hey great barry!good to get cash flow for new projects.
thats the trouble with this diy lark once youve built an amp ,then what ,how many amps do you need!! but theres always a new one to try like the the revC amp which seems to be the best( according to linuxguru ,which he is also now supplying) using chip technology.id recommend going that route.
im making multi channel active crossover amp using the established application style monoboard lm3886's.with my own source quality parts.and they sound great with no noise,better than my yuanjing.
im not sure what a solid state speaker protect is?one without relays?
thats the trouble with this diy lark once youve built an amp ,then what ,how many amps do you need!! but theres always a new one to try like the the revC amp which seems to be the best( according to linuxguru ,which he is also now supplying) using chip technology.id recommend going that route.
im making multi channel active crossover amp using the established application style monoboard lm3886's.with my own source quality parts.and they sound great with no noise,better than my yuanjing.
im not sure what a solid state speaker protect is?one without relays?
Interesting looks like theres a deluxe version of this board on Taobao
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³å5×ê LM3886+LM833¹¦·Å°å(ºÀ»ª°æ) ¹¦ÂÊ2×68WË«ÉùµÀ 3886-ÌÔ±¦Íø
I'm not sure if I quite understand you...How was i powered from 24V secondaries. Is there a second transformer I am missing? So...how is this working?
Thanks.
yea as i stated the transformer i used had several secondaries eg it had 15v wires and 24v wires so i didnt need another transformer.you can get them if you look around.
Hi Barry,
Can you point us to some posts where we can learn about integrating SD card input to a system? That would be great to use with uncompressed FLAC files.
Can you point us to some posts where we can learn about integrating SD card input to a system? That would be great to use with uncompressed FLAC files.
Hi, Sorry for delay, Iv'e been away playing chess. Now back to more important matters! I intend having a look at the revC. Iv'e been too busy upgrading cd players and servicing Naim's. The problem for me seems to be getting a nice case for a sensible price. I would really like a see through one for the next project. Nice to see the gremlins at work, so to speak. I may just obtain some polycarbonate and make a case from that. It would probably cost less than a decent ally case, and might just help with earthing problems also. Nice to see your busy. I still think for the price, and with a decent power supply, you can't go far wrong with the "Yuanjing". The goldmund copy was a belter for the price (with Linuxguru's mods). Barry
I never found any posts concerning the SD card. I bought a chinese module off fleabay and was amazed at the results. It simply needed a small power supply and just hard wired to one of the selector inputs. I'll see if I can find the listing and post it. Barry
I think I may have confused you here. I was mixing up different speaker protect circuits. I beleive the board is marked with 32v dc and earth. plus the AC terminal if you require it. I don't beleive the AC is neccessary with your amp as it doesn't seem to need a soft start. Mine never thumped when turning on or off, but perhaps yours will. You could leave that to last and see how it goes. It is only one wire to add if you need it. Regards Barry
bcmbob, here's the link.
DIY SD MMC USB Card mp3 Player+Display Screen & Remote on eBay (end time 29-Mar-11 16:27:07 BST)
DIY SD MMC USB Card mp3 Player+Display Screen & Remote on eBay (end time 29-Mar-11 16:27:07 BST)
The amp may not need a soft start, but by definition the relays will remain off when no voltage is present at the AC sense pin.
Oh OK, I did not know that. Will he's 22v from his transformer be enough to be sensed. If I remember correctly the module is marked somewhat higher. Maybe a resistor change as I think you described earlier. While i'm at it, did you see my post regarding solid state speaker protection. I don't know if one exists, do you?
I always thought you could use a couple of 10,000uF 63v electrolytics back to back (bi-polar) in series with the speakers. I know it sounds simple but it should apparantly work. Perhaps it has some effect on the sonics or the speaker impedance. Obviously it can't work otherwise we would not be implementing these complex circuits!
So a small 24V transformer + a diode bridge should yield around 33V which would probably work.
Let's forget about the actual numbers. I should just run whatever voltage it says into it? So if it is infact 32V, ~32V. And I would need another transformer. Sorry to sound stupid but can I wire multiple transformers to the same IEC socket. Would that cause like crossloading issues? Or is that alright?
How big of a transformer is necessary. Would a cheapo one suffice or do I need something more (for the protection board).
Yes, that should do the trick. A small 24v transformer + diode bridge will give you near enough to work. You can run more than one transformer from the same socket, no problem. You then need that wire from your main transformer to the ac input on the speaker board. I think Pacificblue says you need to change a resistor to get the voltage right so you better check with him, but I would have thought your 22v would be near enough.
Well I was considering using an 18V transformer to get roughly 25VDC as each channel will really only be able to handle 30W nominal. 40W peak. So I don't need a ridiculous amount of power. But perhaps I used a 24V transformer for the main amplifier board, (24-0-24), how do I steal a 0-24 out of that without causing issues?
Wahh. I wish things were simple.
You would have roughly -32v -0- +32v DC to run your amplifier. You just need to tap into the +32v -0- (from your amplifier supply inputs) for your DC supply to your speaker board. Then you can run your AC wire from one of the 24v wires on the transformer, and I this will do the trick.
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I don't know why you two make such an issue of this when I already explained in post #301 that the protection boards will work fine with the amplifier's 2x25 V transformer. No need for any further power supplies.
You can indeed use two electrolytics back to back and it is actually done in PA speakers quite often. It is usually not done in hi-fi due to prejudice against capacitors in the signal path. It can have an effect on the sonics. And the interaction between such a cap and the speaker impedance is sometimes used to shape the frequency response or to use a woofer in a too small enclosure.
You can indeed use two electrolytics back to back and it is actually done in PA speakers quite often. It is usually not done in hi-fi due to prejudice against capacitors in the signal path. It can have an effect on the sonics. And the interaction between such a cap and the speaker impedance is sometimes used to shape the frequency response or to use a woofer in a too small enclosure.
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