]

Thomas-

Marchands XM-1 works well and is inexpensive.

I have a couple of these if you need some:

Active filter board GB

[c2cthomas]

Originally posted by troystg
Thomas-

Marchands XM-1 works well and is inexpensive.

I have a couple of these if you need some:

Active filter board GB

Hi Troy - Thank You for the offer - I might take you up on it - but I would want to compensate you for the cost. I'm thinking of something very similar - but I'm thinking of adding a header (like the ones used on hard disk drives that select "master" or "slave") to select the values of the resistors and caps and thus let me muck around a bit more than soldering components into and out of circuit and then guess if I'm hearing something better or not. I haven't read the Bob Ellis thread so I think I'll give that a look and see what he came up with there (sharp guy). I for sure want to build the circuit into the amp tho-

I have checked out the Marchand stuff before and was very interested in his OEM line of amps for doing self powered speakers. All things are under consideration pending surplus $$$$.

[Andypairo]

Originally posted by c2cthomas
I've been considering something to slap about 4 of your monoblock amps into (one per chassis - for bi-amp project) along with some type of built in active crossover that could be user adjusted (freq. and slope). Still considering the use of (dirty word) opamps or xsistors for that little guy tho -.

In case I have two boards for the Delta Audio Active filter two that does exactly what you need.

info here : http://delta-audio.com/Active%20filter%20two.htm

These are almost completely stuffed (just some Q- setting resistors missing). I'd gladly trade them for a pair of Krill boards.

Ciao

Andrea

[c2cthomas]

Originally posted by Andypairo

In case I have two boards for the Delta Audio Active filter two that does exactly what you need.
Ciao
Andrea

Ciao Andrea,
Milano! A beautiful place to be living life! During my Navy days I was able to see Venice and Naples several times and fell in love with northern Italy. I was reading about this circuit board last night and regretting that the group buys have gone bye-bye and now they are difficult to obtain unless I would want to make some myself. To many holes to drill to be thinking about doing such a thing! Also - they use a potentiometer in the circuit which I don't like - but I would just put in a fixed value there after determining what I needed. I don't know what Steve's Krill boards cost - but I can inquire. Would you be wanting the boards stuffed or just bare? Also - the boards that Steve has at the moment are for the monoblock amplifier - not the stereo boards that have been discussed in this thread earlier.

Thomas

[Andypairo]

Hi Thomas,
will send you a email shortly to avoid polluting the thread.

Ciao

Andrea

[Samuel Jayaraj]

Steve, I set out to design a PCB for your amp in post #21, wherein upto the driver stage the rail voltage is run higher. I also thought of doubling the output devices to be able to feed them off transformers I readily have which will have higher voltages.

I ran into a problem wondering which devices mount on the output heatsink and if D5-D7 are also in thermal contact with the heatsink?

A clarification will be much appreciated. Thanks.

[Steve Dunlap]

Hi Sam,

E-mail me and I will send you a Zip file with more info.

Doubling the output devices will allow operation up to 100W at 8 ohms and 200W at 4 ohms. Four pair will allow operation to 200W and 400W respectively. For outputs over 50W at 8 ohm I recommend using the same transistors for drivers as used for outputs. This insures greater reliability especially at lower impedances. All of this depends on proper heat sinking of course.

If your supply voltages go over +/- 50V a small heat sink on each of the TO220 transistors will also improve long term reliability.

The drivers and output transistors all go on the heat sink. Diodes 5,6 and 7 are mounted to the heat sink (near the center) for thermal tracking. The art work for this diode board is also included in the Zip file.

Be sure to check the schematic in the Zip file as any errors that I made in earlier posts have been corrected (I hope). The schematic designations are different for many components because I drew it to match the boards I still had in stock.

If you have more questions, please ask them here, not in E-mail, so it will benefit all interested parties.

[Steve Dunlap]

I have redrawn my 50W amp schematic to correct some minor errors and to incorporate the newer part numbers. If anyone would like the new Zip file which includes the schematic, board top and bottom art, stuffing guide, diode board and drawing of the heat sink I used when the 100W amp was manufactured. The heat sink lines up with the outputs and drivers. This gives you the hole spacing to make your own heat sink. E-mail if you would like to receive the Zip file. It is too large to post here.

I have attached the new schematic.