Sure Electronics New Tripath Board tc2000+tp2050 - Page 78 - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 23rd November 2009, 02:58 AM   #771
dr_vega is offline dr_vega  United States
diyAudio Member
 
Join Date: Apr 2006
Location: Southern Oregon
Quote:
Originally Posted by sendler View Post
... Long story short. This is the best sounding amp I have ever had home....
[/IMG]
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
  Reply With Quote
Old 23rd November 2009, 11:34 AM   #772
sendler is offline sendler  United States
diyAudio Member
 
Join Date: Aug 2004
Location: ny
Default 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.
Click the image to open in full size.
__________________
Scott
  Reply With Quote
Old 23rd November 2009, 12:21 PM   #773
dr_vega is offline dr_vega  United States
diyAudio Member
 
Join Date: Apr 2006
Location: Southern Oregon
Quote:
Originally Posted by sendler View Post
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.
Click the image to open in full size.
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
  Reply With Quote
Old 23rd November 2009, 07:15 PM   #774
diyAudio Member
 
MikeHunt79's Avatar
 
Join Date: Aug 2003
Location: Bristol, UK
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.
  Reply With Quote
Old 23rd November 2009, 07:44 PM   #775
dr_vega is offline dr_vega  United States
diyAudio Member
 
Join Date: Apr 2006
Location: Southern Oregon
Quote:
Originally Posted by MikeHunt79 View Post
...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
  Reply With Quote
Old 23rd November 2009, 08:12 PM   #776
sendler is offline sendler  United States
diyAudio Member
 
Join Date: Aug 2004
Location: ny
Default Ticking fan

Quote:
Originally Posted by MikeHunt79 View Post
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.
__________________
Scott

Last edited by sendler; 23rd November 2009 at 08:15 PM.
  Reply With Quote
Old 23rd November 2009, 08:20 PM   #777
sendler is offline sendler  United States
diyAudio Member
 
Join Date: Aug 2004
Location: ny
Default 18ga

Quote:
Originally Posted by dr_vega View Post
BTW, sendler, which were the quiet EMI coils, the 14 ga Belden or the 18 ga cheapo?

-dr_vega
The smaller, 18ga. They must have had better symmetry.
__________________
Scott
  Reply With Quote
Old 24th November 2009, 02:04 PM   #778
matherp is offline matherp  United Kingdom
diyAudio Member
 
Join Date: Oct 2009
Default 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
Attached Images
File Type: jpg trace2.jpg (15.6 KB, 543 views)
  Reply With Quote
Old 25th November 2009, 05:44 PM   #779
dr_vega is offline dr_vega  United States
diyAudio Member
 
Join Date: Apr 2006
Location: Southern Oregon
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
  Reply With Quote
Old 26th November 2009, 01:46 AM   #780
diyAudio Member
 
MikeHunt79's Avatar
 
Join Date: Aug 2003
Location: Bristol, UK
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:

Click the image to open in full size.

  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
FS: Sure Electronics Tripath Board tc2000+tp2050 wimdehaan Swap Meet 9 24th July 2009 11:41 AM


New To Site? Need Help?

All times are GMT. The time now is 01:16 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2