I think he want to ask howto set ccs, bias and offset properly. He confuse about zener and resistor r18, d3. All you ask was covered in build guide. Download and read carefully.
Since the location of the build guide was mysterious, here is a direct link to it. . . click here.
It is actually located in the store, with the boards if one notices the buttons to click on at the bottom of the page, if one happened to scroll down by either chance or curiosity.
Edit:
Moderator, feel free to remove this post after locating an obvious link to the build guide at post 1, if you want to.
Although post 1 is older than the build guide; however, this being a "build thread" doesn't need to postpone a link to the most crucial document, waaayyy down here at post 23.
Thanks.
It is actually located in the store, with the boards if one notices the buttons to click on at the bottom of the page, if one happened to scroll down by either chance or curiosity.
Edit:
Moderator, feel free to remove this post after locating an obvious link to the build guide at post 1, if you want to.
Although post 1 is older than the build guide; however, this being a "build thread" doesn't need to postpone a link to the most crucial document, waaayyy down here at post 23.
Thanks.
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Good job getting the boards in the store. 😀
@Variac, feel free to edit, revise or recycle this post.
A direct link to the original documents.
A version of the schematic with white background for easy printing:
Parts list attached below:
I think I see an error in the values of "R51" and "R52" would not have to be different.
It's possible ostripper was compensating for the high brightness blue LED. D6 is supposed to be a standard red.
Has anyone created a Mouser BOM for this amp yet? I started on it but I'm a bit of a noob and got confused on the types of resistors (ceramic, carbon, film, etc) that would be best.
I put together a BOM from digikey for the softstart and the power supply, but like you got stuck on the amp. There are so many configuration options that will dictate component choice and value. It became confusing. I decided to put this on the back burner because I have a few other projects ahead of it and I want to be able to give this my full attention.
If you want the part numbers I chose for the softstart and power supply let me know. The power supply components were chosen to be used with the diystore boards. I picked the highest amount of capacitance that will fit on these boards that would still offer a safe working voltage threshold with +-64V rails.
i wrote to OS about resistors aroud red and blue light ...... time ago .... and resistors are different to match led current and efficiency.
I've sourced 2SC3503, but difficult to source 2SA1381 in my country.
How about 2SA1209 to replace 2SA1381, or i just use MJE350
Any suggestion?
How about 2SA1209 to replace 2SA1381, or i just use MJE350
Any suggestion?
Maybe these?
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|The secondaries in parallel data was divided by 2 to get the above estimates for split rail amplifier use. There's a variety of considerations when selecting transformers but speaker load seems especially important. What is your speaker load? Do you intend to use stealth, shottky or silicon rectifiers? Do you intend to use a CRC or C,R//D,C power supply or not? Will you be using a mains fuse? Do you have interest in running the amplifier at near full blast for long durations or do you plan to use a fraction of the amplifier's power most of the time? Will you be using dual mono with 2 transformers or virtual dual mono with 1 transformer with or without a CRC? Will you be using a speaker jack fuse? And, I'd sure like you to double-check my estimated transformer current figures before purchase.
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An externally hosted image should be here but it was not working when we last tested it.
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Wow, thanks. My speakers are 6.5ohm, about 87db.
I'm not sure on the rectifiers, I don't know the differences. Same with your questions on CRC or C,R/D,C- not sure what that means.
I will definitely be using a mains fuse. Probably will run the amp at low to mid volume for short periods of time.
I would like to build it dual mono with two transfos.
No on the speaker jack fuse, but I will be incorporating the soft start and speaker protection circuits offered in the store.
I'm not sure on the rectifiers, I don't know the differences. Same with your questions on CRC or C,R/D,C- not sure what that means.
I will definitely be using a mains fuse. Probably will run the amp at low to mid volume for short periods of time.
I would like to build it dual mono with two transfos.
No on the speaker jack fuse, but I will be incorporating the soft start and speaker protection circuits offered in the store.
It seems there is a Ferrari going to the grocery store (more amp than speakers), but that's okay! You won't have clipping.
I've got a couple more questions:
Is the 6.5 ohms measured by ohmmeter?
Are the speakers 2 way or 3 way design?
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No, I have not measured with an ohmmeter, but they are Short Thors and many here have built them. I'm assuming mine are equal to what others have tested.
They are MTM, 6.5" woofer, tweeter, 6.5" woofer.
They are MTM, 6.5" woofer, tweeter, 6.5" woofer.
Matt, my speakers are AMT monitors which have very similar specs to yours and I am planning on using a pair of antek AS4445 transformers for a dual mono configuration. That will provide a rail voltage of +-64V. I assume you are using the DIY store power supply boards also? If so you will have to watch the operating voltage of the caps you choose.
My requirements of this amp seem similar to yours.
Daniel. Are you saying you don't grocery shop in a ferrari?😀
My requirements of this amp seem similar to yours.
Daniel. Are you saying you don't grocery shop in a ferrari?😀
Okay, diyaudio.com member Currentflow pointed me to the answer to my voltage question here: http://www.diyaudio.com/forums/solid-state/192431-diyab-amp-honey-badger-4.html#post2648883 in that post by OStripper.
So, it is possible to use a 28+28vac transformer just fine. It is going to make about 42vdc rails. That is enough to X-Max most or many 8" and smaller woofers. More to the point clear vocals don't come out of madly shaking woofers of maxed out 2 way speakers. Thus the lesser transformer is probably enough voltage if you have 2 way speakers. It simply makes a smaller scale amplifier. You can "right size" if you want to.
What it means to me is that this opens up more possible transformer selections, much of which is less expensive in some way. With the 28+28vac transformer, the caps can be inexpensive 63v models, and you can use double-parallel output with less ballast resistor loss and less expense which is something to consider if your speakers didn't happen to need a super power amplifier.
Not everyone has speakers capable of handling or doing anything useful with 150 watts and therefore not everyone needs 60+60vdc rails, and then maybe not everyone needs the price tag for extra power not used.
At least we have a transformer voltage range: 28+28vac to 45+45vac or anywhere in-between.
I would do that more expensive approach if there was future plans to upgrade the power handling of my speakers. With a 150w amplifier, of course the upgrade speakers would be 3 way or more so that the vocals didn't get scrambled/shaken when the amplifier was run all the way to its maximum potential.
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found discrepancy in DiyAB Build Guide,
schematic say C4 = 0.1uf, BOM say 220uf non polar (voltage rating ??)
schematic say C3 = 220uf, BOM say 100nf (0.1uf) 35-50V
schematic say C4 = 0.1uf, BOM say 220uf non polar (voltage rating ??)
schematic say C3 = 220uf, BOM say 100nf (0.1uf) 35-50V