To me, once you have a circuit board that you are stuffing there's not much difference in complexity. Some amps just have more parts than others. Set up a routine, double check your part values and orientation before inserting and soldering. At my age it is much easier to measure resistors than to read the color codes, so my DMM is always handy. The original Leach articles include construction tips that apply to any amp. Start with the resistors and diodes, then caps then semis. Insert maybe 5 parts and then solder, trim leads and repeat.
Have fun!
Have fun!
Well you seem to have your heart set on the Leach amp, but Nelson's amp camp amp is as simple as it gets, pure class-A amp. His original article is here:
Amp Camp Amp Article
The giant discussion thread on the amp along with listening impressions is here:
Forum Sticky - Amp Camp Amp - ACA
Good luck with whatever you attempt and you are very right if you run into issues folks here are always happy to assist. Regards.
Is there a reason I should pick the $100 toroid transformer from farnell over a $50 dollar one from Hong Kong on ebay? Are there different grades of quality for transformers?
I don't have any electronics background, so my first project was a LM4780 amp. My focus was of several folds: build an electrically safe device, eliminate the ground loop hum - boy, that was tough understanding earth ground versus signal ground and star ground. Then I ran into the issue of oscillation because I went a Chinese kit that had no zobel. In the end, I finished a parallel kit by learning to read the TI schematics and implementing optional components that were not included in my kit. Great learning experience, but take it easy. Good luck.
Hong
Hong
Anyone have any thoughts on the latest Honey Badger vs. the Leach? What are the similarities/differences. Why? Does it matter?
There is currently one of the Leach amp types in a thread started by still4given.
With respect to the long popular design(s), even with full documentation, the guy has had nothing but trouble even after having built other DIY amps OK. I think that starting off complex is not a good idea for confidence building nor for some assurance that you'll wind up with something as good as the prototype. Attempting to build the Leach using scrap parts is really going to make it all much harder again.
It's your choice but I think you'll find support for chipamps need only be simple as there are few parts and no matching required. Audiosector threads (commercial forum) covers many aspects of high-end chipamp building and Peter Daniel has written comprehensive notes which will apply generally too. The ESP website has a good gainclone design and documentation Project 115 - GainClone
Just read how many errors were made and parts consumed on that thread I mentioned, before you start anything. Hong's post should give you some idea of how much is ahead of you, even with the simple chip designs. Take it easy first up because gung-ho and power electronics just don't mix.
With respect to the long popular design(s), even with full documentation, the guy has had nothing but trouble even after having built other DIY amps OK. I think that starting off complex is not a good idea for confidence building nor for some assurance that you'll wind up with something as good as the prototype. Attempting to build the Leach using scrap parts is really going to make it all much harder again.
It's your choice but I think you'll find support for chipamps need only be simple as there are few parts and no matching required. Audiosector threads (commercial forum) covers many aspects of high-end chipamp building and Peter Daniel has written comprehensive notes which will apply generally too. The ESP website has a good gainclone design and documentation Project 115 - GainClone
Just read how many errors were made and parts consumed on that thread I mentioned, before you start anything. Hong's post should give you some idea of how much is ahead of you, even with the simple chip designs. Take it easy first up because gung-ho and power electronics just don't mix.
For a relatively low parts count, really nice sounding amp may I suggest looking at the PeeCeeBee thread? There are several layouts known to work, including my own. In its simplest form it only has six transistors, a few capacitors and a small handful of resistors. Might be something to look at for someone just getting started.
I can tell you one thing...
The leach amp has extensive material on the site mentioned above. Only thing you have to do is make a pcb and assemble it. Do not go for any of the clone designs and do not experiment with the parts, like relacing power transistors of newer version in the attempt to get what was not designed. It is a good relaxed sounding amp with output transistor protection.
It is revered by many around the world and is the most constructed amp. You can read about it on the site.
Remember, there is no ultimate amp in this world till today.
Gajanan Phadte
The leach amp has extensive material on the site mentioned above. Only thing you have to do is make a pcb and assemble it. Do not go for any of the clone designs and do not experiment with the parts, like relacing power transistors of newer version in the attempt to get what was not designed. It is a good relaxed sounding amp with output transistor protection.
It is revered by many around the world and is the most constructed amp. You can read about it on the site.
Remember, there is no ultimate amp in this world till today.
Gajanan Phadte
With all respect to Terry (Still4given), IIRC the Leach superamp he is having trouble with was built on a PCB of his own design. Terry has been very productive, and is an all around nice guy, but his oscillation problems could very well be due to an error in his PCB design, and his good channel a bit of good fortune. His problem could also boil down to lead dress differences of the two channels. He's had some trouble with other builds that he has been able to iron out.
There have been many Leach superamps built on Professor Leach's board design that worked out of the box. The superamp is basically the same front end with a totem pole output stage because the output devices of the day didn't handle the voltages required.
The original Leach or one of the variations that have resulted in group buys are likely to give good results. Remember, it was built successfully by a huge number of college kids as a class project. It is a very good, not the absolute best I've heard, but close and I like it much better than the chip amps I have built. I've got another two pairs ready to go into the Deluxe 4U chassis I just ordered. Leach in the summer, Pass designs when I can make use of the heat. 😉
There have been many Leach superamps built on Professor Leach's board design that worked out of the box. The superamp is basically the same front end with a totem pole output stage because the output devices of the day didn't handle the voltages required.
The original Leach or one of the variations that have resulted in group buys are likely to give good results. Remember, it was built successfully by a huge number of college kids as a class project. It is a very good, not the absolute best I've heard, but close and I like it much better than the chip amps I have built. I've got another two pairs ready to go into the Deluxe 4U chassis I just ordered. Leach in the summer, Pass designs when I can make use of the heat. 😉
One reason to not buy a transformer from farnell is that they charge about twice the price as other vendors for the exact same product. Check out RS for price comparison. Or even check out CPC (which is a farnell subsiduary).
I now out of protest buy everything from Mouser. It doesn't take long to make up the postage cost.
Also for semiconductors consider the onsemi samples program.
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Oh wow, just registering at onsemi and adding almost all of the transistors shaved nearly 70 euro from my farnell shopping basket, thanks for the tip mcd99uk!
You guys keep convincing me of things, first towards the chipamp, then towards the discrete amp, now towards the chipamp again. On the one hand I want to build something that has a high chance of working out, on the other hand the idea of building a time-proven big fat 200W per channel amp is very appealing 😀
BTW, on the OnSemi site a lot of transistors have a G suffix, like they don't have the MJ15004, but they do have the MJ15004G. Is this the kind of modern revision I should avoid or does it mark a fully compatible reissue?
Thanks for all the comments! I love the activity on this thread 🙂 I couldn't react much myself as I worked during the day but I sneak in a peak every hour or so.
BobEllis you mention he designed his own pcb, and that might have given him trouble, would the same hold true if I built the amp point-2-point but following the original design, or is this the sort of thing I should really get/make a printed pcb for? ( I really love doing point to point for some reason )
You guys keep convincing me of things, first towards the chipamp, then towards the discrete amp, now towards the chipamp again. On the one hand I want to build something that has a high chance of working out, on the other hand the idea of building a time-proven big fat 200W per channel amp is very appealing 😀
BTW, on the OnSemi site a lot of transistors have a G suffix, like they don't have the MJ15004, but they do have the MJ15004G. Is this the kind of modern revision I should avoid or does it mark a fully compatible reissue?
Thanks for all the comments! I love the activity on this thread 🙂 I couldn't react much myself as I worked during the day but I sneak in a peak every hour or so.
BobEllis you mention he designed his own pcb, and that might have given him trouble, would the same hold true if I built the amp point-2-point but following the original design, or is this the sort of thing I should really get/make a printed pcb for? ( I really love doing point to point for some reason )
Stick with a chipamp for your first build. You'll learn a lot and be better prepared for a more advanced build on your 2nd go around. Experience is a good thing! 🙂 There are many kit building tips and tricks that aren't always readily obvious unless you're watching someone with more experience do them. And they're not always highlighted in a build guide. Years ago I learned a lot about finishing a basement, simply by watching and helping a Master Carpenter. You learn how to do it the right way first! Good luck and have fun.
Rick
Do you have access to a scope and signal generator? Or have the budget to invest in a scope (PC based or otherwise)?
So, now I'm thinking of going the same route Ianchile went and make the AudioSector LM3875 amp. It looks very clean and he has put together a very thorough guide, it has a clear parts list and he mentions that it can be built point-to-point as well.
If I succeed the Leach will be my next project 😀
edit: I don't have a scope/signal generator, but I can access them at my university. Would I need it for debugging?
If I succeed the Leach will be my next project 😀
edit: I don't have a scope/signal generator, but I can access them at my university. Would I need it for debugging?
Sounds like a plan to me. You won't be disappointed with a leach but could get involved with fault finding. There is much to learn with an amp project. Even doing the PSU right is a challenge. It's not always obvious which way is best and why (as I'm currently learning).
A scope and signal generator is essential gear for doing audio along with bench PSUs. You may need them for debugging but also for checking everything is working correctly and for fine tuning a build.
A scope and signal generator is essential gear for doing audio along with bench PSUs. You may need them for debugging but also for checking everything is working correctly and for fine tuning a build.
I disagree. While a scope is a nice to have you can build an amp without it. Especially if you use a well tested board.
Point to point becomes harder to do well with high speed devices. A chip amp is easy, a Leach I wouldn't do point to point.
Point to point becomes harder to do well with high speed devices. A chip amp is easy, a Leach I wouldn't do point to point.
You may want to look at the Audio Sector LM3875 or LM4780 kits.
They are very complete and simple to build.
I built the LM4780 and I love it, Now I am selling it since that experience led me to build a Pass F4.
The F4 or Standard F5 would be great first projects though, the F4 if you have a real preamp and the F5 if you don't.
They are very complete and simple to build.
I built the LM4780 and I love it, Now I am selling it since that experience led me to build a Pass F4.
The F4 or Standard F5 would be great first projects though, the F4 if you have a real preamp and the F5 if you don't.
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