Leach SuperAmp Photos

Here are pictures of a Leach SuperAmp that I finished last year. The circuit boards I designed myself with two channels per board. The design also features an LED VU meter for each channel that consist of ten blue LEDs for each channel. They light up behind the smoke tinted bezel on the from panel. Each channel does just about 270RMS per channel into an 8 ohm load. I have run the amp into as low as a 3 ohm dummy load and was able to achieve just about 1100WRMS per channel (not simultaneously). It runs hot it you do this. There are two fans which blow across each heatsink to cool them. The Transformer is a 1500VA ordered from Plitron in Canada somewhere. The caps are 55,000uF / 100V for each rail. The power supply generates plus and minus 90V rails which are shared by the two channels. Most of the wiring is neatly tucked, bound, and routed under the board and to the BJTs under the heatsink so that there is no eyesore inside. All of the wiring is teflon so there should be little concern about melting. Though it only gets hot if it is run into low test loads. There is also a clipping indicator on the board and a smaller supply to deliver power to the LED meter, the LEDs, the startup circuit, and the clipping indicator. And that is all I have to say....thought it would be nice to add.

I am currently finishing up a completely custom four channel (4 x 180 into 4 ohm) integrated class-T amplifier. Featuring 3 band tone controls, mute, bridging, volume, balance, switching power, active power factor correction. All less than a third of a cubic foot and less than 8 pounds. Let me know what everyone thinks about this idea. I will post pictures and answer questions about the project, class-T performance, or switching power overall if no one has tried it.

BeanZAudio



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Wow, sharp looking amp BeanZ. I've been dreaming to construct the Leach Superamp ever since I've construct the Leach Amp last year, but the prospect of drilling for all holes for the 8 numbers of TO3 transistors per channel, a huge PCB (as per Prof. Leach's design), countless wires to hook it all together put me on the hold for the moment. After all, even 14 wires per PCB to/from the heatsink for the Leach Amp is already quite a chore. But I have to admit, it's worth it.

Anyway, an excellent job, BeanZ.
 
Hey BeanZ,

Kick *** job. Very cool amp!

What software did you use for the layout and silkscreen? Do you also have a schematic capture program? Do you still have the gerber files for that board? How much did it cost you? I want to build a high power amp but really can't decide on a design. I'd like to build a 600-800W amp that isn't overdesigned. The leach amp "seems" overdesigned. I have heard rave reviews about it though. If not the Leach amp, do you have any suggestions? The transformers, I have access to 2 of them, are dual secondary and give 76VDC each. They came out of a Peavey PV800. Both chanels can provide 800WRMS each. I figure the transformer can do a single 800W amp especially if I parallel the 2 DC supplies. Any suggestions as to a good amp to build, aside the Leach super amp, would be appreciated. Simple and HiFi woulde be best!

Thanks,

Chris
 
The Leach is not overdesigned at all. It is a fairly straight forward design. Let me know if anyone is interested in purchasing the second set of boards. The boards were made from ExpressPCB. I did all hand routing without a schematic capture package. However I do have one now. I have had several people in the past ask about the Express PCB file for these boards and I thought that I did. It turns out that the only thing that I do still have is an intermediary version where it is the two channels on a single board side by side without any further of the "extras" that I included. Just two amplifiers. So if anyone who asked about it so many months ago are intersted in this, I can email it out soon.

BeanZ
 
Hey BeanZ,

If we are to get our own boards made we need the gerber, NC drill and silkscreen files. That's the only way I know that the board shops do it or can they do it from a single file these days? Where did you get your power transformer? Could you use 2SA1943 and 2SC5200's for the outputs?

Chris
 
I do not have a gerber file for these particular boards. ExpressPCB uses their own program which does not allow the export of a gerber file. However, once you order boards you can purchase the gerber file for an extra cost which I did not do. The transformer is a 1500VA Plitron model which results in +/-90V rails. I am not familiar with the transistors you mentioned but if the specs are similar to the M15003/4 then they will operate.

BeanZ
 

Toster

Member
2002-11-03 10:45 pm
Croatia
BeanZ said:
The Leach is not overdesigned at all. It is a fairly straight forward design. Let me know if anyone is interested in purchasing the second set of boards. The boards were made from ExpressPCB. I did all hand routing without a schematic capture package. However I do have one now. I have had several people in the past ask about the Express PCB file for these boards and I thought that I did. It turns out that the only thing that I do still have is an intermediary version where it is the two channels on a single board side by side without any further of the "extras" that I included. Just two amplifiers. So if anyone who asked about it so many months ago are intersted in this, I can email it out soon.

BeanZ


I have your PCB layout that you have sent some time before,
but I can't open it with ExpressPCB 2.6.2 so I don't know if
it is a version with extra circuits.
What version of ExpressPCB did you use?

bye,
mario
 
It is a very accurate amplifier. Fast response with a smooth frequency response. Tons of power at the low end delicate at the high end. That makes all the difference. No matter what kind of music you are listening to it is a good performer. I have done side by side comparisons against high-end, brand name amplifiers and this one was a hands down winner by third party listeners. It wasn't too complicated or expensive to build (relatively speaking). You will find when you listen to music through this amp that you will notice all new nuances that you probably never noticed in the soundtracks before. It puts a whole new dimension on the music. I also use it for the front stage amplifier for watching movies as well. I run the DVD player into it with a fashioned volume control in between. I am using Polk RT55i with a PSW250 which gets its signal hot right from the output of the amplifier. Some will scoff at running a powered sub with high-level inputs but as long as your amplifier is not allowed to clip, the signal will be strong with a high signal to noise ratio. I still have most enough parts left to build a second one....any buyers?

BeanZ