Mini A Board Run

[jleaman]

Does any one want more mini a's / Kit's Im talking to brian when i am here and were talking about doing another board run. *BUT* only if people are interested.

Also im going to do a smd version. If you would boards please post or if your interested please post.

Jase

[eapavant]

I would be interested in anything non smd. The smd stuff I would need to see.

[jleaman]

Originally posted by eapavant
I would be interested in anything non smd. The smd stuff I would need to see.

I'm going to do a bigger run of the through hole. The smd is mainly for me and any one that would like to try a set. I like the smd ones better, the only difference in the new smd ones is that there are a set of ztx transisters are through hole. On Rev1.0 the smd ones got to hot.

[eapavant]

I seem to remember you talking about a smd design. I will go and find it and report back. On the regular mini a's, count me in.

[jleaman]

Originally posted by eapavant
I seem to remember you talking about a smd design. I will go and find it and report back. On the regular mini a's, count me in.

Here is a pic http://www.briangt.com/gallery/mini-a

[JoshK]

What's better about the SMD ones? I have no problems with working with this size smd, so I could go either way with mine.

[jleaman]

Originally posted by JoshK
What's better about the SMD ones? I have no problems with working with this size smd, so I could go either way with mine.

I like the smd ones better because the tollerances on the devices are closer, there is less parts on the board too. I have rev1.0 and love them thus why i am forcing brian to get this done before i leave.

[pixpop]

Are there any of the stereo boards available? I presume these new ones would be the monoblocks in the picture.

[BrianGT]

My current idea for the Mini-A SMD layout would be to keep an almost identical layout to this one:

except for that the transistors will be changed to a TO-92 footprint, as the smaller SMD transistors caused me issues with heat dissipation. The current design is 2"x3" for the amp boards, and is designed only for the Mini-A application. For a larger Aleph amp, the other boards would have to be used. Currently, only non-balanced inputs are accepted for the amp.

For the pcb set, I would like to make a single pcb that breaks into 4 pieces, 2-amp boards and 2 psu boards.

The PSU boards will be similar to these:

with a bridge rectifier, PSU caps, bypass caps and bleeder resistors. Possibly closer in appearance to this:

but with a pair of caps, instead of the CCRC.

The idea here is the create a simple, easy to build SMD Mini-A design. More complex amps, with the ability to accept balanced inputs, or additional output devices can be created with the other Mini-A boards that were created for the use of through-hole devices.

This version of the Mini-A design will be only intended for <= 20vdc rails and 15watts or less.

Let me know if you have any comments on the proposed design.

--
Brian

[jleaman]

The reason that these can't accept no more than 20V rails is because of the smd cap's are rated for 25V each. @ 20V rails i estimated about 15watts. These smd boards are great for small power and great for a pair of small speakers. The project is really good for those who can't afford a aleph 30 and up but want to try a class a.

The mini smd a's are perfect price and cheap to build If required to build more power it is easy to perchase the through hole board's and build a more powerfull amp.