I found quite a nice box today that would be ideal for the this sure board:
I managed to squeeze a TA2020 amp board and 12v SMPS in there, but the Sure TK2050 board also fits with room to spare, but not enough for a SMPS however:
If anyone recognises this box, does anyone know who sells them? I was given this one a while back, and have no idea where they obtained it either, but it would be a good enclosure if only for the shielding, it's 1mm thick steel which I imagine should work well.
This may be good news for people who want to bi-amp. You could use Coilcraft SER2915L-103'x on the left channel to power the woofer, and Ferroxcubes for the right hand channel to power the tweetwe. I'm planning to bi-amp, are there any drawbacks with mixing output inductors on the same board?
An externally hosted image should be here but it was not working when we last tested it.
I managed to squeeze a TA2020 amp board and 12v SMPS in there, but the Sure TK2050 board also fits with room to spare, but not enough for a SMPS however:
An externally hosted image should be here but it was not working when we last tested it.
If anyone recognises this box, does anyone know who sells them? I was given this one a while back, and have no idea where they obtained it either, but it would be a good enclosure if only for the shielding, it's 1mm thick steel which I imagine should work well.
This may be good news for people who want to bi-amp. You could use Coilcraft SER2915L-103'x on the left channel to power the woofer, and Ferroxcubes for the right hand channel to power the tweetwe. I'm planning to bi-amp, are there any drawbacks with mixing output inductors on the same board?
Volume difference?
There might be a slight difference in the relative volume between the channels.
Miniturization?
So the dual coil package is just for miniturization to fit two coils onto one footprint? Or is there an electrical/ distortion advantage for balanced amps depending on how you wire up the phase of the output legs?
So the dual coil package is just for miniturization to fit two coils onto one footprint? Or is there an electrical/ distortion advantage for balanced amps depending on how you wire up the phase of the output legs?
?? IR uses the Sagami 7G17A to get over 400W at less than .01% distortion (see IRAUDAMP7D). That's a lot more than what you will get from a TP2050.
Of course, if you want something a lot bigger, see if you can buy some of the shielded ferrites from Virtue Audio.
My understanding is that they had Coilcraft develop that inductor for them. Regarding your other questions:
MPP cores are available from CSW ByteMark: Products : CWS ByteMark, largest supplier of toroids, ferrite cores, iron powder cores, MPP cores and RF cores
And yes, I think the dual coils are completely independent, for two-channel use or for common-mode filters where two coils are used on the output. (But I don't know for sure.) So they save board space.
That is not a massive problem for me, as I can easily adjust the volume of each channel from my crossover.
I think I may give this a try.According to the parts list in the amp7 data sheet they are available from either Inductors, Inc or ICE Components. You might want to check some of the other parts lists to see if IR lists some other vendors.
Inductors, Inc shows stock on two of the 10uH parts. ICE doesn't list any Sagami parts at all.
If you are interested in duals, AVNET has the TOKO DAEPW-M163S. They had 12 the other day--I left you 4
Also, you might want to put some thought into the filter values that you are using. The "textbook" Tripath filter works very well for 4 ohm loads, but it is possible to get some serious (and very audible) peaking in the 20KHz range at load impedances in the 6-8ohm range. I can't say anything else about this because it is based on measurements that I've seen that were done by someone else, and I don't have permission to release that information. But I noticed that some of the comparisons you described were with different filter values, so some of the differences you heard between the inductors may be due to filter peaking rather than the inductor properties. For a good discussion on class D output filters, take a look at this article: Understanding output filters for Class-D amplifiers | Audio DesignLine. That peak in Figure 3 can have a surprisingly big impact on the sound of this amplifier.
Ordered
Ordered the last 4. Thanks for the tip. Inductors inc is working on getting me the Sagamis.
According to the parts list in the amp7 data sheet they are available from either Inductors, Inc or ICE Components. You might want to check some of the other parts lists to see if IR lists some other vendors.
Inductors, Inc shows stock on two of the 10uH parts. ICE doesn't list any Sagami parts at all.
If you are interested in duals, AVNET has the TOKO DAEPW-M163S. They had 12 the other day--I left you 4
Ordered the last 4. Thanks for the tip. Inductors inc is working on getting me the Sagamis.
So I wound 8 air-core inductors and installed them in the amps for my bi-amped mains (the sub is still running Arjen inductors).
Sendler, after winding 22 turns of 18 gauge wire, I can readily appreciate what you did winding 60 turns of 14 gauge. You are the man!
Well, my system already sounded damn good and I didn't think there was that much room for improvement. I really wound the coils just to say that I did and have them look cool hanging off the amps.
Boy was I stunned! The improvement was dramatic. Much more than installing the Arjen coils. Even more than changing the input caps. First, the attacks are faster and cleaner. And the sustain dies out more smoothly and completely.
Those two things hit me immediately. Especially piano sounded more real, more alive, more vibrant.
More listening revealed gains in held notes, which are richer, warmer, and more involving than before.
The net effect is music with more vitality, more lushness, more jump. It's a joy to listen to.
I'm listening to the Concord Jazz Super Audio Sampler (SACD) and it is pure bliss. So much life. So much warmth and crispness.
I'm not generally effusive about improvements and mods, but this is really special. I've always heard that a coil is the worst thing you can put in the audio path, far worse than caps. It makes sense that improving the coils will bring big rewards. But high quality coils are expensive, so I haven't upgraded them much in the past. And I've never used air-cores before.
But cost is no longer a barrier. These 8 air cores cost me $8 for wire and $2 for formers. Plus a couple of hours of work. And what a payoff.
I have not shielded them yet, so I imagine I'm annoying any of my neighbors listening to Rush Limbaugh. Tomorrow I'm going to make some aluminum foil condoms wrapped in paper for insulation and see how they work. I won't try to ground them to start with.
I encourage everyone to give these air-cores a try. The coils aren't too hard to wind, you get the hang of it after a couple. And they're easier to install than the Arjen coils because their size necessitates longer leads which make soldering them easier.
No downsides, except the EMI and we'll figure that out, I'm sure.
-dr_vega.
Sendler, after winding 22 turns of 18 gauge wire, I can readily appreciate what you did winding 60 turns of 14 gauge. You are the man!
Well, my system already sounded damn good and I didn't think there was that much room for improvement. I really wound the coils just to say that I did and have them look cool hanging off the amps.
Boy was I stunned! The improvement was dramatic. Much more than installing the Arjen coils. Even more than changing the input caps. First, the attacks are faster and cleaner. And the sustain dies out more smoothly and completely.
Those two things hit me immediately. Especially piano sounded more real, more alive, more vibrant.
More listening revealed gains in held notes, which are richer, warmer, and more involving than before.
The net effect is music with more vitality, more lushness, more jump. It's a joy to listen to.
I'm listening to the Concord Jazz Super Audio Sampler (SACD) and it is pure bliss. So much life. So much warmth and crispness.
I'm not generally effusive about improvements and mods, but this is really special. I've always heard that a coil is the worst thing you can put in the audio path, far worse than caps. It makes sense that improving the coils will bring big rewards. But high quality coils are expensive, so I haven't upgraded them much in the past. And I've never used air-cores before.
But cost is no longer a barrier. These 8 air cores cost me $8 for wire and $2 for formers. Plus a couple of hours of work. And what a payoff.
I have not shielded them yet, so I imagine I'm annoying any of my neighbors listening to Rush Limbaugh. Tomorrow I'm going to make some aluminum foil condoms wrapped in paper for insulation and see how they work. I won't try to ground them to start with.
I encourage everyone to give these air-cores a try. The coils aren't too hard to wind, you get the hang of it after a couple. And they're easier to install than the Arjen coils because their size necessitates longer leads which make soldering them easier.
No downsides, except the EMI and we'll figure that out, I'm sure.
-dr_vega.
After listening for a day now, I've got to agree with Sendler: With the air core inductors installed, this is the best amp I've ever heard at home or anywhere else. Nothing I have heard has this level of clarity and realism. It is completely transparent and pristine, but not dry or analytic. It is completely involving and musical.
Having said that, it might not be for everyone. The sound has lost weight and size. In their place are texture and detail. It's a tradeoff that sounds very good to me. But if you like huge sound like rock concerts and dance clubs, then you might want to keep your current coils if you're happy with them.
Clearly the air cores are removing the distortion that gave the sound weight and heft. Distortion is not always a bad thing. I run a tube preamp just to add some second harmonic distortion to make the sound richer and warmer.
We are all so familiar and comfortable with the distortion that coils add to the signal, whether class D output filters, tube amp transformers, or speaker crossovers, that we miss it when it is gone. You may miss it enough to want it back.
In other words, don't throw away the coils you take out, you may want to re-install them.
But for me there's no going back. This is the best amp I've ever owned. The best amp I've ever heard. Not bad for less than $100.
-dr_vega
18Ga air toroids
I have some new coils too. They are made with the cheap 18Ga wire and were much easier to wind and are much smaller but I am dissapointed with the sound. They don't have as much fine detail as the 14 Ga Belden air toroids. I tried removing the wood centers and the outer tie straps but it didn't help much. I am hoping to find that the difference in sound is the gauge and not the wire when I make up some coils with the cheap 14Ga. The price of the Belden is ridiculous and the insulation must be scraped before it will take solder making it harder to work with.
It's interesting that they were among the quietest coils I have wound in regards to radiated emissions including various cored types. I could barely find a slight hiss in the AM radio.
I have some new coils too. They are made with the cheap 18Ga wire and were much easier to wind and are much smaller but I am dissapointed with the sound. They don't have as much fine detail as the 14 Ga Belden air toroids. I tried removing the wood centers and the outer tie straps but it didn't help much. I am hoping to find that the difference in sound is the gauge and not the wire when I make up some coils with the cheap 14Ga. The price of the Belden is ridiculous and the insulation must be scraped before it will take solder making it harder to work with.
It's interesting that they were among the quietest coils I have wound in regards to radiated emissions including various cored types. I could barely find a slight hiss in the AM radio.
I have some new coils too. They are made with the cheap 18Ga wire and were much easier to wind and are much smaller but I am dissapointed with the sound. They don't have as much fine detail as the 14 Ga Belden air toroids. I tried removing the wood centers and the outer tie straps but it didn't help much. I am hoping to find that the difference in sound is the gauge and not the wire when I make up some coils with the cheap 14Ga. The price of the Belden is ridiculous and the insulation must be scraped before it will take solder making it harder to work with.
It's interesting that they were among the quietest coils I have wound in regards to radiated emissions including various cored types. I could barely find a slight hiss in the AM radio.
My guess is that both the size and quality of the wire affect the sound. After all, you could look at these coils as just wound up speaker cables. We know how much speaker cables affect the sound.
Before I moved my amps 4 inches from my speakers, I used 10 feet of 10 gauge, oxygen-free copper cables. You could say I replaced those cables with 10 feet of 18 gauge plain vanilla magnet wire! Because I did not bend my air cores into toroids, I'm using about 1/3 of the wire you're using which may be a benefit. I'm guessing that putting less cheap wire in the signal path is a good thing.
I'm sure we can (and will) experiment more with wire size, quality, and topography, but right now - with the crap wire I'm using - the air cores sound fabulous. It's hard to imagine how it could sound better.
BTW, sendler, which were the quiet EMI coils, the 14 ga Belden or the 18 ga cheapo?
-dr_vega
Well my sure board has finally arrived, and I got around to trying it out today.
Right now it's totally standard, and I'm just using a laptop PSU, which gives out 19v at 5A. Not ideal, but there isn't any mains hum thru the speakers... There is a ticking sound tho, and this turns out to be caused by the fan. When I stop the fan with my finger, the ticking sound thru the speakers also stops.... Would giving the fan it's own independent 5V supply fix this?
Also, does anyone have any links or info about winding air core inductors? I'm really tempted to give it a try now, but I have no idea how many turns to do and where to start, just a pointer in the right direction is all I need.
Right now it's totally standard, and I'm just using a laptop PSU, which gives out 19v at 5A. Not ideal, but there isn't any mains hum thru the speakers... There is a ticking sound tho, and this turns out to be caused by the fan. When I stop the fan with my finger, the ticking sound thru the speakers also stops.... Would giving the fan it's own independent 5V supply fix this?
Also, does anyone have any links or info about winding air core inductors? I'm really tempted to give it a try now, but I have no idea how many turns to do and where to start, just a pointer in the right direction is all I need.
...Also, does anyone have any links or info about winding air core inductors? I'm really tempted to give it a try now, but I have no idea how many turns to do and where to start, just a pointer in the right direction is all I need.
Congratulations! I can't help you on the fan noise, but here's a link on winding air cores:
Martin E. Meserve - K7MEM - Single Layer Air Core Inductor Design
There are several air core inductance calculating site out there, but I found the above one the most useful. It's worth the effort to learn how to walk through the steps at that site. It's very comprehensive and easy to use, once you 'get' it.
I haven't found a site to calculate toroid air cores. Sendler might know, or he may just use an LCR meter.
I now think that the biggest bang for the buck in upgrading Tripath amps is good quality polypro film or foil input caps, air core output coils, and a good power supply. Everything else is marginal by comparison - but still worth doing.
-dr_vega
Ticking fan
None of my amps had any ticking noise in the audio but I did go to a separate regulator just for the fan for a slight improvement of the overall sonics. I use the coil calculator here.
Coil Calculator - Single-layer and mutil-layer coil calculation in javascript
An air toroid's final value will be the average of the inductance value for a coil length of the inside circumference and the outer circumference. Don't forget, cylindrical air cores blast out a lot of EMI right in the AM band at 650kHz which could eventually get you in trouble with The Law.
Well my sure board has finally arrived, and I got around to trying it out today.
Right now it's totally standard, and I'm just using a laptop PSU, which gives out 19v at 5A. Not ideal, but there isn't any mains hum thru the speakers... There is a ticking sound tho, and this turns out to be caused by the fan. When I stop the fan with my finger, the ticking sound thru the speakers also stops.... Would giving the fan it's own independent 5V supply fix this?
Also, does anyone have any links or info about winding air core inductors? I'm really tempted to give it a try now, but I have no idea how many turns to do and where to start, just a pointer in the right direction is all I need.
None of my amps had any ticking noise in the audio but I did go to a separate regulator just for the fan for a slight improvement of the overall sonics. I use the coil calculator here.
Coil Calculator - Single-layer and mutil-layer coil calculation in javascript
An air toroid's final value will be the average of the inductance value for a coil length of the inside circumference and the outer circumference. Don't forget, cylindrical air cores blast out a lot of EMI right in the AM band at 650kHz which could eventually get you in trouble with The Law.
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Nasty Waveform
I've just started playing with the amp and thought I'd have a look at the output waveform on the scope. At normal frequencies it looks like music but with the input shorted and the scope set as per the picture the output looks like this.
The sine wave is continuous at about 650KHz with the spikes occasional. Power supply is a Meanwell set at 32V on the board.
My amp doesn't have the Zoebel components.
Is this normal for a T amp with a SMPS? Are the speakers going to be happy?
Regards
Peter
I've just started playing with the amp and thought I'd have a look at the output waveform on the scope. At normal frequencies it looks like music but with the input shorted and the scope set as per the picture the output looks like this.
The sine wave is continuous at about 650KHz with the spikes occasional. Power supply is a Meanwell set at 32V on the board.
My amp doesn't have the Zoebel components.
Is this normal for a T amp with a SMPS? Are the speakers going to be happy?
Regards
Peter
Attachments
So I tested my air cores for EMI/RFI using the Sendler AM radio test. My AM radio is about 50 feet and three walls away from my sound system.
With two Sure amps pushing 8 air core inductors, I could hear no difference in the level of static at 650 kHz, or anywhere else on the band.
Nevertheless, I made the aluminum foil condoms and placed them on the coils. I also added air cores to my subwoofer amp, so now I have 12 air cores pumping out EMI/RFI. But my radio can't hear it. Neither can the radio in my car which is about 30 ft away in the driveway.
Still, I feel better now that the condoms are in place, but I don't think I was bothering my neighbors before.
Adding the air cores to the subwoofer made a huge difference in the sound quality. That amp was still stock with only a fan added. Now it is running with the air cores as the only modification. It sounds so good, I'm wondering if I should even bother to do any of the other mods.
-dr_vega
With two Sure amps pushing 8 air core inductors, I could hear no difference in the level of static at 650 kHz, or anywhere else on the band.
Nevertheless, I made the aluminum foil condoms and placed them on the coils. I also added air cores to my subwoofer amp, so now I have 12 air cores pumping out EMI/RFI. But my radio can't hear it. Neither can the radio in my car which is about 30 ft away in the driveway.
Still, I feel better now that the condoms are in place, but I don't think I was bothering my neighbors before.
Adding the air cores to the subwoofer made a huge difference in the sound quality. That amp was still stock with only a fan added. Now it is running with the air cores as the only modification. It sounds so good, I'm wondering if I should even bother to do any of the other mods.
-dr_vega
Thanks for the links guys, I've ordered some enamelled 18AWG wire, and hope to give the aircores a go soon.
I've already got my shielding, I found an old coffee tin was a perfect size for this amp:
I've already got my shielding, I found an old coffee tin was a perfect size for this amp:
An externally hosted image should be here but it was not working when we last tested it.
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