Leach Superamp Diy

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Make your own 270W Leach Superamp

IMGDEAD]


This slightly modified board lay out allows for using computer power connectors to simplify the wire connections to the heat sink mounted transistors. You may want to make an "output" board for mounting the TO3 transistors easier.
The "foil pattern" and parts placment for making your own circuit board is located on a server at my ICQ address posted here. If you have trouble getting the files, look to your own computer settings in ICQ. I cannot trouble shoot your configuration. Best time of the day to get the files is after 6PM Pacific Standard Time. This is a T1 line and the files should take about 3 minutes to download if you have a reasonably fast DSL type connection.
A zipped parts list is included with parts as described as on:
http://users.ece.gatech.edu/~mleach/lowtim/ and:
http://users.ece.gatech.edu/~mleach/superamp/
and includes some sources for trannies etc.

A careful and complete reading of these doc's is essential to building this amp so that it works first time. The most rank amateur can build this amp if the instructions are followed exactly. If you decide to modify the amp to suit your own desires by using components other than described in Prof. Leach's parts list, do so at your own peril.

There will be no "group" buy of anything required to build the amp sponsored by me. This is Do It Yourself, not done by some other tweedle-dee or tweedle-dumb. Board parts other than transistors are cheap. The most expensive transistors can be had as samples from:
http://onsemi.com/ and you should decide how to get them.
Prudent purchases of components will allow you to build this amp for about $300-$400, most of which will be in the transformer, caps, heat sinks and case. Press-n-Peel Blue Transfer Film by http://www.techniks.com/ works very well for making your board. You need a laser printer or copier and a large base clothing iron. Beware the WAF.
A good read about power supply design that may improve this amp is by Dejan V. Veselinovic titled Designing your own power supply located here: http://zero-distortion.com/start.htm

Some additional pics will be posted later showing a more complete board mounted on heatsinks and may give you ideas about how to make your own output boards.

You may freely distribute anything found here as most of it is easily found on the web. The images I have provided are yours to use or modify as you please and I take no liability for their use or accuracy.
Requests for modifications, complaints about layout or choice of parts will be ignored. I have built several configurations of this amp without help from anyone and so can you.

This amp is probably over kill for most folks living room applications, but you do get bragging rights to a 270 Watt amp. And most likely you'll discover your speakers really are not that great after all.

Prosit:drink:
 

Attachments

  • superamp.zip
    3.2 KB · Views: 327
I did not make two posts. How that happened is beyond me.
Perhaps our moderator will take down the other one.
And allow me to rephrase ."Requests for modifications, complaints about layout or choice of parts will be ignored." to "ALL complaints will be ignored, including but not limited to the board layout, parts choice, requests for modifications, size of files, ICQ, personel vendettas, etc."


Anyone who wishes to build this amp with the layout may do so as they choose with any modification they see fit.... It's nothing to me if you do or do not. You are free to press on the back button on the browser and go away to some more interesting place.

EVERYTHING that you need to know about building the amp is in Prof. Leach's documentation.

The ICQ icon is not showing in the browser despite repeated attempts to activate it. The number is 310-361-573

Prosit:drink:
 
Hi Ace,

What a great idea! I wish I had used your layout instead of the one on Prof Leach's site. I would have liked to have the extra room and those connectors would have tidied things up a bit, I feel.


I'll be folowing this thread as it progresses.

Blessings, Terry
 
Hello acenovelty,

Arguing so eagerly in the super amp redesign thread against my new PCB layout deserves some sort of help from me to your work, that you have now presented.

First of all, we clearly don’t agree on the choice of output devises. Let’s leave it at that.

I can see some obvious problems like the lack of sufficient track width in high current nodes.
It looks like you tried to make a solution by adding solder to the tracks. This can make the tracks peel off - it might be better to add wider tracks.

The bias potentiometer could be better, I think that a multi turn type will last longer and be less prone to failure.

With all that extra board space, I would add some fuses and extra supply capacitors.

This is just my initial thoughts to help you improve your design.

\Jens
 
kilowattski said:
I still don't understand why you gave Jens such a hard time about improving the layout and amplifier in general when your implementation is seriously flawed.


"Seriously flawed" seems a little harsh or is that your intention?

AFAICT, many, many folks have built the Superamp using the original design. I would think the term "seriously flawed" would be saved for a design that hasn't been so successful.


Excuse me if I'm out of line here, but It seems to me that there may very well be folks who don't want to spend $60 for a pair of PCB's or may just want to build the amp with T0-3's.

I think this thread has merit and it's existance has caused Jens to return to the other thread so it looks like a win, win situation to me unless folks just don't want to let things calm down.

Blessings, Terry
 
Terry,

Maybe it was a little harsh but maybe a bit deserved also. Jens has been attempting to improve the layout of the Leach in another thread and Mr. Acenovelty gave him nothing short of a hard time every step of the way. I also find his opening post rather condesending with a comment like:

There will be no "group" buy of anything required to build the amp sponsored by me. This is Do It Yourself, not done by some other tweedle-dee or tweedle-dumb.

I am sure you have seen Jens layout and it is my personal opinion that it is simply better thought out. Acenovelty's layout has what I consider some serious flaws that Jens pointed out earlier in this thread in the following areas:

The computer connectors are likely to gain contact resistance over time and cause a failure. I have seen one of these connectors melt due to heat generated by contact resistance.

The traces are not near wide enough for power and ground.

The additional solder added to beef up the traces could damage the board and lift up a trace.

Small supply filter capacity.

Two of the flaws I view as serious.

I am not attacking Acenovelty, for he is entitled to his opinions. I am merely curious as to why he gave Jens a hard time when his design and layout has some flaws he should worry about.

I guess I just got a little tweaked when Jens was developing a board for a group buy with only the best of intentions, when along comes someone who gives him a hard time every step of the way. Terry, I am truely sorry if I offended you or caused you any discomfort.
 
Look guys,

Ace has mentioned several times that he is very enthousiastic about the Leach amplifier and has built a number of them.
He has also stated that it is his view that the amplifier is good as is, with the original layout of Prof. Leach.

Ace stated that it is his opinion that this amplifier can be built with the standard components and layout to obtain an amplifier that he is content with.

He also stated that, as the amplifier is good as it is with the original components, he sees no reason to use more expensive parts, and make a different layout that costs more than making one yourself with the layouts he posted.

At the time when Marshall Leach made the Super Leach available to the diy zone there was no other design this powerfull, and many have built it, as it is.

And Ace is right, making it different, with more modern components and a different layout, will make the Leach more expensive.
Ace advocates keeping it simple, the most affordable, and not make things more difficult than handed on a platter by Marshall Leach.

It is his right to think so, his right to tell people diy can be kept basic and the most affordable.
He has the guts to start a thread promoting the original design.
People should respect that, and not keep repeating the same stuff a number have already said several times about the Leach design.

There is a thread on making the Super Leach different, any comment on the flaws of the Leach layout and circuit can be posted there.
This is a site for people to share a passion, not for attacking one another, let anyone judge for themselves.
 
kilowattski says,
The traces are not near wide enough for power and ground.

I'm kind of new to all this. Just trying to learn.
Seems the power recommended is plus and minus 85V. Maybe the current is 6 amps or more.
Is there a rule one can follow about how wide a trace should be for power and ground?
And how thick should the copper on the board be for safety or current/voltage? Since the layout is just a line drawing, I might just take a crack at fixing this if I know what to do. Maybe there's a formula or reference you could point out to me where I could google it and not bother folks too much.
Those computer connectors seem like a reasonable solution, but if they melt that's not so good. And I know there's connectors like those that are more sturdy. Could I just use soldered wires point to point instead?
And I don't understand what you mean about the Small supply filter capacity. Do the Power Supply capacitors go on this board? Always thought that was a separate thing in the box. I'm rambling on, sorry, but before I go, I was looking for the layout of Jens new board and didn't find anything. Am I missing something?
Anyway, thanks for listening and any help you can offer.
No offence ment to anybody by a new guy here, but if you folks spent more time doin instead of arguin, it'd be better for everyone.

Elvin :geezer:
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.