| 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 |
|
|
| 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 |
| quote: | 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. :D Luckily you don't make the rules. ;)
I think you may be playing in the wrong sandpit. :confused:
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?) :D
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 |
|
|
| acenovelty |
Dear Mr. amplifierguru,
The boards from Professor Leach's web site do actually work and are not expensive. Nor is it difficult to make your own from the published PDF.
Your rudeness will not change any one's mind, certainly not mine.
Your overbearing attitude to everyone will not make them change their
minds.
Try some common courtesy along with maxwell's equations.
You're swimming against the tide.
Opine your tirade elsewhere, please, pretty please. With cream and sugar on it. Please.
Best Regards |
|
|
| amplifierguru |
Hi Acenovelty,
I was simply trying to help frckid and all I got was a tirade! Anyone would think I was trying to rework the Old Testament!!
Not once did I link to my amplifiers. You seem happy to search out and buy all the best parts then have a 'devil may care' attitude towards how they're placed. I inform that it matters and all hell breaks loose.
Only trying to help. Remember that saying "you can lead a horse to water..."
Truce.
Cheers,
Greg |
|
|
| acenovelty |
Dear Mr. amplifierguru,
Sir, you know nothing of what and how I purchase parts nor how the boards have been laid out. Most of us know about the word assume.
I inform all that this amplifier design by the esteemed and highly respected W. Marshall Leach, Jr. is most forgiving of layout problems normally associated with sloppy workmanship. I have the hands on experience to say so with impunity.
It's also true that no good deed goes unpunished.
Truce.........
Best Regards |
|
|
| Workhorse |
| quote: | Originally posted by amplifierguru
"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 |
Oh Greg,
Could you please continue this phrase so that i can understand and learn your sayings....
regards,
K a n w a r |
|
|
| Greg Erskine |
| quote: | Originally posted by Workhorse
Oh Greg,
Could you please continue this phrase so that i can understand and learn your sayings....
This is a high impedance sensitive track....
|
Hi Workhorse,
....so imagine its a LM3886. Run the input 2 pins away (2 mm) from V+ and don't think about what happens when those extremely small wires actually connect to the silicon wafer. :D
regards |
|
|
| amplifierguru |
Very good Greg#,
But chip amps are not discrete layouts and have their own set of proximity interactions such as thermal feedback, etc...
Quiz an audio chip designer as to the importance of layout to performance and get back to me.
Hi Kanwar,
These are the lessons that come with experience .. you'll no doubt get there - you have the passion!
Cheers,
Greg |
|
|
| jacco vermeulen |
| quote: | Originally posted by frckid
where I can buy the original Leach Amp v4.5 PCB's? |
Mr Ball,
the way i read Jonathan's line is that he is asking for the PCBs which are endorsed by the designer.
A lot of members here have good memories of the designs of Mr Leach, some less recent than others.
All over the world many thousands of people have built these amplifiers from the first version to the last.
And like a few of the designs of Nelson Pass, they were aimed more at the DIY person than professionals.
The Leach is from the time when we had the Elektor Creshitto here, now there is a design and layout to criticise. That thread keeps popping up time after time on my screen and still people are constructing something that does not sound right, measure right, and tried to launch itself into orbit on many ocassion.
On another Leach thread someone found it a challenge to do an updated Leach design, with contemporary parts and high quality boards. He never claimed to be a professional audio designer, but a person who likes DIY audio and has professional experience in drawing PCBs.
And one who is learning step by step how to improve board layouts.
Because of the time invested in designing such layouts, others who jump on the offer of obtaining boards of a quality that even surpasses many commercial products do not expect the layouts to be perfect.
Some just think of ways how to alter a board in details that will improve it in their opinion.
Bashing such a layout, and thereby the one who enjoyed making it, without offering advice on how to improve it is just criticism.
Most of us are not here for the sole purpose of buying superior products from professional designers, even if they may be excelling, you are :
| quote: | | it's a part of my skill-set I'm not willing to give away. |
Most of us are here for the fun of DIY: doing it yourself and the learning experience. And some of them do measure how it performs afterwards, know how to do an FFT and were even tought Fast Fourier theory, Gauss and Faraday laws in school. Maxwell is the guy from the video casette tapes and CDRs, right ?
Many will not disagree with your knowledge from vast experience in designing audio amplifiers, but get the impression that a Guru who is selling his knowledge to morons is like a Baghwan in need of a new Rolls. |
|
|
| amplifierguru |
Hi Jacco,
Absolutely agree about the request of the thread starter.
Designing of boards for Hi End audio can only be achieved by people with the higher knowledge of what's going on. I pointed him to 'designer endorsed' PCB's because it's a fundamental and crucial part of the final result.
Many people, however well intentioned, don't understand and indeed many, many working engineerts don't know that the finer performance of the product , be it a kit, 'free to air' or finished product - IT'S AS IMPORTANT AS THE COMPONENTS. To just bodgie up a cct boart with no space between components or sensitivity to layout is a dis-service degrading achievable performance.
NB; Bearers of bad tidings are not ogres or necessarily commercially motivated. You just cannot place all expectation for performance on topology and none on layout! DIYers want good outlay/performance value too so let's cut through the self-interest.
Cheers,
Greg |
|
|
| Upupa Epops |
| Hi Greg, whatabout little course about correct design of PCB ? Mainly of PA, I mean... As I see, it is " green field " for many guys here a they they will be grateful to you... ;) |
|
|
| amplifierguru |
Hi Pavel,
It's a rewarding endeavour to learn by experience as I did. I simply want to ensure the window was open. Minds hopefully will follow.
Cheers,
Greg |
|
|
| Byrd |
| You do not make sense. Your intention was not to open peoples minds - I have expalined this already. If it was you intention you would be pointing them in the right direction, not simply telling them there is a direction to go in. |
|
|
| amplifierguru |
Sweetie,
Anyone can build a pretty chassis - but audio, after the hype, is the result of finessing topology, componentry, layout, etc..
I can help, but, just like a spoilt kid who has it all, you won't learn without your own personal endeavour, you'll just expect it all on a platter!
Fck.., buy an endorsed PCB.
Cheers,
Greg |
|
|
| jacco vermeulen |
Mr Ball,
are they to blame ?
PCB design software and Sim software is available for free.
Noticed the number of people here doing Spice simulations without even knowing the fundamentals.
Are they to blame that in their opinion it sounds right because the Sim measures right ?
The ones using PCB software to design layouts learn by just starting to design, and learn from advice offered by those more experienced along the way.
But at some point it stops, those who offer advice have run out and those who have not do not offer any.
Many have known the importance of layout in overall sound quality for decades, they are not after taking over the Chef's place at the stove, just in need of some good recipees.
Telling someone he can eat the good food if he pays for it is not a temptation for the one who enjoys cooking.
A thread on the higher art of layout design would the next best thing to all DIY members; those who design layouts and those who can buy better performing ones.
Just think, you could be the first to post and show some of that Guru magic !
Regards. |
|
|
| Tony |
| quote: | Originally posted by 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 |
same experience here! when i hand over these amps to my friends for their evaluation, the ussual comment was, "this sounds better than my tube amp.!" |
|
|
| acenovelty |
Howdy Tony,
After I hand them over, they try to talk me into building better speakers.
Regards |
|
|
| Workhorse |
| quote: | Originally posted by jacco vermeulen
Many will not disagree with your knowledge from vast experience in designing audio amplifiers, but get the impression that a Guru who is selling his knowledge to morons is like a Baghwan in need of a new Rolls. |
Hi Jacco,
The Bhagwan you are referring is "OSHO- RAJNEESH" who has as many as 90 Rolls Royces in his possession......
K a n w a r |
|
|
| amplifierguru |
Well Hi!
I'm afraid baiting me to divulge the finer points of power amp PCB layout for minimal interaction and the best possible THD from a design, is unlikely to be worth the effort, for a number of reasons -
1. You mostly seem not to care what your amplifiers produce in the way of distortions ( I wasn't talking , in the main, about them being stable or not but meeting a design spec). This is evidenced by the lack of measurements relying on sound only where a bit of artificial bloom is no doubt a winner, but edgy treble isn't - no surprise it's most apparent at HF.
You see, the first thing I would do after completing a build is to see if it met spec by measuring it. Was it Niels Bohr who said something like " Until you measure something you know nothing about it". If my build was then out of spec I would correct it!
2. This talent/skill is (not only intuitive but) self taught , I have no reference - except maxwell's equations. I live inside an amplifier I feel the juices, the impedances, the interactions - how do you explain that to someone without such passion. I can, but it might well consume me and for what?
3. There are fairly simple first level layout rules that are not even commonly adhered to, like putting a bit of space between components - when in doubt always put in some space 1/r2 works wonders.
I'm sorry I can't be more helpful but I needed to alert you just the same as you seem to be partying hard oblivious. Perhaps if you'd asked nicely things might have been different...
Cheers,
Greg |
|
|
| mastertech |
PCB design, the main critirion of it is what i call "field and frequency" and how we go to model for the desired effect
basicly it would be too long of an explanation if i was to go
further into the subject, this type of info could be found in the
rf field, so in other words if the amp is not a wideband one the less critical the PCB design will be
regards |
|
|
| Greg Erskine |
Hey George,
If "a picture is worth a thousand words", why not post of few pictures of your PCBs so we can see how it's done. :D
BTW: Note the use of capitalisation and punctuation. It makes it easy for us old folk to read and comprehend. ;)
regards |
|
|
| acenovelty |
Dear Mr. amplifierguru,
Now, now sir, folks are not baiting you. Please, please, don't consume yourself in a fire of passion on our account.
It's pretty much agreed that you are very qualified and most intelligent. Perhaps we can get some other readers to chime in with praise for the guru. Maybe he's feeling somewhat neglected. I think he is quite right to insist on precise measurements for his own build. But on my build, my measurements belong to me. You see, I'm going to listen to music and enjoy. Party on.
And thank you for sharing 1/r2.
Best Regards |
|
|
| amplifierguru |
Hi Mastertech,
Right on. This stuff is best gleaned from RF tech.
Hi Greg,
Capitalisation and punctuation? am I lax? old folk? You're only as old as you feel. Feel something younger.
Post pics of PCB's - I prefer Destroyers X-rated daughter and that bikini she's trying to get out of! It would show my IP and still not inform - I would need to highlight tracks and comment. I'll think on it.
Ace Novelty,
Please don't call me sir, I haven't been knighted recently.
You see my point then - to measure is to know you're close to spec - the way the designer created it. It's always pleasurable to turn on a new amp that you've built yourself but to best it, layout's an important aspect, both PCB and lead dress as is grounding - and I'm sure you won't argue with that. It simply needs a higher level of consideration than has been given.
Cheers,
Greg |
|
|
| Byrd |
| In other words it is pointless purchasing any of your PCB's as a DIY excersize. The reasons being that wiring layout, type of wire as well as chassis have a drastic effect on performance and most people who would purchase your kit would not have the facilities to measure performance, and as you say - without being able to measure that the amplifier is up to spec you will not know that you have built the amp "the way the designer created it" |
|
|
| acenovelty |
Dear Mr. amplifierguru,
Beg pardon, from my upbringing, Sir is considered polite. At least that's what my momma taught me.
Trust you do not object to being addressed as Mr.
My truce holds, I would not dream of arguing with you further.
My daddy told me it's a bad idea to argure with a man whose mind is made up. Mostly because it is a waste of one's own and time and energy. Good advice that's served me well.
Regards |
|
|
| amplifierguru |
Buying a 'designer endorsed' PCB eliminates one vagary in your build. My instructions for external connection to the module ( included in my instructions) makes suggestions on lead dress to minimise those interactions - because it's important!
If you buy a concept/kit you really don't want to do it a dis-service with a haphazard layout with all sorts of spurious interactions.
Hi Acenovelty,
I enjoy my music , believe me! But I like to dot the i's and cross the t's. To make sure I got what I paid for.
Cheers,
Greg. |
|
|
| Byrd |
Eliminating 1 source of distortion is not good enough - as you know. Do you give details on exactly how long and what type of cables by specific manufacturers should be used?
Do you offer a blueprint for the chassis with the exact formulation of metals used in the chassis?
Do you advise what feet the unit is to have?
Do you advise on the Transformer & power caps to use?
If you don't specify absolutly everything - there is no point in buying a "designer approved" PCB as the result will not be "as the designer created it".
It would also likely be pointless specifying everything as many of the cables / cases / transformers would not be available elsewhere in the world. TO have it as the designer intended - buy a fully built unit from the designer. |
|
|
| Luke |
I find alot too much is made of layout and wiring, pcb traces etc.
I have made at least 10 amps and bought a few amps. I can honestly say without bias that the amps I made cost less and sound far superior to what my budget can afford.
I also dont generally use exotic parts or wire, (although I have used silmics and blackgates and like their sound) but the point is a good amp will sound good if its made by a pro or a novice. It could possibly be tuned to sound better by someone who has test equipment and knowledge, but this is about how big a bang we can make in our basement. Most of us are amatuers with a bug not many of our friends or families get:)
BTW I listened to 20K worth of Naim kit the other day and my Audio research sp6 valve pre, aleph 2's, KLS10 Kit speakers and modded cd6000 sounds better. It owes me 2.5K and Im ashamed of the wiring:) |
|
|
| acenovelty |
I have never used exotic anything on the Leach amps. Because I live near Silicon Valley in California, I buy parts from the surplus houses. Able to get mil-spec parts for pennies. That's about as fancy as it gets.
Even that is overkill on any iteration of Dr. Leach's design IMHO. After one builds a couple of his amps, any further "testing" becomes quite redundant. That is not to say one may ignore basic rules of amplifier electronics or topology requirements. It's easy to make any layout succumb to 60 hz hummmm, and just as easy to prevent it. If one reads and follows Prof. Leach's instructions on the site, all will work well.
With all this yakking, it seems we have forgotten about frckid, whose post began all this. I trust we have not frightened him beyond all sensibility and that he is on his way to building this marvelous amp.
Regards |
|
|
| frckid |
| I appreciate the help, but after some more thinking, I believe I will try to make my own topology using the "old" parts Dr. Leach lists on his site. I really don't mind if it isn't perfect at first because the problems will help me learn to make things better. My goal is knowledge rather than just one cool amp that I really dont have a clue about. |
|
|
| still4given |
| quote: | Originally posted by frckid
I appreciate the help, but after some more thinking, I believe I will try to make my own topology using the "old" parts Dr. Leach lists on his site. I really don't mind if it isn't perfect at first because the problems will help me learn to make things better. My goal is knowledge rather than just one cool amp that I really dont have a clue about. |
Good for you. That is the very thing that got me interested in DIY and what inspires me yet today. Keep in touch and let us inow how you get on.
Blessings, Terry |
|
|
| Byrd |
| :up: Great Stuff :up: |
|
|
| saabie22 |
Hi frckid,
This thread took such a turn that I forgot to mention that I'll sell you a board! (photo attached - 'as is' condition)
After about three attempts I decided that my skills as a board etcher were somewhat deficient so I ended up buying mine from Dr. Leach.
Mike |
|
|
| Rectifrier |
I just completed a Leach Amp with a team for a class. I designed the layout and have a few hints for anyone just starting out. A simple way to begin is to keep it like the schematic. Keep the voltage gain away from the output stage. Leach has some of the output stage trace back to the voltage stage which can lead to some unkind coupling. I would recomment about 1/8" trace for the output section too. If you bring traces underneath components or 2nd layers, do so at 90 degrees. Also avoid making sharp corners in the paths, as these can cause noise.
-Ryan |
|
|
|
