Where to buy Leach Amp v4.5 PCB's?

[frckid]

I am about to embark on a two-channel Leach amp and I was just wondering where I can buy the original Leach Amp v4.5 PCB's? I searched the forum, but could only find stuff for the superamp.

Thanks,
Jonathon

[amplifierguru]

You need to be very careful buying PCB's for a particular amplifier design that are not endorsed by the designer.

This is because performance of a design is highly dependent on the correct layout being adopted. This is especially true of high bandwidth designs.

I can recall the time when I was contracted to Madrigal (makers of Mark levinson products) and their chief engineer at the time was rehashing an old product (not his) into a new shape with some new outputs and couldn't understand why the THD was around 0.5% on the prototype when the previous product had been much lower. I cast my eye over it and in seconds noticed the input stage (a low signal high impedance, sensitive area) was almost encircled by a driver track trying to get from upper to lower drive. I told him to try cutting that away for 1" and run a jumper away from the input.

THD dropped to <0.03% down 2 scales on the old Sound Tech.
He exclaimed "I didn't know layout mattered" I asked who did the layout - "the draftsman!" On what basis " Fit!"

"How do I do it?" So I took time out from my project and taught him. This is a high impedance sensitive track....

Cheers,
Greg

[saabie22]

Prof. Leach will sell them directly. This little snippet from one of his emails is important:

"Please, please put "Low-TIM PCB" in the subject header of any email that you send to me. I get so many spam emails and emails from our school that sometimes I just don't see inquiries about amplifier circuit boards before my email gets deleted. "

Good luck

[acenovelty]

Howdy frckid,
Must have built more than twenty of "the original Leach Amp ". And at least a half dozen of the SuperAmp. Not one laid out like the other. Built them quick and sloppy and long slow neatnik. All performed flawlessly. If you read and follow his instructions exactly, so will yours. If there is an amp design that is more forgiving of the noobies errors, this builder has not found it. You'll get lots of advice from folks who have never heard or built this classic amplifier. Generally speaking in my experience, nay-sayers and detractors usually have their own agenda.
Buy them from Prof. Leach or roll your own from the PDF on his site.
http://users.ece.gatech.edu/~mleach/lowtim/


Regards

[Byrd]

Jonathan

Just would like to point your attention to a slightly newer version of the Leach Amp.

Smaller Leach Amp V1

I agree with Acenovelty's sentiments 100%

[acenovelty]

Byrd,
Mighty pretty amp you built.

[amplifierguru]

Ah ... Flat earthers! Got THD measurements , FFTs on them - no two the same???? Somehow this amp is impervious to the vagaries of every other (wideband) amp? I don't think so.


Back it up with figures and graphs. I do.


Bite me.

Greg

[Greg Erskine]

Originally posted by amplifierguru
Back it up with figures and graphs. I do.

Hey Greg#,

We're DIYers here, we do and say what we want. Luckily you don't make the rules.

I think you may be playing in the wrong sandpit.

regards

[amplifierguru]

Hi Greg #,

You can count on an aussie!

Seems I can't give frckid a bit of advice re quality of PCBs without all the flat earthers coming out of their caves. If he wants to spend his hard earned on expensive boards/project at least he should receive sound advice rather than just blinkered belief.

LAYOUT MATTERS! It's the laws of physics. They apply. Start with maxwell's equations...

Cheers,
greg

[Greg Erskine]

Hi Greg,

Everyone appreciates your advice and experience, I'm sure. Most probably understand a bit about electronics, PCB layout, physics and maxwell was one of the funniest blokes on TV, my favourite (Agent 86?)

Wrongly or rightly, when you start to sell products, any negative comments "can" be seen as a putting down another's "product" to promote your own.

The "art" of using a public forum to help others, while at the same time taking "advantage" to promote a product requires great skill. You can't really afford to say anything negative.

Dr Leach, via his amp, website and lecturing over the last 20 years, has probably contributed more to DIY audio than any other person and he is held very fondly in the heart of many.

regards