Thank you. I naively thought that AM radio is pretty much a thing of the past - the reception is interference prone, the quality of the broadcast is not as good as FM etc.
Regards,
A few things battling fidelity in the commercial AM band.
The low frequency involved, 580-1650 KHz. With the introduction of switch mode techniques, SMPS, Class "D" audio amps, there is so much more low band RFI in the metropolitan areas, these days. I also think enforcement of FCC/DOC rules are minimal.
I think I am wasting my time trying to get decent AM radio performance of my design. It is a challenge however.
At Motorola, we used to use very sensitive pagers as RFI stiffers to check for RF SG RFI spray. We are talking uV levels. Tech's worked tuning/testing pagers, in a copper shielded room, the days of the past.
Enjoy our nice weather, hey it is a sunny 50F/10C here today in the GTA area yahoo.
The low frequency involved, 580-1650 KHz. With the introduction of switch mode techniques, SMPS, Class "D" audio amps, there is so much more low band RFI in the metropolitan areas, these days. I also think enforcement of FCC/DOC rules are minimal.
I think I am wasting my time trying to get decent AM radio performance of my design. It is a challenge however.
At Motorola, we used to use very sensitive pagers as RFI stiffers to check for RF SG RFI spray. We are talking uV levels. Tech's worked tuning/testing pagers, in a copper shielded room, the days of the past.
Enjoy our nice weather, hey it is a sunny 50F/10C here today in the GTA area yahoo.
Cant believe no one has brought a stereo encased version to the market yet..... I know so many people that would buy one if i showed them.
forgot to mention:
The middle dial is for changing subwoofer cut-off frequency in 80-500 Hz range. and the right dial is for subwoofer volume.
no treble correction which is even better I guess...
see post# 2616
The middle dial is for changing subwoofer cut-off frequency in 80-500 Hz range. and the right dial is for subwoofer volume.
no treble correction which is even better I guess...
see post# 2616
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okay, been following along with the upgrades and my guide is Rhing's amp that was posted a while back.
I am working on 2 of the Danzz designed YJ blue/boards.
So, I can compare back and forth.
Currently listening to a board with the following changes:
Replaced the input caps with WIMA 1uf
5pcs WIMA MKP10 1uF 1?F 160V 5 Pich 22 5mm Polypropylene Capacitor L | eBay
Also replaced the power caps with 1500uf 35v Panasonic FM series. Here: http://www.digikey.com/product-detail/en/EEU-FM1V152L/P12409-ND/613770
Seems like it sounds nicer than stock.
Only issue I see with this board so far is that the Panasonic caps in that value are much taller than anything else on the board, like almost 1.5" tall, so now it doesn't fit into my little chocolate tin case with the lid closed. And, the increase in value has started the power jack spark issue discussed a few pages back. I have a switch on order, so that will take care of the plug/unplug nastiness.
My other yj board also has upgraded inductors as per Rhing's parts list, the same Wima caps on the input, and the same series nichicon power caps as stock-- but upgraded to 35v since I am running a 24v supply.
Will listen to this board with FM Panasonic caps and see if it sounds any better.
No idea if I can hear the differences or if it's in my head.
Or maybe it's just the pretty red LED power indicator I also installed?
Also received a set of the HiAmplifier boards. Have not hooked them up yet. I am going to do those as dual mono. Those look really sweet. So small. two of them easily fit in the footprint of danzz's yj blue board.
I am working on 2 of the Danzz designed YJ blue/boards.
So, I can compare back and forth.
Currently listening to a board with the following changes:
Replaced the input caps with WIMA 1uf
5pcs WIMA MKP10 1uF 1?F 160V 5 Pich 22 5mm Polypropylene Capacitor L | eBay
Also replaced the power caps with 1500uf 35v Panasonic FM series. Here: http://www.digikey.com/product-detail/en/EEU-FM1V152L/P12409-ND/613770
Seems like it sounds nicer than stock.
Only issue I see with this board so far is that the Panasonic caps in that value are much taller than anything else on the board, like almost 1.5" tall, so now it doesn't fit into my little chocolate tin case with the lid closed. And, the increase in value has started the power jack spark issue discussed a few pages back. I have a switch on order, so that will take care of the plug/unplug nastiness.
My other yj board also has upgraded inductors as per Rhing's parts list, the same Wima caps on the input, and the same series nichicon power caps as stock-- but upgraded to 35v since I am running a 24v supply.
Will listen to this board with FM Panasonic caps and see if it sounds any better.
No idea if I can hear the differences or if it's in my head.
Or maybe it's just the pretty red LED power indicator I also installed?
Also received a set of the HiAmplifier boards. Have not hooked them up yet. I am going to do those as dual mono. Those look really sweet. So small. two of them easily fit in the footprint of danzz's yj blue board.
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I think FM and FC Panasonics are better for a cap bank not next to the chip. The Silmic and Muse seem to sound better providing the power right on board.
perhaps, but right now I am just swapping things on board since I am such a noob.
Been listening to the upgrades all morning.
Sounds good.
Fleetwood Mac Tusk, King Crimson Discipline, Happy Mondays Greatest Hits, Chris Isaak Greatest Hits, all FLAC. And some deep house music via internet radio.
Every little change seems to bring more detail in the sound.
All of the sudden you start hearing more breathing on the part of the vocalists, more decay and other effects in the reverb and such. hi hats and other cymbals seem to sound better too...
Or maybe I am just listening closer?
I was interested in the theoretical effects of the power caps since I believe the data sheet specs 220uF, and this is what the hiamplifier boards came with--and Saturnus recommended to avoid various RF effects caused by bigger caps acting like antennae, yet the Danzz design has a 1000uF in that spot and now I am running 1500uF in that position.
also wondering if the perceived improvement in sound is more due to the WIMA caps at the inputs rather than the bigger value on the power cap.
But again, it may just be the big red LED I put in...
Still, way more fun and much better sound than you would think you'd have for $19 plus the cost of extra little caps...
Been listening to the upgrades all morning.
Sounds good.
Fleetwood Mac Tusk, King Crimson Discipline, Happy Mondays Greatest Hits, Chris Isaak Greatest Hits, all FLAC. And some deep house music via internet radio.
Every little change seems to bring more detail in the sound.
All of the sudden you start hearing more breathing on the part of the vocalists, more decay and other effects in the reverb and such. hi hats and other cymbals seem to sound better too...
Or maybe I am just listening closer?
I was interested in the theoretical effects of the power caps since I believe the data sheet specs 220uF, and this is what the hiamplifier boards came with--and Saturnus recommended to avoid various RF effects caused by bigger caps acting like antennae, yet the Danzz design has a 1000uF in that spot and now I am running 1500uF in that position.
also wondering if the perceived improvement in sound is more due to the WIMA caps at the inputs rather than the bigger value on the power cap.
But again, it may just be the big red LED I put in...
Still, way more fun and much better sound than you would think you'd have for $19 plus the cost of extra little caps...
I'm running 1500 uF 35v Panasonic FC's in the on-board position and the sound is definitely better than with the stock caps. Maybe silmic/muse caps are better still, but I haven't tried them.
Verstuurd vanaf mijn LT22i met Tapatalk
Verstuurd vanaf mijn LT22i met Tapatalk
Looks like the blue board has found a chassis - Yuan Jing Audio - ON SALE! - TPA3116 Class-D 2.0 Stereo Power Amplifier [50W+50W] - $88.00 - Finished Units
$88.00 + Freight is almost cheaper than doing it yourself! They have managed to take the fun out of building an amp!
Don't worry guangui you can still have fun replacing the volume pot, rca jacks, and binding posts 🙂
LOL...Actually I want to DIY an 80 to 100 WPC, no need for volume pot. Just don't know what would be the best chip/board combo for the build.
did you check freightcost with completed amp?I added some nichicon PW to dc-input on pbtl boards and rather quickly removed them, first high frequencies were very gentle🙂 but soundlevel seemed to vary a little automaticly, after 30 minutes playing I walked back in and ... was like volumepot was full of dust, heavily distorted high frequencies😱 so switched from cd to flac, same thing, removed the PW's and sound was a little more normal like I had before, but I feel high's are still not quite the same, maybe I caught a cold🙂 and too little time to figure out what happened
...
Ups!!! You are so right, usually I get packages from China at ridiculous freight charges, but in this case it is $42.00, so the total is $130.00. Cheaper to DIY! All the fun and headaches are back!!!
alright, still tweaking.
Added the Bourns inductors to my danzz YJ blue board as per Rhing's BOM:
http://www.digikey.com/product-detail/en/2100HT-100-V-RC/2100HT-100-V-RC-ND/2534592
Inductors weren't as hard to work on once I installed a chisel tip on my soldering iron, but the rest of the parts on the board are so small.
That seems to have made the most noticeable and nicest boost to the sound yet.
Cymbal fills and synth fills seem to just roll out of the air.
And the bass seems better too...
Not sure if I can really do anything else to this board.
I will try to boost the gain 4db once I acquire the proper resistors.
Then I think I will start the final case installation.
Added the Bourns inductors to my danzz YJ blue board as per Rhing's BOM:
http://www.digikey.com/product-detail/en/2100HT-100-V-RC/2100HT-100-V-RC-ND/2534592
Inductors weren't as hard to work on once I installed a chisel tip on my soldering iron, but the rest of the parts on the board are so small.
That seems to have made the most noticeable and nicest boost to the sound yet.
Cymbal fills and synth fills seem to just roll out of the air.
And the bass seems better too...
Not sure if I can really do anything else to this board.
I will try to boost the gain 4db once I acquire the proper resistors.
Then I think I will start the final case installation.
You want fast power near the chip. 220uf is very wise, but there's the caviat that it isn't enough power either. Your choicers become stacking them, or using some more power off board.
It's not wise to make a huge difference in capacitor size due to the possibility of a ring.
If you were to put 220uf Muse/SII's on board, and say 10-20kuf off board comprised of a few other capacitors (also helps couple noise to have at least a few instead of one) to provide power for bass etc, you'd be doing good. I can tell you in the CHEAPEST build I did with a red board, I used a 10kuf cap off board and the bass is substantial out of speakers that have two 5 inch drivers a piece (not MTM, they're made for surround or something).
1000-1500uf per "channel" isn't enough power for bass anyway.
It's not wise to make a huge difference in capacitor size due to the possibility of a ring.
If you were to put 220uf Muse/SII's on board, and say 10-20kuf off board comprised of a few other capacitors (also helps couple noise to have at least a few instead of one) to provide power for bass etc, you'd be doing good. I can tell you in the CHEAPEST build I did with a red board, I used a 10kuf cap off board and the bass is substantial out of speakers that have two 5 inch drivers a piece (not MTM, they're made for surround or something).
1000-1500uf per "channel" isn't enough power for bass anyway.
So, we're back to the discussion where you suggested putting 10000uF off board and the easiest way to achieve this is to wire up 10 x 1000uF capacitors-- of something like Panasonic FC type-- in parallel before the VCC+ terminal.
and that is all correct? no need for any diodes, or any other components?
Just a cap bank in parallel.
And prior discussion says while 200uF is spec on board, it may not be quite enough and may be expanded but do NOT use more than 1000uF on board near the chip-- and to use the smallest form factor capacitor possible for this position.
Thanks for explaining this again.
So far, my preferred YJ blue mods are Wima replacement caps on the inputs, Nichicon 35v 1000uF as power caps, and the above mentioned Bourns inductors.
Seems to have good thump and transparency.
and that is all correct? no need for any diodes, or any other components?
Just a cap bank in parallel.
And prior discussion says while 200uF is spec on board, it may not be quite enough and may be expanded but do NOT use more than 1000uF on board near the chip-- and to use the smallest form factor capacitor possible for this position.
Thanks for explaining this again.
So far, my preferred YJ blue mods are Wima replacement caps on the inputs, Nichicon 35v 1000uF as power caps, and the above mentioned Bourns inductors.
Seems to have good thump and transparency.
