So last May (2018) I started a thread looking for some help selecting a transistor for the Zen amp to build in my High School class. We are now starting the builds and I will encourage my students to introduce their projects here. We are starting from ground zero taking in the basic concepts of electicity from a book called "There Are No Electrons: Electronics For Earthlings". This week we will be learning to solder.
Right now they laying out the power supply (from the F5 manual) and position of the amp circuits in old overhead projectors and computer cases.
Wish us luck
George
Right now they laying out the power supply (from the F5 manual) and position of the amp circuits in old overhead projectors and computer cases.
Wish us luck
George
Thanks Meag. I think you saved us a lot of frustration. I wanted to respond more quickly but life to in the way.
I planed on using 25V transformers and using the bipolar power supply to get my 65 70V needed for the amp. So now I need to figure out if I can modify the circuit some how to use the transformers I have, perhaps some hybrid of the Zen and F5. I’m quite aware that my lack of experience is showing but we are all learning here.
The F5 is a push pull and Zen a single ended.
Can I use the circuitry of the F5 between the auido input and base of the transistor or will that not work? My thinking is that I will maintain the voltage across the source and drain. Will I be able to achieve the appropriate biases voltage at the base?
I planed on using 25V transformers and using the bipolar power supply to get my 65 70V needed for the amp. So now I need to figure out if I can modify the circuit some how to use the transformers I have, perhaps some hybrid of the Zen and F5. I’m quite aware that my lack of experience is showing but we are all learning here.
The F5 is a push pull and Zen a single ended.
Can I use the circuitry of the F5 between the auido input and base of the transistor or will that not work? My thinking is that I will maintain the voltage across the source and drain. Will I be able to achieve the appropriate biases voltage at the base?
Hi George,
I would advise to stick with the Zenlite as a first project.
Much simpler and easy to understand and make it work the first time.
You can use your 25V transformer to get around 70VDC (secondaries in series) after the rectifier bridge.
CRCRC filtering will help smooth the ripple.
But if you want even better PSRR you can employ the active regulation from Zen V4, which is actually a Cap multiplier circuit and can also double as a thump suppressor.
Biasing Zenlite is simple and the current that the circuit draws is determined by the light bulb - the higher the wattage the higher the current.
One can experiment here almost to no end.
That of course brings the other issue - heatsinking.
With the Zenlite you have the luxury of dissipating half (1/2) of the heat over the light bulb. That also means that your heatsinking requirements are reduced by half, you only need to care about the Mosfet's heatsinking.
Best bit, it is very simple to build Zenlite Point-to-Point or on a strip board, F5 really benefits from a PCB.
F5 is a great circuit but for a first project Zenlite is a better choice.
Sound wise they both are great and it's all subjective so no recommendation there.
I would advise to stick with the Zenlite as a first project.
Much simpler and easy to understand and make it work the first time.
You can use your 25V transformer to get around 70VDC (secondaries in series) after the rectifier bridge.
CRCRC filtering will help smooth the ripple.
But if you want even better PSRR you can employ the active regulation from Zen V4, which is actually a Cap multiplier circuit and can also double as a thump suppressor.
Biasing Zenlite is simple and the current that the circuit draws is determined by the light bulb - the higher the wattage the higher the current.
One can experiment here almost to no end.
That of course brings the other issue - heatsinking.
With the Zenlite you have the luxury of dissipating half (1/2) of the heat over the light bulb. That also means that your heatsinking requirements are reduced by half, you only need to care about the Mosfet's heatsinking.
Best bit, it is very simple to build Zenlite Point-to-Point or on a strip board, F5 really benefits from a PCB.
F5 is a great circuit but for a first project Zenlite is a better choice.
Sound wise they both are great and it's all subjective so no recommendation there.
I’ll be checking out the Zen V. 4.
I don’t want to do an F5 I don’t have to parts. What ever I wind up doing will be on me ($) to make up the difference. So that is part of the consideration.
Thank you so much for your help and support. I don’t mind my kids (students) seeing me make mistakes and not havin all the answers. I told hem hat this site was a wealth of information and experience and that we might be asking for help if something went wron and I couldn’t figure it out with them. I just didn’t think it would happen so soon. 
I don’t want to do an F5 I don’t have to parts. What ever I wind up doing will be on me ($) to make up the difference. So that is part of the consideration.
Thank you so much for your help and support. I don’t mind my kids (students) seeing me make mistakes and not havin all the answers. I told hem hat this site was a wealth of information and experience and that we might be asking for help if something went wron and I couldn’t figure it out with them. I just didn’t think it would happen so soon.
An externally hosted image should be here but it was not working when we last tested it.
I am building an amplifier in a computer case and wanted to know if you guys had any suggestions. I am also having lots of fun doing this.
None of the pictures are showing up for me, and probably not for others either.
To attach a picture, click on the "paper clip" at the top of the "Reply to Thread" box. A "Manage Attachments" box will pop up where you can then upload pictures to diyAudio. Note that for jpegs, the maximum size is 976.6KB, 6200x2800.
You can then check to see if it has worked by clicking "Preview Post" at the bottom of the "Reply to Thread" box.
I'm sure that once you get some pictures posted, you will get a lot of helpful tips from diyAudio members.
Thanks Ten Mah, we will try reposting today.
I've told my kids how helpful the people on this site are. I hope that we can start building the amplifier circuits today or tomorow. Sofar they have been wroking on prepping the boxes (old dell coputers and old school Overhead Projectors). I think they are all having fun and learning a good bit too. My hope is that some of them will get bitten by the DIY bug and keep going.
I've told my kids how helpful the people on this site are. I hope that we can start building the amplifier circuits today or tomorow. Sofar they have been wroking on prepping the boxes (old dell coputers and old school Overhead Projectors). I think they are all having fun and learning a good bit too. My hope is that some of them will get bitten by the DIY bug and keep going.
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